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CPS bad?

Posted: Mon Jan 04, 2016 10:02 pm
by viper79
Reference only to my symptoms since late November '15.
http://www.pontiacbonnevilleclub.com/fo ... 47497.html

Situation: Starts when cold. Go to store. Temp 200. Come back. Starts then stalls. Start again with gas, runs.

MAF = New
IAC = New
FPR = New
F. Pump = New
F. Filter = New Airtec
Oil = New 5w 30
Drive belt = New
Plugs/Wires = New ACDelco/both
Fuel Pressure @ idle 42psi
I am not showing any codes.

One thing that is leading me to believe it's the CPS is that when I go over puddles it wants to die. When I sit in traffic or drive through I must kick off the heater to keep a smooth idle (not rough, but at times wants to die).

In my google searches and research on failing CPS's that this $35 part can muck up a lot of other components, throw false codes, and fail at the worst times.

Well, my question to you guys is glaringly obvious....what do you guys think?

Re: CPS bad?

Posted: Mon Jan 04, 2016 10:49 pm
by 96 SSEi
hi, please check this site and test the cps with instructions provided.....http://easyautodiagnostics.com/gm/3.8L/ ... sor-test-1

Re: CPS bad?

Posted: Tue Jan 05, 2016 8:24 am
by spoiledred94
Just my 2 cents but I'm pretty sure that with the problem going on for awhile you'd get an SES light if it is the CPS. The shop had to put three CPS' in mine when it was running rough stalling and dying. I got the light, but the first two CPS' they put in were bad :banghead:

Re: CPS bad?

Posted: Tue Jan 05, 2016 12:24 pm
by MrPOPE
Maf and Cps are notorious for being BAD even when brand new... usually go with a junkyard one, re-mans are horrible

Re: CPS bad?

Posted: Tue Jan 05, 2016 6:21 pm
by viper79
Relay? They get hot. I am not getting a light. I'm a computer geek and I know for a fact when relay's get hot they do not open/close properly. SUPER EASY TO CHECK.

Anyone know what fuse box the Automatic Shutdown Relay is located.

http://www.allpar.com/fix/codes/sensors ... tdown.html

Re: CPS bad?

Posted: Tue Jan 05, 2016 7:15 pm
by michtom
I had a car 3800 that would stall on me every so often and always started back up right away. Never once did it set a code. I checked everything imaginable, then changed the crank sensor. Never had a problem again.

Re: CPS bad?

Posted: Tue Jan 05, 2016 8:45 pm
by jradke61
The CPS or the master of all sensors the ECT sensor. The PCM controls a lot of engine functions including fuel delivery and timing based off info it gets relating to the engine coolant temp. Hence the master sensor name.
I'm having a similar issue with my Regal and it's one of these 2 sensors. I just picked up the ECT sensor and throwing it in tomorrow. I've got an added clue of the fans not kicking in but they can work just fine and still have a bad/faulty ECT sensor.

Re: CPS bad?

Posted: Thu Jan 07, 2016 8:22 am
by spoiledred94
It should throw a code at any rate. Mine did eventually give a code. The shop set it up on their sophisticated scanner a ND monitored it. The first 2 they put in showed the cps itself was getting a good signal. Then it began to fade out and died. The third cps never lost its signal. And the code went away.

Re: CPS bad?

Posted: Thu Jan 07, 2016 9:19 am
by michtom
You will not always get a code. Read this- http://www.underhoodservice.com/diagnos ... -failures/
I am not saying this is the problem but, you can have a bad cps without a code. Another way to test this is when it stalls spray the cps with water to cool it then try to start it. If it does start you have a bad sensor.