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New guy problem

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Teamcodee

Probationary Member
4
0
Dec 1, 2016
Pleasant hill, California
Okay, before anyone tells me to use search, I bought this car in may and have been creeping and researching this forums since then without making an account.
1997 Eclipse GSX
I have a random misfire.


~backstory~

I bought this car from a good buddy of mine and I loved it from the first second. I have so many screenshots of posts from day one of me just absorbing information about this car. Aside from my blown t25 this car was amazing. It came with a 16g which I struggled to find a oil dump tube to make fit not knowing anything about these cars. Thanks for the forums already. Then like the noob I was, instead of having my buddy who had the car before me do the water pump I had a guy take care of it for me. Bam. Cars messed up. Long story but had the head rebuilt at napa auto parts. Got it back and have had problems ever since, I love it Even when it runs like shit I love it. But I have been chasing this random misfire since, pretty much everything under the hood has been changed out around cam angle sensor and crank position sensor. Before I get jumped on (if you guys do that) I've read forum posts religiously and my random misfire is driveable.
I've followed and replaced spark followed air from sensors to checking manifolds. Exhaust side is good, I may hollow out cat unless someone has a test pipe. Sometimes it runs perfect I can always boost, even through the misfire, and sometimes it's f***ed. I've had code p0300 and p0302 which is cyl 2. It goes away. I'm reaching out for help before I find a shop to get raped by.If you are Bay Area and have experience with these cars please let me know. Anyways, I'm
New. If you are Bay Area ca, I'm going to be concord Area. Anyways, any info helps I'll try to post some pics
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Check your spark plug wires connections and if they seem good then its prolly your wires have cracks in them. You may or maynot be able to see where they are "leaking" but id start with change your spark plug wires.
 
Since you say sometimes it runs good and sometimes it doesn't, I'm leaning towards an intermittent electrical issue. Doubt it's mechanical in this case.
First thing I would try to do is figure out if it's fuel related or ignition related. You can try swapping injectors from cyl 2 to another and see if the issue follows the cylinder. Same thing with plugs and wires.

That's where I would start at least.
 
What kind of plugs? It could be as simple as a screw on sparkplug tip. Some plugs are solid and some are screw on. Just another simple thing to check.
Swapping plugs, wires and injectors one at a time is a real good "test". Just do them one at a time. Start with the easy stuff.
 
Check wires, plugs, injectors, check them for moisture on connectors. I would do a compression check on the cylinders also could be a faulty head gasket which has happened to me before even with a new head. or could even be that they didn't deck the head right and its leaking into a cyclinder.
 
Thanks for everyone's responses, I couldn't get logged back in awhile back to respond and just got it now, still no luck, and since it's cold start up without boost or with boost I'm leaning towards ecu searching for misfires. So I'm ordering dsm link to turn that off, and if that doesn't work I'll be finding a Mitsubishi mechanic or shop that can do a full diagnostic of the engine Bay Area to find what I've been missing. So if anyone knows a shop in the sf Bay Area

I've tried everything, i worked at oriellys so I brought pretty much all the parts and swapped them out. Fuel regulator and pump swapped. All spark from cool down to plugs is changrd out. Gaskets done. Injectors swapped out. Nothing. I've tightened down manifolds on both sides. The car drives. It misses for awhile till it's nice and warm and then it's fine, I dunno. I'm at a loss but I know dsm link will turn off misfires so I'm praying this is finally it

Timing has been checked 4 times by different people, I had 4s in it but went back to 5s for stock purposes. Wires were swapped out for new stuff just to see. I've swapped 3 ecus into it. Original a 97 gst and a 99 auto gst. And it still misses on warmup and randomly driving.
 
You didn't mention the leakdown test being completed. That would be good to know the result, given that you just had headwork done.

There's only one electrical component left in the system which has not been checked, or replaced: the trigger wire leading from the ecu to the coil pack.

That would explain why the misfire is consistently on the same cylinder. It is not easy, but you can run a new trigger wire right alongside your harness for a test.

My preference would be to de-pin the old wire from the connectors, and then crimp on the correct pin to insert the test wire into each end's connector.

But, it is also possible to use a wire tap connector at each end instead of buying new pins, but it will leave an insulator cut mark in the jacket of the wire at each end, which must be sealed with a minimum of electrical tape when you are done.
 
I had this problem before on my car and what it was that the aftermarket sensors u get from the parts stores are in different specs from the OEM sensors so maybe the crank or cam sensor are not in spec even if they are new. also u mentioned getting dsmlink to turn it off, really the only people who should use it in my opinion are people who did the 6 bolt swap. if its a real misfire u cant just click that check and think things are fine ya know. I would at least pull the plugs and give us a picture of them to see what the cylinders are seeing. my misfire was drivable as well but it was slightly misfiring and could tell by the spark plugs.... just my .02
 
I'll look into that trigger wire, Im still learning the electrical side, but the last time I pulled the plugs they were rich around the outside ring and slightly lean in the middle and gap was set to .28-.30, but the misfire used to occasionally show p0302 but usually just shows p0300. I I'll pull the plugs in the next few days car has boxes on it from moving. But I'm kinda at the point where I'm ready to find someone experienced in the Bay Area to get it fixed instead of chase and chase it to no avail. I emailed one place and they told me they don't really touch dsms anymore due to age and problem platform.
 
I know exactly how frustrating it can be, I spent a month checking and replacing and rechecking everything till I came to the root cause... the crank sensor which was a brand new aftermarket one! if at all possible throw the old original one back on and see if that fixes the problem along. I have a hard time believe auto shops most the time with my car
 
I'll do that this weekend, and pray Lol
Same as before with the plugs. Rich around the ring and the light brown on the ceramic. Cylinder 2 is showing the most lean from what a buddy said. I may need to look into coil swap and redo the wire housing
 
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