Experts Help - CSL Airbox - Violent Jerkiness and Bucking Under 2k RPM Under Load

[BMWahba]

Mine did that w the stock csl BIN and two tuners could get rid of it. It wasn’t until I went w Randy from epic that all is fixed now.

Granted at the track I’m hardly ever at 2k rpm.


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Yeah. I would need to get it on a dyno or with an AFR for Hassan to see what is going on and smoothen it out, but part of me wants to make sure there isn't a mechanical failure somewhere, or like others said, something with the section 1 pipe I'm running.

This is the exact hesitation I was always talking about when I used to mention the finnickyness of this mod. Others on the older forum had also literally described it as a bucking bronco like you just did. It wasn't till later on that I realized some people's hesitation issues were a very subtle lag in acceleration

Definitely try to source a section 1 without a crossover.
My hesitation issues were briefly solved by switching from an aftermarket sec2 with no crossover back to stock

Glad I wasn't the only one - the stock section 1 is my next test, I just need to find one locally.

I just had my airbox installed with the Kassel dme conversion and a Kassel base map.

the car fuel cut very hard under 3k in any gear especially under load. When I went to Kassel to get a dyno tune, he said the car was super lean and needed a lot of fuel down low that’s why it kept happening.

id recommend getting a tune ASAP! Don’t drive anymoe, just to get tuned that’s it.

Did you have the same type of bucking when it was lean? I'm tending to think it is way too rich when it's happening. What was your car's setup when it was doing it?

Hassan did mention that he had experience with another S54 swapped e36 which had the same problem, had the section 1 pipe with a crossover, and was able to basically smoothen out the fueling and tune it to fix the bucking that it was causing. I'm not sure if that has any pros/cons versus just swapping to a different midpipe if that is indeed the problem.

[BMWahba]

I'm not sure disconnecting the MAP rules it out. If anything, that makes me think that it's not working, as the car is behaving the same with and without it present.

Good point and something to consider, but even with the stock DME which has no MAP at all? Hassan was informing me how the car runs in pseudo alpha N when there is no MAF or MAP present.

[BMWahba]

Those are good questions. I may be misunderstanding but you tried stock dme/tune with the CSL box or with the stock airbox and it STILL bucks?
Another thing I must say if you had Kassel give you their CSL "tune" on a DME you bought from them, it will likely have CSL spec camshaft offsets, these must be changed to US offsets, this is of course assumed you have stock cams. My DME I bought from kassel had US offsets and when I sent my partial off to have someone else look at it they said it was 99% stock CSL fwiw.
I had to use Tunerpro to change the offsets from CSL to US. I wouldn't always throw a code, but it would sometimes, I think it was the intake cam would show an adaption value of 0 in Martyn's software.

Also, which location is your IAT in, stock CSL airbox or elsewhere? If you used the "US" IAT that can be relocated a bit easier it does use different scaling.

I tried the stock DME/Tune with the CSL box still installed. Same behavior. I have not yet pulled the airbox off and gone back to the stock intake, I was hoping to avoid it but I will if I can’t figure this out.

The Kassel tune I did specify to them to let them know I'm running US Spec cams, and again, when Hassan tuned it, I let him know I was running stock cams.

The IAT is located in the little brake duct tube coming from the fog light duct. I drilled a hole into the piping and installed it there right before the snorkel.

[Onefastsicilian]

I just had my airbox installed with the Kassel dme conversion and a Kassel base map.

the car fuel cut very hard under 3k in any gear especially under load. When I went to Kassel to get a dyno tune, he said the car was super lean and needed a lot of fuel down low that’s why it kept happening.

id recommend getting a tune ASAP! Don’t drive anymoe, just to get tuned that’s it.

[jet_dogg]

Mine did that w the stock csl BIN and two tuners could get rid of it. It wasn’t until I went w Randy from epic that all is fixed now.

Granted at the track I’m hardly ever at 2k rpm.


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Who were those two tuners?

[usdmej]

This is the exact hesitation I was always talking about when I used to mention the finnickyness of this mod. Others on the older forum had also literally described it as a bucking bronco like you just did. It wasn't till later on that I realized some people's hesitation issues were a very subtle lag in acceleration

Definitely try to source a section 1 without a crossover.
My hesitation issues were briefly solved by switching from an aftermarket sec2 with no crossover back to stock

[sc_tr0jan_m3]

Mine did that w the stock csl BIN and two tuners could get rid of it. It wasn’t until I went w Randy from epic that all is fixed now.

Granted at the track I’m hardly ever at 2k rpm.


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[heinzboehmer]

I'm not sure disconnecting the MAP rules it out. If anything, that makes me think that it's not working, as the car is behaving the same with and without it present.

[Cubieman]

Right, but I disconnected the map for some of the testing when I swapped to the stock DME and the same behavior, so I have ruled out the MAP entirely at this point. At least for now.

