[torrque]

Here is an event; see how rpm dips whilst I was on the gas, then I release the pedal when I feel it. It was a small event, not as bad as ones before, but I caught it on file.

https://datazap.me/u/mhainal/log-152...1&zoom=190-232

[buster84]

Originally Posted by torrque

Thanks for you suggestions. I have Rheingold, and scanned it completely with it... all modules are green, show no problems.

I also tried stage 1 from MHD and it is the same (more pronounced bucking as it obviously boosts more). I have a brand new OEM ground to the chassis, and all battery cables and Junction box have been checked; no signs of overheating or spark or anything like that... I have eliminated the injectors as being a problem by removing the injector and coil pack connector; ran like that in 5 cylinders one by one ; the stuttering is exactly the same, no difference with any of the injectors removed.

I also eliminated the DME as I said by replacing it... It is the stock tune that came with it for a N54. What I have not eliminated, is the wiring harness from the engine bay, the one connecting all sensors, injectors and coils to the DME. A couple of injectors had stray wires exposed (when I bought the car) , somebody really abused it when working on the engine. I have insulated those wires (cut, solder, shrink wrap) now, but I am thinking of buying a new wiring harness soon.
Many thanks.

First thing, i looked at the log on page 3 but its far to short at wot to see whats going on. Return the tune back to stock, do a full pull to 5.5k to 6k rpms then post the log, that is if the car let's you go that high. From what i saw on page 3 you were in the 17's for air fuel which is extremly lean, but because the rpms and log at wot is so short its hard to say why its doing that and if it continues on.

Also, use inpa to double check to make sure the injectors are coded correctly. Doesnt hurt to double check this. Also what mods are on the car if any?

[torrque]

Originally Posted by buster84

First thing, i looked at the log on page 3 but its far to short at wot to see whats going on. Return the tune back to stock, do a full pull to 5.5k to 6k rpms then post the log, that is if the car let's you go that high. From what i saw on page 3 you were in the 17's for air fuel which is extremly lean, but because the rpms and log at wot is so short its hard to say why its doing that and if it continues on.

Also, use inpa to double check to make sure the injectors are coded correctly. Doesnt hurt to double check this. Also what mods are on the car if any?

The tune has always been stock; I did a small test on stage 1, but reverted back to stock (did a backup) right away. No mods what so ever on car.
Injectors are correctly coded, I double checked (got pics of all injector numbers and spreadsheet of them). As I said, I removed them one by one; stuttering still persists with each one of them disconnected; you can feel it when she's warmed up even running bad on 5 pistons.

I can't really do WOT runs... the bucking is so severe that I am afraid I will blow the transfer case or something in drivetrain... But it happens on steady throttle on all gears, the lower the gear the more severe, as it has more torque.
I will do another run, but what you saw in there is on all of them.... Try to zoom out of that log, it shows 2 drops in RPM...

Many thanks

[buster84]

Originally Posted by torrque

The tune has always been stock; I did a small test on stage 1, but reverted back to stock (did a backup) right away. No mods what so ever on car.
Injectors are correctly coded, I double checked (got pics of all injector numbers and spreadsheet of them). As I said, I removed them one by one; stuttering still persists with each one of them disconnected; you can feel it when she's warmed up even running bad on 5 pistons.

I can't really do WOT runs... the bucking is so severe that I am afraid I will blow the transfer case or something in drivetrain... But it happens on steady throttle on all gears, the lower the gear the more severe, as it has more torque.
I will do another run, but what you saw in there is on all of them.... Try to zoom out of that log, it shows 2 drops in RPM...

Many thanks

I'd be shocked if you break the transfer case. I'm pushing 650hp and that's holding stong. If it's bucking really bad at higher rpms it's got to be a airfuel or electrical issue.

Have you done a compression test on the engine? If one of the piston were broken or something maybe that could cause it? Ive never had a blown engine before so I'm not sure on that regard. Did you ever change your vanos?

Originally Posted by torrque

Here is an event; see how rpm dips whilst I was on the gas, then I release the pedal when I feel it. It was a small event, not as bad as ones before, but I caught it on file.

https://datazap.me/u/mhainal/log-152...1&zoom=190-232

The reason why its hard to see anything happening in the log is that you release the pedel once it starts to happen, so your log is basically a mix of idle with some surging. In order to see whats actually happening you really need a good long pull without releasing the throttle.

[torrque]

Originally Posted by buster84

I'd be shocked if you break the transfer case. I'm pushing 650hp and that's holding stong. If it's bucking really bad at higher rpms it's got to be a airfuel or electrical issue.

Have you done a compression test on the engine? If one of the piston were broken or something maybe that could cause it? Ive never had a blown engine before so I'm not sure on that regard. Did you ever change your vanos?




The reason why its hard to see anything happening in the log is that you release the pedel once it starts to happen, so your log is basically a mix of idle with some surging. In order to see whats actually happening you really need a good long pull without releasing the throttle.

