e32 740i will not stop stalling. Lots replaced- can you guys weigh in? Shogun?

[bertoneguy]

Semi new to BMW, not new to fixing cars in my spare time. Last year i had an 86 e30 vert, 76 Orange 2002, Earlier this year i owned an 87 e30 (ES) for just a month, such a fun little car. I just did not fit well in the car- i'm a little too tall. I was lucky enough to get an E32 740i (203Kmi) off my wife's uncle a couple months ago. He is a mechanic....and right in front of me, ran the car out of gas. I had no idea it was low enough- it was the day i brought the trailer to his house. I don't know for sure if my stalling issues are still related. He did not tell me it was running like S***. He said it was a great car and just never drove it. It's embarrassing I haven't found the issue yet. I have ONE code; #15- ignition-circuit monitoring. I'm using the Schwaben BMW/mini/Rolls scanner from ECS.

It needed several things, and a bunch of things it did not; I am well aware these cars do not like aftermarket parts, the only aftermarket i tried was the MAF. It can stall at anytime, usually seems when shifting into gear, but also while sitting in neutral or park.. Any RPM, hot or cold. Almost always starts back up, but might die right away or stay running for a little while, it's incredibly random. I've even driven it slowly say less than 25mph for a few (5-7) minutes, then all power will be taken away, buck up and down, and eventually stall. It seems when triggered the DME is taking fuel away and stalling the car to prevent damage- which i know it's capable of. Sometimes instead of stalling, it feels like a misfire, but maybe only one cylinder- because it's not idling perfectly smooth. One issue i was aware of, was her uncle had it leaking power steering fluid profusely from the PS Fluid filter housing. That was the first thing i fixed- just needed the housing o-ring; Then i bled the PS line, but the system still cavitates and sounds like crap for 20ish minutes before the engine is warm. I'm not sure yet why the bleeding didn't make the noise go away. If you feel the PS line you can feel where the sound is coming from. Is the PS in these cars vacuum assist in addition to hydro!?

List of replaced:
MAF - aftermarket, fuel pump, crank position sensor, used DME, plugs, oil, all filters, IAC, dual fuel filters, compression test (170 on all 8), alternator rebuild, battery, fuel pressure regulator, injectors, inspected diaphragm/spring inside the PCV on the back of the intake- mint condition. Inspected air intake bellows, no tears, tried the BMW "Reset Procedure"; while i was waiting the 5 minutes during idle after reconnecting the battery- it stalled... Tap test on the new and original mafs both passed. Unplugged the throttle position sensor- big change in idle.

I can only think of pre-cat 02's, mouse chewed wires, intake gaskets? I don't know. As another heads up, sometimes it will run flawlessly during idle. It can rev to the moon and back and not cough or shudder. But then, the rough idle will start for a second and the engine just shuts off. This is what starts to make me think pre-cat 02's.... but no codes!?

Thank you guys for any and all insight and help. You can image how frustrating this is.

[chazsandiego]

Congrats on the new to you vehicle! Sorry it's not running smooth yet. I had a similar issue awhile back.

https://www.bimmerforums.com/forum/s...el-issue-fixed

I replaced a lot of parts that weren't the issue. In my case the crank position sensor ended up being the problem but the Camshaft position sensor can cause similar stalling issues.

I had another stalling issue at one point when i installed the incorrect plugs (no platinum!).

Good luck!

[shogun]

As for power steering, that is controlled speed dependent by the control module behind the speaker kick panel driver side. At the bottom of the steering gear box is a torque converter servotronic = a regulating valve for the servo power
https://www.realoem.com/bmw/enUS/sho...diagId=32_1914
There is a small metal mesh filter there which sometimes can be clogged , I have a pic on my website under fixes>>steering.
Another reason could be that the hydraulic hoses are too old and inside swollen, similar to old brake hoses.

