Alright a thread was started in the general discussion by a friend of mine but I thought I would post one here too. I have swapped a 4.0L out of a 97 XJ into our 76 CJ5 and I am having spark issuses. I am using a computer out of a 96 XJ, I think it was an auto where the CJ is a manual. I heard it didn't matter of course that could have been for the earlier computers. The computer is working, it kicks the fuel pump in the on position and builds pressure. Anyway the coil has voltage but we are still getting no spark. 1. could the distributor be that far out oof alignment that it wouldn't fire at all. 2. I guess it could still be the CPS although I have checked it many times. 3. I guess it could also be the pick up in the distributor, junk yard Item. I got the diagnostic connector finally hooked up and I am only getting 3 codes. 1. Battery temp sensor input voltage too high.(no sensor) 2. Colant temp sensor input voltage too high.(guy at part store sold me one with the wrong connector on it). 3. Evaporative Emission Control System Purge Control Valve Circuit Malfunction. (don't have it). Are any of these codes enough to keep it from letting it spark?

I put a 98 tj 4.0 in my 94 yj. I had everything hooked up correctly but still couldn't get a single spark. all the research I did and all the wiring gurus I talked to (hesco was one of them) said my problem was that there are only about 4 people in the US that could successfully wire an ODBII computer. I am pretty sure (not posative) that the computer you are using is an ODBII. if it is you may just be SOL.

what I did was I went to a junk yard and yanked a computer and harness and sensors off of a 94 XJ. spliced the exact same wires and it fired right up. sort of (will explain in a sec) from what everyone told me is that an ODB II computer requires every sensor and every little thing to report before it will fire. also the ODBII uses ASCII to communicate and not resistance like the older computers.

long story to short one: get an ODB I computer and harness and you should be in much better shape.

as far as your timing question. the CPS and the computer does all the timing. there is not rotating the dist to dial in the timing any more. as long as you have a bellhousing to fit the CPS, the flywheel with the grooves in it to do the timing and the computer to understand it you should be fine. Hesco also makes a CPS relocator thingy that moves the CPS but does the same thing.

now what I said about fired right up, what really happened is that I spliced the same wires and it didn't work for a week. what I did was I FORGOT to hook up the little three wires on the dist!!!! DOH! it was sitting in between the block and the dist and I just didn't see it. any way I pluged that together a week later and it fired right up. the point I am making that is that I had the spliced the same wires as I did with the ODB II computer that didn't work.

this is just what happened to me yours might be completely differnent I just thought I would give you a few suggestions.... HTH



EDIT: I am also using a computer from an automatice XJ in my Manual YJ so you are right it doesnt' make a difference this way. can't gaurentee it the other way.

Good info.... I just put a 98 TJ 4.0l in my 87 YJ I am using the 98 comp and harness, I connected everything up and the fucker fired right up and runs. I am no mechanic, I had a buddy help me with all the wiring hes good at that.... But he is no world class mechanic no offense YUNA... So I say fuck hesco they are a bunch of fucking idots they just want to sell you on there wiring harness and there comp.. only 4 people in the world can wire up a OBDII they are assholes, actually i know someone else who did it to Partsmike hes in CAli... So for anybody out there stay away from HESCO they are a bunch of morons who just want to sell you on there products.....

I am impressed. I am not a mechanic but I had one helping me, but I am an eletrical engineer and couldn't figure the fucker out.

again I am impressed.

I would LOVE to see what all you spliced. Oh yea I also used the stock YJ interior harness and I think that was part of my problem.

when you did this swap with the OBD2 computer did you draw up any diagrams of what wires you connected where? Also what did you do about the fact that it has a returnless fuel rail? Anything?

