need help diagnosing problem with 1990 eclipse gst


first the car barely holds idle with , car is running a little bit rough

but the main part is the car is not letting rev past 3.5k rpm somtimes 4k rpm

it seems like its hitting the rev limiter

under full throttle it just sounds like its hitting rev limiter.

like a wah wah wha wha sound.

i drove the car for a little bit and at some points in the rpm, the car feels a little healthy

its not the engine, but soemthing electrical

just change the transistor, still same thing. not ecu as i pulled it out all conections are fine and nothing is blown or disconnected inside it

so i narrowed down to the MAF or maybe cam angle sensor

what do you guys think?

the car does nto really drive so i can take it to a shop, can anybody come and take a look?

all help would be appreciated


BTW if i do need a MAF does anybody have one for sale?

which mitsubishis MAFS are compatible?

 

First thing do a boostleak test put new plugs and wires in it, do a compression test when you pull the plugs. Check all electricle connections. If that all checks out fine pull the ECU and take a wiff, if it smells like shit that would be your problem. If it all checks out, next get it to idle then set the timing.

 

check all electrical connections, cleaned them also, ecu is mint, just checked it

wires are new, will check plugs in the morning

could it be theMAF?

 

it seems like rev limit is coming in pre maturely

 

sounds like a boost leak to me.check all your ic piping,usually if its a maf it will still run just will idle surge.but if it wont go over 3500rpm could be a small boost leak.
my 0.2

 

Swap ECUs with a known good one before you assume your ECU is working properly.

 

that is very true also check to see how much fuel pressue you are runnin.

 

youre ecm may be in "limp in" mode.normally when your ecm loses contact with a harness, it will go into limp in mode, which is a term used for a preset running mode.all your computers communicate on what is called a bus wire.if this wire is broken anywhere along the harness, you can lose all regular functions or run like shit.all along your harnesses,pull off the conduit surrounding the harness and check for broken or frayed wires.if this is the problem, you can half ass it and sodder in a new piece of wire or go all the way and replace the whole harness. i work at plant city chrysler dodge and jeep and i see morons trying to wire gauges in to there harnesses and frying pcms and harnesses all day long.Good luck buddy... keep me posted.

 

I like that limp-mode theory, something to check. If you're near the Temple Terrace area I've got a spare 1g maf you could try out if you narrow it down to that.

 

Have you tried the a known good ECU yet?