Did you already test the fuel pump pressure and conveying volume? Old fuel pumps can die in different ways, some stop suddenly, some slowly by losing volume and pressure, others intermittent. As your fuel tank was empty it might have sucked a lot of dirt from the bottom of the tank.
740 has one fuel pump, but 2 fuel filters, and a third fuel filter in front of the suction side of the fuel pump at the bottom of the tank https://www.realoem.com/bmw/enUS/par...MW-740iL&mg=16

Did you check the fusible links? https://www.bimmerforums.com/forum/s...=fusible+links
maybe a haircrack in the fusible link which goes from the battery to the engine bay and e-box, you can test for volts inside the e-box, see page 7100-01, X6400, B+ junction post http://shark.armchair.mb.ca/~dave/BMW/e32/e32_92.pdf

[theBMWbeast]

OEM MAF

There is no other way. If it’s too pricey, I remember there being a compatible VW MAF from my m62 days, unsure of the m60.

[bertoneguy]

chaz thank you for the response. I did a test for resistance on the cam position sensor and got right around 1200 which has said to be where it should be, but who knows maybe the sensor is still bad. Your link is broken! I tried it on a few different browsers.

[bertoneguy]

Shogun thank you for all the info to go on. When i replaced the in-tank pump, i replaced both the external, dual fuel filters and what BMW calls the strainer (filter) that attaches to the bottom of the in-tank pump. I don't have a valve anywhere on the fuel rail to check pressure... I'm checking the fusible links now. I found one right next to the battery that was turned white-ish in color, but when jumped together without the link, it still stalls. Do you know where another link in the positive cable might be? The pictures on the PDF are very dark and not easy to follow. Also- just now i had the car idling for a few minutes, and this time, it did not stall until i moved the shifter into reverse- then it immediately stalled, and upon restart- stumbled, failed to start, then eventually restarted rough- Doesn't this sound like vacuum issues? Also now for the first time, I see "Trans Program" on the dash. Since it needs vacuum while idling but does not need vacuum when in gear/on the gas....right? I know the boot between the airbox and throttle body is fine. Already tried a new MAF. Big difference when MAF is unplugged..

[shogun]

first 2 pics is the fusable link which goes to engine bay, is is hidden in shrink wrap, just follow the red wire from battery towards the rear door, this is important for you in this case. 3rd pic is the fusible link which supplies power to the driver side fuse box under rear seat, supplies power to central chassis control like the GM, RM etc http://www.bimmerboard.com/forums/posts/377728/

Trans program can also be caused by too low voltage supply to the control units, check the volt at test 09 on the OBC http://bmwe32.masscom.net/johan/obc_...c_secrets.html

When you disconnect the MAF, the DME uses Limited Operating Strategy (LOS) https://www.bimmerforums.com/forum/s...ic-1-1-1-3-BMW

[theBMWbeast]

Already tried a new MAF. Big difference when MAF is unplugged..

Did you try a new aftermarket maf? If you have the original Bosch, I suggest swapping it in see what happens. What was the big difference, good or bad?

[bertoneguy]

Did you try a new aftermarket maf? If you have the original Bosch, I suggest swapping it in see what happens. What was the big difference, good or bad?

Sure did. I tried a new aftermarket, and then swapped back in my original. Both make the same amount of change in engine rpm when disconnected. The difference was big, in a bad way.

[bertoneguy]

Shogun thanks a ton for all that. I used your info to find both my links, replaced them with the same amperage (80A) fused links from Kicker (they fit perfectly, same length and terminal size). Unfortunately after starting the engine and letting it idle again, it still stalled as usual. I also found that the black rectangular harness next to the battery with about 12 or so pins has either melted a little bit, or was chewed by mice or something. When i separate the harness, all the pins look good still so it's only minorly damaged. Do you happen to know what this hardness is for? The damage is closest to the thick gauge brown wire, which made me think it was the power wire since it is ONLY melted/possibly chewed on that side. My other question is- since this car has 203K, one thing i haven't replaced yet is the cam position sensor. It is reading what it should, right around 1250ohms. Do you think i should throw one in just in case the sensor is still bad (it's original). Its one thing i haven't tried yet. OR, do you know how the car should act when disconnected- and is that even safe to try?

