[CBMAC7]

Hey guys so in my previous post I had a misfire on cylinder #2 and after everything it ended up being dielectric grease on the connector to the coil. Everything was cleaned out on everything and recently there was a misfire on cylinder #3. New injectors, spark plugs and coils. Only around 500km on the car after all this. I swapped coils, plugs and still misfire on cylinder #3 under load. It is driving me crazy and now we have a huge event this weekend for Street Wheelers. Cars from everywhere come to this. Any help would be fantastic guys. Cheers.

[924er]

Originally Posted by CBMAC7

Hey guys so in my previous post I had a misfire on cylinder #2 and after everything it ended up being dielectric grease on the connector to the coil. Everything was cleaned out on everything and recently there was a misfire on cylinder #3. New injectors, spark plugs and coils. Only around 500km on the car after all this. I swapped coils, plugs and still misfire on cylinder #3 under load. It is driving me crazy and now we have a huge event this weekend for Street Wheelers. Cars from everywhere come to this. Any help would be fantastic guys. Cheers.

Probably a leaky valve cover gasket?

Try logging it maybe he injectors are dying out

[CBMAC7]

Hey man valve cover gasket was replaced around 1000km ago. And the injectors are like brand new, all 6 of them to the newest version. They are coded as well. My car ran good for awhile then there was issues.

[CarAbuser]

what DME is in the car? msd80 or 81?

[CBMAC7]

It is MSD80

[Fitz335]

Fuel pump?

[CBMAC7]

Would that cause a single cylinder misfire? LPFP and HPFP looked good last time Buraq check my logs. I'll prob go and log again now.

[CBMAC7]

So I just changed my tune back to stock. Took it for a drive and now I'm getting a misfire on cylinder 6!?

[AWSAWS]

Tune? Stock plugs? How much boost? Fuel being run?

[CBMAC7]

I've changed my plugs a few times. Misfire cylinder 6 on stock mode and cylinder 3 on protune 94 and e40. It only happens under hard acceleration usually between 3-6. New plugs, coils, injectors(coded) and VCG.

[CarAbuser]

Originally Posted by CBMAC7

It is MSD80

I believe that it's possible to have a failed transistor on the MSD80 ECU. There is 1 transistor per injector which acts as an amplifier from the ECU to the injector.
There was a good DIY somewhere from Roy Cormier. I think Wedge knows a guy who can fix it for a small fee if you aren't kitted up to solder a new transistor on.
Not sure how to diagnose a failed transistor other than open up the ECU and get a multimeter in there.

If the misfire was just in 1 bank then it could be the O2 sensor but you said it happens in cyl3 and 6.

Run a log that has low and high pressure fuel values monitored and post it here.

Another thing to check is the injector installation. take the engine cover off and check that the decoupler is fitted to each injector and that the metal tabs are still attached. A few guys including me have had dealerships forget decoupler and snap the metal tabs off injectors which leads to the injector moving around in the cylinder and knocking the spray pattern out.

[CBMAC7]

Originally Posted by CarAbuser

I believe that it's possible to have a failed transistor on the MSD80 ECU. There is 1 transistor per injector which acts as an amplifier from the ECU to the injector.
There was a good DIY somewhere from Roy Cormier. I think Wedge knows a guy who can fix it for a small fee if you aren't kitted up to solder a new transistor on.
Not sure how to diagnose a failed transistor other than open up the ECU and get a multimeter in there.

If the misfire was just in 1 bank then it could be the O2 sensor but you said it happens in cyl3 and 6.

Run a log that has low and high pressure fuel values monitored and post it here.

Another thing to check is the injector installation. take the engine cover off and check that the decoupler is fitted to each injector and that the metal tabs are still attached. A few guys including me have had dealerships forget decoupler and snap the metal tabs off injectors which leads to the injector moving around in the cylinder and knocking the spray pattern out.

Here is my data log. Couldn't get much because it misfire right away in 3rd gear on WOT. Thanks for the help in advance.

http://www.datazap.me/u/cbmac7/misfi...-9-10-11-12-15

[CBMAC7]

When I started my car this morning before my log checked for any codes. These codes popped up now.

P29CF
P29D1
P29D2
P29CC

I ran my log and the codes were cylinder 3 and cylinder 6 misfire.

[CarAbuser]

Originally Posted by CBMAC7

Here is my data log. Couldn't get much because it misfire right away in 3rd gear on WOT. Thanks for the help in advance.

http://www.datazap.me/u/cbmac7/misfi...-9-10-11-12-15

Compare it to this log of mine, ignore the low pressure fuel value, my car has no low pressure fuel sensor as it's a Z4; http://www.datazap.me/u/rich/ina0s-v...zoom=3748-3916

You can see my bank 1 and bank 2 afr are following eachother quite tight. Yours seem to be drifting apart. If you check your short term fuel trims it looks like they are working hard to try keep things in check.

