Will Other Types of MAF's Work in an e34? - solved

[jehu]

I am seeing MAF prices for Bosch replacement MAF's about twice what I last paid.

I see others which appear to fit the application yet some are described as Platinum Wire or Magnetic Induction ..

Has anyone used anything other than the Hot Film style sensor for these cars?


these guys are really going for the jugular.

https://www.ecstuning.com/b-genuine-...f/13621702078/

[shogun]

Bosch, VDO, Siemens vs China Made MAF copies:
Here's what I have heard from a Bosch electronic engineer when we discussed about the M70 MAF: the HLM (hot-wire MAF, among others also for M70) are repaired/remanufactured in a Goettingen/GER Bosch location. Here for the repair new platinum wires are installed. To my knowledge, this is not done in any outside workshops, but it is a Bosch-internal refurbishment process. I would advise against the cheap copies from eBay for 60, - € or so. Samples of these so-called "repro" parts we receive often in our quality department. The parts only look the same externally (even partly with Bosch lettering and part number). In most cases, the characteristics is far different from that output by a original Bosch MAF. In the best case, you "buy" a higher fuel consumption, in the worst case, it leads to further damage -for example, due to too lean mixture- of the engine.

[fo3]

I am seeing MAF prices for Bosch replacement MAF's about twice what I last paid.

I see others which appear to fit the application yet some are described as Platinum Wire or Magnetic Induction ..

Has anyone used anything other than the Hot Film style sensor for these cars?


these guys are really going for the jugular.

https://www.ecstuning.com/b-genuine-...f/13621702078/

That's OEM BMW genuine/dealer price. Bosch price from FCP is almost half that https://www.fcpeuro.com/products/bmw...ter-0280217800

[The Chauffeur]

That's OEM BMW genuine/dealer price. Bosch price from FCP is almost half that https://www.fcpeuro.com/products/bmw...ter-0280217800

And don't forget the lifetime warranty! Also, be glad you don't have an M50nv...

[fo3]

Yeah, I didn't want to go there...
Look on the bright side, if our MAF was bad we probably wouldn't even notice E: off topic rb swap stuff.

[eddycooper]

The Bosch unit is even cheaper on RockAuto and Amazon - $190. I'd consider this a pretty good price for a new MAF sensor.

Just be glad you're not shopping for a MAF for an M5...

[fo3]

You'd want to be careful if shopping just on price because Chinese bosch MAFs are everywhere. The m50NV is straight up NLA (it's a unique 3 wire rather than standard 4 wire) but I followed the bosch part number for m50NV and fakes are made in China available on ebay and even in the USA B&M stores- found some at walmart! They're $70 from china sold in volume and retailers were selling them for ~$130ea
rockauto sells cheap junk sometimes (wouldn't buy unless they are explicitly stated made by bosch Germany) and especially the same for amazon

[The Chauffeur]

Not wanna deviate from the topic but, how reliable are refurbished MAFs, assuming they come from a reputable place?

[jehu]

My engine is backfiring and the MAF read .2 v while running with no change at all... I swapped in an old MAF I had [Bosch] but its still doing it.


I am totally stumped and the next step may be a smoke test. Is it going to damage the engine if I drive it like this? Shakes occasionally, hesitates, but smooths out and can cruise ok at highway speeds.. whenever you change speeds however it seems to lose settings and shakes..


Is it at all possible for the M60B40 to be "out" of timing? How could that happen with a chain? Engine idles fine.

Yeah, I didn't want to go there...
Look on the bright side, if our MAF was bad we probably wouldn't even notice E: off topic rb swap stuff.

[fo3]

Don't latter models have a stomp test? There's a fault code for MAF.
From what I know a bad MAF could cause bad/rough idling or a richer, safer/default fuel map. That's why I joked we in a m50NV would never notice - large cam, huge valve overlap, dumb DME without sensors and bad fuel economy But anyway, you don;t have symptoms typical for a bad MAF with the idle being fine and not running rich. I don't think a MAF would cause hesitation and shakes.

