Help, power loss problem.

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'91 Laser RS turbo with, gulp, 174000 miles. Having a power loss problem all of a sudden. The car has to be driven for a varying amount of time before the problem shows up. Never happens cold. Sometimes I will get a mile or two in before it starts, sometimes it takes 12 miles. Engine starts missing, exhaust note changes, barely has enough acceleration/power to be driveable. Sometimes when it happens the Check Engine idiot light comes on, sometimes not. When it IS on if I let off on the gas and let it idle the light goes out and the engine sounds normal. When it's happening, any amount of gas pedal at all and it has no power - doesn't seem to be RPM related (other than idling or not at idle). bi*** of a problem to find because when it's sitting at the curb idling the problem doesn't occur. The longer I drive it the more likely the problem is and the more steady it is. Right now it averages about 70 degrees outside. I haven't noticed any strange looking exhaust.
I took it to a local mechanic who couldn't find it. He said he thought it might be a clogged fuel filter but he replaced it without any change. He thought it might be a blocked exhaust system but he disconnected that without any change. He said he disconnected the "mass air flow sensor" and that wasn't it. I replaced the spark plug wires because I remember a similar problem with the car years ago that was corrected by replacing the wires. Wasn't it. The mechanic said he wasn't able to connect to the computer to get it to tell him what's wrong because he doesn't have the proper equipment/programming. Recommended I take it to a Plymouth dealer. Anyone have any ideas? Can I hook up to the computer myself with just an ohmmeter (no oscilloscope)? Would it make any difference if I could given the fact that there's no problem when the car's idling?
Maybe the car's history. It's been a good car. It doesn't owe me anything. I've driven it for 13.5 years and 174,000 miles without problems other than routine maintenance and the occasional dead battery but I don't want to part with it if I don't have to. I really wanted to pass 200,000 miles.

Andy

 

[Kevin90GSX]

Things to check:

1. Maybe a bad coil pack
2. Maybe a bag ingnitor. (Found right under the coil pack bracket)
3. Check to make sure one of your injectors isnt bad
4. Check to make sure one of the injector clips didnt pop off and your injector isnt plugged in.

That should give you a start and let me know how it turns out.

Good idea would be to find someone with a datalogger and they can tell you what the CEL is for.

 

[adgrey]

Hello Kevin. Thanks for responding. You're going to have to assume I'm a newbie here. I'll look in my manual for now but what's a coil pack (ignition coil?) and where is it? How do I decide if an injector's bad?

Andy

 

[Kevin90GSX]

Hello Kevin. Thanks for responding. You're going to have to assume I'm a newbie here. I'll look in my manual for now but what's a coil pack (ignition coil?) and where is it? How do I decide if an injector's bad?

Andy

the coilpack is located under your intake manifold. Its basically where your spark plugs connect to. They tend to go back and need to be replaced. Start with that. Lets not get ahead of the game.

Also attached to the bracket the coil pack goes to is the ignitor.

Try to get to a parts store or junk yard and pick both up. Swap those out and see what you get. Even if its not those, those two parts are good to have extras of.

 

[Chaddsmcollecto]

you said :


"Having a power loss problem all of a sudden. The car has to be driven for a varying amount of time before the problem shows up. Never happens cold. Sometimes I will get a mile or two in before it starts, sometimes it takes 12 miles. Engine starts missing, exhaust note changes, barely has enough acceleration/power to be driveable. Sometimes when it happens the Check Engine idiot light comes on, sometimes not. When it IS on if I let off on the gas and let it idle the light goes out and the engine sounds normal. When it's happening, any amount of gas pedal at all and it has no power - doesn't seem to be RPM related (other than idling or not at idle)."



i have three letters for ya ECU

this is a common symptom of the center capacitor on the ecu board begining to fail this will occur over time on all of the DSM computers some just faster than others but however this is a repairable problem if you catch it in time.

remove the computer located behind the radio by removing the side center console panels and the radio then there are four 10mm bolts that hold the ecu in place remove the bolts and unplug the three pigtails for the computer

after you have the ecu out then take the four set screws off the out side then remove the cover of the computer
examine the circuit board for
1 burt smells
2 visual black marks
3 capacitors that are sitting crooked
4 whitish gray gel substance comming out of any of the capacitors

if in fact the ecu is the problem and you catch it in time the capacitors can be replaced with little to no trouble, however if the board has burn marks clean through it then there are some vital control wires in the board which will also be damaged and in that case the everyday soilder person cannot complete this task and you will have to consult a curcuit board engineer for the proper tools to reattach the control wires. or you can find new ones on the net with are going for about $1300.00 from the dealers

i have ran into this problem many time while working on DSM of all types and im currently working with a computer engineer on a board from a 92 Laser RS turbo AWD with the same problems as you are describing

there are many other sensors and vac problems which can cause your symptoms however if you have check all thoes then the ECU takes about 10 min to remove and check to see if that is your problem i always look there first anymore when i start to diagnose any problems expecially with Turbo cars they play hell on ECUs