[shogun]

try to find that out with the ETM http://shark.armchair.mb.ca/~dave/BMW/e32/
and/or post pics, so someone might help based on pictures.
The cylinder identifaction sensor of the M60 also has 540 +/- 10% ohm (not 1250 ohm), there the Bentley manual and if I remember the shop manual are wrong http://www.bimmerboard.com/forums/posts/1072189/

The engine will probably run without working cylinder identification
Crankshaft position sensor is most important. Without working crankshaft position sensor you have problems.
If the inductive sensor/donut on the plug wire fails then it goes into gang firing, since for example the M30 engine is a semi sequential design meaning that it triggers the injectors in 2 banks of 3 every other revolution, when it goes into the gang fire, then it triggers all six at the same time every revolution but decreases the volume of fuel by 50% . At least that is known from M30, probably same with M60

[bertoneguy]

Here is that harness i was talking about Shogun. Mounted right next to the battery.

[shogun]

what are the part numbers on the female and male plug? Need your help to identify. How many pins in total? On page 7100-41 component location views there are pics of under RH side rear seat, there is a connection X260 21 pins.
Page 7000-19 says X260 21 pins below right hand side of rear seat near battery, in case that is the part, search in the ETM what purpose this X260 has http://shark.armchair.mb.ca/~dave/BMW/e32/e32_93.pdf
In any case you have to fix that part.
Maybe the electr. experts can tell you from the pic what it is.

[Timm]

Try disconnecting the CAMshaft sensor - the engine runs fine without it but goes into 'lost spark' mode where it will use a little more fuel and the power will be down - but, if it still stalls you can rule it out.

As already said, do not use aftermarket MAF's, they are the biggest cause of stalling by a large factor. You may have a faulty original MAF and have replaced it with a Chinese copy renown for causing stalling.

[shogun]

stay away from aftermarket MAF's, somebody in Germany has set up a test stand and re-adjusts the original ones and he also compared original Bosch and aftermarket ones made in China etc, here a brief translation, he talks about the MAF for the M70 engine, but the result is the same for other engines:
these replicas do not have platinum wire
• furthermore, the cleaning function is apparently not available
• These are dimensionally not clean, have a flange diameter between 69 and 69.5mm, the Bosch LMM have exactly 70mm. However, the case is solid and does not have the otherwise often existing burrs on the plastic as it is known from cheap products.
• Testing results, the replicas are clearly out of tolerance, the 3 trial parts scattered all (in contrast to the used Bosch parts) upwards, i. too much fuel is injected, especially in the higher load range. This explains also the description of some users here in the forum that a "Russing" of the engine was recognizable.
• Furthermore, I noticed that the replicas of load changes (ie when changing the accelerator pedal position) tend to produce short-term signal peaks which are not part of any case and none of the Bosch parts has been made.

To get a feeling about the deviations:
A brand-new or factory-reconditioned Bosch original air mass meter compared to a brand-new or factory-reconditioned Bosch part is the deviation in a sensationally low range of about 15-20mV, so less than 0.02V deviation.

Deviations of old / defective Bosch used parts compared to new parts as replicas
The deviations of the replicas are here about 3x as high as the deviation of the worst air mass meter from Ebay I have measured. At this point, in any case can not be advised to the replicas after this finding, as it is still much better to hope for a good used part.

diese Nachbauten haben keinen Platindraht
•weiter ist die Reinigungs- und Freibrennfunktion augenscheinlich nicht vorhanden
•diese sind maßlich auch nicht sauber, haben einen Flanschdurchmesser zwischen 69 und 69,5mm schwankend, die Bosch LMM haben genau 70mm. Das Gehäuse wirkt jedoch stabil und hat auch nicht die sonst oftmals vorhandenen Grate am Kunststoff wie man es von Billigprodukten kennt.
•Messtechnisch sind die Nachbauten deutlich außerhalb der Toleranz, die 3 Versuchsteile streuten alle (im Gegensatz zu den gebrauchten Boschteilen) nach oben, d.h. es wird zu viel Kraftstoff eingespritzt, insbesondere im höheren Lastbereich. Dies erklärt auch die Schilderung einiger User hier im Forum dass ein "Rußen" des Motors zu erkennen war.
•Weiter ist mir aufgefallen, dass die Nachbauten bei Lastwechsel (also bei Veränderung der Gaspedalstellung) dazu neigen kurzzeitige Signalausschläge (Peaks) zu erzeugen die da in jedem Fall nicht hingehören und auch keiner der Boschteile gemacht hat.

