Cold start problems

[Laserman2431]

Hi all. I am new to the forum and I appreciate the opportunity to access the collective genius of the members

I am having a problem. I have searched the forums and, while I have found similar issues, I have not found one that is just the same.

I bought a used 2003, Z4, 3.0 last summer. I have had no problems with it until the weather started getting colder (I live in Ohio). I should mention that I did notice higher than expected oil usage. The car had under 30,000 miles when I bought it. It has about 35,000 now.

Since it started getting colder here (maybe below 50 degrees F) it has had starting problems when I start it the first time in the morning. I bought a Peake code reader. When I first start the engine, it will start immediately and idle smoothly. After about 30 seconds, it usually hiccups but continues to run smoothly for about another 15 seconds, then the engine quits. When I check the codes at that point, it usually shows the code for rpm limit; reset. I then clear the code and restart.

Next, it will start and run smooth. If I drive off it might hiccup again and then illuminate the amber brake light, the EML light and the SES light. The engine might also stall or just quit the first time I stop at a light. Sometimes the triangle hazard icon will also appear.

During the second phase, it will show codes for electronic throttle controller and electronic throttle controller adaptation wrong.

Sometimes, It will restart then go into a mode in which the idle fluctuates between about 700 and 1300 rpm. Occasionally, it will not want to start at all but if I turn the key off and try again, it will usually start right up.

After maybe 8 start attempts in the course of 3 to 4 blocks, it will suddenly straighten out and run fine. If I clear the codes, it will remain code free for the rest of the day. I can drive it all day with no problem. Turning the engine off and back on works fine. Everything is good until the next morning when it will start over again.

I am suspecting the throttle body but I wanted to try a few free things before I take it to a dealer or start spending money on parts based on a hunch. I removed, cleaned and inspected the MAF. The MAF looked very clean when I took it out. I removed the duct that goes from the MAF to the throttle body and the ICV. The duct was clean and intact with no cracks. I removed the ICV and cleaned it. The ICV looked black on the inside but moved freely when I took it off. I then sprayed some throttle body cleaner into the throttle body. I did not touch the throttle body valve so it was closed when I sprayed the cleaner inside.

At this point, I am thinking maybe the throttle body or the engine wiring harness.

Does anyone know:
-is there a benefit to removing the throttle body for a more thorough cleaning?
-is there a way to test the throttle body?
-I think it may be a good idea to refurbish the CCV gear. Could a CCV malfunction cause the throttle body to become fouled and malfunction? Can there be a connection?
-Are there any other things I should be checking? I have read about replace VANOS seals but could a VANOS leak cause the symptoms that I described?

If anyone has had a similar problem and found a solution, please let me know.

Thank you for your help.

Update:

Today, after the initial attempts, it would start with the fluctuating idle. Codes displayed for DME checksum and Throttle adaptation. If I cleared the codes while idling, the idle would smooth out and the car would seem to run with normal power, however, the triangle caution light and the amber brake light would remain illuminated.

I think I will remove and clean the throttle body today. Does anyone have any other ideas?

Thanks.

[Laserman2431]

Update:

Today, I removed the throttle body then cleaned it. I forget t mention before that the PO told that he always laid the car up during the winters. This would suggest the possibility of fuel varnish, I guess.

The engine side of the TB did have some stuff built up on the inside. I did a pretty thorough cleaning paying special attention to the part where the shaft goes into the body. When I was done cleaning it, I put a little WD40 on the shaft pivots.

Then I sprayed CRC QD on all the electrical connectors for the TB, ICV, MAF and DISA. The job was fairly easy but the air tubes were a PITA.

When I first started the engine, it started right up and threw some codes. I then turned the engine off, cleared the codes and put the key in the run position for one minute. Then I put the key in the off position for one minute. Then I started the engine and it started fine, idled good and did not show any codes. I drove it around and all seemed good except it seemed to hiccup one time. After driving for about 20 minutes, there were still no codes.

I would like to be optimistic but I think another factor may be that I was heating the garage with a kerosene heater for the couple hours it took to clean the TB. Also, the outside temp had increased from 20 F to 40 F.

I'll try it again tomorrow morning and update the forum.

If the problem persists, I will have to consider a trip to the dealer or a new TB. does anyone have any advise on where to buy a good TB?

[sgd98]

I don't have any advice on where the problem might be. But I am curious if you have any particular reason that you think the throttle body is the cause?