I would do a couple of quick checks first. One is on the coil. You said that you were getting B+ to the coil on one side. (powered up by the ASD relay). You should check the pcm's ability to control the ground side of the coil. Take a simple 12 volt test light and clip the wire to the battery + side. Everytime you touch the probe to a ground it will light. Now unplug the coil and probe the ground side while somebody is cranking the engine. If it is flashing, chances are pretty good your coil is bad. Mopar had a rash of bad coils in those years. If it dosn't flash, you have a problem with either the crank position sensor, cam position sensor (in the dist.) or the 5 volt vref signal going to both. This will take a DRB or any generic (Snap-On) scanner to diagnose. If the 5 volt ref is gone, chances are good that some other circuit that uses this ref is grounded. Don't worry about a grounded 5 volt vref frying the PCM, Mopar uses a good protection device on this vref that will re-set itself when the short to ground is repaired. Some places to look for a shorted vref is the vss sensor in the t-case, map sensor, tps, and any 3 wire sensors. You should check for voltage on all these sensors. Using the DRB or scanner you can watch crank and cam counts, and also see if there is "sync" between the two. These are the only 2 sensors that are required for spark.

Thanks for the input. I am pretty sure it is one of those sensors also. I will have to try checking thier voltages. I swapped the coil with a friends and his didn't work. But he drove to the house and left in his jeep so his was good. I am using a CPS relocation kit like Hesco's that I built. We were also unsure on the wiring to the CPS. I know the 3 wires going to its plug. But when I bought one from Napa it didn't have the same plug and the wiring coloring is none existant. How much do you think a new distributor sensor(cam sensor) is? Well I will give this stuff a try whenever I get some free time. I have a set of rock sliders to build for my roomates D90 and a front bumper to build for a friends XJ. Before they leave for Moab on Sat. O well, I guess it is not going anywhere!

FYI, If you are doing some sensor swaps and re-wiring. The older (pre'96 SBEC) fuel systems used an 8 volt ref to both the crank and cam sensors. The newer JTEC controllers use a 5 volt ref. I don't know if there are any compatability issues interchanging them, but it may be something to consider when buying sensors. If you are building a front harmonic sensor based on Hesco's balancer and using an automatic's sensor, you should look a '96 and newer sensor because of this.

Originally posted by RJLynn67
when you did this swap with the OBD2 computer did you draw up any diagrams of what wires you connected where? Also what did you do about the fact that it has a returnless fuel rail? Anything?

no diagrams butI can tell you what I did about the fuel rail. I used an adjustable fuel pressure regulator. got it from Jegs
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=33473&prmenbr=76

I know this one says it is for a carburator but it also comes with springs to make it the right pressure range.


it works great and you can adjust the pressure when you put on new engine performance stuff.

GAjeep94yj, I really need to come check your jeep out this weekend. I too put a 97xj motor in my 90 yj. I ditched the new computer system for a harness from hesco because after a week of studying wiring diagrams and splicing stuff I couldn't get the newer comp. to work. Mine looks like crap under the hood, I still have the factory harness under there. Not sure which wires I can cut out yet and I drive it all the time so it will wait.

Originally posted by Rodney YJ
GAjeep94yj, I really need to come check your jeep out this weekend. I too put a 97xj motor in my 90 yj. I ditched the new computer system for a harness from hesco because after a week of studying wiring diagrams and splicing stuff I couldn't get the newer comp. to work. Mine looks like crap under the hood, I still have the factory harness under there. Not sure which wires I can cut out yet and I drive it all the time so it will wait.

I will be at the jeep meeting.

here is my jeep:
http://communities.msn.com/_Secure/0LwDlBagOUD4ek05zqg07Dz8BCrQ3r8tcMTQ9zYjaCsOGqH!wi hOk*f48qMqlsFbB8MaiWKoZqp8/DCP00138.JPG

but I will have a black hardtop and full black steel doors.

Originally posted by GaJeep94YJ


I will be at the jeep meeting.

here is my jeep:
http://communities.msn.com/_Secure/0LwDlBagOUD4ek05zqg07Dz8BCrQ3r8tcMTQ9zYjaCsOGqH!wi hOk*f48qMqlsFbB8MaiWKoZqp8/DCP00138.JPG

but I will have a black hardtop and full black steel doors.

damn it I can't get the freking pic to work:mad3:
just stand up and holler for me I will answer!

GaJeep94YJ

Did you use a CPS from the 94? Also what about the Cam sensor in the distributor. Was it compatable from the 98 motor to the 94 computer? I have a CPS out of a 92 or so. so this makes me think that the computer(OBD2) does not recognize it.

