1993 Mitsubishi engine reves up and down

Tiny
PAMSKY
  • MEMBER
  • 1993 MITSUBISHI
  • 4 CYL
  • 2WD
  • MANUAL
  • 106,000 MILES
The engine was dropped in with 60k miles on it, cant figure out why the engine reves up and down when stopped at a stop sign, sometime it dies but mostly its reves, and sometimes the idle goes really low.
Could this have anything to do with a vacuum hose stuck or does it sound like a sensor?
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Sunday, December 9th, 2007 AT 10:21 PM

4 Replies

Tiny
MHPAUTOS
  • EXPERT
Hi there,

Check for engine vacuum leaks and a faulty idle control motor. If this has been the case since the engine was fitted, have the base idle adjustment re set, these are the most probable causes.

Mark (mhpautos) :D
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Sunday, December 9th, 2007 AT 10:35 PM
Tiny
QUINTIND
  • MEMBER
I have a 93 Colt Mitzu product with same problem. The common causes seem to be all throttle body related. A dirty throttle body, faulty throttle position sensor, or fouled/faulty Injector Servo Control are apparently the common culprits. Mine has improved after a simple cleaning of the throttle body - but not completely.

I will remove the throttle body again in a couple days, crack it apart, try to identify the ISC, clean and reinstall. Apparently there is a sensor that can be fouled by carbon build-up. I will report back if this works. The TPS was replaced once by the PO, if the cleaning doesn't work I will replace it as well.

I am flying blind as there are NO repair manuals available locally. Dodge will NOT diagnose or check engine codes - claiming the vehicle is essentially Mitzu, and have washed their hands of it. My Mitzu dealer will also not diagnose - saying Dodge claims propietary ownership of the technology pre 1994 in Canada. Dodge claims to not carry the computer equip necessary to diagnose a pre 96 vehicle. Yet another reason to abandon Dodge altogether. Is there anyone left in North America stupid enough to drive their vehicles with such lousy support? :Evil:

I am currently searching for a Mitzu Colt/Mirage/Summit/Lancer(?) Repair manual for the correct year. Am searching US sites as they are N/A locally - once again due to Dodge proprietary ownership.

If any of this works, I'll try to remember to include a detailed photo.

Cheers
Dale
:D
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Monday, January 14th, 2008 AT 12:55 PM
Tiny
MHPAUTOS
  • EXPERT
Thank you for your input Dale, it all helps.

Mark (mhpautos)
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Monday, January 14th, 2008 AT 3:00 PM
Tiny
QUINTIND
  • MEMBER
My dad took the throttle body off last night while I was working. By the time I got to the garage he had it cracked apart. We did not identify the ISC per se - but cleaned everything there was, coolant pump etc, reassambled and reinstalled, vehicle is now running normally. Of course I forgot the pic, but there was not much to the thing in the first place.

Fixed for about $2 worth of cleaner.
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Tuesday, January 15th, 2008 AT 1:53 PM

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