Ignition activation DTC issue solved, this was a weird one

[nonturbodan]

Last weekend I wrapped up an M52TUB28 install into my 03 325i. It fired right up and was running well. Once the lifters primed and the valvetrain quieted down I plugged in the scan tool to check for DTC's. There was no check engine light but you never know. Lots of things were disturbed and I wouldn't be surprised to have left something unplugged or disconnected. I was surprised to find DTC's for every cylinder, ignition activation, and a DTC for ignition current measurement on multiple cylinders. They came right back after clearing.

The coil ground wire was installed, as was the ground strap on the engine mount bracket to the frame rail. The engine was running great, so clearly the coils were firing. These coils and this harness never exhibited any issues on the previous engine so I had no reason to suspect a problem there. I did pop the ignition wire rail open and test the shunt resistor in the coil ground circuit. With the ground wire installed, it read 0 ohms across the shunt resistor. With the coil ground wire disconnected it read 238 ohms, indicating a short to ground between the resistor and the other end of the coil ground wire. The ETM indicates that the brown coil ground wire originates at pin 2 of each coil and all six splice together and run to ground through the shunt resistor. The entire ground portion of that circuit is on the valve cover.

Looking at the old M54 and the M52TU in the car I noticed that the M54 plug tubes in the head are machined visibly larger than the M52TU. The M52TU uses the early style coils with the long boots and the M54 uses the pencil style coils like every BMW to the present. Even though the part numbers cross over between the M52TU and the M54 heads, there is at least one difference in that regard. Due to a slight variation in tolerances, the valve cover was slightly offset over the spark plug tubes which allowed the coils to contact the cylinder head. Apparently this contact was providing a ground path for the secondary circuit of the coil other than the shunt resistor. I wrapped the metal portion of the coils with one layer of laser jet paper secured with a strip of masking tape and reinstalled them, which was slightly difficult due to the contact between the coil and the plug tube. Luckily the paper stayed in place and as I was relieved the find out the DTC's were gone and have not returned.

The DME was not attempting to correct fuel trims until these DTC's were resolved so I had to fix the issue. The car runs better with additive and multiplicative trims functioning normally.

I did find a few threads about this issue but none with any resolution. It is a rare problem. You won't likely see it unless you try to install M54 coils into an M52TU or perhaps if the valve cover is removed and replaced for a valve cover gasket. The bolt grommets have a self centering effect which should prevent any displacement but I suppose it is possible. The coils are a tight fit, it doesn't take much. Another solution is to replace the metal coils with later style coils from an E90 or many other models which are curiously rubber coated. Rather than spend $60 for a set of used coils I opted to try the paper wrap and it worked great. Hopefully that helps somebody. One of the threads I found had a guy in it that had replaced his DME which of course didn't fix the problem. Don't do that.

[MIKYZZ4]

Replacing with a new proper set of coils is still the long-term solution,
as basically you applied a band aid to function in an emergency or for the short-term.

[nonturbodan]

Function was good before. If I didn't have a scan tool I would not have known I had DTC's, no check engine light. I believe these coils were replaced in 2005 or 2006 going by the date code. There was a recall on them and I believe these are the newer style coils. Sucks that they didn't replace them with a proper set back then when it was free.

Next time I feel like spending $60 I'll get a set of e90 coils. I'll keep these as spares for my wife's car.

[randy72877]

Why not just use the m52tu coils, valve cover and ignition harness? The old style bolt in coils are better than the new push in ones which seem to fail more. My 01 330i has all of the original coils with new boots. New coils don't have replaceable boots. I think you need to move a few terminals in the dme connector similar to what you would do to install m56 valve cover on m54. Wiring diagrams would show difference. An ms43 ignition harness (01-02) may be another option if it is not the same as ms42 that you can find at a junkyard for a few bucks. Are you using the original ms45 dme, throttle, injectors ect on the m52tu?

Sent from my SAMSUNG-SM-G870A using Tapatalk

[nonturbodan]

I have the coils and valve cover the M52TU came with and I have a ignition harness on the way, that was plan B. I believe the early style coils and harness would require splicing or at least rearrangement of pins at the DME connector. I probably won't bother going any further with that. I used to have an e39 528i with the early coils and I had a few fail. One dropped out, dead cylinder, another failed in a way that would only manifest itself as a slight miss under transitional throttle movements. No DTC's on that second one which surprised me.

