Ok, someone will hopefully be able to help me with this engine problem. I am pretty mechanically inclined and my roommate is VERY mechanically inclined when it comes to engines. Here's my predicament, I'll describe as best I can...

About two weeks ago, I sunk the Jeep in a river/creek, nothing on the top end got wet except the battery, it just sucked water into the intake, but didn't hydrolock. The water was above the tranny and starter but the starter was the only engine part underwater, also water up to the back window on the hatch (~8" lift and 37's just to get an idea of how deep it was) Anyway, we winched it back to shore, pulled the plugs, cranked it, siphoned the remaining water out of the intake, pulled the air filter, after we put everything together, after a little good lovin, it cranked right up, obviously it ran like crap but it ran. So the next day, replaced air filter, oil filter, drained both diffs, and refilled them. Next weekend, drove it 2 and a half hours on the hwy (no fun w/o a working radio) up to Skyjacker Rocks Tennessee (our club was leading trails for the event). Ran fine the whole way. Wheeled it Friday and Saturday, ran fine. Coming off the trail on Saturday, the engine starts to stumble like its running out of gas. Eventually it dies completely, it cranks and will idle for a short time but idles REALLY rough like it has a cam in it. Have to get pulled back to camp. Work on it all night, replace the spark plugs, TPS, and CPS, still doesn't fix it. Checked the injectors by unplugging each one while revving a little bit. All of them worked, pulled fuel filter, emptied it out, looked good. The fuel pump still works I assume because I hear it turn on. Now the weird part, the MAP sensor was unplugged so that was why it was idling rough I thought. I plugged it back in, idled fine for a while, but when I drove it would run up to about 1200 rpm and act like it wasn't getting any gas. Now it idles rough like before and when I hit the gas it skips and then revs, but when I rev it slow it will go all the way to redline just fine, but when I floor it, it seems like its not getting enough gas. I pulled the gas tank and emptied and cleaned it and am going to put it back in when I get back to my house on Sunday. Neither me nor any of my Jeepin' friends can figure this out. The best I can figure is that its fuel related or vaccum or some sensor I don't know about. Someone please help me!! I just finised the front leaf/D44 swap and I wanna wheel it but I can't cause of the engine!! GRRRRRRRRR....any help much appreciated! Thanks!!

ID CHECK FUEL PRESSURE.

Originally posted by kajeepxj
Ok, someone will hopefully be able to help me with this engine problem. I am pretty mechanically inclined and my roommate is VERY mechanically inclined when it comes to engines. Here's my predicament, I'll describe as best I can...

About two weeks ago, I sunk the Jeep in a river/creek, nothing on the top end got wet except the battery, it just sucked water into the intake, but didn't hydrolock. The water was above the tranny and starter but the starter was the only engine part underwater, also water up to the back window on the hatch (~8" lift and 37's just to get an idea of how deep it was) Anyway, we winched it back to shore, pulled the plugs, cranked it, siphoned the remaining water out of the intake, pulled the air filter, after we put everything together, after a little good lovin, it cranked right up, obviously it ran like crap but it ran. So the next day, replaced air filter, oil filter, drained both diffs, and refilled them. Next weekend, drove it 2 and a half hours on the hwy (no fun w/o a working radio) up to Skyjacker Rocks Tennessee (our club was leading trails for the event). Ran fine the whole way. Wheeled it Friday and Saturday, ran fine. Coming off the trail on Saturday, the engine starts to stumble like its running out of gas. Eventually it dies completely, it cranks and will idle for a short time but idles REALLY rough like it has a cam in it. Have to get pulled back to camp. Work on it all night, replace the spark plugs, TPS, and CPS, still doesn't fix it. Checked the injectors by unplugging each one while revving a little bit. All of them worked, pulled fuel filter, emptied it out, looked good. The fuel pump still works I assume because I hear it turn on. Now the weird part, the MAP sensor was unplugged so that was why it was idling rough I thought. I plugged it back in, idled fine for a while, but when I drove it would run up to about 1200 rpm and act like it wasn't getting any gas. Now it idles rough like before and when I hit the gas it skips and then revs, but when I rev it slow it will go all the way to redline just fine, but when I floor it, it seems like its not getting enough gas. I pulled the gas tank and emptied and cleaned it and am going to put it back in when I get back to my house on Sunday. Neither me nor any of my Jeepin' friends can figure this out. The best I can figure is that its fuel related or vaccum or some sensor I don't know about. Someone please help me!! I just finised the front leaf/D44 swap and I wanna wheel it but I can't cause of the engine!! GRRRRRRRRR....any help much appreciated! Thanks!!

