1992 Plymouth



January, 9, 2011 AT 11:06 AM

This car has been idle for almost 8 years, started every few months but not driven. I'm the original owner and I have a shop manual. I drove it a few months back and found the transmission was stuck in 3rd gear (in fail safe mode). I replaced the transmission control module and all forward gears came back. I then tried to drive it but it was running very poorly. The car is pre-OBD1. I used an analog voltmeter to check the pulsed diagnostic output and this indicated a fuel injector problem. The manual recommended checking the resistance of the injectors. I did this but the resistance of all 4 injectors looked fine. I stopped there. At that point (last October), the car would start but was running rough.
I tried again today and the car would turn over (with a jump), but wouldn't fire. The diagnostic output with the voltmeter was continuous short pulses (no pattern), which means everything is OK according to the manual. I took out a spark plug and had somebody turn over the engine. There was a spark visible. Also, I could smell some gas through the spark plug hole.
Any ideas? I know it's quite a mix of recent events. I'm sure being idle for so long is a factor. I changed the timing belt about 10,000 miles ago, so I don't suspect a timimg problem. I just read about lifting the oil cap and looking for camshaft movement, I'll try that tomorrow.


3 Answers



January, 9, 2011 AT 9:46 PM

You can use the voltmeter ont eh drb connector. I've sent instructions. First charge the battery as that can cause a myriad of problems. You can look under OBD1 to see what codes are set. However I would reccomend trying tostart it first before you try to retrieve codes. Also you can go to the site here under diy and check yoru iginiton system out. It should be listed. Clean your cables at the battery though. Then charge it. If the cam didnt' move the belt would be broken.



January, 10, 2011 AT 10:02 AM

Good call on the battery. I took the battery to an auto store for a charge and they said it wouldn't even take a charge, so I bought a new one and installed it. The car started up right away. Before driving it, I did another diagnostic check with the voltmeter and again it read everything OK (continuous short pulses). I drove the car around the neighborhood, no freeways, about 45 to 50 mph max and it ran fine - normal power, idling, shifting (automatic transmission), etc. However, after about 10 minutes it started to run rough and acceleration became very poor. When I got back home, the Check Engine light was on. I did another diagnostic check and this time I got code #41. The shop manual says that this is an injector problem - injectors don't operate for a continuous 4 seconds while engine is idling or running. It gives three probable causes: - injection malfunction
- open circuit or short circuit in injector or connector contact is defective
- engine control unit malfunction

I checked the resistance of all 4 injectors back in October, the first time this fault code (41) registered and all 4 were fine.

Also, there's a little smoke coming from the bottom of the engine, maybe from an exhaust gasket. It may not be related to the injector problem, maybe a gasket replacement needed?

Since the car ran fine when it was cold but the loss of power happened after 10 minutes, what do you think the problem could be? Injector pressure? I haven't worked on injectors before.





January, 10, 2011 AT 4:37 PM

Fuel pressure should be 47-50 psi at idle and check that first. It can also be a fuelpressure regulator problem as well. You have the manual so it will show you how there. Also injectors 13-16 ohms resistance. Also check for a vacuum leak or hose off as that can do it as well. Also check the ocnnections for the injectors, they may not be good. The smoke could be oil on exaust or a gasket. Run your hand by it to see if you feel any leakage while running but be careful not to burn yourself or harm yourself in any way. You might try some injector cleaner like sea foam to clean them up but the car really needs to be driven for a longer distance for that to work.

Please login or register to post a reply.

Crankshaft Position Sensor Replace Chevrolet
Crank Angle Sensor Replacement Mercedes Benz
Fuel Pump Test Chevy Tahoe
Fuel Pump Pressure Test
Fuel Pump Replacement Done Right