I am using the original 03 325i DME and throttle body. Don't know what hardware version the DME is. I had previously installed an M54B30 intake on the B25 just to see what it would do and I carried that over to the B28. Was originally running the stock 2.5/2.8 injectors on the B25 but I installed the 3.0 injectors later on as it was running up to about +11% on the multiplicative adaptation with the B30 intake and B25 injectors. Now it's in the -6-8% range. I think I had a dirty injector or two in the B25 injectors I was using originally, a good set would probably be most suitable. Either that or I install a B30 throttle body, air boot, MAF and airbox. That might get those adaptations right where they need to be. As it is it runs good though, the B25 software is fine.

[vasuonline]

Hi

I stumbled upon your thread because I have the same errors as you described in the thread. See attached pic.

I swapped my engine M54 2.2 litre to a low mileage M54 2.2 litre engine to avoid rebuilding my old high mileage engine.

I cannot fix these errors every time I reset DME and after I press throttle, it would return.

I am running on new sets of Delphi pencil type coil packs.

Your conclusion of that valve cover is offset and the coil pack is touching the cylinder head somehow or producing more spark on the coil pack body that interferes and finds a ground with cylinder head..

Your temp solution was a insulation paper to cover the coil from body to toe ( I guess) while installing the coil for each cylinder. Understood that.

You are also referring to two different coil types. A) old bosch style b) new pencil type.

I have replaced my old bosch with new pencil type now and I have these errors ever since.

So your recommendation is to use the original Bosch rubber type ones?

Appreciate your answer as this is driving me nuts and even the BMW dealership has given up.

[nonturbodan]

If your coils have a metal casing they may be grounding out to the head casting. Earlier M52TU and possibly M54 cylinder heads have smaller diameter spark plug tubes machined into the head and you can have issues with the later coils in the early heads. You may also have an unfavorable set of tolerances between the head and valve cover. In any case, if you have the metal casing around the body of the coil it will, as I found out, ground out the ignition monitoring circuit. Instead of grounding through the harness and the 5000 ohm shunt resistor it shorts directly to ground through the head and pisses off the DME.

Many newer models use the same coils with a rubber coating. E90 coils for example. Same part but with a neat coating of insulation.

[vasuonline]

Hi,

I changed my 2year old delphi to the black bosch coils today.

There was still no improvement and car is still sluggish.

Generally it runs smoother on cold start every morning but once car reaches operating temperature that's when car feels like you have to throttle harder to get the same amount of torque.

Then once you hook IN PA, you get these 7 error codes. Would you suspect the shunt resistor harness itself in this case because I haven't checked it yet and I saw the sleeve of the wiring harness is damaged due to age.
Or would you suspect the crankshaft position sensor that was carried out from the engine swap?

Guidance appreciated.

[nonturbodan]

If it is unhappy with the crank sensor I would expect a DTC specifically for that.

Check your ground points on the valve cover as well as the grounds from the engine to the chassis. The harness could be the cause but I don't know if I've ever seen one that was bad. What you should do at this point is test the harness at each coil. There are three pins on the pencil type coils. Pin 1 at each coil connector goes to the DME, pin 2 at each coil goes to ground through the 240 ohm shunt resistor and pin 3 is switched 12 volt power.

You know the coils are operating since the car runs, so pins 1 and 3 are working normally. You should have 240 ohms of resistance between pin 2 at each coil connector and ground. In my case I had a short to ground between at least one coil and the head, so I had zero ohms resistance instead of 240 which interrupts the ignition monitoring functionality. If your harness checks out I would make sure all of the grounds are correctly installed and secure. The circuit is very simple and if the problem was not present before it is almost certainly something that happened during the engine swap. Ground points are easy to miss.

[bobinyelm]

This is a problem I have been dealing with myself.

2003 325i with the M54 engine.

Had numerous cylinders with misfires mixed in with DME Activation codes for some of the cylinders. Coils would fire fine at times, and not others.

