S50B32 Missfire & surge at 3000rpm & rev counter fluctuating

[Dean M3]

Hi guys , we are having endless issues with a friends M3 were the revcounter goes crazy at exactly 3000rpm and causes the car to bog & jerk aswell as missfire at times , it does it especially when its cold , when the car warms up it doesnt do it all the time , we have changed the vanos solenoids , change the MAF ,changed the cam sensors aswell as crank angle sensor , swapped the coils around, put in new O2 sensors & changed the plugs

It seems to lose spark when the rev counter does that

we are now out of options :bangdesk:
I have attached a video clip to see what happens but u may not hear the bog & surge
any help on this is apreciated

[video=youtube]http://i.ytimg.com/vi/RNqoJGFCNYk/1.jpg[/video]

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sorry here is the attached video

http://www.youtube.com/watch?
v=RNqoJGFCNYk&feature=player_detailpage

 

[osiris]

Hmmm this happened to my german spec and after 7 months of trying to fix it I got rid of the car! I changed all the same things you just mentioned, My car seemed to over fuel and would start bogging and cut out.

Maybe take the car to Gizmo to have a look at? although he is in jhb...not sure where you are.

 

[ClassicB]

You ruled out many of the common causes, but are you sure it is spark causing the problem?

Have you checked the fuel pump?

 

[wikk3d88]

fuel pump?

 

[Dean M3]

Thanks for the replies im Durban so going to Gizmo is not an option
im not sure if its spark, im just assuming lol
I have put in a new fuel pump also
It also doesnt pick up much on diagnostics as whatever fault codes it did throw i have attended to , so now we out of options

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are you guys able to view the video ? im not sure if i have attached it correctly

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http://i3.ytimg.com/vi/RNqoJGFCNYk/mqdefault.jpg

 

[calypso]

I had similar with cracked spark plugs.

 

[Sheldon13]

link for video

 

[Dean M3]

I had similar with cracked spark plugs.

what has me puzzled is what causes the rev counter to fluctuate as thats the only time its starts giving issues

 

[Ozelator]

i dont know much about cars, but whats the chance of a faulty chip...

 

[ClassicB]

How did you swap coil packs.

Seeing as you have the same car, why dont you remove yours and swap? all 6. Maybe more than one faulty and you just swopping them around

I cant view the video at work, so tell me what happens after 3000rpm?

 

[Dean M3]

i dont know much about cars, but whats the chance of a faulty chip...

as in performance chip ? if so the car has no chip or software of any sort

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How did you swap coil packs.

Seeing as you have the same car, why dont you remove yours and swap? all 6. Maybe more than one faulty and you just swopping them around

I cant view the video at work, so tell me what happens after 3000rpm?

i swapped from mine and from a complete motor that i have standing in my garage .... at around 3000rpm the rev counter starts jumping all over the place , sometimes way past 8500rpm but if u keep below 2500-3000rpm its fine

 

[ClassicB]

Sounds like crank sensor from your description, but you changed that already.

I would do a compression test next, if you havent done that

 

[abm333]

Sounds like crank sensor from your description, but you changed that already.

I would do a compression test next, if you havent done that

i had the same problem, unplugged the unichip, and it dint ever come back. Also check your earth cables!

 

[Frany]

Sounds like a faulty ignition MOSFET.... try getting hold of a performance chip that bypasses the EWS then swap out the entire ECU with another one with the chip installed, If your problems are resolved it’s either the ignition outputs that are fried or the original chip’s maps are corrupted. Can’t hurt checking if you've tried everything else.

 

[Dean M3]

Sounds like crank sensor from your description, but you changed that already.

I would do a compression test next, if you havent done that

i had the same problem, unplugged the unichip, and it dint ever come back. Also check your earth cables!

no unichip , but will check earth cables

 

[wikk3d88]

my 2cents : check both electrical/spark and fuel components in a systematic manner

Otherwise you're taking potshots in the dark

 

[calypso]

Sounds like a faulty ignition MOSFET.... try getting hold of a performance chip that bypasses the EWS then swap out the entire ECU with another one with the chip installed, If your problems are resolved it’s either the ignition outputs that are fried or the original chip’s maps are corrupted. Can’t hurt checking if you've tried everything else.

Suddenly everyone in the room gets the "what's that smell?" look.

 

[Fordkoppie]

Also check your earth cables!

I was thinking the same thing.
I once had a car did the same thing with the Rev counter and spluttering and it turned out to be something as stupid as dirty battery terminals

 

[Julz]

Check for Vacum leaks aswell.I had a similar problem where the revs where fluctating.I ended up replacing the entire intake and it was fine again.I would suggest Googling these symptoms as much as you can,I'm shure somebody out there has experienced the same or something similar.
Check out your ECU box and make shure I'd didn't sustain water damage with all this rain we've been getting.
Don't forget to trace the harness and check for any damage

 

[hoosain]

+1 on the computer box