I've never tested my MAF because if it was faulty then what? I can't buy one anyway (they were $800+ when they were available), so I have no idea about sensor volts. Do a stomp test and if no fault found, look at ignition system (plugs, boot and coils). E: For the record my ex's holden commodore carried on exactly how you describe whenever there's an ignition problem. Starts fine, idles fine cruises fine, but shakes on throttle or hesitates occasionally. Start with spark plugs and boots and smoke tests if there's no MAF fault code.

[jehu]

I have done the stomp test... I got one short blink and then one long blink over and over which I gather is end of output [1000]... then I held the pedal down till it stopped did it again and got 1444.. when this started a last week I got a TPS code 1216.. i swapped in another TPS and haven't thrown another code of any kid yet but its till runs badly.

Don't latter models have a stomp test? There's a fault code for MAF.
From what I know a bad MAF could cause bad/rough idling or a richer, safer/default fuel map That's why I joked we in a m50NV would never notice - large cam, huge valve overlap, dumb DME without sensors and bad fuel economy

I've never tested my MAF because if it was faulty then what? I can't buy one anyway (they were $800+ when they were available), so I have no idea about sensor volts. Do a stomp test and if no fault found, look at ignition system (plugs, boot and coils). For the record my ex's holden commodore carried on exactly how you describe when there's an ignition problem

[Honolulu]

if no further MAF code(s) are generated, then (maybe) the second MAF you installed is good and you're barking up the wrong tree. Might then be that the previous MAF was good too.

But, y'know, codes aren't EVERYTHING. You should always read them if at all possible, and surely they can HELP, but an engine can run poorly without throwing a code. DAMHIK.

[jehu]

This is why say I am totally stumped it's totally perplexing There was a question about whether when I changed throttle position sensors the mechanism was oriented correctly when I replaced it so I suppose the way that you test that is that you hook up an ohm meter to the sensor after removing it and dial it through its range position the rotating center to the low reading position and then install it with the throttle plate closed so you know you're starting from the right position the only question I have if that were the cause the cars behaving in exactly the same way with this other throttle position sensor in place as it did before so nothing is changed so if the same behavior is occurring I'd be surprised if it's only cause was the throttle position sensor was not oriented correctly to start off reading in the Correct position.

Someone suggested the Bosh Motronic unit goes through a period of adaptation if there's been use with faulty sensor input but I've been driving it for several days even a few 100 miles and nothing has changed substantially I thought it was changing at 1st but it still bogging and hesitating

[fo3]

The TPS and MAF usually don't do much. They can affect idle because they are a sensor that the DME checks and is really unhappy about them if they are sending garbage signals - but they aren't critical - that a car can generally run without them even plugged in is usually an indicator that they are used for trimming the default map on the DME and aren't the cause of a misfire under load.

Your TPS being bad was probably something you would never notice if it went bad for most of the time on most cars. It's not a drive/throttle by wire car and even in something like my barra falcon which is drive by wire the TPS does very little.
I doubt it would cause hesitation or misfires when under load. It may have been bad for ages but only came up when you did a stomp test. I've seen YT vids of bad MAFs in a stalling or poorly idling car which can be temporarily 'fixed' by unplugging the MAF and driving off to buy a new one.

E: If your fault codes aren't re-occurring or persisting I'd be testing things that the stomp test can't tell you about - ignition, air leaks, fuel pressure and regulator. It may not be them, but it sure beats throwing sensors and more expensive parts at a car.

[jehu]

I had another scan done which showed faults in coils #1 and #6 and a Pulse Modulator fault [Crank Position Sensor] so I put in another pair of those on a reading about a faulty CPS there are suggestions I'm on the right track. If the sensor housing melted during the overheating episode or was damaged by that giant hunk of solid core jacketed cable I somehow picked up and found in the right bank headers finally had been interfering with that maybe I can see a light at the end of this dark tunnel.. The car did seem to behave slightly better with tow new coils but still had some hard drop offs and shaking which from what i read are consistent with a faulty crank sensor. New sensor on Monday.. wish me luck.

[shogun]

The TPS and MAF usually don't do much. They can affect idle because they are a sensor that the DME checks and is really unhappy about them if they are sending garbage signals - but they aren't critical - that a car can generally run without them even plugged in is usually an indicator that they are used for trimming the default map on the DME and aren't the cause of a misfire under load.