I have an XJ and the exact same thing was happening to me. Replaced every sensor thinking that it had to be one of them. Never suspected the pump because it would run just fine for a time and then do exactly what your describing. Most electric pumps Ive had either worked or didn't. Took the tank out to inspect it and it was very clean. Decided to replace the pump just in case and have not had one problem since. so, I'd say it is very possibly the pump.

Bud

Make 100% sure there is no water in your fuel tank.

It is possible for an electric pump to have enough pressure but not enough volume for the engine to run. Thats why it will idle fine but when you get on it, the pump cant keep up.

Originally posted by The Rockslut
It is possible for an electric pump to have enough pressure but not enough volume for the engine to run. Thats why it will idle fine but when you get on it, the pump cant keep up.

On my CJ I have JFI injection with a remote pump. When it goes south it's done, period! The "in tank" pump on the XJ can go south in stages it seems. I know I sure have a lot of good used sensors for spares figuring that one out. So, yes I would say it can happen. And when it did, the XJ exibited the exact same problems that Kajeepxj had. Not saying that is what his problem is but it sure sounds like it to me.

Bud

Originally posted by The Rockslut
It is possible for an electric pump to have enough pressure but not enough volume for the engine to run. Thats why it will idle fine but when you get on it, the pump cant keep up.


That's what happened to mine. It had good pressure but no volume. Unplug your fuel line near the intake and it should squirt damn near across your driveway, if it just dribbles out, you need a new fuel pump.

deffinately fuel pump related simptoms, however make sure you don't have crap on the MAF wire

hey guys, bringin back an old topic cause i'm still having problems, this is what i have done so far....CPS, TPS, plugs, wires, dist cap and rotor, 3 fuel pumps, fuel filter, fuel pressure regulator, 02 sensor, and just did the injectors, i'm about to go to the store to get ANOTHER pump to see if thats it (talk about a run of shitty luck if it is), anyone else got any other ideas?

Originally posted by kajeepxj
hey guys, bringin back an old topic cause i'm still having problems, this is what i have done so far....CPS, TPS, plugs, wires, dist cap and rotor, 3 fuel pumps, fuel filter, fuel pressure regulator, 02 sensor, and just did the injectors, i'm about to go to the store to get ANOTHER pump to see if thats it (talk about a run of shitty luck if it is), anyone else got any other ideas?

could be another pump...... the pump I put in mine was bad, so I had to do it again a week later. :mad:

Also, did you clean your tank out real good, preferably with alcohol? Possibly dirty fuel lines?

Also, your catalytic convertor could have gone to sh!t since you died in the water. The water could have seaped into the exhaust and killed all the junk in there.

Well, I don't run a cat actually, and you'd think that would mess up the computer but I ran it like that for about 5 months and it ran like a top, sounds damn good too, I think I have enough backpressure in the muffler so the comp still thinks I have a cat. Anyway, I guess I'll try another pump since all other possibilities are ruled out except for the comp (crossing fingers its not that) I'll let ya'll know what happens, if anyone thinks of anythign else chime in

I had the same problem on a buddies jeep that we put a inj. sbc in the pump run but not enought pressure. put in another "new" pump same problem. Finally put in a new pump from dealer worked fine. Wifes 97 xj started acting up about two weeks ago I thought it might have had bad gas or water in it, filter was in the tank. Had dealer put new filter on it with new o2 sensor fine now. Have you checked all the grounds for the computer, what about the fuel pump relay.

Yeah we checked the relay already, we're also gonna follow the wires to the comp and see if maybe they are grounding each other out or something weird. Those are my last two ideas, the wires and the pump, we're gonna hook up a multimeter to it too and see what we can find out. Any other ideas, keep em comin.

Just another idea and something to check.......
I've got a friend that was having the same problems intermittently as you are and I was and he was told by his mechanic to hard wire the CPS. He did and said he has never had another problem since. so, maybe you can either try that or at least double check the connectors. If the CPS is not functioning right the engine just plain sucks!

Bud (just a thought);)

Two things - have you cleaned the engine to computer connector and the body harness fuse block connector - both are possible corrosion issues; second have you tried replacing the balast resistor for the fuel pump - if this has degraded or been damaged by water the pump will not be getting full voltage during accelleration...

Lastly - trace all the wiring and look for shorts, inspect your fluid to look for any lingering H2O - have you tried some water remover - took several treatments to get it all out after swapping a tank in mine

:confused:

Good luck

Matt

those are some good ideas, i haven't tried the ballast resistor yet, we'll put the meter on it this weekend and see what the deal is. to hardwire the CPS, where should i ground it to? does it have to be somewhere on the tranny bellhousing or can I just ground it out anywhere? i'll check all the wires and relays and crap again this weekend and see what happens. all these good ideas i and can't work on till this weekend, i need to tow it up here to school so i can work on it all the time!

