Question I have a 91 mitsu GSX manual with 171k miles, which has been driving fine the 4 months I've had it, except that when I start it up cold I have to let it heat up about 2 minutes or when i give it gas it dies.
I noticed that it doesnt start at higher rpms like it should when cold, it just starts and idles at 800. If I get on the gas very slowly it stays running but any more and it dies unless I let it warm. If I give it some gas while its cold and then let off too quickly the rpms fall below idle speed and it dies.
Last week I found a leak in the top of the radiator while on a very short trip, i patched it and checked the coolant level and it seemed fine. When I started it again it idled very rough and stayed rough even under throttle. It will drive but it wants to stall when stopped.
The car is modified with a number of bolt on parts including an evo3 turbo limited to 15psi by a TurboXS manual boost controller, has an aftermarket intake, crushed blow off valve, rewired fuel pump with 12-gauge wire, ported evo3 exhaust manifold, 2.5" downpipe, high flow cat, and 3" exhaust from downpipe on and a 2500lbs clutch. None of these mods have caused any problems for me in the past so barring any complications from these, I was wondering what you would make of these symptoms... I was thinking it be the idle control motor and since its never shown a check engine light and I hear it's a common failure on DSM's but I didn't think that would affect it while under throttle and with cold starts so much...possibly a temp sensor(also)?
Any suggestions would be much appreciated,
-thank you
AnswerChris,
The idle air control motor may be the culprit. But I would recommend pulling the throttle body assmebly and cleaning it thoroughly. The best is to have a factory service manual, but a Haynes or Chiltons manual give good references. Since the IAC is attached to your thottle body, it's pretty easy to test. You can also pull and clean out your EGR valve. You can inspect your fast air idle valve, but that rarely goes bad. With the amount of pressure being built up in your crank case due to the mods, you should replace your PCV valve every oil change. And it's best to spend the extra dollar and get the PCV valve right from the dealership. You should also check the base idle setting screw (BISS) on top of your throttle body. Many times, the o-ring can start leaking air, and cause poor idling. There is also a procedure in the service manuals on how to set your idle speed. If any sensor went bad, it typically would set off your check engine light. But you may even want to check your car's computer. Read this article for more information:
http://www.90gsx.com/eclipse/cap/caps.htm
Hopefully the previous owner replace the capacitors in your ECU, but it can't hurt to check. The smell of unburned fuel may be do to the aftermarket exhaust. If a high-flow cat or a simple straight pipe was used in the exhaust system, you will end up smelling more unburned fuel. Many times highly modded Eclipses do not respond well to cold temperatures so much if several electrical upgrades were made. But you can read up on a lot of more Eclipse mod info from this site:
http://www.vfaq.com/index-main.html
Good luck!
