The more I do the worse it gets

[BlackViper]

My car started misfiring while driving dwon the freeway at 70mph. When I got home I checked the plugs to see if I could tell if it was lean or rich. When I put them back in and went for a drive I could barely go 20mph. I talked to someone on here and told me about blocking off the EGR. So even though I'm in CA I do it and after I get it on I take it for a drive. Now it was a little better than before while I was driving around 25-30, but once I got the turbo making some power it misfired until I let off. I just changed the oil yesterday becuase its been about a month since my rebuild and I wanted to get some better oil in. I fixed my leak coming out of the turbo's oil line so I have no oil leaks anymore. I put in some oil with a quart of oil treatment. I drive around my neighborhood fine and when I try and go over 30 it misfires til I got back to my house and put it in park. So now tonight I take it out and it runs fine while going about 40-50 for about 20 minutes. Then I stop at a light and it just about dies before the light changed. From them on it misfired every once in awhile. It seemed almost like it misfired when I'd stop going faster than about 30mph. I was really taking it easy on the car too, not even getting up to 4k rpms. This is really annoying to me becuase I can't figure out what the problem is.


I did all the checks on the ignition system that were in my manual and I am very very sure that its not my wires or plugs, becuase I just bought the damn things from a Mitsu dealer when I rebuilt the engine.

I'm getting a new fuel filter and a Walbro 255 pump tomorrow or tuesday so I'll see if that helps anything, cause I am begining to think its my fuel system. I am quite sure its not an intake leak anywhere becuase that was the last problem I had with it and I know what that feels like trying to drive it.

If anyone has any ideas about what I can check on the fuel or ignition system that would be great, becuase I really don't think I'm going to find the problem. Thanks for your time.



BlackViper

 

[Kevin90GSX]

Well a misfire issue can be a load of things but the things Id check first would be:

1. Plug wires. Make sure they arent arched (sp) and make sure they are fully seated in the coil pack

2. Maybe your coil pack is bad. I had to replace mine once when it was doing the same thing. After that it was running great.

3. Power transistor may be shot. About 3 months ago my car was misfiring extremly bad. After some research I found a hole in my power transistor and replaced it. Now the car is running well. (This is located directly below the coil pack.

Those are my suggestions. Good luck man!

 

[Newlogics]

If you have EGT gauge, look if temps rise quickly.

check base timing. being off WILL cause very poor performance, missfiring and lack of power.

This may seem simple, but double check plug gap.

Ispect all air-duct tubing. Loose clamp will not spoil idle, but will leak under boost, thus causing condition you're describing.


Although missfire can be due to numerous reasons, your specific circumstances narrow is down somewhat. If, as you say, you're getting it at boost, while idle is fine, then logically, I'd place my bet of these things:

A) Plug gap. It's harder to spark under boost.
B) Loose clamps, hoses etc. Whatever can leak at boost, but seal at vacuum.
C) Screwed base timing.

 

[BlackViper]

I think I'm going to take it to the Mitsu dealer if I can't get it working by this weekend. I really need to get this car running. The last 6 months I've been rebuilding and fixing little problems like this and haven't had any fun. Thx for your suggestions, I'll try the ones I know how to do and let the dealer take it from there if its not working.



BlackViper