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Car wont Idle, Cant figure out why

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tstkl

20+ Year Contributor
3,889
74
Feb 10, 2005
SoCal, California
OK, so i recently replaced the following with the parts listed:
oem intake manifold gasket, dejon tool sheet metal intake manifold, oem throttle body gaskets, dejon tool upper intercooler pipe (short route with gm maf), used gm maf, maft, johnny racecar front mount intercooler, dejon tool 2.25 inch lower intercooler pipe, dejon tool j pipe (1.75-2.25), dejon tool intake pipe, k&n airfilter, some off brand air filter for the positive crankcase ventelation thingy (the intake manifold is still hooked up to it, i did it correctly)

what happens? when starting the car normally: she gets to about 800 rpms and then dies as fast as possible. when starting the car at about 35% tps: if she makes it to about 3k shes fine, but if i let go of the gas she dies fast. while looking at the logs for this, it would appear that the rpms start to drop DRASTICALLY around 2500, so im assuming that above 2500 shes fine, and that seems to be true.

what have i tried? in short everything. old 1g maf, even worse.... pressure test, cant hold any psi at all. so its a vacume leak, right? so i take some carb cleaner, have someone keep her at 3k, and start spraying to find out where... nothing... when i cleaned the throttle body with this stuff, and i tried to start it, it went up to 3k by itself... then died... so i know this stuff will change the rpm if its in the intake.

i smell fuel... BOY do i smell fuel... badly...

the other day i checked the spark plugs, they are practically brand new, it looked a little darkish and had some oil on it, im assuming thats from the top tho, because earlier in this cars life (about 1k miles ago) it had an oil cap leak that got oil all over the valve cover, so im assuming its from that... didnt have time to check any other cylinders tho, just #4...


ANY IDEAS? any at all will be greatly appreciated....i PROMISED myself i would finish my car this 9 day weekend, and its almost over with no luck, (although im almost done with everything else i wanted to do, so maybe ill just give up and take it somewhere once im done...satan.... :cry: )
 
tstkl said:
the other day i checked the spark plugs, they are practically brand new, it looked a little darkish and had some oil on it, im assuming thats from the top tho, because earlier in this cars life (about 1k miles ago) it had an oil cap leak that got oil all over the valve cover, so im assuming its from that... didnt have time to check any other cylinders tho, just #4...
)

Are you asking if your leaking oil cap caused the electrode of your spark plug to accumulate oil on it? If you are, you should know that answer.

My advise would be to clean everything up, and sandblast those plugs. Also, if your pressurizing the turbo and its not holding anything at all then you have a serious leak somewhere. If its leaking off immediately then the leak should be so easy and obvious to spot that you shouldnt need any WD40 or Soapy Water. Good Luck
 
no im saying that oil got on the electrode of my spark plug as i was taking the plug out, because some probably leaked into the chamber above the spark plug and fell through when i took the spark plug out, either way im not too worried about that, what im worried about is the fact that when i pressurize it at the gm maf it wont hold any boost, thats eliminating all the lower piping, the intercooler, the turbo, the intake pipe, and a good portion of the upper intercooler pipe, YES, it should be obvious, BUT ITS NOT... this is my problem.... theres enough of a leak at either the throttle body or the intake manifold to make the car need to be at 2500 rpms just to stay alive,... but whats weird is i got the same exact results from when i had the intercooler off (for other reasons), so its not that at 2500 the turbo is pressurizing the intake enough to make the leaks not leak as much (im saying its not that the turbo is canceling out the vacume the engine creates, so i dont know what having the engine at 2500 would change other than basically overflowing the maximum cfm that the leak has.... or something like that...
 
more info, the maft when key on, the red led turns on, then the green, then they both turn off at the same time (or the other way around, either way, one turns on, then the other, then they both turn off..)

o2 volts are at a constant .03 dont remember if i said that already...

i guess i just have to leak test it again...
 
oh. and i checked the compression, 150 across the board. changed the ecu, new plugs, new injectors, adjusted biss, adjusted the cas. could it be the ISC? thats the only other thing i can think of
 
i'm having the same problem.coming to light car usually dies.going to take it in again.let me know if you find out the prob.
 
same problem. I am suspecting that it is the 1g head on my car wit hthe cas wired wrong. I will be doing ab oost test today. But i mean word for word im having the same problem. Smells like gas bad, car pops a little til 2500 then it runs fine, a little hesitant but not too bad. Also if you let the car idles will it slow down to a stall? thats what mine does.
 
I would check the ISC When you turn the ignition on have some one listen to see if they can here it turn on. Or pull it out and check it with a 5-6 volt power source. i think there was a pin diagram on vfaq.com to determine the power and ground.
 
I've currently got the same problem:cry: no dsm for me. I changed battery, comp test is 160, 155, 145, 150, just did timing belt double checked it yesterday, its perfect. My afc now all of a sudden doesn't turn on. I don't know what the heck is going on. Im with you guys. I was thinking about getting a new ecu chiped but I don't know if that would fix it.
 
mine is the same deal also...almost word for word .well i made my car run till a CEL was threw....got p0100 which is my MAFS. so ill see if that fixes mine.
 
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