I replaced all six, only to find I got a set with probably 3 bad coils. I say "probably" because despite trying to create 6 good ones from the 12 I had in hand, at times even coils I thought were good would be fine, and then the car would almost strand me after it warmed up by driving, and wouldn't idle.

I got 6 new ones that finally seem to be doing OK except ALL of them show "DME Activation" though NO misfires. Sometimes I can get only a trip or two w/o setting DME Activation codes, despite wrapping ALL of them with high temp insulating tape over the complete metal barrel. I tried previously wrapping the metal portions of the old coils showing that code with paper and tape, and it didn't help misfires, but reduced the DME Activation codes. A tech friend shared he has done that with success.

The car presently runs perfectly with the activation codes (the CEL is OFF).

A friend has one coil in his vehicle that shows DME Activation, then a misfire where the DME apparently is shutting off that injector as a safety precaution. If he resets the activation code, the cylinder functions normally (no shaking/misfire) until the DME Activation comes on again, shutting down the cylinder.

This is completely different than my experience where the cylinders operate fine, yet st the DME Activation DTC, so I am not exactly sure WHAT DME Activation means or causes.

Not that this is with M54 engines, and not M52 that supposedly have smaller spark well bores.

Bob

[MIKYZZ4]

WHAT ARE THE ACTUAL CODES ALONG WITH DEFINITIONS OF EACH ,PLEASE !
Help us to help you.
PS-along with what scan tool displaying said codes.

[bmw2fix]

nonturbodan........What a great ``job of sticking with it....You have made MY day...and most likely a few of my customers will be really happy...Your find in this post hopefully has solved many an ongoing problem...
I recently experienced this situation AGAIN on another car....Cylinder activation codes...7 of them that you can't clear...
Can elaborate later if needed..... but replacing Delphi Coils (metal shielding) with Bosch coils ....last three digits of BOSCH part number is 470... cured the problem of not being able to clear codes...First time in months and a few other cars...years...of seeing those codes...Driven both a hundred miles...no codes in either DME..
We have experienced this a few times in the last 15 years.....but long story short....Autologic Assist Plus, Autoland and Snap on solus SCAN TOOLS with European package read all these codes on good driving cars. We have ISTA but saw no need to try that ..(GT1 buried in obsolete drawer).. After replacing the Delphi metal shielded coils with Bosch ones with "rubber" insulation...., we were able to clear up two cars.... both 2003 m54 motor cars.. Both Were 325i..but I'm not sure it would not happen in 3 liter cars..
We use the Delphi on most later BMWS...meaning the N series engines ( I think they are the BEST in most situations)...ON lots of the earlier cars with pencil coils..new Bosch coils right out of the box were no good so we avoided them.....It started with the ones we put on VW's....They really had a quality control problem..DIY people also be warned that the offsets of the pins don't really allow you to use the "wrong " coil...but some people figure out a way around that....Exchange the clips....have fought that battle as well...Delphi coils are still my choice BUT...I've learned from this...Good thing we keep a few sets of both brand...they are not expensive anymore..
Anyone trying to trouble shoot misfires needs to be warned....buy good coils....not best deals (China) and certainly not used unless you heard the car run that they came off of...Of course you need a scan tool..even a cheap one is better than nothing..
THANK YOU AGAIN.........This was puzzling a few of us....and SO FAR we have not seen codes return on two cars ....only been two days BUT...if the problem comes back, I'll update....
Makes me wonder about the few cars a few years ago we worked on...they seem to run OK showing those codes....but I do not think they can accurately be read on any scan tool if those 7 codes will not clear...
Its been a year since you posted that SOLVED....but it is nice to hear when you helped someone...
Kind of like door lock actuators in e46 cars draining battery in three days>>>>
Happy motoring...

