This '91 3.1L has serious stalling issues

[MarkStack]

QUOTEFrom a previous post in Feb: Background
'91 Beretta 3.1L; 160Km (approx 80k miles).
Car was running very well but started to die intermittently. Had codes: 22+34 from computer: 22=TPS voltage low; 34=MAP voltage low. Don't ask me why, but I changed a bunch of sensors ith new ones: new Crank sensor (CPS); new O2 sensor; new Idle Air Control Sensor (IAC).  Started right up and ran great for two weeks. Then one night after driving downtown a couple of weeks ago and getting hot, car died; difficult to start; stalling; cooled down; restarted; drive couple of km's, died; restarted; etc, finally got it home; read codes: 22+34 again!!
This time, changed the TPS and did some tests: fuel pressure check: 43 psi at rail; fuel lines and filter are only two years old, moderate driving; approx 11.5 ohms resistance on each injector; spark on front three cylinders confirmed. Therefore, I conclude that I have Ignition, Fuel and compression for ignition because the car runs, but I did not do a compression check.

Fired up car. Idles but revs high (approx. 1600rpm) and throws the nasty codes 22+34 again  When I blip the throttle, car dies. I have not taken it out to drive around cause of the above problems in my driveway. I should add that I have meticulously checked for ground faults and vacuum leaks. I found none.  Changed MAP.  Car runs. ÂÂÂ

Car ran for a month but when it got hot one day downtown stuck in traffic...died.  Stared up, ran rough and died often, but evertime i press on throttle...it dies.  Seems to be largely dead now.  Engine light on...codes 22, 34, 45, 66...which I chalk up to PCM being confused.  Soon I will have changed all the parts, lol.  Any thoughts?  For lack of any logical option...what about the coil packs?

[EmeraldGreen3.1]

well, my car was having simular problems with stalling and such and it ended up being my egr. after i got that replaced it ran fine for about a month and it started throwing off egr codes at me, but it didn't have the stalling issue again. so what i did was i went to clean the TB and discovered my hose going from the airfilter to the TB wasn't conected all the way, so i was sucking in all kinds of dirty air. so i cleaned the TB and made sure the hose was all good. might want to try that. just a thought

[ifixalot]

Had a problem with a 92 buick v-6. It would die at idle, it would re-start ok. While driving, it seem to surge, anyway,,, Check each plug wire for resisitance and compare to each other.  If you find one that has much higher resistence, that is your rpoblem. Sometimes they arc internally, once they do that, it burns up the core. These were newer cheap no name wires. I replaced with Delco and it was the end of that problem.

[MarkStack]

Update on the 3.1L '91 that is subject of this thread:
Today took out rad and a/c condenser to access coil packs.  The a/c was gone, so no issue breaking seal on the a/c lines to the condenser. ÂÂÂ
Took out coil packs and the ignition amplifier and switching control module (ICM) they are mounted on.  Tested ICM at local Partsource on a rather complex computer-based DIS Test System (www.distester.com)  that ran 28 different tests on the module and it checked out okay on all tests.  Therefore, module good (although I know that some ICM's can test good cold but then fail hot.  Checked the resistance of coil packs..were 0.5 ohms on prims and 7,500 ohms on secondaries...so I believe these are within spec and assume good. ÂÂÂ
Decided to check the wiring to ICM and the other wires in the harnesses that run under the alternator and the power steering pump.  They were not in particularly good shape as the plastic shields were crumbling and breaking apart as I took them out.  The main issue I saw was the two grey-red wires in the 3-wire bundle running to the a/c compressor pressure sensor had worn through the wrap and you could see copper exposed on both.  Referring to the wiring diagrams, I see that one of those wires runs directly to the PCM and the other is a +5V Reference wire from the PCM but is shared with the reference wire for the MAP sensor.  This could be significant.  I suppose if the ref for the MAP is grounded through vibration, or otherwise, the car could experience the kinds of intermittent issues I am seeing.
I don’t have the last chapter of this effort at this time, but I will re-wire the section that is abraded and let you know what the outcome is.  I wonder if anyone out there has seen similar abraded wires under the power steering pump.  Sounds like it could be a chronic issue with these cars, given the wire bundle routing.  Comments welcome.

[MarkStack]

Update on the 3.1L with major stalling issues
Got the car running today.  Fixed the abraded wires reported above by splicing in new ones, heat-shrunk the splices and put new plastic shielding on them.  Replaced the power steering pump too as it had blown a seal.  Replaced the tranny cooling tubes going into the rad.  Put everything back together and fired it up.  Took several attempts to start, but finally after giving it some gas, it fired and runs beautifully.  Took the car out for a long drive with lots of stops and starts, etc. ÂÂÂ

Seems to run like new. ÂÂÂ
So, all the work I put into this car over the past months may just have been those two wires that were abraded, grounding out.  Will advise if status changes.
Bye...

P.S. I noticed the battery had all kinds of white powder around the pan it sits in with powder all over.  Apparently, this can come about if the alternator is overcharging the battery (or so I read in a book).  I noticed the copper ground strap from the area around the starter wiring was partially broken and probably had a huge amount of resistance in it.  I replaced it with a new heavy-gauge wire to a new ground spot.  Hope that fixes the white-powder issue.

[Jeff P]

Great, I hope it keeps running well I've never had any trouble with abrasion in that area, but it seems like it could happen pretty easily considering how brittle the wire loom gets.  You're right about the white powder (corrosion).  A lot of it is caused by gases released during charging.  It can also be caused by a leaking battery and can eat up the battery tray, so keep an eye on it.  I've never had any trouble with DieHards leaking, but returned a brand new unused Interstate battery because it leaked.  I think my '89 GT had a Kirkland when I bought it, and it leaked too.  If you can keep from having to replace a welded-in battery tray, it's just nicer Good call replacing the ground strap too - most people never pay attention to them.

[MarkStack]

Hello everyone:
just want to say that the '91 3.1 that is the subject of this thread is running very well.  No issues.  all the best.

[Jeff P]

Awesome, great to hear