M3 VF Tune - Drivetrain Malfunction Issues

[JBruder]

I recently took my M3 out of storage to get the (CS) Hex tune applied. Pfaff tuning had some difficulty loading the file to the vehicle and notified me that the car was going into limp mode under open throttle above 4K after the tune.
If ignition is cycled the vehicle will run fine. Sometimes an engine light will appear. They found a code for low pressure system. Pressure found to be dropping to 4.5bar and not increasing to 6 bar at load. BMW dealership Installed LPFP and no change found under load however fault (drivetrain Malfunction) returned. Connections to DME highlighted low pressure sensor possibly faulted. Replaced Low pressure fuel sensor and fault reoccurred during road tests. BMW Pfaff and BMW PUMA recommend to check the rail pressure at the high-pressure rail and possible replacement of DME module.

The car was also reflashed by BMW to the latest DME software which didn't solve anything.

I recently picked up my car to take it to another dealer after the tuning covered a portion of the costs as I want to take it to another dealer in Toronto. I felt like they were just throwing parts at the car. Any recommendations on another dealership are appreciated? I’ve heard JPM Motors and JR Auto Performance are good but they haven’t seem keen to touch the car.

From my research it seems the DME may have been improperly flashed and needs to be returned to stock (Pre-hex) or has been damaged?

[M4 GTS.]

Pfaff Tuning is one of the best shops in the GTA. You should direct your questions at VF.

[Revvvm3]

I was getting a similar issue with a different tune. Swapped out my spark plugs to NGK's and it resolved the issue. Hope this helps.

[JBruder]

Thanks Rev - were you experiencing these issues with the car on a stock tune or was it still tuned?

I would expect this issue if the car is tuned but would have thought once it was returned to stock it wouldn't be an issue.

Either way I'm going to look getting them replaced in the next few days.

[Taran Rodrigues]

I'm having a similar issue with my car at 4000rpm my car completely cuts power.. and when I check logs it's my HPFP that completely shuts off.. but when I test the fuel pumps through ista they work fine.. so let me know if you manage to sort out your problem.. because I can't seem to find the problem with my car

[Revvvm3]

Originally Posted by JBruder

Thanks Rev - were you experiencing these issues with the car on a stock tune or was it still tuned?

I would expect this issue if the car is tuned but would have thought once it was returned to stock it wouldn't be an issue.

Either way I'm going to look getting them replaced in the next few days.

Once I got the error, I had posted something on the forums and another member mentioned this as a fix. Did it 24hrs later and I was up and running. Best of luck, keep us updated.

[JBruder]

Update - The dealership replaced fuel high pressure rail sensor and inspected it for leaks but nothing was found and the computer is still giving the error codes for a high pressure error. In addition it has now started to have issues with the new low pressure pumps I installed last week. There recommendation is to try and repair the DME or buy a new one. So far the difference between a new and used part in negligable and they costs roughly ~$4000 in parts and labor. Does anyone have recommendations regarding a place to repair existing DME modules?

I'm following up with Pfaff tuning the shop who originally was have difficulty installing the tune and who had the car in their possession when these issues appeared as I believe they should be paying the cost to fix the issue. They have stated they didn't bench flash the DME but VF engineering has confirmed the car would have required the DME to be benchflashed in order to be unlocked as it was running the newest software.

[JBruder]

Update - Its been 100 days without my car and it would appear Pfaff tuning and VF engineering are throwing in the towel. We've tried two used replacment DME's but can't get the car to run correctly without misfiring on banks 3&4.

When we put back in the original DME the car runs and idles properly. As I was preparing to pick up the car and take it to BMW I took the advice of this forum and asked Pfaff to change the sparks plugs and this is what we saw..brown coils and spark plugs.

We're going to swap them out coils and plugs today and see if that fixes the solution. For everyone that has experienced High pressure rail pump malfunctions after tunes I would recommend to start with plugs and coils. Whats interesting is the original DME doesn't tell us the car is misfiring and runs properly at idle (Other than going into limp mode above 4K) but the used DME won't idle smoothly and has firing issues on banks 3&4.

I will say the VF and Pfaff have been pretty solid through this situation but I'm definitely frustrating this wasn't diagnosed earlier.

Hopefully I'll have my car back tomorrow!

[BPMSport]

Both DMEs should trigger the same faults if the hardware and software is correct in them. Clones shouldn't act differently. There must be some difference in hardware or software between the two control units if there is different behavior. Good luck with resolving the situation.

[JBruder]

Thanks BPM - that's what I'm thinking as well.

Today we tested the original DME with the new coils and spark plugs and the problem continues. Low pressure fuel maintains, rail pressure drops from 3500psi to 53psi when at 5000rpm. Nothing specific related to cyl 3 & 4 or triggered in the misfire counter while logging.

Nik from VF also reached out other dealers to see if they have seen an issue similar based on the plugs we pulled and thought is maybe leaking inside the cooler. However, we pressure tested that charge cooler and its all good.