Um mal ein Gefühl zu bekommen zu den Abweichungen: Ein fabrikneuer bzw. werksüberholter Bosch original Luftmassenmesser gegenüber einem ebenfalls fabrikneuen bzw. werksüberholten Bosch Teils befindet sich die Abweichung in einem sensationell niedrigen Bereich von ca. 15-20mV, also weniger als 0,02V Abweichung.
Abweichungen alter / defekter Bosch Gebrauchtteile gegenüber Neuteile als Nachbauten
Die Abweichungen der Nachbauten sind hier ca. 3x so hoch wie die Abweichung des schlechtesten Luftmassenmesser aus Ebay den ich gemessen habe. An dieser Stelle kann jedenfalls nach dieser Erkenntnis nicht zu den Nachbauten geraten werden, da es immer noch deutlich besser ist auf ein noch gutes Gebrauchtteil zu hoffen.

these replicas do not have platinum wire
• furthermore, the cleaning and clearing function is apparently not available
• These are dimensionally not clean, have a flange diameter between 69 and 69.5mm fluctuating, the Bosch MAFs have exactly 70mm. However, the case is stable and does not have the otherwise often existing burrs on the plastic as it is known from cheap products.
• Measurements: the replicas are clearly out of tolerance, the 3 trial parts scattered all (in contrast to the used Bosch parts) upwards, i. too much fuel is injected, especially in the higher load range. This explains also the description of some users here in the forum that a "Russing" of the engine was recognizable.
• I also noticed that the replicas during load changes (ie when changing the accelerator pedal position) tend to generate short-term signal peaks that are not part of any case and that none of the Bosch parts did.

To get a feeling about the deviations:A brand-new or factory-reconditioned Bosch original air mass meter compared to a brand-new or factory-reconditioned Bosch part is the deviation in a sensationally low range of about 15-20mV, so less than 0.02V deviation.

Deviations of old / defective Bosch used parts compared to new parts as replicas
The deviations of the replicas are here about 3x as high as the deviation of the worst air mass meter from Ebay I have measured. At this point, in any case can not be advised to the replicas after this finding, as it is still much better to hope for a good used part.

[bertoneguy]

Appreciate the tip Timm. I did try that a couple weeks ago (pull cam sensor), the car still ran about 5 minutes down the road, stalled. I also have since replaced that sensor just in case; didn't help. Also, I tried an OEM Bosch MAF, didn't help. Yesterday, I started the car, let it idle without touching the throttle or gear shift. It probably idled for about 10 minutes without stalling, running perfect. Then, i revved the engine to see if it would trigger the stall, which it didn't. Then, I shifted the car into reverse - stalled. Upon restart- misfiring, running rough, stalled again. Today, upon cold start (stayed outside overnight) started up, stalled immediately. Restarted, ran fine, let me pull it into my garage. I'm finally about to spend some time fixing the x260, 21 pin harness next to the battery that Shogun sent me a PDF about. I still need to see exactly what the wires are for, in this harness. It almost seems like i have a phantom voltage/amperage issue that once the car comes out of idle and into gear, the supply to the engine, fuses, dme, something is being starved of amperage and causing misfires/limp mode of sorts and the stalling; but of course, i don't know for sure. But am very interested to see if my semi melted x260 harness is to blame or not.

Thanks again for your responses.