Also if you look at the high pressure fuel on your chart it drops pretty sharply midway through the pull whereas mine is sticking to 2000~.

Read this awesome post from PTF. It should give you an idea of what to look for in the way of fuel in the logs. (http://www.e90post.com/forums/showthread.php?t=1120250)

I don't fully know how the fuelling system operates so I couldn't tell you if your HPFP is on the way out or not. It looks like it's dropping way below the minimum of 1500 that PTF recommend but maybe it's programmed to do that when it sees that it's running really rich in bank 2. Could even be a dud O2 sensor giving false readings.

I would ask a tuner like Wedge/BQ or PTF. They might be able to instantly tell you what's wrong as they deal with these issues regularly.

[CBMAC7]

Originally Posted by CarAbuser

Compare it to this log of mine, ignore the low pressure fuel value, my car has no low pressure fuel sensor as it's a Z4; http://www.datazap.me/u/rich/ina0s-v...zoom=3748-3916

You can see my bank 1 and bank 2 afr are following eachother quite tight. Yours seem to be drifting apart. If you check your short term fuel trims it looks like they are working hard to try keep things in check.

Also if you look at the high pressure fuel on your chart it drops pretty sharply midway through the pull whereas mine is sticking to 2000~.

Read this awesome post from PTF. It should give you an idea of what to look for in the way of fuel in the logs. (http://www.e90post.com/forums/showthread.php?t=1120250)

I don't fully know how the fuelling system operates so I couldn't tell you if your HPFP is on the way out or not. It looks like it's dropping way below the minimum of 1500 that PTF recommend but maybe it's programmed to do that when it sees that it's running really rich in bank 2. Could even be a dud O2 sensor giving false readings.

I would ask a tuner like Wedge/BQ or PTF. They might be able to instantly tell you what's wrong as they deal with these issues regularly.

Thanks I just emailed BQ. Could this be caused by a dirty VANOS solenoid by chance? Was gonna check those today. Also the my log is me driving and the car misfiring, then letting off and driving WOT still to get a little more out of the log.

[CarAbuser]

Originally Posted by CBMAC7

Thanks I just emailed BQ. Could this be caused by a dirty VANOS solenoid by chance? Was gonna check those today. Also the my log is me driving and the car misfiring, then letting off and driving WOT still to get a little more out of the log.

Not sure about the VANOS, may be worth searching for the common faults causes by VANOS problems. To me it looks fuel related.

I just read your sig and since you already have a Wedge tune I'm sure he would be keen to help out.

[CBMAC7]

My DME is actually MSD81. I just pulled it out to open it to check transistors. I thought it was MSD80 for the longest time.

[BQTuning]

Previous log last month after everything was squared away with the dealer shows a perfectly healthy running and performing car

http://datazap.me/u/cbmac7/bqe40-rl-...7-18-20&solo=9

Most recent log you HPFP is falling on its face which was doing that before

http://datazap.me/u/cbmac7/misfire-c...-3-9-15&solo=9

Ive seen countless car's HPFP drop below 1000 PSI and never throw a misfire. It definitely something fueling related. the trims don't make sense of failing HPFP though.

[BQTuning]

I see why your misfiring now in that last log. AFR's are going too rich especially on E40-E45 fuel. The DME is trying to achieve AFR target but it just keeps going rich. So the DME pulls trims and reduces fuel pressure, but fuel keeps going rich which is causing your misfire.

You should be smelling a lot of fuel. Bank 2 looks like where its dumping the most fuel.

Something is failing mainly in bank 2 . The other crazy part is after the misfire fuel was kept on being dumped in bank 1 after bank 2 leaned out

You got to be smelling a lot of fuel. Back to checking injectors, plugs and coils.

[CarAbuser]

Originally Posted by BuraQ

I see why your misfiring now in that last log. AFR's are going too rich especially on E40-E45 fuel. The DME is trying to achieve AFR target but it just keeps going rich. So the DME pulls trims and reduces fuel pressure, but fuel keeps going rich which is causing your misfire.

You should be smelling a lot of fuel. Bank 2 looks like where its dumping the most fuel.

Something is failing mainly in bank 2 . The other crazy part is after the misfire fuel was kept on being dumped in bank 1 after bank 2 leaned out

You got to be smelling a lot of fuel. Back to checking injectors, plugs and coils.

If he's not smelling any fuel then do you think it could just be a bad O2 sensor on bank 2?

[BQTuning]

Originally Posted by CarAbuser

If he's not smelling any fuel then do you think it could just be a bad O2 sensor on bank 2?

If he is smelling fuel or not the O2 sensors could be another possibility

[CBMAC7]

I haven't really noticed the smell of fuel guys. My thoughts were o2 sensor as well but now that you say HPFP I wonder what it really is. It's booked to go back into the shop on Monday. I reset all adapations and had my DME out of the car because I thought it was a MSD80 but its a MSD81. Battery was also reset. Now my car as an error light "Lightining System! Stop vehcile" Any help on this would help also.