Originally posted by RJLynn67
GaJeep94YJ

Did you use a CPS from the 94? Also what about the Cam sensor in the distributor. Was it compatable from the 98 motor to the 94 computer? I have a CPS out of a 92 or so. so this makes me think that the computer(OBD2) does not recognize it.

I used the CPS from the 94 YJ on the 94 XJ harness. I went to autozone.com and looked up both and they were the same part numbers.

the ODB2 sensor would not recoginize the older CPS. if I remember right there are even different number of wires on the ODB1 and the ODB2 CPSes.

the 94 XJ didn't use the cam sensor, the only thing I used from the dist was the three wire plug that sticks out the bottom of the cap.

Well if there were only 4 people who could correctly wire an OBDII computer controlled 4.0L. There are now 6 of them! Got it running today. Probably would have had it running the first time except we had two wires backwards. Swapped them and then she fired right up! Thanks for all the help. I did however have to get an OBDII CPS.

Originally posted by RJLynn67
Well if there were only 4 people who could correctly wire an OBDII computer controlled 4.0L. There are now 6 of them! Got it running today. Probably would have had it running the first time except we had two wires backwards. Swapped them and then she fired right up! Thanks for all the help. I did however have to get an OBDII CPS.

What two wires?

Problem we are having on a freinds 99 4.0L swap is that we are getting 9V to the sensors when the TJ FSM states that the sensors should be getting 5V. We are using a 99TJ 4.0L with a YJ wiring harness and computer. But the sensors, and gas tank is from a TJ.

We get no spark. We tested out the system and it comes on then seems to shut off. Checked the computer and no real significant codes. I guess he is SOL. We thought maybe using a CPS from a YJ would help as it would like the 9V but still no spark.

I guess the OBDII realies on quite a bit into order to "boot" sort of speak....

I can see how they can say only 4 people have done it. Although if they have... where are they?!?!! Anyone can drop in a complete TJ motor and TJ harness, supply ignition,power,fuel and it will start. Oh well. It was worth a shot

I beleieve the plan now is to put a TJ wiring harness and computer, then just wire the gauges individually.

We even tried supplying the system with 5v to see if the sensors would like that. same thing

The problem that you are running into gave me some problems also. The old computers use the 8v signal where as the new ones (OBDII) use 5v. This will make a difference on any sensor which gets its voltage for the computer. Meaning you can only use the sensors that match the computer. This also includes the pickup that is inside the distributor. This pickup and the CPS are the only two sensors which have to be functional for spark. Without these you can try anything but you will still get no spark.

Good job RJLynn67.

Putting in a newer ('96 up JTEC) isn't that hard. The problem lies in the check engine light. To make it smog legal you have to hook up the light. The light is controlled via the CCD buss which also controlls the instruments. The instrument cluster is actually a computer (M.I.C. mechanical instrument cluster). If you are swapping in a newer JTEC pcm into an older Jeep with analog gauges, no problem, just use your present analog guages.

The engine will run just fine without the cluster hooked up. Most people think it is hard to interface the two harnesses together. Don't. Just make your engine harness modular and seperate from the rest of the Jeep.

Originally posted by RJLynn67
The problem that you are running into gave me some problems also. The old computers use the 8v signal where as the new ones (OBDII) use 5v. This will make a difference on any sensor which gets its voltage for the computer. Meaning you can only use the sensors that match the computer. This also includes the pickup that is inside the distributor. This pickup and the CPS are the only two sensors which have to be functional for spark. Without these you can try anything but you will still get no spark.


Thats waht we firgured so we hooked up an external power source with 5V in hopes teh sensors would work. It was worth a shot.

Tonight we are installing the TJ harness and Saturday wiring up some gauges cuz they aren't electronic, we got rid of the mechanical ones.

I just recently ran into a similar problem on a friends '98XJ 4.0L in a '89 YJ (was 2.5l) using a '97TJ 'puter (Auto VS Manual didn't matter) Turned out to be the ASD relay circuit & also had to wire in an external voltage regulator. Also, only have 1 O2 sensor hooked up. It's running fine now. What a frustrating mess though - it was the day he was leaving for TDS & I had the entire wiring harness torn out of the jeep, including from under the dash...
Matt B

Well I finally got to drive it tonight. Man it will fly now! With the 4.88's I could possibly lift the front tires off the ground! Best mod yet!