Will do, problem is, it does not do it as much when you hit it hard, but rather when you keep it at constant speed for some reason. So steady throttle, 4k + rpms on warm engine, it starts bucking like a wild horse. Without throwing any codes that it, which is killing me. I also think it is electrical...
Vanos is original, I cleaned the solenoids, but they don't throw any codes and apart from the stuttering; engine idles, starts, and runs perfectly. It even sounds nice, no vanos rattle, nothing.
I am getting a new oscilloscope to scope the signal on the crank angle sensor, the drop of rpm needle tells me that something is still amiss there.... After German Motorsports changed that sensor, it ran so well that they gave it back to me saying it's fixed. I needed to get on it hard on the freeway to make it shake again. From then on, it's gotten worse and worse.

Thanks a lot for the comments all.

[buster84]

Originally Posted by torrque

Will do, problem is, it does not do it as much when you hit it hard, but rather when you keep it at constant speed for some reason. So steady throttle, 4k + rpms on warm engine, it starts bucking like a wild horse. Without throwing any codes that it, which is killing me. I also think it is electrical...
Vanos is original, I cleaned the solenoids, but they don't throw any codes and apart from the stuttering; engine idles, starts, and runs perfectly. It even sounds nice, no vanos rattle, nothing.
I am getting a new oscilloscope to scope the signal on the crank angle sensor, the drop of rpm needle tells me that something is still amiss there.... After German Motorsports changed that sensor, it ran so well that they gave it back to me saying it's fixed. I needed to get on it hard on the freeway to make it shake again. From then on, it's gotten worse and worse.

Thanks a lot for the comments all.

Out of curiosity, are you for sure the bucking is actually the engine? What if all the shaking is caused the transmission or drivetrain? If it happens when your just crusiing is very odd especially with no codes. Are you still using the ebay ecu? Have you considered going back to the original ecu since it didnt fix anything after the swap? Considering that many other parts were changed after the ecu it wouldnt hurt to revert it back to test.

Maybe your issue was never the ecu, but out of pure bad luck you ended up buying a bad ecu making and you might have fixed the original problem with all the new parts but because your using a different ecu its like finding a needle in a hay stake. If replacing the ecu didnt fix it you should revert back to the oem ecu and continue your testing. At this point, you really have nothing else to loose considering how much youve already tested, but if it was me i would put the original ecu back in since the new ecu never fixed the problem anyways and thats just putting in another variable into the problem when trying to uncover the real diagnoises.

[torrque]

Originally Posted by buster84

Out of curiosity, are you for sure the bucking is actually the engine? What if all the shaking is caused the transmission or drivetrain? If it happens when your just crusiing is very odd especially with no codes. Are you still using the ebay ecu? Have you considered going back to the original ecu since it didnt fix anything after the swap? Considering that many other parts were changed after the ecu it wouldnt hurt to revert it back to test.

Maybe your issue was never the ecu, but out of pure bad luck you ended up buying a bad ecu making and you might have fixed the original problem with all the new parts but because your using a different ecu its like finding a needle in a hay stake. If replacing the ecu didnt fix it you should revert back to the oem ecu and continue your testing. At this point, you really have nothing else to loose considering how much youve already tested, but if it was me i would put the original ecu back in since the new ecu never fixed the problem anyways and thats just putting in another variable into the problem when trying to uncover the real diagnoises.

I am not sure how a manual transmission could cause my RPM's to drop though, and cause all that shake . Remember I am seeing a 2-4 V drop in battery voltage every time it shakes, so it's definitely electrical problem, somewhere...

I could swap the ECU, good idea; I would eventually go back to it though, being a MSD81, and known to have less issues... but the previous ECU also did not log any errors, so.... something tells me it's something else

[Nexus313]

Try a new wiring harness

[parksjm7]

Originally Posted by Nexus313

Try a new wiring harness

Genuinely curious - you've seen wiring harnesses go bad? If so, could you provide more details on what could go wrong there?

[torrque]

Originally Posted by parksjm7

Genuinely curious - you've seen wiring harnesses go bad? If so, could you provide more details on what could go wrong there?

It will only go bad if it's been abused, or car is very old or it's been sitting a lot in the sun or overheated... Insulation could go brittle and crack, causing shorting between wires when moved.

I am inclined to do that also, especially because I found 2 injector connectors with stray wires; obviously been abused. God knows what else is wrong with it... I would only replace the injectors and sensor wiring harness (one piece).
A short in wiring would explain my symptoms, voltage drop and engine stutter, with no codes, as DME power is also affected. I am waiting on some tools to eliminate other issues before I do that, as a new harness is just over 400 bucks.

[anorphirith]

I"m dying for you to solve this so I know what was the cause ! good luck and keep us posted either way

[buster84]

Originally Posted by torrque

It will only go bad if it's been abused, or car is very old or it's been sitting a lot in the sun or overheated... Insulation could go brittle and crack, causing shorting between wires when moved.

I am inclined to do that also, especially because I found 2 injector connectors with stray wires; obviously been abused. God knows what else is wrong with it... I would only replace the injectors and sensor wiring harness (one piece).
A short in wiring would explain my symptoms, voltage drop and engine stutter, with no codes, as DME power is also affected. I am waiting on some tools to eliminate other issues before I do that, as a new harness is just over 400 bucks.

