M60 Intermittent Stall - FIXED

[gregeast]

My '93 M60 740i has recently developed an intermittent stall. Forgive me for posting on the E34 forum but this board is quite a bit more active than the E32 board.

EDIT: Issue resolved, replaced the MAF. See lucky Post #13 for full details.

Symptoms:

1) The engine dies/stalls randomly. Sometimes the car will run fine for 20 minutes, other times it will die multiple times within a few minutes. So far it has never failed to restart after dying.
2) No shudder or hesitation, it just dies, in fact the first few times I didn't realize it had actually died.
3) The tach still indicates RPM even when the motor has died (Don't know if this is significant or not?)
4) Generally goes longer before stalling on the first start of the morning, when the car is cold.

What I've done so far, with, alas no improvement:

1) Replaced crank speed sensor with OEM sensor
2) Replaced DME relay
3) Replaced Fuel Pump relay
4) Replaced fuel filters
5) Replaced fuel pump
6) Swapped DME with used DME from Ebay (transferred DUDMD chip from old to new DME. I've had the DUDMD chip in the car for 3+ years w/o issue)

Diagnostics:
1) The Check Engine Light has never come on
2) No codes found using my Oil Reset/Scan tool
3) Stomp test gave '1444', which is 'No Codes Stored'

TPS and Cam position sensors are the only things left that I can think of but research on the boards leads me to believe that the Cam Position Sensor would throw a code and that the TPS may cause a rough idle and poor running/economy but not cause the engine to die while running.

At this point I am open to any and all suggestions as to other things to test/try, any thoughts??

Thanks much.

[gregeast]

I am open to silly wild ass guesses and postulates...

[bennyg]

Intermittent without other symptoms does sound electrical. Battery/alt good? Wiring issue? Something leaking into a switch?

Could the ignition be causing it (sending a pos 1 signal even tho the key doesn't move)? Interesting the car seems to think nothing's wrong. That implicates the dme but you've swapped that already.

I had a stall issue that was tough to identify but it was fuel return related with different symptoms

Sent from my Redmi Note 3 using Tapatalk

[tomquic]

My '93 M60 740i has recently developed an intermittent stall. Forgive me for posting on the E34 forum but this board is quite a bit more active than the E32 board.

Symptoms:

1) The engine dies/stalls randomly. Sometimes the car will run fine for 20 minutes, other times it will die multiple times within a few minutes. So far it has never failed to restart after dying.
2) No shudder or hesitation, it just dies, in fact the first few times I didn't realize it had actually died.
3) The tach still indicates RPM even when the motor has died (Don't know if this is significant or not?)
4) Generally goes longer before stalling on the first start of the morning, when the car is cold.

What I've done so far, with, alas no improvement:

1) Replaced crank speed sensor with OEM sensor
2) Replaced DME relay
3) Replaced Fuel Pump relay
4) Replaced fuel filters
5) Replaced fuel pump
6) Swapped DME with used DME from Ebay (transferred DUDMD chip from old to new DME. I've had the DUDMD chip in the car for 3+ years w/o issue)

Diagnostics:
1) The Check Engine Light has never come on
2) No codes found using my Oil Reset/Scan tool
3) Stomp test gave '1444', which is 'No Codes Stored'

TPS and Cam position sensors are the only things left that I can think of but research on the boards leads me to believe that the Cam Position Sensor would throw a code and that the TPS may cause a rough idle and poor running/economy but not cause the engine to die while running.

At this point I am open to any and all suggestions as to other things to test/try, any thoughts??

Thanks much.

Sounds like the typical symptoms of a Cam Sensor on the way out ... that would be my first port of call ... seen many of these on the 7's .. esp one of that era .
I'd also check yr MAF too . ( as a supplementary ) ... but I'd go with the Cam sensor first . If you are looking for just 7 series ... also look at Timms site - www.meeknet.co.uk/E32 (http://www.meeknet.co.uk/E32) and the seven series register site in uk ... Members from all over ... www.the7seriesregister.co.uk (http://www.the7seriesregister.co.uk) only 7 series though. cheers and good luck .

Here's Timms site for the M60 cam sensor replacement ... should help .. http://www.meeknet.co.uk/E31/BMW_E31_840ci_Camshaft_Sensor_Replacement.htm

[shogun]

Cam sensors rarely fail and there are 4 of them. http://www.e38.org/e32/M60EngineSpecs.pdf
I would start with the TWO ! fusible links which might have a haircrack. One of my buddies had the same, sometimes no problem, sometimes the engine died. See my website under fixes>>>electrical >>>Photos and locations of E32 fusible links, there is a pdf to open
Fusible link A X6400 is for the power post inside the E box. It feeds only DME loads. Fusible link A is under a heatshrink in the red wire from the battery towards front/ right rear door wire funnel. Difficult to find. On A you have to concentrate.
Fusible B feeds all the Rear Power Box loads. It is usually located under the rear seat opposite of the battery in a black plastic box and can be easily seen. Just squeeze the cover open.
573591
http://www.bimmerforums.com/forum/showthread.php?1531141-Fusible-Links/page2

[gregeast]

Thanks for all the suggestions everyone.

Shogun, I'm only seeing one camshaft sensor, both in the document you linked to (good stuff btw!) and on RealOEM, are you sure there are 4?

I'll check the fusible links as well, I've been suspicious of some sort of wire break. Are the fusible links something that can be purchased as a part?

Thanks again.

[Mykk]

I'd be inclined to say the problem is in the ignition switch.

