S54 EML question

[BimmerBreaker]

Started getting the EML again yesterday and escalated to full blown limp-mode, EML and CEL on every restart within a day. INPA indicated the usual shadow e-box code and pedal potentiometer again...

With 2 bad used pedal potentiometers on the shelf (a $45 investment that got me by for 7 months...) I decided to bite the bullet and buy new. Now the question is, is my car killing these pedal potentiometers? The unit I put in was pretty high mileage, maybe I just had a failure of two units? Ordered the brand new one from FCP Euro so they have a lifetime warranty but would rather not replace this part every 7 months. Hmm. Maybe an artifact of something screwy in the engine swap?

[BimmerBreaker]

FCP was pretty quick with this one, although they told me my tracking number was 9.41E+2.1 (which it most definitely was not)...
I'm a pro at getting these things installed now. I practically had it in before the postman who delivered it finished dropping off the mail for my street

Decided to spend a little extra time today though and de-pin the harness and clean the pins really good for the pedal sensor harness, I also removed the battery ground strap and cleaned it really well as well as the post for it and the engine ground strap too.





I read online that there should not be any calibration or anything required after replacing the pedal. So today I just started it after replacing it. There was no EML when I parked it that I remember (it was still somewhat intermittent) but there was also no EML on startup. Went on a drive and it didn't come back yet, it also has slightly different characteristics than it did before. It used to be razor sharp in sport mode - almost annoying so. Now its a bit more tame (maybe that is adaptions reset when battery was unplugged?). Perhaps more importantly, as long as I can remember with this car it was weird over bumps. Like at constant throttle I'd go over a bump, the bump would bump my foot and for a millisecond the throttle would be dabbed. So I got in the habit of going off-throttle just before big bumps. It was worse during turns sometimes, I assumed it was just a "feature" of DBW but when I started to notice a bump would cause an EML I started to wonder if this was related to grounds or something.

Fingers crossed. The way I look at it, you swap in a known good used MAF to diagnose a MAF if you have a code for it but aren't sure that's the problem. I wasn't 100% sure the problem was the pedal, didn't want to spend the $340 on the part without knowing it'd help, so $45 got me a known good used part that worked and helped further

[Randy Forbes]

Not so much from an I've worked on an S-54 perspective as an I've worked on process controls for decades viewpoint, but I'm inclined to think that ANY position-sensing device (aka potentiometer) needs to be told what its end-points are__0 & 100%.

I know we've been over this before, but the AL does run a calibration procedure for the both the throttle pedal and actuator.

Still not convinced that removing a battery cable clears adaptions, but I guess to prove it, I'd have to hook up AL to one of my cars, READ the adaptions (puts them all right there on the screen for you) disconnect the battery for a while and then reread them once it's powered up again...

[BimmerBreaker]

Well I don't know why exactly the pedal behavior is different, but it is. Adaptions may not have cleared but the pedal is behaving very differently.

I don't have an Autologic, I can't afford one, but if there is an INPA test or something else I can do to calibrate the pedal, I'm more than happy to do so! I was just stating that based on my research I did not think I needed any sort of calibration, there is not a lot of information out there on this topic - I ended up researching E39 M5's with similar problems since the pedal sensor part is shared with them. It made sense to me that it didn't need calibration since the linkage is what seems to set the end points of the system. The linkage has to be removed from the old pedal and put on the same exact splines of the new one.

I suppose I could at least hook up INPA and verify that at WOT the pedal is reading 100% and see what its reading through the pedal motion to make sure that its not reading 100% when im only halfway down the pedal movement...

I did find this snippet but a few people said it was jibberish. I'll try it in the meantime

Key in position two with engine off. Slowly but steadily depress accelerator until it is all the way to the floor. Turn key off. Let sit for 10 or so minutes. If that doesn't do it, repeat. Sometimes, I have had to do the foregoing, then slam the accelerator all the way to the floor and THEN turn off the key for 10 or so minutes before the PP sensor adapts.

[Randy Forbes]

I got nothin...

Abel will best be able to give you the INPA scoop, and I readily admit the AL has spoiled me (I hear the latest version isn't well received on the newest cars, but the whole company was bought some years ago and slid down several levels; the original owners bought it back and are trying to regain their reputation and marketshare. Since I have an older Blue Box and primarily use it on 1998-2002 cars, it's OUTSTANDING for me).