JEEPCLUB
Yeah the sensors are a bitch! I haven't decided what kind of gauges I am going to try and make work yet. Let me know how yours goes.

hungryjpr
What did you need an external regulator for? The alternator is regulated in the computer. Or are you talking about the sensors? I too only have one O2 sensor hooked up now. I am gonna see how it goes like this. so far mine too runs great. We actually wired in another relay to work as the ASD.

Thanks for everything everyone!

[QUOTE]Originally posted by RJLynn67
[B]Well I finally got to drive it tonight. Man it will fly now! With the 4.88's I could possibly lift the front tires off the ground! Best mod yet!

JEEPCLUB
Yeah the sensors are a bitch! I haven't decided what kind of gauges I am going to try and make work yet. Let me know how yours goes.


Not my Jeep, but he has 95 gauges now which are electric, so it's just a matter of splicing. I think we should have it running on Saturday.

Originally posted by hungryjpr
I just recently ran into a similar problem on a friends '98XJ 4.0L in a '89 YJ (was 2.5l) using a '97TJ 'puter (Auto VS Manual didn't matter) Turned out to be the ASD relay circuit & also had to wire in an external voltage regulator. Also, only have 1 O2 sensor hooked up. It's running fine now. What a frustrating mess though - it was the day he was leaving for TDS & I had the entire wiring harness torn out of the jeep, including from under the dash...
Matt B


We shecked the ASD and even bypassed it, still the same thing. Time to give up to get this Hunk of Junk on the road again so he can head down to Tellico in April.

I am the one who did los yj swap The best way to do the swap i go to you local shop and get wiring dirigram for both jeeps and figure it out that way Thats the way i did it you are going to have problems with gauges but you can get the thing to run and run right I can try together a digram of the wires that i spliced i am going over sunday to finish up the wiring so i will get every thing and try to post it sunday Just one more thing do you have the pdc cause you need it

Yuna

And dont listen to los he didnt do shit but watch

Listen to Luna, I relied heavily on a CarDoc you know one of those places hooked to an Advanced Auto Parts. They printed out any wiring diagrams I needed. It is funny how hard you try to figure things out and don't get it right, then look at the right diagram and it becomes soo clear!

On a side not, are there places on the 4.0l block to mount the mechanical sending units? Should I use all new electric guages? Can I run them off the PCM?

Yes, you could just hook up your analog gauges to their original positions on the block that were designed for the 258. The oil pressure isn't required for JTEC operation. The coolant temp sensor is the one on the top of the head, not the cts in the t-stat housing. This will make your original gauges work, not part of the injection.

Another note is going all out, and hooking up the CCD buss. You are all ready there. Just run the CCD buss to a newer '97 up Grand Cherokee cluster. These clusters have nice movements and are quite large. They mount in a rectangular pattern that should be easy to fab up into an early CJ dash. This will give you a check engine light and power all the cluster on just those 2 wires. The CCD buss sends data for tach, vehicle speed, coolant temp. oil pressure, etc. There is only a 10 way connector on the back of these heads. 2 for the CCD buss, one each for the left and right turn signal lights, one for back ground illumination when the headlights are on, a switched 12 volts for the volt gauge, and a couple of grounds. You can pick up the buss wires from your data link connector. Pull the wiring diagram for a '98 or '97 ZJ dash and read it over.

Originally posted by yunatj
I am the one who did los yj swap

Yuna

And dont listen to los he didnt do shit but watch

I'm doing a 4.0 swap too and having problems. Just wanted to know what I should do in your opinion.

I have an 89 Jeep YJ. I put a 99 4.0 motor transmission, transfer case and gas tank. I bought a 95 dash wiring harness and gauges so that they would be electrical and work with the 4.0 computer. So if I just splice in the gauges and ignition? The Jeep should run? We have tried other harnesses from a YJ first and it did not run. this has been a 4 month project now. And I'm getting real frustrated.