If the wiring harness has a short you will almost always get k-can fault codes reported from the computer. If your nothing getting these codes the lines are usually good. You'd have to be extremely unlucky to have damaged wires with no codes. Since your already using reingold you'd have seen these fault codes already since that's the main program that sees these types of codes.

Your having a fueling or ignition problem wince those are the only two things that causes bucking like that so it's either the computer screwing up from defects (you'd have to have A 100% new one to rule it out) or some kind of mechanical fault with fuel or the ignition system. The last possability is very low cylinder compression for an engine on it's way out or the cylinder head is damaged where the injectors sit and now they move up and down when driving (bad injector installs will cause this)

Hopefully I'm wrong because if I'm not it'll be expensive to finally get it all fixed. I still feel like it's a computer issue or a crack in the injector, injector line or hpfp.

[MJ80.]

Edit.

[buster84]

Originally Posted by MJ80.

Didn't you say this car had been in a flood ? Replace every bit of wiring you can. I reckon a flood might affect wiring too.

If the car was flooded it's a car i would never touch. You'd literally be chasing a needle in a hay stack. The car would never run right ever again.

[torrque]

Originally Posted by buster84

If the wiring harness has a short you will almost always get k-can fault codes reported from the computer. If your nothing getting these codes the lines are usually good. You'd have to be extremely unlucky to have damaged wires with no codes. Since your already using reingold you'd have seen these fault codes already since that's the main program that sees these types of codes.

Your having a fueling or ignition problem wince those are the only two things that causes bucking like that so it's either the computer screwing up from defects (you'd have to have A 100% new one to rule it out) or some kind of mechanical fault with fuel or the ignition system. The last possability is very low cylinder compression for an engine on it's way out or the cylinder head is damaged where the injectors sit and now they move up and down when driving (bad injector installs will cause this)

Hopefully I'm wrong because if I'm not it'll be expensive to finally get it all fixed. I still feel like it's a computer issue or a crack in the injector, injector line or hpfp.

Not if the short is in the power/ground. DME will get zapped just like other components are, causing an rpm drop and a short reset; which explains lack of codes.
I am still suspect on the Crank angle sensor, I am waiting on delivery of a new Oscilloscope to scope that signal; old one I had had some very old connectors, which were causing noise in the signal so high, I couldn't tell when it was stuttering if it's from the sensor, or from my connections

I can do a cylinder compression test no worries; that is on my "to do " list. Will post soon ... Just need a spark plug adapter for now to do it.

[torrque]

Just hoping this threat of snow and crap stops in Boston, so I start taking out my baby out, the Shelby. then I can retire this shaky, rattly BMW, and split her open and work on it

[MJ80.]

Must have been thinking of another car.

[torrque]

Originally Posted by MJ80.

Must have been thinking of another car.

Sorry, no, this has never been flooded, or it doesn't show in any Carfax history reports or it's own condition.

It looks pretty good , no oil leaks, paint in very good nick, feels extremely tight; previous owner had bilstein shocks fitted not long ago, control arms are new both sides, bushing replaced , etc. Manual gearbox is a pleasure to shift, clutch is fine; it is a sport pack with logic 7 and gps, only thing missing is M sign
If I fix this darn problem it's a keeper....

[Nexus313]

Originally Posted by parksjm7

Genuinely curious - you've seen wiring harnesses go bad? If so, could you provide more details on what could go wrong there?

Not really. I suspected my cars was bad when I couldn't figure things out. But it wasn't. But it looks like OP is second guessing his harness too.

[musa]

Originally Posted by Nexus313

Not really. I suspected my cars was bad when I couldn't figure things out. But it wasn't. But it looks like OP is second guessing his harness too.

@parksjm7, did you eventually figure out what was wrong with your car? What was the issue?

[parksjm7]

Originally Posted by musa

@parksjm7, did you eventually figure out what was wrong with your car? What was the issue?

I haven't figured it out yet but all symptoms lead to vanos solenoids at the moment. will try cleaning them and see.

[torrque]

OK, been away for a while, and my wife's car battery ran out, she had to drive the beemer for a bit. She says to me it not only cuts out, but it "coughs"...

Ok, now I can replicate it standing still. You let the engine warm up, rev her to 3000 rpm's steady, and in a few seconds (10 seconds to a minute) it starts coughing , like misfiring harder and harder. I got a misfire or stutter that bad, I heard pressure coming out of intake, a big bang, and engine stalled.
Caught the event on MHD log... here it is attached.

See how RPM dropped all of sudden, then it recovered, but it never really manage to catch up, engine stalled after that. Still no errors in the DME. Sticky valves ? Could be; will take intake off soon to see how clean or dirty they are .
History said they have been cleaned, but I don't trust that, that was on my list to do as soon as it bloody warms up here in New England.

Any other ideas, I am all ears. Thanks all.


https://datazap.me/u/mhainal/log-152...a=2-9-10-11-18