Shogun thank you for this detailed explanation on MAFs. I copied and saved this information for future use. Please see my last reply i just made to Timms message. Thank you very much for that PDF to find the x260 harness. I need to find out now exactly what those wires are for and if they were actually compromised in the harness or not.

[bertoneguy]

Nevermind guys - the stalling had nothing to do with the harness next to the battery. I repaired the melted wires, it didn't make a difference. I think next i need to remove the intake and do plenty of poking around. That is one thing i haven't removed yet even though i DID smoke test the engine. But, there is evidence of mice living underneath the intake so there is probably something chewed, who knows.

[Timm]

I'm not sure if you have mentioned it - but the Idle Control Valve can often be the cause of stalling. These have a lightweight armature that continually vibrates finely controlling the amount of air into the inlet manifold - it is only used when at idle (as signalled by the main throttle position sensor) - and they can get gummed up or electrically fail. So, those two things would now be at the top of my list, the ICV and the main Throttle Position Sensor....

[bertoneguy]

Yep this is in my list of replaced parts above (IAC). I'm going to show you guys some photos that I took the other night after I removed the intake. Looks like I might have found the issue.

[bertoneguy]

Yep this is in my list of replaced parts above (IAC). I'm going to show you guys some photos that I took the other night after I removed the intake. Looks like I might have found the issue.

Check out this massive stash of acorns from the mice down in Cape Cod. I don't know how long it was kept outside by the previous owner, but it must have been a while. All 4 of my knock sensors were toasty and falling apart. One port on my intake was dry like no fuel had been fired by the injector, the other 7 were fine. I'm wondering if these knock sensors were this bad, it was causing all types of fuel delivery issues, sending signals back to the DME to stop fuel to protect engine damage.

[bertoneguy]

Shogun- can't thank you enough for all of your replies. Turns out my main issue was with the knock sensors. Now, the car will only stall when i try to drive it while cold. Also, when the car is warm, when i step on it 100%, there is almost like a fuel cut situation going on that makes the car stop accelerating, and the second I left off, it is fine again. But if i floor the gas pedal, its almost like the gas is being shut off until i left off of the pedal. At least I am now on the right track, now that it can be driven when warmed up.

[shogun]

could be a problem with ABS, maybe, read here common problems http://www.bba-reman.com/gb/content/hints_and_tips/
for example:
ENGINE APPEARS TO MISFIRE OR STUMBLE INTERMITENTLY , MODELS AFFECTED: 5 Series(E34), 7 series(E32), 8 series(E31) all equipped with ACS.

FAULT: Under certain specific conditions an apparent engine misfire or bucking may occur. This is not an engine misfire.
CAUSE: Short (less than 100 milliseconds) fuel injection cut-off, as a result of MSR (engine drag torque control) regulation. This is a normal ASC function that may occur under these conditions: -The vehicle is equipped with ASC -Vehicle speed between 45 and 60 MPH -A rough road surface (e.g. potholes, railroad tracks) -Light throttle(accelerator pedal only depressed 1/8) -ASC not switched off.
SOLUTION: Replace the ASC control unit. no further diagnosis of the ABS/ASC system should be necessary.

I once had the sensor cable broken from sensor to engine bay, there are plugs from/to engine bay, they get brittle

Also check the temperature sensors for coolant

[LysanderSpooner]

If the inductive sensor/donut on the plug wire fails then it goes into gang firing, since for example the M30 engine is a semi sequential design meaning that it triggers the injectors in 2 banks of 3 every other revolution, when it goes into the gang fire, then it triggers all six at the same time every revolution but decreases the volume of fuel by 50% . At least that is known from M30, probably same with M60

That is a real brain twister... reminds me of the "big bang" two strokes near the end of the 500GP motorcycle era. I need to look into this more.

[goinstrong]

Did you spray the Bosch MAF with MAF cleaner? It is worth a try, and could be that simple. Also, spray the air intake temperature sensor with brake cleaner. (usually on the air filter box). They can affect the idle too. For me, it took away my trans failsafe mode, and in my X5, it stopped my very rough idle. Hopefully, it will help your car too!
Tim