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4.3 CPI Vortec help needed

9.2K views 17 replies 8 participants last post by  4runner  
#1 ·
I'm just finishing a 4.3 swap into my Suzuki Samurai and need help answering a computer question.

Engine is from a 93 s-10 4x4 Blazer. I have completely rebuilt motor all new parts. even replaced all engine sensors.
I'm using a Painless wiring harness. This one.
I'm using GM part #16197427 ecm/pcm. I had no ecm when I got the motor so this is an ecm I got at the wrecking yard got two of the same part #ed ecms.

Problem I'm having is low idle. Its low enuff that the engine will just die without warning. It will run for quite a while then just die it will restart very easy run a while and die again. This is all while the rig is parked.

Engine runs great while driving and I am on the throttle, but once I let off the throttle to to start coming to a stop the idle drops and the engine will die.

I have tried both ecms. one ecms will cause the engine to idle better while parked but will still die when letting off the throttle while driving. The other ecm will idle low while parked and will die once off throttle while driving. Both ecms have the same GM part number and this is the numbered ecm that Painless said I would need for the engine I have.

My question is, Do I just need to get a differant PROM for thr ecm or can I get the PROM reprogramed?
Would getting a new PROM help with my idle problem?

This is the motor in my Samurai.

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#3 · (Edited)
what do you have for a vehicle speed sensor? it sounds like the problems ive heard with the VSS. ive been looking into this motor closely because of the swap ive been doing.

EDIT - Just saw your post in my thread. :)
 
#4 · (Edited)
Check your IAC, it controls idle, and verify your not getting any false air, or have any vacuum leaks.
Make sure you have a vacuum hose connected to teh back side of the intake by the distributor, its hidden, you'll ahve to feel for it. I don't see a vacuum line running to it in your pic, it may be there and hidden by other hoses.
 
#5 ·
Thanks for the info. I did replace the IAC, but according to the direction I've read. The IAC will not set itself untill the rig is driven above 40mph. Is this info correct? and is there another means to setting a new IAC? I still havent got the all the bugs worked out with the transmission so I cant drive very fast yet.

The only two vacuum lines I found on the engine are one going to the brake booster, its connected and the other one used to goto the stock T-case, that one I just capped off.

Is this the vacuum line you are talking about or is ther another one that I'm missing.

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#6 ·
I forgot to also ask, does anybody know what base timing should be set at on this motor? The chiltons manual I have says to look at the emissions lable under the hood for base timing, Well I dont have the rig the motor came out of. So I have been just guessing on the timing.

Motor came out of a 93 S-10 Blazer with a "W" vin#
 
#7 ·
well, the CPI should only have one mark, correct? 0 is what alldata says... mine only has one mark - 0 - ... thats with the timing connector unplugged.
 
#10 ·
I only have an alternator and a TC style power steering pump. I diched all the stock GM brackets and built all my own.

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Built in a manual belt tensioner and got rid off the auto tensioner.

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Built all the mounts on my lathe.

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#11 ·
I did a swap in a 72 FJ40 and only needed the alt. as well. You can remove the P/S pump and run a shorter belt without a problem using the stock brackets. If you are interested I can dig up the part number for the Napa belt I used.

Almost forgot.... I used the a/c pump as well, but its not plumbed for air. The owner thought he may want to used it as an air pump later. If you wanted to remove the a/c pump there is an a/c delete pulley available from Summit.


Will
 
#12 ·
not to get off track, but what headers are those? do you like the CPI? im excited to get mine driving and see how it does. :smokin:
 
#13 ·
They are Headman headers.

http://store.summitracing.com/partdetail.asp?autofilter=1&part=HED-69400&N=700+115&autoview=sku

I wouldnt buy them again. The collector outlet on the drivers side is very close to the flex plate/torque coverter dust cover. I had to notch out the dust cover to make it fit. It is also very close to the tranny shift linkage. I'm running the 4l60e trans, same as you.
The pasengers side header fit fine.

You might give these a look. In the picture the drvers side header looks like it would clear the trans a lot better, But I dont know that for sure.

http://store.summitracing.com/partdetail.asp?autofilter=1&part=HED-69410&N=700+0&autoview=sku
 
#15 ·
Well for a temp fix,
There is a wire on your painless harness to make the engine idle up when the AC comes on. Hook that wire to a micro switch, put the micro on the throttle,so when throttle is closed the micro is switched on and the engine idles up.
Really like your brackets.
Or try to get it on a scanner.
Is that other 16197427 for sale?
PM me
Im doing this in a toyota right now. Same harness.
I have heard VSS is only for emmisions.
Call Painless.
Jeremy
 
#16 ·
I did get this problem fixed. I had a vacuum leak on the intake where the hose from the PCV is connected, also got another E-prom. One of the two or both got it fixed. I wheeled the rig last weekend and the engine ran great all day.

I do like your idea about connecting the A/C signal wire to a switch, that would be cool to be able to switch on for winching. Does the A/C signal wire just need a 12v supply?

I think I'm going to keep the other ecm for a spare.

Thanks, about the brackets. That took me a lot of time.

I'm running the 4L60E transmission, so I need the VSS and a DRAC module to make the transmission shift correctly. If you were running a non electric tranny you would not need the VSS.

I did call Pianless a few times and they were almost useless.
 
#18 ·
I have that engine, wiring harness setup in my 4runner, but I am running a 700r4/np241 now.
originally I was running an R151/toy tcase...

the engine has never run "right", sometimes hard starts, sometimes runs hot, sometimes, idels high, sometimes idles low...you get the idea...never got better than 10mpg out of it with the manual trans, running 35" tires and 4.88 gears.


now I have 38 tires and still 4.88 gears. I hope that when I finish setting up the drivelines, I can figure out how to make it run right.

I am using the little silver computer box...and the engine originally had the black OBDII(???)....I had to swap out the dist and coil to make it even run...is there a chip or something in the little silver computer box that can be accessed to make things better?
I am not running any VSS(I was told it was for the electric speedo and emissions???)...I used the cable driven toy speedo, but now need an adapter to go from toy cable to gm 700r4...


so many issues, so little money.