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Chrysler Repair/'91 imperial 3.3 L v6: starts then stalls

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QUESTION: just put the third pcm in and have the same symptoms.. will run great for a few days then will go to start and it stalls right out

ANSWER: Hi Lee,
You didn't mention whether you had checked the memory of the pcm for stored fault codes. If not, then turn the ignition key: "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains 'on', to see it begin to flash, pause. flash, etc. Count the number of flashes before each pause. Then repeat the process to be sure of an accurate set of flash counts. Then tell the counts in the order of appearance and we'll go from there.
By the way, do you have a vehicle theft security system that was installed at the factory? That has the symptom of allowing the engine to start but then shutting it down after a couple of seconds of running. But I am not clear as to how it would be ok for a couple of days and then start doing that rather than just doing it right off the bat if the theft system had been armed but not disarmed.
Also, what led you to changeout the pcm?
Please 'rate/nominate' this answer/me (see the PS below).
Thanks,
Roland

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QUESTION: HI,THANKS FOR THE QUICK RESPONSE,ORIGINALLY I HAD THE CAR TOWED TO CHRYSLER THEY SAID IT NEEDED THE PCM THEY WANTED $1100. I COULDNT AFFORD IT SO I HAD IT TOWED HOME AND REPLACED IT ON MY OWN ,THEN IT WAS GOOD FOR 7 WKS WITH NO PROBLEM BUT SAME THING AGAIN AND THEN WAS REPLACED UNDER  WARRANTY AND RAN FOR 2 WKS BUT HAD ROUGH IDLE AND THEN REPLACED UNDER WARRANTY AGAIN AND BACK TO THE ORIGINAL PROBLEM  WILL TURN OVER AND STALLS RIGHT OUT... NO FACTORY THEFT SYSTEM OR ANY THEFT SYSTEM.. THAT WAS ALSO CHECKED WHEN IT WAS AT CHRYSLER THE CODE IS 3-5-5 THANKS FOR ANY HELP.

ANSWER: Hi Lee,
I suspect that the '3' code is actually either a 12 or a 21 (i.e. there is a pause that you didn't notice). The 12 just means the battery was disconnected recently, while the 21 means the oxygen sensor is not varying in its reading. In either case those would not cause a shut  down or a hard start.
So basically we have a 'no start' with 'no codes'. One of the most common causes for that is the exhaust gas recirculation valve being stuck slightly ajar. It is located on the corner of the engine closest to the driver, very near the throttle body, and is mounted horizontally on the intake manifold at rear corner of the engine facing the firewall. It has a round vacuum operated top (a vacuum hose runs to it from the egr solenoid which is mounted higher up just adjacent to the throttle body). The egr valve body in mounted in a small diameter exhaust pipe that branches off of the rear exhaust manifold. Between the round top and valve body proper you will see a flange that separates those two parts and partially hidden by the flange is a rod with a circumferential slot (this is the egr valve stem). You can put the tip of a screwdriver in the slot and move the stem back and forth, against spring-action in one direction that is designed to close the valve. Over time the valve gets gummed up by exhaust gases and then fails to close tightly, thus leaning out the mixture at start up too much to sustain an idle. The first thing to do is spray some WD-40 on the stem where it enters the valve body and then exercise the stem via the slot. It should feel like it comes to a dead stop via the spring-action. Then try and start the engine and see if that solves the no start.
Please do rate/nominate me as I am competing to be 'volunteer of the month' at Allexperts.
Thanks,
Roland

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QUESTION: i checked with my relative that is a mechanic for dodge.. he looked it over and said there is no EGR valve.. the car has has a federal emission system ,he is also stumped but he did say it is loosing injector pulse

Answer
Hi Lee,
The injector pulsing is 'driven' by the camshaft position sensor. That is located in the chain case cover of the engine (near the right engine mount). It could be that sensor is flakey and failing when it warms up (but that usually won't cause a failure to start, so this may be not the cause if the symptom is a cold no start). It might be that its tip is too far from the camshaft surface so you could remove it and get a new spacer to put on its tip. It has a 0-ring and is likely to be a bit stuck when you try to remove it. Loosen its bolt enough to allow the slot in the sensor to slide past, don't pull on the sensor lead, tap lightly on the sensor head to help free it. Be sure used or new sensor has a spacer on its tip. Put a bit of oil on the O-ring, press the sensor in until the tip touches the camshaft, then hold it there and tighten retaining bolt to 105 inch pounds.
You can check the output of the sensor by measuring the pulsation between the signal wire and the sensor ground wire as you rotate the engine by hand with the key 'on'. It should vary between 5 and 0.3v on the tan/yellow and black/light blue wires (at the sensor or at pins 4 and 44 of the pcm). Also check the gray color 10-pin disconnect near the battery which is where the wires to the injectors pass through.
Your relative is correct about the egr; it was not required on the non-California engines.
Please "rate/nominate" this answer/me.
Roland

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Roland Finston

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Get a Free Fast answer to your repair question about a Chrysler/Dodge/Plymouth car, minivan, SUV, or truck. Problems with electronically controlled engines and transmissions as well as body wiring problems are my specialty. This free troubleshoot advice forum helps you diagnose faults, minimize repair costs or do-it-yourself.

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I have do-it-yourself experience (50+ years) and a library of 100 1982-2012 Chrysler factory shop manuals and 20 multi-manual Chrysler Corp. CD's.

I was voted "Top Expert" 2010-2015, here at AllExperts, and have answered 20,000+ questions.

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Five decades as a 'do-it-yourselfer' on domestic and imported cars.

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Yahoo Autos Group called The Chrysler Lebaron Club (co-moderator)

Education/Credentials
Advanced degrees in Physics/bruised knuckles

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"Top expert" of 2010, 2011, 2012, 2013, 2014 and 2015 here at Allexperts. Quickest "average response time" at Allexperts (currently no. 1).

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