Weird misfire problem

[Clutch450]

I've owned this car for 4 months now with no problems. But today I went to the store. The car ran great there. Then after 10 minutes in the store I come out to start it. It starts but starting it seems like the motor kicks back. Like starter is struggling.
Once it's started it idles rough. And misfires. When trying to drive its like driving on 3 cylinders and backfires bad

I shut it off and start it a few more times. Runs perfect again.
Same situation occurred when I got home and go to start it a few minutes later

No CEL's. Changed plug wires and power transistor and checked plugs. But the problem still occurs

Car is a 2.4 block run by dsmlink v3
It's been raining a lot here recently, not sure if driving it in the rain for the first time today has an effect on it or not.

Any helped would be great!

 

[ghostd'GST4life]

when you checked the plugs, they should have only had residue thats sticky on #3 to indicate misfire.. new plugs are cheap enough, make sure you gap them correctly and you should be on your way

 

[cola]

Do a basic check of the ignition and fuel system, pull the spark plug wires and ensure you get a bright blue spark by shorting them to a ground.

 

[shanebro]

Do you still have your fuel pressure regulator solenoid? It might be vapor lock.

 

[Clutch450]

No that is taken out.
Vapor lock?
Please Explain

 

[boostin90gs]

kinda sounds like a igition coil problem. Could be getting hot then starts misfiring.

 

[Clutch450]

That's what I was thinking. I have to switch it out
It is not vapor lock. Taking the vac line off the fpr doesn't change anything.
And now the problem is constant. It always runs and starts like this. Even when cold. I can't drive the car because it has no power, bucks terribly, and back fires really bad

 

[KrazyRob]

Check harness connection at ECU. Happened to my 97 GST just out of no where after I came out of a store, had to hold harness to the side to make contact inside ecu so I could drive it home.. The 97 gst was all stock though, you might have mod issues..

 

[Rs AWD]

there are a few things, the first thing i would do is make sure you have all your injectors plugged in 100%, if the metal clips have been removed they tend to slide up due to vibration. if you have a spare spark plug laying around check the spark in each cylinder. pull the wire put the spare plug in, lay it on the head and have someone crank the car over. make sure to pull all the wires because the car will start on 3 cylinders. if everything is good there you make have a sticky valve, bad rocker or clogged lifter. thats just a guess im not really 100% sure becuase without actually being there and seeing it there is no way of knowing.. also its a second gen, check if that is a symptom of the crankshaft position sensor or camshaft position sensor going bad. im not very familiar with 2g's so maybe those going bad could cause that. if its none of that check for leaky caps in your ecu

 

[mchustle]

You could try to clear the dtc's in link if there are any and check the box to ignore random misfire, and see if it runs right after that. On long trips after about 75 miles it would catch a random misfire code and run like crap until I pulled over and cleared it with my laptop. I assumed it was because of my 6bolt swap and made link ignore random misfire and haven't had a problem with misfire since. May not fix your problem, it's just a thought.

 

[boost97gst]

Ive been getting a random cyl #3 misfire and the wb goes lean. I believe its the injector 3 which really sucks. It only happens about 30 seconds after startup and about 1 out of 10 starts will it even happen at all. Soon as i cycle power, its fine. Go figure.

 

[91boostedgst]

On my girlfriends gsx cylinder 2 had a misfire do to a clogged injector swap it out with another and it ran normal again.

 

[Clutch450]

I pulled the injectors today. They had a black sticky residue on them. I cleaned them really good. Car started up just fine.
I come back a few hours later and the problem is there again. The motor is kicking back so hard that the starter is completely toast now. And no I was not sitting there cranking for 30 seconds at a time. These were like 5 seconds turn overs. The motor just kicks back hard and back fires.

I cant really just swap injectors since they're 2150cc on e85. Car would start and run pretty bad on smaller injectors.

This is a serious problem. Ive been working on these cars for years and have not yet come across a problem that has confused me so much.

Coilpack is good
Plugs are good
Plug wires are good
Power transistor is good
I do have spark
Fuel pressure is were it should be
Fuel pump is working good.
I can't really believe it would be an ecu related problem as I just bought this eprom and link setup from ECMtuning only 30 days ago.

Link is setup to not search for random misfires, so it cant be that.

I seriously need some help. I was planning on taking this car to a huge car show in OCMD next week. It was running perfect up until a day ago. Figures!

 

[boost97gst]

Its backfiring you say? Huh.... And you checked timing?

 

[Clutch450]

I have not checked time. But I honestly can't see how it would be. The problem was intermittent. Would happen then would go away. If timing was off the problem would always be there

 

[Rs AWD]

try starting it with the whole fuel system hooked up but not firing the fuel into the cylinder head, hold it off the head, but still shooting into the cylinder head(to not get fuel all over the place) and let it just spray out and see if you have a clogged injector, you say it happens on start up so you should be able to tell right away. if not i would pull the ecu and look for something in there.


my brother in law bought a vr-4 and the ecu was just replaced before he bought it and i pulled the ecu and it was burnt up. due to a bad isc that should have been changed out before the ecu was changed out. who knows, cars a weird things...

 

[Clutch450]

I'm going to pull the ecu tomorrow.
I can't really test much more until I replace the starter.

 

[Tiki2777]

Make sure its not something stupid like a boost leak or a bad terminal. (ive always had similar symptoms like that and it has always been dumb stuff)

 

[Pyros95GSX]

You said you pulled out of a gas station and it had been raining right? It could be bad gas. it probally isnt it, but i've had bad gas a few times with my old gs but havent had a problem since i got my gsx. But it's a good thing to check jus to be sure.

 

[Clutch450]

It's good fuel. It's E85 and it's from a very reputable seller. All my other car friends get their e85 there. Never any problems

 

[flipper47]

hey clutch, not sure if you have adjustable cam gears on there i didnt read it in your mod list, however my cousin is not brilliant when it comes to cars but with his 2g misfire he had me take a look at it and i realized that the small three bolts that hold his adjustable cam gears in their location were not tight but just snug and due to starting the car and running it the cam moved slightly from its stock setting point...this then causing a backfire and poor running. he was freakin lucky as hell that it did not slide all the way to the end to create any bent valves. just thought id throw it out there that it was a very oddball situation that i found.

 

[Clutch450]

Thanks for the input flipper. Unfortunately I don't have adjustable cam gears. So that does rule out that situation.

I will be pulling out the injectors tomorrow and seeing how well they are spraying. Injectors are the last things that I think can be causing this problem.

 

[Rs AWD]

hey, i just thought of something that could be doing it.... if you have a lifter that gets sticky and holds the valve open... and it doesnt get stuck all the time sometimes it frees up and runs good but it has a clog in it. just a thought

 

[Clutch450]

My one friend gave me the same suggestion about a sticky lifter.
I'm not too sure on how to check for one of those.
And when it is running bad like this I don't hear any valve train noise. I figure there would be a good amount of noise with a stuck/sticking lifter

 

[Rs AWD]

i have had them make no noise and show 0 compression