Need a Mitsubishi engine expert!
 

One of the delivery guys for our shop sputtered into the lot a week ago with a sick engine. We are not engine mechanics, and certainly not Japanese specialists! Anywho, the engine is the 1.8 in a 1995 Eagle Summit (rebadged Mitsu) and has had the catalytic converter removed. The downstream O2 sensor is missing and the only code is the one for that signal missing. With no way of getting datastream numbers or even a compatible fuel pressure tester, we took a shot in the dark and went with low fuel pressure due to the OEM filter and pump being almost 400,000 miles old! Replaced both, no change. Finally found a local shop with the proper scantool, only relevant data it provides is a TPS that works fine, an upstream O2 sensor reading that jumps around as one would expect, with a generally rich at idle and lean when throttle is given and engine stalls out. MAF sensor reads, but seems a bit low compared to US models and seems very sluggish. Rev engine and the reading doesn't go up for a few seconds. Rigged in a fuel pressure tester they had, 40 psi regardless of throttle position or revs.

Anyways, the engine will idle OK once started, but give it any gas and it dies. Put it in gear, it knocks and misses and dies. VERY SLOWLY add throttle to allow the engine to "catch up" with the throttle setting, and you can get it to rev up to redline, spitting and sputtering if you go too fast on the throttle action. Get it moving say 10mph and adding throttle slowly while manually shifting at higher than normal revs will get light acceleration up to abut 50+ mph. Hills and such, it loses power and ya have to downshift. Come to a near stop, be prepared to bump the tranny in and out of gear to get it up to 10mph again without killing it. Driver says it ran "pretty good" up until the current problem took hold as he decelerated to come off the exit to our shop.

Has good spark and killing each injector dropped revs. Driver grabbed a MAF from junkyard and tried it, worked worse. Bad junkyard unit, maybe?

Guy lives 75 miles from here, so a tow is more than the car is worth. Any ideas or tests we need to do?

By no means am I an expert. However, sounds like timing belt/chain skipped a tooth or more.

kernel..
 

I am less of an expert, than the worst expert.. What 5953 is saying may be it.
Have a 1990 Mits. pickup in the driveway.. Just got over 200,000 miles on the little damn sewing machine that got 38 miles too the gallon..
I was out of town and the girlfriend took it too Daytona to pick up her mother.
Engine temp light came on.. Steam coming out of the hood..
So she did what a proper Woman driver should do, sorry Women members.
She kept driving to bring it home, so I could check the problem..
Hello AAA..
Not sure on yours, but like 5953 is saying. Mine calls for a timing belt change every 70 thousand..
Also look at a manual.. My, blown up truck, has a computer board under the glove compartment box.. Not sure on yours..
That goes bad, it aint going nowhere.. Mine did. Used to be $1,300 out of Canada..
Now a guy in Orlando here re-builds them for $300.. I could probably get you one for $150 if the guy is still around..
Hell check if the one from my truck will work, you can have it..
Damn I loved that little soup can.. Girlfriend keeps begging me to get rid of it.
We pulled it on the front lawn, put an old toilet in the back and planted flowers..
Then I bought her a barley used Chevy Silverado, $30,000 truck with all the fixens. I hope she learned her lesson. :)

i got a 86 mitsu dodge d-50 2.5L that has about 300K --

it did the same shit --get very weak going up hills, lose power --back fire and so on.

the solution on it was there was rust in the gasoline tank --when going up hill the rust flakes would puddle up over the fuel screen restricting the fuel just enough to cause the problem.

all i had to do was drain the tank a couple times and it runs fine now.

don't know for sure if this is the problem with yours because it is another model--but it won't cost much to check it out===

otherwise the scrap yard was offering $300---LOL!

kernel..
 

I can send my girlfriend to drive it.. Do you guys have insurance on it?
She can not fix it, but she will sure show you how to finish it off..

Timing belt could have jumped I guess, never seen that before, just broken and "teeth" stripped off. Doubt it's a fuel delivery issue, at least mechanically clogged as the tank looked clean when the lid was off and have 40psi pressure. If the fuel is not getting delivered it's because the comp is not calling for it.

kernel..
 

Check if mine will fit. Hell you can have it.. Telling yah, that board goes bad, nothing runs..
Just using the truck as a lawn ornament.. I will show her who wears the pants in this family..

Not an expert. Work at a parts house. When some converters are removed the ECM goes full rich trying to compensate for it. Ask him if it has backfired. If so he may have blown out the mass air flow sensor(MAF). If this doesn't help tell him to sell it and buy American. LOL.

The Cat has been off for years, problem just started. It backfires a lot now, but the MAF still reads, it is just sluggish. Takes several seconds to show a change in flow. Dunno if it is really slow or if the comm setup is just slow, like on Chryslers. Those, the data you are seeing is actually from 2-3 seconds ago as the comm connection is so slow.

I wonder if it's the fuel pressure regulator, if it even has one?
I had a ranger that had a vacuum operated regulator and it ran like shit (but still ran), a guy told me to pull the vacuum line off the regulator after running it fo a few minutes and see if it had fuel coming out of it. This ment the diaphram when out in the regulator which would cause flooding while driving it.
Other then that I have no clue