Originally posted by pokey
Just another idea and something to check.......
I've got a friend that was having the same problems intermittently as you are and I was and he was told by his mechanic to hard wire the CPS. He did and said he has never had another problem since. so, maybe you can either try that or at least double check the connectors. If the CPS is not functioning right the engine just plain sucks!

Bud (just a thought);)

Yes that is a PITA Connector but the CPS will prevetn spark and he has spark.

Is you TPS adjusted correctly?
TPS (Throttle Position Sensor) (http://www.partsamerica.com/product_images/img/Nie/NIEFE4027.jpg)
special order form checker about $55, can cause hesitation and stalling when retuning to idle, also see EGR
First clean all connector connections and sensor using Carberator cleaner and electrical contact cleaners.
TO TEST:Use a multi meter to test the three wires. Orientation of the three wires may differ, but one is a ground one, is 5V source,
and one is .75V signal. Do all tests with the engine off and the key in the on position.
First find the ground, put meter on ohms setting, and put one terminal on the clean broudn terminal,
the other terminal probe the TPS. I use T-Taps to tap into the wires so not to hurt the connector. My ground wire showed 15 ohms,
Not great but not TOO bad, Some guys jump this wire to a better ground. Now put your Volt meter on volts setting and
probe your ground on the connector, and look for the 5V source, 4.5V is acceptable. Try with respect to your battery gound also.
Next test your signal for about .75 volts at idle. If it has no voltage at idle its BAD, but if it has the .75 volts, you then need
to slowly move the throttle from idle to open, looking at the voltage to make sure it slowly rises with the
throttle movement upward. If the voltage hops and is not a nice even rise, replace.

EGR (Exhause Gass Return) Is a vacume controlled valve that alows exhaust to circulate back to the intake,
When the drifram is ripped or gunked up it may cause stalling at idle. Clean with carb cleaner, $80 ish dealerreplacement.

Id also check, clean, and or replace your
MAT sensor (http://www.partsamerica.com/product_images/AAP/GPS/AU-AZ/AX9.jpg)

Well I replaced the TPS so i'm pretty sure thats not it, would the MAT sensor really have that much affect on fuel delivery? I would think if it had anything to do with the manifold it would be the MAP sensor more than anything, but I know that works.

ok... this is stupid.. but i dont see where you said you have checked it. HAVE YOU MADE CERTAIN THAT YOU DONT HAVE A GAS TANK FULL OF WATER??????????????

Originally posted by kajeepxj
I pulled the gas tank and emptied and cleaned it and am going to put it back in when I get back to my house on Sunday.

Except for where he said he already did that - :flipoff2:

Matt

Originally posted by kajeepxj
Well I replaced the TPS so i'm pretty sure thats not it

Test it with a volt meter and Ill be happy to say its good.

aight we'll give it a test to just to satisfy ya, even though thats more work :flipoff2: i just gotta get this thing running for our big spring break run

alright well i tried yet ANOTHER new fuel pump and thats not it. i am beginning to think its the computer. i can just bypass the ballast resistor with some wire and rule out that possiblity right? if i do that it should run fine if that were the problem? also, does the pump have to be grounded to the tank and then the tank grounded to the chassis? tonight after i did the fuel pump i ran around the neighborhood and it ran fine for about 5 min, then it started to run like crap, but i noticed that my temp gauge was reading normal while it was running good, then when it started acting up the temp gauge shot up to 260, and i know my radiator is full, i just did it the other day.

what fuel pressure do these jeeps have. i have a fuel pressure gauge that reads to 15 for my carb, but yours is probably more then that. it would be interesting to see what the pressure does when it starts running like shiat. this could help trouble shoot the issue to see if its the fuel or not. if it holds pressure something else is hay wire. i would check the computer next borrow your buddies and put it in. thats my two cents.

Pressure should be between 31 and 39psi - I would check you temp sensor sending unit and ground - may be giving the puter false signals and making the fuel managment system flip out...

Clean up all the electrical crap and then if all else fails try a new ECM... I don't know what the pull-a-parts are out there but around here 91+ is pretty scarce...

Good luck

Matt

fixed that shit....yyyyyyyyyyyyyyeeeeeeeeeesssssssssssss, i just bypassed the ballast resistor and now it runs like a damn top cause i replaced all that other crap. thanks for the help though guys!!!