[Laserman2431]

I guess I might be grasping a straws. It has consistently given throttle control and throttle adapter codes during the times when it was messing up. I have to admit that cleaning the throttle seemed like an attractive solution because it can be done with no expense.

I looking for any help in diagnosing this one before I have to surrender and take it to a dealer.

Well. I just tried to start it again after leaving it overnight. The outside temp is 19 degrees F. It started right up then after idling for about 15 seconds, it started to idle poorly then died. I checked the codes and got:
28b2 - rpm limiting : reset
27a1 - Electronic throttle controller: self check

I then cleared the codes and tried again. I then got:
2796 - electronic throttle controller: adaptation wrong
2830 - DME self test: checksum

I tried the adaptation procedure of put key in run position with the engine off for one minute then put key in off position for one minute. After that, it will not start at all. I am going to try again in a few minutes.

So I'm still leaning toward a new throttle body. It seems that my cleaning efforts had no effect.

So, I just tried it again and got a new code. This time, it was 2869 - DME self diagnostics RAM fail.

I just found this info and it seems to fit my symptoms. Anyone have any experience with this?

SI B 12 49 06
Engine Electrical Systems April 2007
Technical Service

This Service Information bulletin supersedes S.I. B12 49 06 dated
November 2006.

designates changes to this revision

SUBJECT
DME MS45 - FC28B2, 28AA, 28AC; Internal RAM Faults


MODEL
E46 M54 with MS45.1 from 9/00 to 7/06

E83 M54 with MS45.0/MS45.1 from 9/03 to 9/06

E85 M54 with MS45.0 from 10/04 to 1/06

E60 M54 with MS45.1 from 9/03 to 3/05


SITUATION
Customers may complain about a crank/no start or a rough start situation.
The "Service Engine Soon Light" or the DSC light is illuminated, and one
of the 3 scenarios may apply:

FC 28B2 "rpm limiting reset " is stored in the DME together with one, or
more of the following faults which are caused by the 28B2:

FC 28AC - "nominal torque",

FC 2796 - "throttle flap: adaptation wrong",

FC 27A1 - "throttle flap: start check",

FC 2869 - "DME self diagnostic: RAM check failed".

FC 28AA "idle speed regulator" is stored in the DME.

FC 28AC "nominal torque" is stored in the DME.

CAUSE
Fault codes 28B2, 28AA and 28AC indicate an internal DME RAM fault.

PROCEDURE
Perform the appropriate DIS/GT1 test modules for the 28B2, 28AA or 28AC.

Replace the DME if prompted by the DIS/GT1 test module results.

Important: Do not replace the throttle body for the throttle faults,
stored in conjunction with FC28B2, even when the test plan recommends to
do so.

[Shipkiller]

Do a little research on BMW Vanos O-Ring issues for the M54 engine. Very rough idling is one of the symptoms. Not saying this is it but it could be one of the issues.

Edit: Just saw your DME error. That sucks... sorry

[Laserman2431]

Update: Yesterday, I removed all connectors from the DME and sprayed them with CRC contact cleaner. I let them dry then reconnected. This was to see if there might be some slight corrosion that was causing the problems. It had no effect.

I then put a kerosene heater in the garage and pointed it toward the car with the engine compartment open and the lid of the DME box. I let the heater run for about 2 hours to check the effect of temperature on the starting problem. After a couple hours of warming, it was still difficult to start with the same symptoms listed above but it didn't seem as bad as previous days.

At this point, I think I've reached the end of my trouble shooting abilities on this one. I took it to the shop last night and asked them to leave it outside overnight then diagnose the problem in the morning. I'm just trying to brace myself for the bad news. I am now fearing that it will turn out to be a bad DME.

I've communicated with RPM motorsports in British Columbis about a replacement kit that includes reman DME, matched EWS and keys. The kit is $549 plus shipping. I will have to send my EWS and a key to them. They say the reman DME will be aligned with my VIN and include all current software updates. It seems like a pretty good deal since the dealer wants $220 just to install software updates. The reman DME includes a 1 year warranty. Has anyone had any experience with this company? Can you offer any reviews?

I found another person in Venice Beach, FL that will recondition my DME for about $650. I sent him an e-mail but I haven't heard back yet.

Does anyone have any other suggestions for DME replacement? I know I haven't determined that I need one yet but I'm just trying to get a head start on doing the research in case it turns out that way. I really don't want to pay $1800 to $2000 for a new one installed by the dealer.