See the charts below ( shows low pressure command vs supply and command vs supply) and error below.

I think both VF, Pfaff, and myself are running out of ideas here. We're going to try the used cloned DME tomorrow with the new coils and plugs but if that doesn't work we might have to investigate replacing the HPFP.

[JBruder]

We think the original DME is faulty and the new cloned DME is working correctly.

It is likely the car's injectors need to be replaced in cylinder 3&4. Do people know if the injectors need to be coded to the car or if you use the base value that is pre-programmed in the car and the DME does the rest ?

[JBruder]

VF has recommended to check the Injectors because the vehicle is firing so badly on this (Used cloned DME).

At this point I think the car needs to go back to a dealership to see if this misfire can be solved and if that can't be fixed we need to put a brand new DME in the car to be sure.

Anyone have thoughts?

[JBruder]

We'll I think we're getting close to solving this issue.

Dealership has replaced Injectors and it's now shorting / causing issues with the cloned DME. The Dealership has confirmed this has happened before for them and the vehicle will require a brand new DME. In the past BMW has covered this replacement but I should hear back in the next day or so if they will do so this time around.

In total we've spent just over ~$10K+ in parts and some labor diagnosing this issue ( not including all the labour that went into diagnosing this problem or replacing with cloned DME). We've replaced the faulty injectors (2), spark plugs and coils (6), low pressure fuel pump and sensors, and the car will have gone through 3 DME's!

Given that I've had numerous previous mechanical issues totaling $35K with the car during my fours years of ownership most covered by warranty (including full transmission replacement) I think I'm going to have to sell this vehicle after its fixed

[chewbakam4]

This is crazy. I’d be so lost with all this hope you fix it soon

[coldsteelrain]

Damn
That sucks and I agree I would probably sell it as well once you get it fixed. You would be at a big loss but sometimes it's just better to move on to something else.

[MR RIZK]

Sell it and buy a lotus. Least you know it is designed to fall apart.

But seriously kudos for sticking with it and hopefully you find an answer cheaply soon.

[JBruder]

BMW has agreed to cover the new DME at a cost of ($4K).

Hopefully a new DME fixes all the issues but everything is back ordered and will take 2-3 weeks. I'll update everyone once I hear back.

On another note, what car should I trade this in for? Budget is ~$80K CAD.

[Taran Rodrigues]

JBruder I've sent you a pm I think i'm having the exact same issue as you, and we battling to sort this issue out and would love to know if the new dme fixed the car

Thanks

[JBruder]

Looking for any suggestions. But as of last week the dealer called and informed me that the DME was installed along with new injectors and car was running well.

As soon as I picked up the car and made it onto the on-ramp the car gave me a drive train malfunction similar to before. The issues happens almost under WOT above 5KM or under 3/4 load in higher gears.

To date BMW replaced the DME, injectors (numbers 3/4), spark plugs, and coils, high and low pressure sensors, and low pressure pump We also completed a pressure test to see if any coolant is leaking into the car from the radiator and overall system but it came back with no issues.

The only error we're getting from the car now is a catalytic converter integrity code. Once I get the exact code I'll post it to the group. I'm picking up the car later today and will drive it for a bit but not sure where to go next. Possibly check the manifold, head gasket, or HPFP?

Does anyone have any ideas!?

[Commanderwiggin]

Would need to see a datalog of a pull where this problem is clear/not active at the start of the pull and then DTML appears during pull...otherwise anyone replying in this thread is grasping at straws.

Upon reading this full thread, the first post mentioned the LPFP not reaching target of 6bar and falling to 4.5bar. There has been no mention of EKP diagnosis or replacement. The LPFP is a brushless variable frequency drive and the EKP controls the speed/modes of the LPFP. So *If* the low pressure fuel system is the culprit, there is no mention of the diagnosis of this key part. I also wouldn't hold my breath that this is the issue since I've seen partial logs where this low pressure fuel circuit will drop suddenly on a quick load change; however quickly comes back up to 6bar target. Either way it's all pointless without a log.

[EvaaWilli]

I also changed my spark plugs to NGK, and this solved the problem.

[JBruder]

I am still receiving a drive train error that no one has been able to solve (2 Dealerships and 2 Independents). After all our fixes we are getting a single code "catalytic converter protection due to insufficiently low pressure in high pressure fuel system". Will confirm exact error code tomorrow.

Dealership and BMW PUMA are recommending replacement of both HPFP at a cost of $8K. Given my service history and issues with this care the dealership has requested BMW Canada to help cover the costs but I'm not holding my breath. At this point it appears they're just throwing parts at the car.

As of today all the tests show the car is running at full pressure under under load and the EKP analysis has not shown any issues.

I"m thinking the issue is a leaking coolant or air charge cooler but when we pressure tested the system the dealership couldn't find any leaks.I might take the car for a few weeks and drive it around to see if the coolant drops.

I'm out of ideas but if anyone has any recommendations it would be much appreciated. At this point I'm going to have to trade in the vehicle although I desperately don't want to!