Any opinions would be great. Thanks,:confused:

Well one of your problem will be that some of the sensors will be different from OBDI `91-95 to OBD II 96 and newer. There are only two sensors that will keep a 4.0L from sparking that is the CPS, which for you will be mounted on the Bellhousing, and the Pickup in the distributor. The two different computers used different signal voltages. OBDI used a 8 volt signal I believe where as the OBDII Computer uses a 5volt signal. I would try swapping one or both of these two sensors and double check your wiring since all the color codes probably didn't match. Let us klnow how it goes.

I had no luck finding a complete 99 engine wiring harness from a junk yard. So I just bought one a our club discount at the Jeep dealer. All in total with tax $1,360.45 Canadian. It should be in, in a week. I will keep you posted of how it goes.

Thanks,:barf:

Ok I just put the 99 harness in and made sure all the sensors were on and still no spark. What wires have to be pluged in, inside the Jeep for it to work? I have one pluged in that lets me turn the gey to get the starter to work. And I have another wire that feeds the fuse box (a couple of the guages seem to work) :question:

When you turn the key to the on position do you hear the fuel pump prime? Also when you go to crank it you should hear some sensors click. What year is the computer from? a 98?

Computer is a 99. (just like the motor and harness and transmission, transfer case and gas tank) All 99 TJ parts. Dash is 95 (gauges all 95)

I don't here the pump go on but othere guys from the club tell me that the TJ fuel pump is almost imposible to hear.

I don't hear any sensors click. :confused:

I checked the CPS and it's pluged in and I checked the cam sensor and it's in and all the other sensor like the battery is in and so are the exhaust two.

I'm starting to wonder if I did not ground a wire but I could not see any that were not pluged in. when the key is at the ON positon the blower fan in the jeep works!

What are you using for your wiring diagrams? What do you have connected from the C plug on the computer? I will try to scan in some diagrams and post them on my site.

Under the hood I have everything pluged in that I know of. Under the dash I have only two wires pluged in. Should I have more pluged in? I'm off work all week this week so I have time to figure this out. any ideas?:confused:

You really don't need anything running under the dash that wasn't already. You can get the wires you need to hook up the computer and stuff under the hood. Which wires are you talking about? Off the computer? What pin and plug numbers?

Under the hood I have one wire that is to get the ignition to turn the starter over, It's one wire that I pluged to Connector C106. The other wire is giving power to my fuse box under the dash that went to a pin in C106 aswell. Now the fan turns on and a couple of the dash instuments work like the battery gauge etc...
I'm going to try to get a friend to come by with his 99 Jeep so that I can take a look at where all his conectors go.

Are you using the YJ Starter of the TJ starter? Also I am not understanding the C106. If it is the same style computer as the one I have the C connector should nly have 32 pins. Are you trying to use your stock YJ gauges? If so didn you install all YJ senders in the 4.0? Also what did you do about the Auto Shut Down Relay and Fuel Pump Relay?

I'm using 95 YJ gauges. I did not do a thing about any relays. Why what do I need? What did you guys use? Is there a way to get around those relays? I don't understand the C connector your talking about. It's a 99 TJ computer. What's yours? Can you email me off list? shawn.fraser@rogers.com

Thanks,

Have not herd from anyone about any suggestions lately. Still no spark and I want to know what the problem is. Do I need the TJ dash (gauges) plugged in for it to work?

Never mind I got the Jeep to run last night. I just had some ignition wires and the fuel pump pluged in wrong! It sounds way better then the 258 did and no nocks or leaks

Originally posted by sfraser
Never mind I got the Jeep to run last night. I just had some ignition wires and the fuel pump pluged in wrong! It sounds way better then the 258 did and no nocks or leaks

Glad I could help :D Told you we would hear the fuel pump.

Once the fuel pump, ASD, etc. were actaully powered up, it started good. He had "start" connected, but "run" was not connected properly.

Still lots of work left for us to wire the non-engine junk, but at least its running now.