Objection, your honour, a defective MAF and TPS can cause a lot of trouble, read this thread in the German E34 forum, several cases of transmission trouble https://forum.e34.de/thread.php?thre...lightuser=1131
defective ones can for example cause rough shifting of automatic transmissions. One member there even changed the transmission because of these shift problems, did not help, then he changed the TPS and problem was solved, here the most important of the first post translated (extract): E34 540 with 5HP30 had been a problem for a long time with rough changing gear (upshifting). In the end, even the gearbox was replaced, but brought no improvement. Effect was the following: For example, when accelerating to about 50km / h (no matter how speedy) and releasing the accelerator, the subsequent shift 2-3 was very rough. The engine RPM went down just above the idle speed. The same problem occurred in principle with each gear change, if this was done after an acceleration phase. Gear changes during acceleration were unremarkable. After various specialists with readings, experimenting with various software versions of the AGS, conversion to EGS, revision of the control unit, trans flushing, ATF change etc then came at some point the resignation in the way "is so - you have to live with it". Similar to a dachshund owner, he must also cope with the fact that the critters have a crooked chassis. At the last spare parts order, I have now ordered a throttle valve potentiometer. The built-in part was completely unobtrusive and all readings in the norm. There were also no "dropouts" in any position detected (check for values ​​on the CAN bus). total mileage 235tkm. Nevertheless, the change has brought the almost complete cure. A small jolt is still there, but in contrast to previously hardly remarkable. I still can not justify the change, I am completely at a loss when it comes to the connection between the error picture and the solution.
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Later in that thread I posted a comment from the German 7 forum from a popular ZF transmission expert (shop owner and E34 owner), he already mentioned abt. 10 years ago that defective MAF and TPS can cause transmission trouble.

[jehu]

I didn't quite think that statement of our esteemed t poster above had been well thought through.

Is it legitimate to correlate the faulty shifting in the automatic transmission when up shifting with the shaking of the engine I feel increasing in intensity when I with the manual shift into higher gear and very severe in 6th gear unless I'm out on the highway and can accelerate through that rough phase when it will even out and run smoothly?

Seems like with inaccurate feedback from these sensors the engine doesn't know what to do and it's randomly dumping fuel or cutting it off in very rapid succession combined that with my condition where I possibly had faulty coils as well which was again not obvious because the engine idled perfectly smoothly and would not shake on the highway once it emerged through the Roughness

[fo3]

It's all about context shogun. I know that tps and MAF aren't put there for decorative purposes, just saying it didn't line up with jehu's symptoms.
I know enough to be looking at TPS for auto trans gear selection problems, MAF for bad idle or poor fuel economy, and in this case (good idle, cruise, nothing said about trans) and misfires at load accel to looking at either ignition or fuel instead.

E: Late edit because I was in the middle of something. I assumed 6spd meant man trans, am I correct in that?
The TPS is important to automatics because that's how the trans knows you have you foot off the accel pedal (ie engine braking to slow down and it can shift if it wants), or are giving a lot of accel (don't shift until RPMS are higher). In a manual trans it might just do a bit of fuel.ign map trimming for more responsiveness and economy but it's not going to cause engine shakes - under load but no other time - if bad, and if it is giving out garbage data you might see idle problems anyway.

[401michael]

my engine was backfiring. I went and pulled a cam sensor off a 95 540i that was sitting at u pull it. solved my backfiring issue. perhaps could be the issue you're having.

[jehu]

If the new Crank Sensor yields no improvement I'll examine those. Disregard the MAF fault in this scan. I had disconnected it earlier [with no improvement btw]

Attachment 650510

[401michael]

If the new Crank Sensor yields no improvement I'll examine those. Disregard the MAF fault in this scan. I had disconnected it earlier [with no improvement btw]

Attachment 650510

my car would start and idle okay-ish and then start surging and if I made a pull for instance it would feel like a fuel cut at higher rpms backfire and sometimes quit. I thought it was my crank sensor as well and I had gotten both sensors to replace mine. replaced my cam sensor first and started it to check if there would be any difference and it fixed the issue.

[jehu]

It was the crank position sensor