So, my saga continues. I'll update later when I get the diagnosis from the dealer.

Well. I just got the call this morning. The dealer said my DME is bad and I also need a new GM. The price tag for that combo is $2343 plus tax. So I'm thinking the remanufactured kit from RPM is looking like the way to go. I plan to send them my EWS and one key on Monday. It sounds like they have a fast turn around. I hope to have everything done by the end of next week depending on my work schedule. I'll let everyone know how it turns out.

[Shipkiller]

Before you buy a new GM5 module, check out this page:
http://www.bmwgm5.com/

You can drive the car without a GM5 module, although is sucks to do so...

[Laserman2431]

Good information. Thanks for the link

[sgd98]

These two errors sure seem to point to a bad DME:
2830 - DME self test: checksum
2869 - DME self diagnostics RAM fail.
Hopefully a new or reconditioned DME will get you going again.

[Laserman2431]

These two errors sure seem to point to a bad DME:
2830 - DME self test: checksum
2869 - DME self diagnostics RAM fail.
Hopefully a new or reconditioned DME will get you going again.

That certainly makes sense. I guess the thing that bothers me is that it will run just fine after it warms up a little. I wonder how a failure in the DME can be related to temp or warmed up engine condition?

[Shipkiller]

A possible cold solder joint on the board of the DME?

[Laserman2431]

That's an interesting theory. Maybe I should open the case and inspect the board.

Well. I was just about to pull the trigger on a reman DME/EWS/keys from RPM motor sports in BC after getting confirmation from the dealer last night that my DME is defective.

I went out to try it one more time this morning and it didn't really seem to have a problem. It did hiccup one time and show the EML light. I just restarted it and the EML went away and the car ran fine from that point on. It had a 28b2 (rpm limit:reset) code which I cleared. I drove it for about ten minutes intil the H2O temp reached normal limit. Checked again and no codes.

While this isn't perfect performance, it is a huge improvement over what's been happening for the last week or two.

The outside temp was a little warmer this morning at 51 degrees F but not really that much warmer than before. I wonder if this supports shipkiller's theory of a cold solder joint? Now I wish it would turn cold again so that I could see if the outside temp will make a difference.

I guess I should just get the DME but I hate to spend $600 until I'm certain that I need to.

[Shipkiller]

Remember, H2O temperature is NOT engine temperature. Oil temperature is really engine temperature and that temperature always lags water temperature.

Man, that's a lot of temperature's.........

[Laserman2431]

So. Here's another update. I have been driving the Z4 today and it runs like a top. No problems and no codes. It has been unseasonably warm in Ohio today and it's now up to 60 degrees F. The forecast low tonight is 30 degrees. I'm eager to see how things go in the morning.

Today, I did remove the DME and I inspected the circuit board for any obvious signs of trauma. I didn't test any components but I just looked for crystalized solder joint, evidence of burnt components and swelled capacitors. Just the obvious stuff. I did spray the entire circuit board with CRC electronic parts cleaner. I also removed all connectors inside the DME box and I sprayed all of those contacts with CRC. I let everything dry before reassembly. I should mention that I did disconnect the battery before starting. I also connected the positive and negative battery terminals for 30 seconds after disconnecting the battery to make sure that any residual charges would be dissipated before I started poking around.

I do have a question. Does anyone know if the DMEs for the 2.5 and the 3.0 are interchangeable? They seem to have the same part numbers. I know they can't be swapped but I just wonder about the feasibility of buying a used DME and having one of the wizards hack it so that it can be aligned to my car.

Anyway, I'll let you know what happens tomorrow morning. I'm not expecting good news though. I just hate the idea of replacing the DME when it functions properly most of the time.

Maybe I should insulate my garage and buy a space heater. I'm not serious about that but it would probably cost a lot less than a new DME.

[sgd98]

A bad solder joint does seem like a possibility, since the problem seems to be temperature related, although I think many electronic modules these days have microcontrollers with integrated RAM and ROM (Flash memory). The reason I mention this is because a couple of the error codes seemed to indicate a problem with RAM and/or ROM. If the RAM/ROM are separate components on the circuit board then a bad connection to the microcontroller might cause such a failure. But if they are integrated into the microcontroller then the microcontroller itself is likely bad. Regardless, you could take a soldering iron and touch up each solder joint on the board. Touch the soldering iron to the joint long enough to melt the solder then let it cool and harden. You should ground yourself to the DME chassis when doing this to avoid any discharge of static electricity which can damage electronics. It is a shot in the dark but who knows, you might get lucky! You are planning to replace the DME anyway, so you don't have too much to lose.
(FYI, I tried reflowing the solder joints on the DME in my 1998 Z3 and it didn't help, but it didn't hurt either.)

