bad misfire, boost leak?

[se0nz]

so after the fmic install i had an alarm problem and i got through it this morning. however when i turned the car on after having the negative terminal unplugged it seemed like the car was running rough almost like the MAS was unplugged but it was plugged in nicely. so after a few mins it starts to idle fine and i go for a drive... it boosts fine but once i build boost and the rpms start to climb it starts to buck and sputter until i get a bad misfire and the car dips forward and bucks pretty hard. dont think it's fuel cut at all, but just a bad misfire... boost leak maybe?

 

[Gstclipse69]

Definitely sounds like a bad boost leak. Have you done a boost leak test since you put the fmic on? You can check the plugs and wires but that would sort of "cut out" more than buck like you are describing. Put a tester on there, pump some air and see what you're working with.

 

[se0nz]

haven't done a boost leak test only cause i finished the car super super late last night and had to be to work by 6:30 this morning... finished last night around 2am or so and by the time i cleaned up it was 3am at least . i'll do a boost leak test tonight when i get home and see what turns up... hope it's an easy fix... had me down after i finished the install

 

[se0nz]

any other ideas anyone else can chime in? thanks!

 

[GofaST4life]

I currently have this same problem with my 1g. I know its a bad boost leak. Just have to find it.

Do a BLT and then go from there.

BLT = Boost Leak Test not a Sandwich haha

 

[707GSX]

You are describing exactly what is going on with my car right now. I thinks its a boost leak tho.

*EDITED

 

[xioca]

Yes that sounds like a boost leak. Do you know how to make a boost leak testor? and don't talk about street racing or you'll piss off the mods.

 

[turbobluers]

and don't talk about street racing or you'll piss off the mods.

x2000

 

[se0nz]

You are describing exactly what is going on with my car right now. I got beat by a scion tc today on the freeway. How humliating is that . I thinks its a boost leak tho.

wow that's pretty bad... you keep driving the car like that huh? i went back and got my beater and drove that to work and parked my dsm i'll work on it tonight i think and try to find my leak which i think i know where it might be.

 

[Bluefire16]

Hello again my fellow friend, same thing happened to me. First thing i did was check for boost leaks, im sure this is your problem, but for me, i was hitting fuel cut actually. I was boosting 15psi and with the air being so cold here in Michigan its causing fuel cut. I turned my boost down to 12 psi and im fine now. The air is just to cold and combusts so much better now with the help from the front mount getting more air to the engine.

 

[se0nz]

Hello again my fellow friend, same thing happened to me. First thing i did was check for boost leaks, im sure this is your problem, but for me, i was hitting fuel cut actually. I was boosting 15psi and with the air being so cold here in Michigan its causing fuel cut. I turned my boost down to 12 psi and im fine now. The air is just to cold and combusts so much better now with the help from the front mount getting more air to the engine.

i guess that may be a secondary problem if it's not a boost leak... i went from that tiny little sidemount to a giant front mount so i'm sure it's doing much better.. but i'm only boosting 15 psi on the little 14b so i dont think that's too much but it very well could be. i'll check it out tonight and see what i come out with. thanks for all the info everyone... i really appreciate the help

 

[707GSX]

My bad guys

 

[Bluefire16]

If you dont find a boost leak turn down the boost a tad and see if that helps. I doub its fuel cut for you however, it is only fuel cut for me due to the cold weather.

 

[Maranello993]

My car does this also, but it doesn't do it when I lower the boost. So this is because the air is cold (which it is)? So it's fuel cut? e316g at 15psi it buckles, at 10psi it doesnt. I tightened all of my couplers from turbo to TB, but it still does it. Regapped the plugs to .028 from .030 and it still does it. The thing is, by other descriptions, it doesn't feel like fuel cut, just a misfire at higher boost and rpms. I want to be sure that shelling out the dough for new plug wires will be worth it before I do.

 

[Gregory]

How long did you have the negative terminal uplugged? After about 15 minutes, your fuel trims will reset, and the first couple minutes of rough idle was probably just the ECU trying to correct you fuel trims.

Everyone is right about the BLT. No mayo.

Check plugs and wires too. Whenever I have a missfire from anything, I always just buy new plugs. They are cheap, and it's a good idea to replace them if they haven't been done in a while anyways.