I need to get the car back to when it was running normally. All of which was before the intake. That’s what I’m failing to understand. If it was vanos related, why is it all of a sudden so much worse with the CSL intake installed, even when back on the stock DME and stock Tune?

Those are good questions. I may be misunderstanding but you tried stock dme/tune with the CSL box or with the stock airbox and it STILL bucks?
Another thing I must say if you had Kassel give you their CSL "tune" on a DME you bought from them, it will likely have CSL spec camshaft offsets, these must be changed to US offsets, this is of course assumed you have stock cams. My DME I bought from kassel had US offsets and when I sent my partial off to have someone else look at it they said it was 99% stock CSL fwiw.
I had to use Tunerpro to change the offsets from CSL to US. I wouldn't always throw a code, but it would sometimes, I think it was the intake cam would show an adaption value of 0 in Martyn's software.

Also, which location is your IAT in, stock CSL airbox or elsewhere? If you used the "US" IAT that can be relocated a bit easier it does use different scaling.

[BMWahba]

Ok, so that sounds good, I used the same pins for MAP. There was one member, jbfrancis3 who used pin 16 as IAT ground and had some erratic readings if I recall correctly but I think the consensus was pin 16 is a suitable ground for MAP/IAT.

You can use testo and see the Kassel MAP adapter voltage going up/down up/down etc. during idle as it's positioned in a TB whereas the the voltage of a MAP sensor adapter that ties into the brake boost line is smooth steady line at idle.
But once you press the gas and get the car up to ~1200RPM the Kassel MAP location's voltage smooths out so I don't think that is the issue, just food for thought. You might try the MAP adapter from member COVID-19 is all else fails.
What I just types might not be very coherent as I'm a few drinks in but I made a thread a while back in regards to this, which is likely a non-issue.

Right, but I disconnected the map for some of the testing when I swapped to the stock DME and the same behavior, so I have ruled out the MAP entirely at this point. At least for now.

I need to get the car back to when it was running normally. All of which was before the intake. That’s what I’m failing to understand. If it was vanos related, why is it all of a sudden so much worse with the CSL intake installed, even when back on the stock DME and stock Tune?

[Cubieman]

I used Pin 16 yes for the ground. 7 for power, 18 for signal.

Ok, so that sounds good, I used the same pins for MAP. There was one member, jbfrancis3 who used pin 16 as IAT ground and had some erratic readings if I recall correctly but I think the consensus was pin 16 is a suitable ground for MAP/IAT.

You can use testo and see the Kassel MAP adapter voltage going up/down up/down etc. during idle as it's positioned in a TB whereas the the voltage of a MAP sensor adapter that ties into the brake boost line is smooth steady line at idle.
But once you press the gas and get the car up to ~1200RPM the Kassel MAP location's voltage smooths out so I don't think that is the issue, just food for thought. You might try the MAP adapter from member COVID-19 is all else fails.
What I just types might not be very coherent as I'm a few drinks in but I made a thread a while back in regards to this, which is likely a non-issue.

[BMWahba]

Like Heinz just mentioned, double check your wiring, what pins did you use for IAT/MAP? I used the Turner IAT harness and I believe stock configuration = pin 17 is MAF ground which then becomes your IAT ground with the Turner harness, did you use pin 16 for MAP ground?

I used Pin 16 yes for the ground. 7 for power, 18 for signal.

[Cubieman]

Like Heinz just mentioned, double check your wiring, what pins did you use for IAT/MAP? I used the Turner IAT harness and I believe stock configuration = pin 17 is MAF ground which then becomes your IAT ground with the Turner harness, did you use pin 16 for MAP ground?

Edit: Also on the Vanos topic, make sure Atone used an OE disc, I am pretty sure he re-drills OE discs, not trying to shit talk here but the aftermarket discs have had theirs issues, mine being one example.

[BMWahba]

Yeah on mine I would have to purposefully try to get it to do it. Definitely wouldn't happen under normal driving conditions, like when rolling into the throttle from below 2k rpm.

Have you made sure your IAT and MAP are working correctly? You also said swapping in your stock DME yields the same result, so are you sure you're running CSL software on the other one?

I unplugged the MAP, no effect. So, I would presume it is not really a culprit in the behavior.

Yeah, Hassan checked the bin and it is a CSL software. He tuned it from there and same problem, so we flashed it back to the Kassel base tune.

[BMWahba]

Did you perform a VANOS test? Rebuilding the VANOS did not solve his issue, only a completely new unit from BMW. For these exchange services, it would be really nice to get your original unit back rebuilt, not another one from another car (just to eliminate variables).

Interesting man. That is really not a bright future for my wallet, and here I was thinking it'd definitely not be my vanos...

No VANOS test yet, need that software..

I spoke with a few other guys and they mentioned the solenoid. I will try to swap one out for my buddies verified working solenoid and see if that can be ruled out also.