Still having the same problem, checked all fuel issues , filter, pressure, injectors all check out good. new plugs, wires, cap rotor. Problem being when warmed up, on hard accell, the car is falling on its face. Sound like it is going to explode. 91 formula 350 TPI 65k, auto.

 

did you check the ignition module? or MAF sensor? sounds like you need a scanner....hard to diagnose *it only happens when = when vrs when*

sounds ignition related somehow.

coil or ignition module ...thats my vote ....

 

yeah that's where I was headed next. Thanks for the input.

 

Just wondering if you solved the problem?

 

no i have seemed to isolate when it is occuring though. It seems when it gets warm, and damp. It is not doing it daily. Actually I thought I had fixed it, because I had no issues for a while. Then it poured last week and when i fired it up no problems but after about 20 mins, It started again. I am going to recheck all my ignition stuff, module, wires, grounds, etc. Any other advise?

 

For problems that only onset when the engine is warmed up, I usually go straight for the Coolant Temp Sensor and the O2 sensor.

CTS is what tells the ECM it's time to go closed loop. When it fails, the car usually runs open loop full time and doesn't behave well.

O2 sensor is only used in closed loop, so if the CTS is working right and the ECM goes to closed loop, it will behave badly if the O2 sensor is sending bad data.

Both are cheap parts if you want to swap them, stick with Delco parts for both if at all possible. If not, NAPA's Echlin brand and Borg-Warner are good substitutes. Avoid all others.

 

Kevin,

I presume the CTS you are referring to is the one for the ECM located at the front of the intake?

Robert

 

That's the one, it will cause the problem you described. The sensor costs about $7 and can cause all kinds of driveability problems.

 

alright.
thanks for the assistance. I will pick one up on the way home. What's 7.00 anyway. Sometimes it is the simplist things. Short story here. I had a 88 Mitsu Starion 2.6l fi turbo. pretty quick car. I had major problems with bucking, missing, backfiring, etc. It took me a month to fix this car. i tried everything, i found that for some reason all the valve /timing was off. so I checked the chain it did not jump, tensioners were all good, it was indexed properly, So I reset the valves, still was not working right. i swear I tried everything on that car. Well i finally decided to pull the timing gears and chain, and redo all that stuff. Well upon disassembly I found the stupid little dowel pin that held the cam gear to the cam had sheared and spun about 1/4 of the way and was screwing up the timing. It cost me .78 to get a new dowel pin from ACE hardware. Down for over a month for a .78 cent dowel. Man I could have kicked my own ***.

 

Anyone knows the part nr. for the Delco coolant temp. sensor for an '88 5.7 V-8?

 

oem part# 15326386, list 22.90

 

Hey gonzo,

I found a completely different part nr. for the coolant sensor in my parts CD-rom:
25036979

 

Looked further into the part # you have that is a CTS for 89-90 M Body?
Verified correct part #15326386 for cts for the ecm.

 

Gonzo, I looked again in my 1982-1992 Pontiac Firebird Parts & Illustration Catalog CD-Rom, and this is what I found:

1987-1992 F-Engine asm. 5.7 L V-8 L98

Sensor Eng.Coolant temp (at int. manif.) interfaces with ECM

Part # 25036979 group 3.682

Where did you find 15326386?

 

I have direct access to alldata /motors on line, that is were I got the part #. I then also called my local Pontiac dealer marquardt pontiac, 847-381-2100. That is were I got the info for the part# you supplied also.

 

Did the new temp sensor get you fixed, or still having trouble?

 

I too would like to know the resolution to this problem.

 

 

Hey Gonzo, stil trying to get the car fixed?

Anyone who can confirm the part numbers for this CTS?

 

Well, it seems that we are good to go. I have not experienced any problems since replacement of the CTS. Had it running all day yesterday(finally). It also rained pretty hard, and I had no problems at all. Thanks for all the input.

PS. picked the part up at Elmhurst Pontiac.
part# was correct 15326386. right on the box. It was like $24. and some change w/tax. Very simple to replace.

 

Howdy all. I appreciate all the clues I've picked up so far. But what will a bad CTS do as far as your temperature readings in the dash? Will a bad CTS leave your temp gauge on zero? Or will you get normal readings even if the CTS is bad?
My 2.8 is lurching and stubling in the lower RPMs but my temperature gauge appears to be working...Thanks.

 

The CTS has nothing to do with the temp gauge. That has its own sensor. So it's possible for one to be accurate and the other completely wacked.

 

Coolant temp sensor goes to the ECM
Coolant temp SENDER goes to the dash guage...2 different animals.

 

Agree two different parts #'s

15326386 Temp sensor for ECM = list= 22.87
8993146 Temp sender/sensor for gauge= list 31.17

 

All,
Gracias, merci, danke, domo and thanks. Replaced that coolant temp sensor and the stumbling/lurching is gone. Only hard part was reaching in and lining up the socket over the old one when removing it. Replaced the thermostat and coolant while I was 'in there'. Had some time left so I knocked out an oil and filter change as well.

I got 'kung fu arms' after getting singed on the manifold.
TTFN
-ART