Hi - I'm not really sure if this post belongs on this form, but you guys are the best match that I was able to find that may help with my problem.
My gf has a 1992 Mitsubishi Mirage (I4 1.5L NA, Auto, 89k). When she starts the car and its cold, it will not idle itself. You need to manually hold the throttle open and idle. You also need to give the car gas, kinda like it was carburated (sp?), but of course its not, it has FI.
Anyways...took it to a dealer (thinking maybe it was a sensor, ECTS or O2 or something) and they said that they wanted to replace the engine, or at least rebuild the top half. They said it basically has 1 good cylinder and three that are shot. We walked out with the car like it was, as I wanted to look into it more.
So, I did a compression test and here are my results (in PSI, cylinders 1-4 in that order):
170, 130, 70, 35
Then I added a cap of oil (5w-30) to cylinders 2, 3 and 4 and did the test again...
170, 170, 120, 55
Now onto what's wrong. I'm hoping its the head gasket out of simplicity sake. Figure a day of work and a $50 part to solve the problem would be great. This seems to be reasonable, because of the exhaust, coolant (she's loosing it slowly) and adjacent cylinders having problems.
However, the higher numbers on the wet test lead me to believe that the piston rings aren't in great shape either, and cylinder 4 may be in big trouble no matter what (totally shot rings, hole in piston, etc). Another possibality is stuck valves.
One more thing...once the car is up to temp it runs like a champ. The plugs looked good, so I don't think its a fuel issue or anything like that.
Now my situation. We're buying her a new car in a few weeks, so I'm not that worried about this. I was thinking of keeping it to toy with and tear apart and see if I could rebuild it. I'm not looking to swap engines or anything, I would just like to fix this one if it wouldn't be that expensive.
Has anyone seen a problem similar to this with these cars? Any thoughts on what the problem is? I don't have the tools to do a leak down test. However, I'm fairly confident that the head gasket is at least part of the problem.
Thanks!
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