Phil "could easily steal a TJ now" Jensen

Man I am glad you got it running! Now there are mor like ten of us who can wire one of these bad boys up. Of course I always thought that was a bunch of shit. Anyway its good that you got it running. It is a huge improvement from the 258. I am still trying to iron out my fuel regulating problems.

for future reference, the following should apply to all 91-95 4.0L HO's in YJ's and XJ's, and I'm working on the post 95's

http://www.dana60.com/sundowner/scheme2.jpg
http://www.dana60.com/sundowner/Scheme1.jpg

Ah yes thanks for the post of the pics. However they were working on a `96 and newer OBDII system. I have a bunch of diagrams. I just haven't had time to scan them in yet. You know finals, graduation, new job, new truck, and o yeah that whole getting married thing.

I'm aware of that, but the logic in the circut is pretty much the same with the relays as the ones shown here with some extra fluff for the second o2 sensor, the canister purge valve, and the newer AC request stuff.

I guess we are now wiring gods - since we figured out the OBDII system that only five people can do. :flipoff2:

What a crock of shiat! :rolleyes:

Phil

it doesn't take rocket science, just a six-pack of Sierra Nevada, a pair of crimpers, and some spare time.:rasta:

Ok finnaly got a chance to work on it some more. The last fuel pump went out due to not being regulated. Well the regulator is now in and all is well.

Still one problem though. It will die upon coming to a stop at a light or such. Not sure why either. I was thinking either an idle air sensor or something. Could it be unhappy about the fact that I still only have one o2 sensor? Any thoughts?:confused: :mad: :beer:

I was wondering the same thing. Because I only have one spot to put the O2 sensor? I could just zip tie the sensor to the side but would that f$%K things up since it would be getting fresh air? I had unpluged the sensor and the Jeep did not seem to act different! So what do I do? unplug it or zip tie it to the side out of the way?:confused:

The second 02 sensor is to check the operation of the cat. It does NOTHING to the engines parameters. Just leave it off and keep it as a spare.

Phil

I'm new to the sight and didn't realize so many were doing the swap.

Anyway I have done three now using the 97 4.0 which I assume has the OBDII. So far it has been a piece of cake. No need for the HESCO harness you have to wire in only about 8 wires. I can provide my diagram if needed. I guess there are now five people that can wire it up!

The only issue I have had to date is the crank sensor kit from HESCO. The magnetic pick up didn't have enough pull to read the harmonic balancer, I bought a stock 97 sensor from NAPA and the beast fired right up. HESCO said it the failure was due to the green protective paper was still on the sensor, which is suppoesed to wear off on the first start, anyway they were cool and credited me for the NAPA sensor and took thiers back. All in all it is a good kit.

I also have found a way to make one of those $200 air cleaner kits out of the existing 97 air box tube and a K&N filter, for only $28.

My 99 4.0L TJ motor has beed runing great in my 89 YJ all year. I just still don't have any working gauges. Just have not had time to sit in front of two FSM and figure out every wire that goes fromt he TJ harness to the 95 YJ gauges i'm using.

For oil I used the original 4.2 sensor and original wire, left the 4.0 one hanging, water HESCO sells A $15 dollar kit adapter that allows you to use original heater sensor in an adapter that goes in your heater hose, volts just positive and ground. If you have a stock tach I can look at my diagram for the computer pulse wire, worked great on mine!

Scott,
Can you email me that wiring diagram?
jagert59@yahoo.com

Thanks

Tom

It's on the way to your email address.

Scott....any way I could get a copy of that diagram as well? It would be much appreciated!

Thanks!

Address is: mmorelan@aftac.gov

I have a problem, I have finished retro-fitting
the fuel injection to my Jeep. I got everything all
hooked up, and tried to start it. Needless to say, it
didn't start, I can smell the fuel on the exhaust, so
I know it is getting fuel. The problem I discovered
was lack of spark. I put my meter down on the
positive side of the coil, and then turned the
ignition on, and there was only 12V there for about
half a second, then nothing. What would cause that?
I pulled a spark plug wire off and put a screw driver
into it, and put it next to a ground source then
touched the starter, no spark then.

This is a retro-fit from a 1995 Jeep Wrangler to my
1986 CJ-7. I have gone over this severl times and
can't figurre out what is wrong, does anyone have
any ideas???

Thanks,
Glen

Sounds like you don't have the ignition wired up properly.

Do you have both FSM's? Because that's what helped us out allot! The wiring is hard to figure out if you don't know what your doing.