[Machbuffet]

nonturbodan........What a great ``job of sticking with it....You have made MY day...and most likely a few of my customers will be really happy...Your find in this post hopefully has solved many an ongoing problem...
I recently experienced this situation AGAIN on another car....Cylinder activation codes...7 of them that you can't clear...
Can elaborate later if needed..... but replacing Delphi Coils (metal shielding) with Bosch coils ....last three digits of BOSCH part number is 470... cured the problem of not being able to clear codes...First time in months and a few other cars...years...of seeing those codes...Driven both a hundred miles...no codes in either DME..
We have experienced this a few times in the last 15 years.....but long story short....Autologic Assist Plus, Autoland and Snap on solus SCAN TOOLS with European package read all these codes on good driving cars. We have ISTA but saw no need to try that ..(GT1 buried in obsolete drawer).. After replacing the Delphi metal shielded coils with Bosch ones with "rubber" insulation...., we were able to clear up two cars.... both 2003 m54 motor cars.. Both Were 325i..but I'm not sure it would not happen in 3 liter cars..
We use the Delphi on most later BMWS...meaning the N series engines ( I think they are the BEST in most situations)...ON lots of the earlier cars with pencil coils..new Bosch coils right out of the box were no good so we avoided them.....It started with the ones we put on VW's....They really had a quality control problem..DIY people also be warned that the offsets of the pins don't really allow you to use the "wrong " coil...but some people figure out a way around that....Exchange the clips....have fought that battle as well...Delphi coils are still my choice BUT...I've learned from this...Good thing we keep a few sets of both brand...they are not expensive anymore..
Anyone trying to trouble shoot misfires needs to be warned....buy good coils....not best deals (China) and certainly not used unless you heard the car run that they came off of...Of course you need a scan tool..even a cheap one is better than nothing..
THANK YOU AGAIN.........This was puzzling a few of us....and SO FAR we have not seen codes return on two cars ....only been two days BUT...if the problem comes back, I'll update....
Makes me wonder about the few cars a few years ago we worked on...they seem to run OK showing those codes....but I do not think they can accurately be read on any scan tool if those 7 codes will not clear...
Its been a year since you posted that SOLVED....but it is nice to hear when you helped someone...
Kind of like door lock actuators in e46 cars draining battery in three days>>>>
Happy motoring...

Hi guys
i have this very issue and was looking at using the later Bosch coils (ending 470) for my 2005 M54 330ci.
But, some forum users are saying they don’t fit, keyed differently etc. have you used these in M54 engines and do you have to use a fix to make them fit?
thanks very much in advance

[vasuonline]

If your coils have a metal casing they may be grounding out to the head casting. Earlier M52TU and possibly M54 cylinder heads have smaller diameter spark plug tubes machined into the head and you can have issues with the later coils in the early heads. You may also have an unfavorable set of tolerances between the head and valve cover. In any case, if you have the metal casing around the body of the coil it will, as I found out, ground out the ignition monitoring circuit. Instead of grounding through the harness and the 5000 ohm shunt resistor it shorts directly to ground through the head and pisses off the DME.

Many newer models use the same coils with a rubber coating. E90 coils for example. Same part but with a neat coating of insulation.

"

Hi Nonturbodan,

I see that my DME is happy with Bosch coils with rubber insulation from head to toe.

It doesn't like the Delphi coils for some reason and you could be right about shorting with cyli der sleeve instead of short to ground

But haven't you noticed that the car runs better with delphi while slightly sluggish with Bosch? It's not noticeable unless you are a caraholic who picks up on every bit of imperfection.

I even bought BMW Original Delphis by paying a premium and still had those DME activation codes on all cylinders together with Ignition measurement errors.

Today after few years of trying replacing DME, I am going to try your paper wrap method.

In 2019, To be honest, I tried using a simple masking tape directly wrapped on the delphi metal body of the coil pack, and it didn't work still had those errors.

But i revived this error from the dead when my mechanic suggested rece try to buy BMW Original coil packs and that again turned out to be Delphi metal coil pack in a BMW box.

Since I have paid for it and its sitting in my M54 I will try your method of laser jet paper and mask tape. I will report back my findings in 2 days.

Have you managed to keep those errors off with your experimental paper wrapping approach for many years without them returning ever again?

I didnt check the fuel trims to verify whether there is DMe fuel trim correction on the multiplicative side. I will check that too tomorrow.

But car runs really fine without any CEL or engine vibration with Delphi, infact runs better on Delphi.