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2G im at a loss...

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TuJay

Proven Member
94
1
Aug 16, 2016
Wadsworth, Ohio
Heres a video link to what my GST has been doing. Itll sputter, backfire and wont idle when cold but when its warm it almost never does it and idles. Once I get in boost it wont misfire at all. I have no idea.. I cleaned my MAP sensor and that helped a little but not much. Skip ahead in the video where I get on the road and you can really see what i mean.

(sorry for belt squeal)
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I could be wrong but your idle air control sensor on those can cause the the same out come when I had a 2G that’s what caused mine
 
Pull it, open it up (it’s really simple) check for leaking caps, corrosion Etc.
I have a spare ECU (previous owner left it in the back seat when he sold it to me LOL) guess I’ll plug it in and see what happens. What’s the worst that can happen right LOL

How and when did this start? Was it after you were working on the car? Or was it when the weather started to cool off? Or did it appear out of no where?
Drove it to work one day and ran fine all day but when I left it started
 
Last edited by a moderator:
I have a spare ECU (previous owner left it in the back seat when he sold it to me LOL) guess I’ll plug it in and see what happens. What’s the worst that can happen right LOL
Worth a shot, I would still open it up since it only takes a few minutes to check and then you can cross that off your list.
 
P0443. Just emissions stuff

ECU looks fine.

It’s great that you are finding the cause of your problems, without taking the car to a shop — as you stated as a goal in your profile.

However, you’ll have to adopt a more methodical method of diagnosis, like shops use.

There are more than a dozen causes of what is happening to your car. The only way to track the culprit down is to positively eliminate one posiibility at a time. It is painstaking. One whole summer I didn’t get to drive one of our DSMs because it was coughing and dying whenever it warmed up. Every sensor was checked three times, and the cause turned out to be a faulty secondary fuel pump relay.

You’ll find the members here more willing to help if you actually test the values of the sensors. This gives us more data to help you better.

When a seller leaves ‘extra’ parts in the back seat when selling, it’s often because there was a problem even before you bought it.

What emissions items were eliminated that are causing your CEL?

There are how-to’s on this forum that will show you how to test every single sensor in your car. Personally, I would start with testing the operation of the ISC, and then test the sensors related to emissions.

Report back and we’ll see if we can help further.
 
It’s great that you are finding the cause of your problems, without taking the car to a shop — as you stated as a goal in your profile.

However, you’ll have to adopt a more methodical method of diagnosis, like shops use.

There are more than a dozen causes of what is happening to your car. The only way to track the culprit down is to positively eliminate one posiibility at a time. It is painstaking. One whole summer I didn’t get to drive one of our DSMs because it was coughing and dying whenever it warmed up. Every sensor was checked three times, and the cause turned out to be a faulty secondary fuel pump relay.

You’ll find the members here more willing to help if you actually test the values of the sensors. This gives us more data to help you better.

When a seller leaves ‘extra’ parts in the back seat when selling, it’s often because there was a problem even before you bought it.

What emissions items were eliminated that are causing your CEL?

There are how-to’s on this forum that will show you how to test every single sensor in your car. Personally, I would start with testing the operation of the ISC, and then test the sensors related to emissions.

Report back and we’ll see if we can help further.
My CEL is p0443. Evap emissions control purge valve. Previous owner redid the whole fuel system with walbro 255, braided lines to the rail and back with an aero motive FPR. I’m not sure if he messed with the injectors, if you’d like I can go take pics
 
Good information. Focus on the fuel system first. Fuel pressure regulators are known to act up.

Start by verifying the fuel pressure before, and during, the car running poorly.
 
Good information. Focus on the fuel system first. Fuel pressure regulators are known to act up.

Start by verifying the fuel pressure before, and during, the car running poorly.
What is it supposed to be at? And I can’t check it while it’s acting up because it only really does it when I’m driving and I don’t have a camera I can stick in front of it
 
Sudden issues are typically electrtical from my experience. Try the basic issues, Plugs, wires, all electrical connections, vacuum lines (less likely since it ceases when warm). You need a method to datalog. You are in open loop until it warms up. Could be any number of issues. I doubt it's fuel pressure either as it likely wouldn't magically fix itself when warm. This looks like a control issue. Open/closed loop changeover. Possible ISC problems, ISC drivers.
ECU is fine....how do you know? What did you actually check? Are you sure there are no other aftermarket parts lurking?
Does the problem go away completely as engine warms up? Is there a definate point where something seems to change all of a sudden? Can you free rev when cold?
 
Sudden issues are typically electrtical from my experience. Try the basic issues, Plugs, wires, all electrical connections, vacuum lines (less likely since it ceases when warm). You need a method to datalog. You are in open loop until it warms up. Could be any number of issues. I doubt it's fuel pressure either as it likely wouldn't magically fix itself when warm. This looks like a control issue. Open/closed loop changeover. Possible ISC problems, ISC drivers.
ECU is fine....how do you know? What did you actually check? Are you sure there are no other aftermarket parts lurking?
Does the problem go away completely as engine warms up? Is there a definate point where something seems to change all of a sudden? Can you free rev when cold?
ECU is fine regarding its condition. It’ll still do it when warm but not nearly as bad or often. I can kind of free rev, it’ll rev but every couple times it’ll hesitate and misfire then rev.
 
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