Crazy Misfire/Breakup 3K-4500K RPMS

[DSM Chase]

We cant seem to figure this problem out on our own... Our 2.3 Fp black powered Car breaks up and misfires at 3-4500K rpms while building boost at wot. Even when just cruising and not at wot in those rpm ranges you can feel it missing. The car went 10's last Friday breaking up like this so we know there is a lot left in it. We noticed that during this rpm range at wot when the car is studdering the wideband goes way lean like past 17.0... This doesn't make any sense because as soon as the boost comes on the car pulls hard and runs our normal AF/ Ratio... We are running 116 VP IMPORT race gas

No Boost Leaks
Brand New plugs
Brand new wires
Fuel Pump good
Fuel pressure good
Fuel filter good
3G MAF good

Other notes- the car struggles to idle at times, wideband goes from 14.7 to maxed out lean and then back to jumping around 14.7 at idle. O2 sensor??? It's not in our tune the car ran absolutely perfect then just started this.

Literally everything on this motor is brand new... Just randomly started.

Once the car gets into the boost past 15psi and past 5K it pulls like a rocket ship.

Any ideas?

 

[BlackKnight2013]

have you checked your MAF sensor?? maf sensor can cause hesitations and misfires from faulty inputs to the ecu.

 

[athlete3344]

Have you done a boost leak test yet?

 

[DSM Chase]

Have you done a boost leak test yet?

Have you read yet?

have you checked your MAF sensor?? maf sensor can cause hesitations and misfires from faulty inputs to the ecu.

Maf is good we swapped in two different 3G MAFS that we know came off our other running dsms. MAF IS GOOD

 

[BlackKnight2013]

Have you done a boost leak test yet?

he just said there wasn't any boost leaks in the original post

Have you read yet?


Maf is good we swapped in two different 3G MAFS that we know came off our other running dsms. MAF IS GOOD

ok the only other thing i can think of is fuel tables. i read that it has good fuel pump and fuel pressure but that makes me curious to know if its getting the right fuel mixture during that part of the rpm band

 

[athlete3344]

Was asking if the test was done, not sure if you just visually checked or actually did the test.

What size and kind of injectors are you running and how are you tuning?

 

[DSM Chase]

Fic 1150s ECMLINK v3

 

[BlackKnight2013]

Fic 1150s ECMLINK v3

do you have any data logging capabilities??

 

[DSM Chase]

do you have any data logging capabilities??

This is a 10 second car of course we data log, I'm guessing you don't know what ECMLINK is...

 

[AbsolutGS-T]

Are your spark plugs gapped down enough? Running high boost I had a problem at about the same rpm and once I gapped the plugs lower the Misfire/Breakup went away. Also, you should be able to tell with ecmlink if the o2 sensor is working by watching it cycle from rich to lean in a log.

 

[WES_393]

We noticed that during this rpm range at wot when the car is studdering the wideband goes way lean like past 17.0...

This is indicative of misfiring. So I'd check the ignition system first, mainly plugs/wires/coils.

 

[BlackKnight2013]

This is a 10 second car of course we data log, I'm guessing you don't know what ECMLINK is...

i know what ecmlink is i just didnt know if you were using it to help you with the diagnosis. if i affended you then i appoligize

 

[athlete3344]

This is a 10 second car of course we data log, I'm guessing you don't know what ECMLINK is...

Whats with the condescending attitude dude? Just because you have dsmlink doesnt mean you have the laptop or are the person tuning it. Lighten up a bit, and post a log. It would have been helpful from the beginning Mr. 10.95 second car.

 

[DSM Chase]

This is indicative of misfiring. So I'd check the ignition system first, mainly plugs/wires/coils.

We changed the plugs and wires today, can anyone tell me how to properly ohm out a 90' coil pack.

Whats with the condescending attitude dude? Just because you have dsmlink doesnt mean you have the laptop or are the person tuning it. Lighten up a bit, and post a log. It would have been helpful from the beginning Mr. 10.95 second car.

Didn't mean the attitude, very frustrating problem... We may change the front o2 and post up a log here soon.

 

[athlete3344]

Very understandable!!

Have you checked the transistor in the coil pack? Check this thread Misfire, Coil pack/transistor CEL - DSM Forums: Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon Forum: DSMtalk.com

 

[DSM Chase]

per Mitsubishi the coil pack ohms out fine...

 

[curt-s]

Very understandable!!

Have you checked the transistor in the coil pack? Check this thread Misfire, Coil pack/transistor CEL - DSM Forums: Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon Forum: DSMtalk.com

Agreed -- something else to check. Possibly heat induced failure? (strictly, it's not IN the coil pack, but located near).

I just say this because I've been having this crazy intermittent unstable idle problem for a while, so in swapping components until I found the culprit (thought I had fixed this a while ago with a replacement injector resistor pack), I swapped to a spare transistor... It started with slight breakups while cruise and accel, and then went into all-out mayhem to the point where I would swear I'd throw a rod before I got two blocks. Swapped back and it cleared that particular problem up.. just left with the original one still. Anyway, give it a look. Maybe relocate the transistor away from the stock heatsoaked location and run it for a bit?

 

[My1GLaser]

What plug wires and plugs and what gap?

I had a similar issue on a coil that ohmed fine. It more than likely didn't rear its ugly head until the coil was hot. Replaced the coil with a used one and haven't had a problem since.

 

[Dude McGee]

Coils can be like the ISC, test completely fine, and still be garbage. Id start with that and recheck the harness just to eliminate the wiring as a sorce of problems. The only other thing Ive seen cause this was non linear injectors/poor deadtime setup, but that was always consistant, not randomly occuring as you descibe. It has to be isolated in the igniton system from what you describe.

 

[BurrowZ]

I had this same problem last year! I went colder on the plugs to BR8ES and had to gap them twice before the problem was solved. I can't remember the gap but I think I started at .029 and went to .025. You might want to try just regapping your plugs, and if that doesn't work my next guess would be to check the rest of the ignition system. Swap to known to be good working coils/wires etc.

If that doesn't solve it my next things to swap out and test would be CAS or CPS(if your car has one). Definitely check transistor too. This is why it's always good to have a DSM friend who's car runs nicely.

Can you post a log? Some of the gurus here would be able to tell if anything was wrong there pretty easily.

 

[92-laser-rs]

this is exactly what my car does to

 

[gseclipse93]

Was there ever a fix for this issue. I'm having the exact same issue and can't figure it out.