is it my ecu

[Rahdigga8188]

Ok here goes. I just bought my laser (its a 90 ) from a used car lot. they told me it needed a fuel pump. so i replaced the fuel pump and it doesnt work. so after a bit of reading i decided to check my ecu. yep bad. Also my injectors were stuck. so finally i got them freed and bought a 91 ecu from a shop. now my car will run, kinda. it has terrible idle, wont rev at all, runs really rich, wont run with intercooler piping connected to throttle body, and when i pull off 2 of the plugs idle doesnt change. i know im getting spark and fuel on all four. so I open this ecu and the capacitor has leaked on this one also. would it still run and have problems like this? Is it something worse. This is my first dsm so I dont really know where to begin. Is there anyone in the Savannah Ga area who could come take a look at this for me? I talked to the previous owner and he said that it ran fine before it died. I dont know what to do next and I dont want to buy another ecu to find out its something else. Oh yeah, I did switch pins. When I pull the plugs all 4 are pitch balck and the car is completely stock. Is there anyway to tell what year the motor is from, being as i think it was swapped. The old ecu number was MD128625. New one is a eprom from a 91 gsx, not sure of the number though. Thanks in advance.

 

[GSntncT]

Well, either just have the car down for a while to get that ecu fixed, or you can talk to Jeff O. at www.dsmchips.com. I can GUARANTEE nothing but quality work from him. I recently bought on of his ECUs, and I'm wholly impressed with his work. After that, I would take a good look over the whole car. i.e. fitting, clamps, hoses, etc. etc.

Good luck on getting her up and running hard!

 

[oldman]

There are things you need to do when swapping a 91'+ ECU into a 90' car, fixing the leaking capacitors aside.

 

[Rahdigga8188]

So the fact that this is a later year ecu could be contributing to these problems? I thought I just had to switch the 2 wires but seeing that the ignition is different i can see how that could contribute. it almost feels to me as if the timing is off, but i was told if the timing is off it wouldnt even run.

 

[steve]

I'm sorry, what is your question?

There are degrees of bad from flakey all the way to it doesn't work.

If you can pull off two plug wires and the idle doesn't change then those cylinders aren't doing anything. Since you know that the caps have leaked on this ECU you need to get it fixed or get a good ECU. You could have additional problems like a bad CAS, PTM, coil or simply fouled plugs but you have to eliminate the know problems first and work through the rest.

Steve

 

[Rahdigga8188]

Ok, but for the record, i read on another post that some pulled the maf sensor and the car actually ran, so i tried this and mine ran to. it ran like crap but I could actually put the uicp back on and rev it. does this make sense. and even though i can pull the plug wire on 1 (yeah i rechecked and its only cylinder 3) and the idle wont change, when i actually pull out the plug its black just like the rest. is this wierd?

 

[Rahdigga8188]

Isnt there anyone in the Savannah Area??

 

[Rahdigga8188]

ok, so i got my new ecu and put it in and it started right up and idled at 1000, but was shaky. so i checked and its still only running on cylinders 1 and 2 does anyone have any idea why this could be?

 

[steve]

You could have additional problems like a bad CAS, PTM, coil or simply fouled plugs but you have to eliminate the know problems first and work through the rest.

Time to start looking at the other possible causes.

Are you sure that 1 and 2 are working? The ignition system has the cylinders paired (1 and 4, 2 and 3) so it's somewhat unusual to have 1 and 2 work but 3 and 4 not.

Steve

 

[dsmsucks]

send the ecu to Steve. Great guy and great at fixing dsm ecus

 

[Rahdigga8188]

ok i got a chance to check it out again. I say it seems as if its running on only 1 and 2 because when we pull 3 and 4 he idle doesnt change. but i pull the plugs and they all look the same. when we open the oil cap the idle changes though. so we checked the timing marks on the crank and cams and it seems to be off by a tooth or 2. could that make it seem as if it is only running on 2 cylinders? A friend thinks i am losing compression on those 2, and there is no smoke at all so he thinks it may be valvs. does this sound right. how much will it cost me to get my timing done? I just called pep boys and they quoted me 500. does that sound right? thanks in advance.

 

[steve]

Sounds like your testing correctly. Run a compression test to see where you stand before doing anything else.

I wouldn't let PepBoys touch my car even if they offered to do my timing belt for $20.
How good a price that is depends on exactly how much stuff is being replaced. Depending on how many miles are on the car and the engine parts there is a list of things to be replaced.
At minimum, the timing belt, balance shaft belt, timing belt idler and tensioner pulleys, balance shaft belt tensioner pulley and timing belt auto-tensioner need to be replaced as part of the job.

Right now I would worry about being off 2 teeth until you check everything else.

I hope you got a real good deal on this car because it's possible that your going to be rebuilding the engine.

Steve

 

[Rahdigga8188]

ok so i found the problem. finally gave in and pulled the head and low and behold, i had 2 broken exhaust valves so now what should i do. im workin on limited funds so i need to fix this on a budget. i was thinking of just getting another head and slapping tha bad boy on. would that be ok? my pistons and cylinder walls look great and i pulled the turbo and everything looks ok, so i guess I got lucky when the peices flew. I called the guy I bought it from and he said the timing was done under 20,000 miles ago. the belt looked new but im gonna replace it anyway. should i still get new tensioners and pulleys as they should have been part of the job that was done, or would it be bad to assume they did it the right way. I will post pics later when i get more batteries for my camera. im just happy the damage was obvious cause i didnt wanna have to go lookin around.