[BimmerBreaker]

Maybe I'll pester Abel about it in a few days. I was just having him help me a few days ago on a 650i aux-in install, I don't know how, but he linked to my laptop from his phone, while at work (probably simultaneously delivering a baby, or performing brain surgery or something) and managed to do some workaround to force my laptop to work despite having out of date drivers for that chassis car, all through his phone. So I don't want to wear out my welcome with every simpleton problem I have... I ask him for help when I'm stumped... I'll at least see what INPA says the sensor is seeing before bothering him

Maybe that adaption method works after all... I tried it... I'll also try stomping the pedal

I just had a kind of funny thought too. During these 7 months the car hasn't had the EMLs as often I had an issue with my starter and would occasionally no-start. When I had the no-start issue I'd have the key in position 2 and occasionally stomp the pedal. What if that is how its calibrated and I was accidentally calibrating my pedal every time I did this, inadvertently delaying the return of the EML? *If* that is really the calibration procedure, this is very possible

[Randy Forbes]

Stranger things have happened, and they make the best drinking stories!

I picked up on Abel's ability a while back; yes, we don't want to use him too much and force him go underground on us!

[328 Power 04]

I will look if there's a calibration procedure that can be done with the computer. I haven't been around S54s enough to see, but if Autologic can do it, INPA + Tool32 will do it... Autologic is based on Tool32 jobs, after all.

[BimmerBreaker]

It might be getting a little laggy already, hard to say for sure. I can't find any calibration procedures mentioned directly except the one I posted up above and some people say there is an INPA procedure but I can't find it... Driven about 250 miles so far, did the swap around 160400 just for reference

[BimmerBreaker]

Little update, it started getting really really laggy, so we looked at it in INPA, no shadow codes, everything was reading fine. I decided to delete the adaption values though and that actually seemed to have done the trick. We had to do that last time we installed the replacement pedal, and that pedal was fine until it failed recently.

I ordered a MAF and both CPS sensors for it thinking that the lag may have been an actual engine issue. I may just go ahead and install them anyways, they seem ok but the engine has 160K so might be needing them anyways. I'll keep the old parts, having good spares around is never a bad thing.

[BimmerBreaker]

Took the car out tonight again for the first time in awhile - throttle response was a bit laggy, but seemed mostly ok. Engine output felt a bit limited though.

Figured I'd unplug the pedal, reset the adaptions and it'd be good to go! So I stopped by my shop and fired up INPA. Pedal codes in the error memory, but no EML interestingly enough. Cleared the codes, unplugged/replugged sensor, cleared adaptions. Started car. EML. Um, thats weird? It wasn't there before. How bad is the throttle response? Oh my... NONE at ALL!!! I'm literally stranded. I had my dog with me too...

Unplugged the sensor, routed the car-side pedal harness connector out of it's little nook and down out to where I had access. Peeled away the electrical tape and voila...

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Hard to see but one of the wires came loose from the splice. I have these sweet heat-shrink connectors with a solder ring you just hit with a heat gun, couldn't find the heat gun go figure, so soldered them the old fashioned way. I am gonna re-do them in the future with the heat shrink connectors though - they have adhesive rings on either side as well which secures the connection very well. I think what happened here was the wires were run right next to the heater core which was really hot (it literally runs like, almost touching them the way this was routed). I think over time the heat melted the solder, and the connection eventually vibrated loose. I think this explains why it was intermittent and why it became worse over time. Unplugging the harness, I theorize, jostled the wires just enough to make contact and allow it to work momentarily again. I also have to postulate that it getting better after clearing adaptions was either just placebo, or it reset the system, and if the wiring happened to be good in that moment - which it seemed to be often at the start of a drive - then it would be good after resetting for a bit until the wire came loose again.

The black one was loose and the blue one came loose too. I tested it and it was fine, then routed the wire and it did the no-response EML again. Re-did the other splices on the wires, even ones that seemed ok, and suddenly - boom. No EML, razor sharp throttle response.

I hope this settles it once and for all... I think it should, seeing as how finally there was an actual concrete source of the issue found

I'm also going to test one of my old pedal potentiometers. FCP has an amazing return policy - I'll get a full refund (at least for store credit...) if I end up not needing the pedal potentiometer I bought from them. They are not normally an item that fails, and I have 3 spares now, so I'll see...

edit 4/2/19: After a lot more driving it seems this has conclusively found the issue. Lag did come back at one point, but I traced it back to a pin on the harness I knew was not making great connection. I am going to return the new pedal to FCP and hardwire in an old pedal.

[BimmerBreaker]

Fixed this once and for all a few weeks ago. I was parting an S52 roadster and removing the center console gauges when I realized the harness was the same as the pedal. I can't re-use the harness here because the pins are in different spots and I don't have a de-pinning tool for this harness. BUT... it did have a different part number on it I was able to cross-reference against an E38 part so I could order it and some pins!

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Work station set up...

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Wires being soldered to the pins

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Nerve wracking as all heck... cutting the wire for the pedal! Eek! No going back now

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Luckily I got it all wired up fine and its been perfect since. I've put about 400 miles on it just joy riding it the past few days. I did have to clear the adaptions at one point using INPA. But since then it's been perfect

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Decided to treat the car by repairing and reinstalling the CF intake. I also needed the manual intake manifold for my E36 S54 swap (that engine was from an SMG car)

So glad this is finally done!!!