[Laserman2431]

sdg98. Good points. Thanks for the advise.

Here's the latest update. This morning, I started the car. It had sat all night and the temperature was 32 degrees F this morning. It started right up but the idle seemed a little rough after about 10 seconds. Then it hiccuped and the EML light came on. I restarted it and the idle was still a little rough. I check the codes and got a 28b2 rev limit reset and a 27a1 electronic throttle controller: start check. I cleared the codes then then restarted the engine.

After it restarted, I drove around for about 20 minutes and it had no problems. After driving, It still had no codes. About an hour later, I tried it again and everything worked perfectly. Today, I had no codes related to the DME.

At this point, I wonder if the DME is bad. I would like to get this problem fixed but I guess it won't hurt to continue to drive it and check things out. I don't think I'm hurting anything at this point. I'll let you know what happens tomorrow.

Good morning Bimmer Forum.

I started the Z4 this morning. As usual, it started right up and idled smoothly for about 15 seconds then hiccuped and the EML and amber brake lights came on. I turned it off and checked the codes. Just like yesterday, I found these:

28b2 rev limit reset
27a1 electronic throttle controller: start check

I cleared the codes and tried again. After the second start, it idled rough and died. This time, the code was 2796, Electronic throttle adaptation. I cleared that code and started again. This time, it ran fine and there were no codes or other abnormalities. I drove it for about 20 minutes with no problems. I believe I could drive the car all day and never have a problem.

To review, two days ago, I disconnected the battery and connected the pos and neg bat cables remove any charge that could be lurking in capacitors. I also removed the DME and sprayed it with CRC. I also sprayed all the connectors located inside the box where the DME lives. Since doing that, I have had some throttle related codes but nothing that says anything about the DME. The current situation is also much easier to deal with in terms of getting past the daily morning ritual.

One other thing I did was to check the battery voltage. When I put it away last night after driving for about an hour, the battery read 12.6 volts. Before I started it this morning, I check and the battery was still at 12.6 volts. I guess that eliminates the possibility of a weak battery losing some potential over night in a cold garage.

At this point, I'm back to wondering about the throttle body. Is it possible that there is still a little varnish around the shaft that is just enough to cause some issues with the self test? Could the problem go away when things warm up a little?

In spite of being annoying, this condition doesn't seem to prevent me from getting around yet. I think I'll continue to see what happens next. So far, I've only spent $110 on BMW dealer diagnostic fee which indicated a defective DME that may or may not be bad. I am reluctant to just start buying parts until I have a better idea about what's going on.

I'll let you know what happens tomorrow.

[Laserman2431]

***UPDATE***

I decided to buy a used DME from a seller on Ebay. I know that's a risky proposition but I thought there could be a chance of getting a decent one from a wrecked car.

I found an Indy shop bear me that agreed to align the new/used DME for $190 plus tax.

I was reluctant to have the shop align it because if it turned out to be defective, I could get a refund from the seller but not from the shop. So, I decided to learn how to USE WinFPK to program it myself. I bought and modified a vag-com cable for $18.00 then installed the software. I will admit that it took some time to figure out how to used WinFPK and I still didn't feel confident when I tried it.

I decided to try programming my current DME while waiting for the new/used one to arrive. It was scary but I was able to program my current DME. Since I programmed my original DME, it has worked flawlessly. I admit that I have not experimented with enough to declare victory yet but I do feel encouraged at this point.

I wonder if the firmware just got corrupted somehow and just needed a fresh install? Anyway, I'll monitor the situation and report back with future updates.

So, I started the car this morning and experienced NO problems. It was nice to not have to go through the usual process required to get things working.

At this point, I think there is a good possibility that my problems were caused by some kind of problem in the firmware on the DME. So that makes me wonder what caused the problem in the first place? Was it a one time event that is unlikely to happen again or is there still a problem. I guess time will tell.

When I took the car to a dealer to be diagnosed, they determined that the DME had a problem and needed to be replaced. I understand the logic. Of course, the techs do not make the decision, they simply go with what their systems recommend. The system cannot tell the difference between a problem with the hardware or the software. If they recommend reflashing the DME and that does not fix the problem then they have wasted my time and money. Replacing the DME is a safer option because it covers the possibility of either a hardware or a software problem.

