[N3m3sis]

Fbo
New plugs
New coils
Jb4

Doesnt matter what map i have it on, anything low rpm heavy load the car misfires cylinder 1,3,5...

2nd gear 40mph can rail on it, no misfire, hit 3rd all the way through, no misfire.


As long as i stay in it, its fine.

40mph put it in third, hammer down... Misfire 1,3,5...

Narrows down to the obvious, injectors, or hpfp both original with 80k on them.


Took the jb4 off car runa flawless with exception of cel from downpipes. So wont be able to recall any parts.

Anyway to pinpoint the hpfp or injectors or anything else i may be having an issue with?

[Miller335]

WHat do your csv logs look like?

[FRMTL2_335i]

here are his files...

[FRMTL2_335i]

logs 1, 2, and 4 show a huge dip on the HPFP. highly doubt it could be the injectors. log #3 was on map0, the rest either on map 1 or 2

[Bme30]

Get better logs of your hpfp and the lpfp.

[Bme30]

I was having similar issues and it ended up being my lpfp. But also had my hpfp changed in the past.

[N3m3sis]

Originally Posted by Bme30

Get better logs of your hpfp and the lpfp.

Cant log any better. The car breaks up wayyyy to bad


Lpfp stays solid

[///Mposter]

Originally Posted by N3m3sis

Cant log any better. The car breaks up wayyyy to bad


Lpfp stays solid

Can you pull the plugs out and clean them? They may be fouled enough that they are not able to ignite . Also check the coils for being installed all the way down . They are tear drop shaped. If they are not pointed to about 2'oclock and then pushed down onto the spark plug, the coil spark will have to jump to the plug. Some people didn't notice and had problems shortly after replacing them .

[N3m3sis]

Plugs are new, and coils are new, and in place how they should be

The car runs 100% with the jb4 taken off

[Morpheus]

i was having similar issues. Try dumping in a bottle of octane booster at the next fill up. Solved my problem. Switched stations too. Might be bad gas-and an easy and cheap diagnosis. I paid a few bucks for the stabil 104+ product.

[N3m3sis]

Originally Posted by Morpheus

i was having similar issues. Try dumping in a bottle of octane booster at the next fill up. Solved my problem. Switched stations too. Might be bad gas-and an easy and cheap diagnosis. I paid a few bucks for the stabil 104+ product.

Thanks for the imput, ive tried everything already lol

93 from diff stations
E85
Race gas
Octane booster

Nothing works. Still same breakup no matter what gas

[Kenu8187]

How old are the injectors?

[N3m3sis]

Originally Posted by Kenu8187

How old are the injectors?

Oem injectors so 80k

[///Mposter]

This is what I was trying to say. I know that the plugs are new but if they are fouled it will be a lot different running under little or no boost versus 2 or 3 times the normal amount. The following is from NGK: Q: What is a "fouled" spark plug?

A: A spark plug is considered fouled when the insulator nose at the firing tip becomes coated with a foreign substance such as fuel, oil or carbon. This coating makes it easier for the voltage to follow along the insulator nose, leach back down into the metal shell and ground out rather than bridging the gap and firing normally.

Many factors can contribute to spark plug fouling. The air/fuel ratio may be too rich as a result of incorrect carburetor adjustment or a poorly performing fuel injection system. Worn piston rings or valve seals may allow too much oil to leak into the combustion chamber, leading to oil fouling. The ignition system may not be performing properly. Prolonged idling or continuous low-speed driving may keep the spark plug from reaching its optimum operating temperature. Using too cold a spark plug can lead to the same problem. Finally, a dirty air cleaner can create a too-rich condition which can lead to fouling.

Fuel, oil and carbon fouling can all be the result of different causes but, once a spark plug is fouled, it will not provide adequate voltage to the firing tip and that cylinder will not fire properly. In many cases, the spark plug cannot be cleaned sufficiently to restore normal operation. Therefore, it is recommended that a plug be replaced once it is fouled.

[N3m3sis]

Right i get it. But would be a super freak coincidence if it was only 1,3,5 on both the old plugs and new plugs lol.

Thats why im down to a fueling issue. Just trying to determine if its the hpfp bc as you can see in the logs, that it dips far down.

Only wondering why its only misfiring on cylinders 1,3,5 and now all of them?

[///Mposter]

Originally Posted by N3m3sis

Right i get it. But would be a super freak coincidence if it was only 1,3,5 on both the old plugs and new plugs lol.

Thats why im down to a fueling issue. Just trying to determine if its the hpfp bc as you can see in the logs, that it dips far down.

Only wondering why its only misfiring on cylinders 1,3,5 and now all of them?

Okay cool. Can you check the ground wiring under the engine cover and see if there is a severed or damaged wire ? I can't remember if they are ganged together 1,3,5 on one stud and 2,4,6 on another. I think they are brown wires .

[N3m3sis]

I looked over everything, it "looked" OK, but ill give it another check


Ninja edit. If it was a bad ground it would be a consistent issue, no?

[///Mposter]

Try to eliminate the visual first, If you can, then we can move to other things . As for wiring , it's like magic, once the smoke leaves the wire , you can't put it back, yet you are still mystified . Any way, most wiring will work when cut or damaged but you have to think of it this way. You would use a larger gauge wire for to reduce resistance and to carry more current to its destination . A small wire may have 20 strands, and a large gauge wire way have 80+ strands. If you have a cable ( wire) cut and it lost half it's strands then it may be unable to carry the current of the load. Wires for your injectors or coils or sensors could be affected as the car warms and causes further resistance issues.

[///Mposter]

I found this thread as well.

[Morpheus]

what year is your car? There was also a thread on a failed resistor in the DME causing misfires. I believe it was the msd80 one.

[Morpheus]

http://www.e90post.com/forums/showth...=msd80+misfire

[N3m3sis]

Originally Posted by Morpheus

what year is your car? There was also a thread on a failed resistor in the DME causing misfires. I believe it was the msd80 one.

I am msd81 (08)

Again i think if the dme, it would happen with or without the jb4 on?