MAF numbers for an M62TU. Are they good?

[ExGermanica]

So, I'm obviously running rich, evidenced by the short term trims both running at exactly -6.98 on each bank. My MAF is reading at between 28-30 kg/hr, which is roughly 8g/s. That seems high to me. If so, that could be why I'm running rich due to it reporting more air then there actually is.

What do y'all think?

[ExGermanica]

Anyone?

I'd really like to have an educated thought process here to avoid throwing parts at the car

[jicaino]

Doesn't seems particularly high to me unless that's idling

[ExGermanica]

It is at idle. The idle is a tick high due to the current issues. If the idle happens to be on point, the MAF reading are pretty much the same.


Regardless, 7 g/s just seems high to me but I don't have a basis in fact to back that up and that's what I'm after.

[jicaino]

It is at idle. The idle is a tick high due to the current issues. If the idle happens to be on point, the MAF reading are pretty much the same.


Regardless, 7 g/s just seems high to me but I don't have a basis in fact to back that up and that's what I'm after.

I will log mine and let you know. I'm on the road with another car, will report back on Sunday. You want cold start data or operating temp?

[ExGermanica]

Both if you can, thanks. The numbers I'm reporting here are at operating temp

[BimmerBreaker]

I'm not sure the MAF reading would even change much during a cold start vs operating temp; although I am curious for both to be logged just for the sake of knowing.

[ExGermanica]

I just started it up now and right upon startup, MAF read 61kg/h but once it went into closed loop, it went down to 27-28. Of course, idle is high at 700, so that number would be a bit less at the correct idle speed.

What I've also noticed is my fuel pressure is 45psi prior to starting and goes right to 50 once started and stays there. If I disconnect the vacuum line to the fpr, I notice no difference. I may be looking at the filter/fpr first

[BimmerBreaker]

If that fuel filter is like the M54 style, then the vacuum nipple does not control pressure in any way. It is merely a vent line.

[ExGermanica]

Not sure. It does connect directly to vacuum at the throttle body boot

[jicaino]

Not sure. It does connect directly to vacuum at the throttle body boot
M62TU has a permanent recirculation valve at the filter, has no fpr, if it's over the spec'd pressure it goes back to the tank

[ExGermanica]

Ok. I read on Timms site that if I had 50psi at idle that short term trims would be affected. I guess that's only the case for non-TU motors? I ordered one regardless as I don't know it's history.

Something is making the car run rich. MAF or precats next. That's the question.

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I grabbed this from his site and it does appear to apply to TU motors

Adaption Value Additive - If the Lambda Integrator reports that the mixture is too lean (at idle) then the ECU will slowly increase this value to increase the injector dwell so that the mixture enriches. If you have a value here that it greater than +10 you can be sure you have a vacuum leak - or the MAF is mis-reporting the actual air mass.If the value here moves to less than -10 (especially if combined with a negative value for the multiplicative adaptations) that usually points to a failure of the vacuum pipe that runs between the PCV and the Fuel Pressure Regulator (FPR) - at idle the PCV will be supplying a vacuum to the FPR which limits the fuel-rail pressure to 3.0 Bar - if that vacuum is missing (the pipe is kinked, torn or missing) then the fuel-rail pressure will increase to 3.5 Bar and adaptations will be seriously skewed trying to pull the fuel/air mixture back to the correct levels. A slightly negative reading indicates less than perfect combustion (plugs, coils)•Adaption Value Multiplicative - This value is modified if the mixture is not ideal at higher engine loads and speeds (when cruising for instance). If this one moves to far away from 1.00 then things are not right - a vacuum leak is much less likely as the manifold vacuum reduces with engine load and that proportionally reduces its influence. However, a large additive and small multiplicative positive increase does point towards an air or vacuum leak.A large negative number here could be excessive fuel-rail pressure - but it could also be poor combustion in one or more cylinders - the smoothness values would help us differentiate the two possibilities

[jicaino]

It is high. Mine has a tune and larger air intake and reads 6.5 (25/26) on startup and then settles at around 19.8 to 20.3 @1.39v
My guess is you have a faulty maf or some sort of electrical mishaps.
My car's tuner rich BTW so your will definitely be very rich.

[ExGermanica]

Thanks for the data. I have a fuel filter/regulator on the way. MAF will be next in line

[jicaino]

Thanks for the data. I have a fuel filter/regulator on the way. MAF will be next in line

Glad to be of actual use. I'd replace MAF first, with your values.

[ExGermanica]

Definitely very helpful. Thanks again. According to Timm @ meeknet, if my fuel pressure is high at idle, and it is, then it will throw adaptation values off. I figured it's a filter that I haven't replaced so let's see how that goes. Plus I seem to also have a battery on the way out. The dme is raising the idle to compensate

[jicaino]

Definitely very helpful. Thanks again. According to Timm @ meeknet, if my fuel pressure is high at idle, and it is, then it will throw adaptation values off. I figured it's a filter that I haven't replaced so let's see how that goes. Plus I seem to also have a battery on the way out. The dme is raising the idle to compensate

A dying battery or a bad voltage regulator can throw everything to the gutter for sure.

Regarding fuel pressure, the only thing that I can think of being bad it's the actual fuel pressure regulator inside the fuel filter, failing in stuck mode and then raising the pressure linearly Your car is a TU, right? Can you log sensors? Like a ELM327 dongle and torque app? I'd drive around monitoring battery voltage, in different situations (more and less rpm, consumers off and on, etc)

[ExGermanica]

I just replaced the battery and the fuel filter. The battery definitely made a difference. While the DME randomly calls for the idle to be raised, it's no longer due to insufficient voltage.

The fuel filter/regulator didn't net the results I had hoped for, however. The warm idle fuel pressure went from 50psi with the old filter to 55 with the new. The new one is a Hengst, as was the old so it had been done at least once in it's lifetime.

Yes, the car is a TU. I know Timm had said on his page that the pressure at idle shouldn't be over 45-46psi and even though he says that about a TU motor, there are E38s that have the TU that still have the regulator at the rail using manifold vacuum as a reference. Perhaps one the ones with the regulator on the filter, such as mine, are programmed for that pressure. Hard to say without known comparisons.

MAF will ne next, as I noticed while watching the scanner today, the MAF would hold OK at 6.5 g/s(24 kg/hr) with a perfect idle. Then randomly the MAF numbers will jump for seemingly no reason and the idle goes to around 700. I can log with the Autel so I'll start watching a few things in the near future but as I said, I'll get the MAF and go from there and see if anything changes.

[ExGermanica]

Replaced the MAF. Warm idle readings went from 8g/s to 5. After a decent drive, the trims settled to very acceptable numbers, very slightly rich. Low/mid-range power is much better so that appears to have been the issue.

I'll do the primary O2s at some point this year since they're likely just as aged.

[JimLev]

Your fuel pressure is OK. I’ve had a gauge on mine for years, it always reads 53-54 PSI.

[ExGermanica]

Good to know Jim. Car does run a lot better now. Just have to tackle the Vanos issue on Bank 2. I'm gonna first try to push that UTC cover down lower and recheck the numbers.

[jicaino]

Maybe it's wise to reset the adaptations now that your MAF is good

[ExGermanica]

I was considering doing that. Good idea. I did like how the trims did come down after a long drive though.