Even though it took a lot of time to figure everything out, I think it was definitely worth the trouble. If you have a laptop computer, It is possible to get the capability to program the DME with an investment of only $18 and some time.

[sgd98]

Very interesting post, Laserman. I hope that it keeps working okay for you.

My thoughts about what happened...

The firmware is presumably stored in flash memory in the DME. Flash memory typically holds data for a long time but cannot hold it forever. This is referred to as "retention time."

From the Renesas web site:

Flash memory retains data by storing a charge. The reliability of flash memory is evaluated by two main indices. One is the "data retention time". There are cases where the charge written to the flash memory can be lost a tiny amount at a time as time passes. The time that the flash memory can retain the data, measured in years, is the data retention time.

The flash memory in Renesas flash MCUs has a guaranteed data retention time of 10 years. Renesas also provides automotive flash MCU products that guarantee the long data retention time of 20 years, and these products have been widely used.

I don't know what brand/type of microcontroller (MCU) or flash memory is used in the E85 Z4 DME. But it does seem possible (but probably unusual) that after 8 years or so, one or more bits in the flash memory lost their charge and changed from a '0' to a '1'. Reprogramming the firmware restored the charge in those cells and now hopefully you are good for another 8 years.

Question: where did you get the $18 cable and what mod did you have to make? For that kind of money I am tempted to get one too just to see what I can do with it.

[Laserman2431]

I used the blue vag-com KKL 409. It was $17.00 and change including shipping.

To mod, you solder a jumper between pins 7 and 8. And change a couple parameters on the FTDI chip using ft prog software. There is moe detailed info in the diagnostic software section.

[Nickvjr]

Laserman2431,

Your symptoms are exactly what is happening to my '04 BMW 330Ci Vert. I just got the car back from the shop and they also pointed the problem being the DME and they stated that SIB 12 49 06 recommends a replacement DME. Price for this is $3-4000!!!

I have INPS, SSS/Progman and DIS V57 up and running on my laptop as I try to do my own fault code reading and car/key memory coding. But I can't for the life of me get WinKFP to work correctly; this is where I feel lost.

Can you offer and insight into your install of WinKFP and how you were able to flash your DME? I figured I could live with this cold start problem for a while but if I could solve it and save $$$ from replacing the DME that would be great!

Thank you very much for your time!

[Laserman2431]

Nickvjr. I feel your pain. It took me forever to get WinKFP working. All I can say is to keep searching the diagnostic forum and just keep working at it. I'm no computer expert so I can't really help with that.

I can give you an update. Since I reflashed my DME in early January, I have had absolutely no problems at all. I don't blame the dealer for recommending the DME and EWS solution. They just go by what their diagnostic programs tell them. I am still very happy that the $2300 problem was fixed with only a $17 cable and a bunch of my time. Good luck. Sorry I can't be more help on the WinKFP issues. Just keep at it and you will eventually get it.

BTW. I agonized about getting a heavy duty power supply to maintain electrical power during the programming. Eventually I just used a 6 amp battery charger. I had no problems.

[Laserman2431]

I just wanted to report back. It has now been approximately 9 months since the original problem and fix. To date, the problems have never returned since I reflashed the DME.

[1ragincajun]

I need to remember this.

[phlorida]

An interesting thread. My cold start issue has been similar:

This winter the car would stall several times when the ambient temperature was low. The problem went away when the engine warmed up and the engine worked normally.

This summer the problem occurred whenever the engine was cold. Rough idle and the engine would stall several times. Once the engine was warm the car performed normally.

My mechanic says that there are no error codes being stored. He is ready to replace the throttle body and I think that it is the DME.

Interestingly, yesterday my wife went to start the car and the engine would just race in idle and couldn't be driven. I pulled the ground cable off of the battery for a few minutes. The car started normally and didn't rough idle when I started the car today.

[phlorida]

I replaced the DME on my car today and all of the starting/running issues disappeared. I wish that I had done this a long time ago.

I bought my DME from RPM Motor Sports. They are the cheapest that I could find for an OEM DME. The DME and EWS took about an hour to remove (it would be twenty minutes if I had to do it again.) I sent the DME, EWS and an ignition key to RPM on Wednesday and the new, programmed DME was delivered on Friday.

The DME with overnight shipping both directions and programming was $901.