It's strange that there would be no stumbling, hesitations and then it would stall then fire right up again. Just to turn itself off as if the key were turned.

[shogun]

I am not sure, I do not know the M60 so well, so someone else has to chime in, I just refered to my link above. on page 10 is mentioned
1. Battery 17. Coolant Temperature Sensor
2. Ignition Switch 18. Oxygen Sensors (2)
3. Light Switch 19. Spark Plugs (8)
4. Instrument Cluster 20. Ignition Coils (8)
5. Engine Control Module 21. Shunt Resistor (Engine Ignition)
(DME) 22. Fuel Injectors (8)
6. CAN - Bus 23. Fuel Pressure Regulator
7. EGS Control Module 24. Twin Inline Fuel Filters
8. IHKA Control Module 25. Fuel System Liquid/Vapor
9. ABS/ASC Control Module Separator
10. Hot Film Mass Air Flow Sensor 26. Fuel Pump
11. Idle Speed Control Valve 27. Fuel Tank
12. Intake Air Temperature Sensor 28. Charcoal Canister
13. Throttle Position Sensor 29. Fuel Tank Vent Valve (Purge)
14. Camshaft Position Sensor 30. DME Relays, 1. Main Relay 2. 02
15. Knock Sensors (4) Sensors Heating, 3. Fuel Pump
16. Crankshaft Position Sensor 31. Diagnostic Plug (TXD,RXD)

The fusible links were available from BMW but usually also from online shops. The one in the black box is bolted on, so you can and must remove the bolts, because often the cracks cannot be seen as the link often breaks under the 10mm nuts. The other one is riveted, so a new one has to be bolted on with screw and nut if from aftermarket or like this one http://www.ebay.de/itm/NEW-OEM-BMW-61131382065-FUSE-BATTERY-CABLE-POSITIVE-80A-/161739387356
. example
http://www.ebay.co.uk/itm/322112261872?clk_rvr_id=1037851431439&rmvSB=true
http://www.realoem.com/bmw/enUS/showparts?id=GD83-USA-03-1993-E32-BMW-740iL&diagId=61_0656#61131382065
FUSE BATTERY CABLE POSITIVE 80A 1 61131382065 ENDED

[gregeast]

Thanks as always Shogun. I have a camshaft position sensor on order and will be looking at the fusible links in the next day or so...fingers crossed!

[gregeast]

Quick update on this: Replaced the camshaft position sensor this weekend. Car died/stalled again within a block of leaving the house. Started right up and drove home :-(

Time to get serious about the fusible links and possibly the ignition switch. I am suspecting the power supply to the DME, which would explain why no codes are getting captured.

To review, so far I've:



Replaced Crank Speed Sensor
Replaced DME Relay
Replaced Fuel Pump Relay
Replaced Fuel Pump
Replaced Fuel Filters
Swapped chip into used DME and installed in car
Replaced Camshaft Position Sensor


No codes are being thrown as indicated by my Peake Code Reader and the Stomp Test.

Sigh...

[moroza]

I'm dealing with something very similar. In my case, it failed a smoke test on the intake in a few places, all of which I patched up. One came back a while later, so I'm replacing the boot. I had previously also checked and/or replaced a bunch of sensors and the IACV, to no avail.

The tach still showing something with the engine dead is, however, weird.

[gregeast]

Thanks moroza. I replaced the MAF accordian and resealed the intake about a year ago and had it smoke tested afterwards.

While I wouldn't be surprised if I still had a small leak I don't think the way it dies is indicative of a vacuum leak. It doesn't stumble at all, it just dies, which leads me to believe that the injectors are being shut off as well as the ignition.

Hoping to have a root around for the fusible link tomorrow.

[gregeast]

SUCCESS!!!!

After 3 months of failure I am ready to declare victory.

Sytmptoms: Car would die randomly and suddenly. No shudder, no stumble, just die. Tach still indicated RPM's. No codes. Car would always restart. Sometimes it would run for several minutes, other times it would die immediately after restart. Trans Program would come on occasionally.

Here are all the things I tried/replaced without success:

· Replaced Crank Speed Sensor
· Replaced DME Relay
· Replaced Fuel Pump Relay
· Replaced Fuel Pump
· Replaced Fuel Filters
· Swapped chip into used DME and installed in car
· Replaced Camshaft Position Sensor
· Replaced ignition switch
· Replaced fusible link with 80 amp circuit breaker

In addition to swapping parts I also did some fairly extensive electrical testing with my DVM to try and understand what was happening. I confirmed constant power to the DME, even when the car died, as well as to the coils.

After extensive Google searching the only clue I found was the Trans Program indication that would come on some times. I initially assumed that this was due to low voltage from the battery since I was having to restart the car multiple times. However, in researching MAF failure modes I discovered that when the MAF dies the car goes into limp home/Trans Program mode as the transmission uses the MAF signal to determine load on the engine. I confirmed this by unplugging the MAF. The car didn't die but the Trans Program came on.

Somewhat skeptically, I ordered a new Bosch MAF from ECS, installed it and then, with my fingers and toes crossed started the car. No Trans Program and it ran and idled as well as it ever has. Went for a series of ever longer drives over the past two weeks without it dying. Finally got brave enough to take it on my hour+ commute to work two days this week, over 180 miles without issue.

Thanks for all the help and suggestions, I hope my experience and solution helps someone out someday.

Cheers!

[shogun]

Congrats, Greg, I will copy this thread for the E32 forum for further reference.