I have since sold my Jeep and I still have the 95 YJ FSM for sale if your interested? Let me know!
http://members.rogers.com/frasersh/

[B]I have a question about the CPS trigger plate on a 90 YJ vs 95 XJ
On the 90 YJ 258 motor the plate trigger looks like a flywheel with flat teeth and some of the teeth are missing which is for the injections pulse timing, On the 95 XJ Motor the trigger plate looks totally different . It looks like a flat peice of sheet metal with places cut out in specific locations. What are the differences between them. I am putting the 95 XJ 4.0 HO into my YJ , Need to know if the trigger plate from my 90 YJ 258 will work the same or not.

Thanks for any help

why would there be a trigger plate on a 90 yj? It's carbed.

I didnt read this whole post yet, but this pisses me off~!

the wiring gurus I talked to (hesco was one of them) said my problem was that there are only about 4 people in the US that could successfully wire an ODBII computer. .

THAT IS THE BIGGEST LOAD OF PURE BULLSHIT I HAVE EVER HEARD.
CJOFFROAD.COM HAS MANY, MANY MORE OBD2 SUCCESS STORIES THAN THAT, INCLUDING MINE OUT OF A 99XJ INTO A 87YJ!
IT TAKES 5 FUCKIN WIRES TO FIRE., 4 MORE AND YOUVE GOT SCANNER ABILITIES TOO

FUCKIN LIAR BAGS-O-SHIT :mad3:

the key for my swap was I took an ENTIRE 99XJ, stripped it cleaner than a flock of vultures, got a 98TJ gastank complete with sensor and pump, AND incorporated the XJ gauge cluster.

Its easy IF you use all the parts to let the computer do its job.

BTW, I'm not an Engineer, I'm a Ghetto-BootyFabologist. I had a buddy of mine (Electrical engineer) wire it up. I did all the muscle gruntin and wrench spinnin and knuckle bustin/bleedin,,,,,,,solo,,,,,,under a tarp,,,,,,on a trailer,,,,,,,,,last nov-dec,,,,,,,,,during a snowstorm,,,,,in NJ before moving west!!!

AND I PASSED CALIFORNIA SMOG :flipoff2:

TELL HESCO TO PUT THAT IN THEIR PIPE N SMOKE IT!

I have a problem, I have finished retro-fitting
the fuel injection to my Jeep. I got everything all
hooked up, and tried to start it. Needless to say, it
didn't start, I can smell the fuel on the exhaust, so
I know it is getting fuel. The problem I discovered
was lack of spark. I put my meter down on the
positive side of the coil, and then turned the
ignition on, and there was only 12V there for about
half a second, then nothing. What would cause that?
I pulled a spark plug wire off and put a screw driver
into it, and put it next to a ground source then
touched the starter, no spark then.

This is a retro-fit from a 1995 Jeep Wrangler to my
1986 CJ-7. I have gone over this severl times and
can't figurre out what is wrong, does anyone have
any ideas???

Thanks,
Glen

that sounds like one of the little quirks mine had as we were wiring it up.
I forget the name of the shit we needed to bypass, but my electrical guy knew about it.
Here is my short thread in CJoffroad with a couple wiring issues explained.
http://www.cjoffroad.com/forums/topic.asp?TOPIC_ID=2612&SearchTerms=4

CB

I just smogged an '84 CJ7 w/ '98 TJ 4.0 OBDII. Passed Calif. the first try and left the tech shaking his head. Everything works and I kept my stock dash. Your posts gave me the right direction to go. The only thing I really did different was to strip down the Instrument cluster to the PCB and installed that in a sealed box under the dash where the old BBD carb compter went. Had man help for the heavy stuff and the rest is mine. Thanks for all your inputs

always glad to help any jeepchick ;)

alright its 06, lets see how many guru's are still here.

88YJ - 4.6L stroker.

93XJ harness and comp.

swapped complete 93 XJ harness into eng. comp. Also into dash. spliced in guages. Some work some don't.

Crank sensor and cam sensor each have 3 wires. with ignition on, orange reads 7.53. blk/blu .00. yellow/tan 5.01

swap in 92 comp. orange reads 9. b/b 0. Y/T 5.0

only sensor I dont have hooked up is the SS.

Engine fired but ran real rough, backfired, shut down. got a code 54 no sync.

When I swaped comps. to the 92, wouldnt start, and I got a fuel ballest rely code right of the bat.

wont fire now. Got good spark, but seems to be flooding out.

One thing I noticed was the 93 harness did not have a fuel ballast in line, but the 90,92, and other 93 I have all have this ballast on the firewall.

Whats happening?

I am still not having any luck. Spent another 10 hrs in the shop yesterday chasing down wires, testing sonsors. did figure out why it was not turning over by the key. Neutral sensor wireing needed a jumper. Am I missing something else like this. Still getting the no sync code. Gonna get another new rotor and dist. cap, as well as regular stock wires.

I seem to have no shorts, good grounds, the right power at the sensors. F this is getting old.

On a second project pulled the head of the DJ5 and cylinder 3 is wiped out. What else? This is getting old. Any help would be great.

well just bougth a 90 sahara with the 4,o partially installed have a computer out of a 94 cherokee {6028296} and wiring harness..fuel tank with internal fuel punp assume its from same donor . original trans no hole for spark sensor.assume flywheel is from 94 {have to replace slave cylinder and clutch slave leaking .} any info how on putting hole in bell housing. or just replace while out . can i plug the 94 harness into firewall. and route plugs and connetors?also how can i make sure flywheel is from 94 .numbers to check or identifying ?alot of questions i know would like to get this right before i attack it main concern is the wiring . need the diagram with what to cut not worried about gauges now . but will be! thier a luxury ..thanks so far this has been the most informative post . hope u are stil out thier tks robert

Hey, I know this thread is like a year old now but I am in the middle of this swap. I started with an 89 YJ (258) and I am putting in a 96 XJ (242) OBD2 OBDII . I could really use some help on the wiring. I have the FSM for a 97 XJ which is the OBDII as well but I'm still lost.
1. It seems like I'm not getting any thing on the signal wire to the fuel pump relay from the PCM when I turn my key.I can hotwire the fuel pump and make it run.
2. I seem to have the starter going in some way but it is very intermittent.
3. I don't have spark.
4. My head is starting to hurt.
5. I am not sure where I should have power to my computer.
6. I am confused as to what to do with the bulkhead connector and what all I need to move in there.

Thanks a lot guys.

Hey, I know this thread is like a year old now but ...

Acually its more than 8 years old!:flipoff2:

true. But the last reply was like 6 months ago. bump

Hey, I know this thread is like a year old now but I am in the middle of this swap. I started with an 89 YJ (258) and I am putting in a 96 XJ (242) OBD2 OBDII . I could really use some help on the wiring. I have the FSM for a 97 XJ which is the OBDII as well but I'm still lost.
1. It seems like I'm not getting any thing on the signal wire to the fuel pump relay from the PCM when I turn my key.I can hotwire the fuel pump and make it run.
2. I seem to have the starter going in some way but it is very intermittent.
3. I don't have spark.
4. My head is starting to hurt.
5. I am not sure where I should have power to my computer.
6. I am confused as to what to do with the bulkhead connector and what all I need to move in there.

Thanks a lot guys.

Sounds like an ASD (auto-shutdown) Relay issue ...

Are you sure that the wiring is exactly the same between the 96 motor and the 97 FSM ?

Here's how i spliced mine together: http://www.wilhelm-tech.com/jeep/mods/HarnessSplicing.htm

Good luck,
Tony W

I'm pretty sure the wiring is the same but the colors are definitely different. I don't quite get your charts. Did the ASD wires need to be moved? Which wire signals the relay to close and send power out of the ASD? What all is hooked up to the ASD?

So on your website on the "How to splice together part 2" page where it says "to" "from" that means the wire is going between those two parts correct? Would it say if they bridged off anywhere else? Did you have to move all of those or were some of them already in the right spot?
What wire tells the PDC what position the ignition switch is in? A2 Fused Ignition Switch Output (Run/Start)? Which side of that wire should there be 12 volts on? Why doesn't it seem to go to the bulkhead connector where it would pick up the 12 volts?