[ideloera]

Originally Posted by 335duff

My car seems to run pretty much fine with no MAF? The way i diagnose faulty maf is to unplug it and run the car, if it runs better replace maf. Without the hfm, the engine runs in a "safe" condition. This means reduced power and mpg. My car seems to churn through a sensor in about 25k-35k miles.

Edit: Are people using genuine bmw maf (~$400 from dealer) or the non-bmw bosch one (~$200, fcpeuro or similar)? I've had two replacement bmw ones under warranty and have the bosch on the car now. So far it seems the same? The two parts are visually identical, same part numbers etc. Is the only difference the box they come in?

Im using the Bosch MAF which was IDENTICAL (even the part number) with the BMW one which was in my car. The Bosch one comes in a bosch box.

[335duff]

Originally Posted by smassey321

Rock Auto has the Bosch one for $193. Did yours fail with a code or just lower than normal power?

thanks

I had codes for two of them and the third time it just felt sluggish. I didn't so much notice a loss of power, but there was a massive loss of the smoothness of power delivery.

It was difficult to get a little bit of power, the throttle was like an on-off switch. I figured that as the sensor got worse it would eventually throw a code, but I didn't feel like waiting for the code just to have it warrantied.

I've had the bosch one on the car for 3 months now, It seems to perform just as well as the BMW one. As far as i can tell, the only difference is the box and $200

Cheers!

[Bob@BPC]

Originally Posted by lnxguy

MAP based smoke limiter, no reason why you can do this on the 335d. VW TDI guys have been doing it for years.

Yep, the 335D can be ran off the smoke based lambda maps w/o the maf in place. I have already done all the testing on the dyno and on the street. Its best to have the MAF if you DD and want the best gas mileage.

NOTE, in order to run the car with this setup it needs to be retuned.

[lnxguy]

Originally Posted by TheHolyCobra

+1

Diesels and their corresponding power are regulated by fuel. If you don't provide enough fuel, the motor just doesn't make as much power. No engine-busting detonation to worry about. So deleting the MAF, especially in a MAP sensor based car like lnxguy said, is do-able with proper tuning.

In the gasser world, if you don't provide enough fuel, then the motor goes BOOM. Pre-ignition and detonation can wreck havoc on internals. Hence why a properly working MAF is critical to a healthy running engine...unless you are running a MAP based engine control system and/or standalone engine management system.

You got it, diesel engines are basically giant air pumps, it can never be too lean (ie like it can be in a gasser).. If it is, you just won't make squat for power. No damage to the engine.

[Hoooper]

MAFs are made for better normal around town and highway cruising driving. Any motor with MAP and MAF sensors can be tuned to run fine on just the MAP sensor but you will likely see some reduction in drive quality for normal driving. Not that long ago there were gas cars designed with just a MAP sensor (the infamous Jeep 4.0 that runs forever comes to mind). Ive personally tuned an LS V8 on MAP only so its definitely possible, but if your car is not your weekend joyrider I would keep the MAF working.

[lnxguy]

Originally Posted by Hoooper

MAFs are made for better normal around town and highway cruising driving. Any motor with MAP and MAF sensors can be tuned to run fine on just the MAP sensor but you will likely see some reduction in drive quality for normal driving. Not that long ago there were gas cars designed with just a MAP sensor (the infamous Jeep 4.0 that runs forever comes to mind). Ive personally tuned an LS V8 on MAP only so its definitely possible, but if your car is not your weekend joyrider I would keep the MAF working.

I've DD'd a car with a MAP based smoke limiter for the past 5 years. It's really not much of a difference. Your car is only as good as your tuner.

[Hoooper]

Originally Posted by lnxguy

I've DD'd a car with a MAP based smoke limiter for the past 5 years. It's really not much of a difference. Your car is only as good as your tuner.

On my LS it wasnt much of a difference either. Biggest key in that application is getting the volumetric efficiency dead on for fueling.

[DWR]

If you have mods that change flow charateristics of the engine, then a generic MAFless tune is improbable. MAP only tunes are based on the idea that volumetric efficiency can be determined by pressure, temperature and rpm. That's not a bad asumption, but it does not have the same robustness of MAF based control. MAF measures air flow improvements, MAP does not.

Still, I'd like to find a tuner who can adjust plausibility limts to allow greater tunability, while still being able to detect defective equipment. That's the criteria that determines whether the DDE uses the MAF signal or reverts to MAP based control

Finally, counterfeit parts are rampant in the aftermarket. Even dealers have been known to source "original equipment" parts from contaminated distribution channels. The modern Bosch MAF is a specialized piece of electronic circuitry. Purchasing a MAF made with inferior chips and components on the internet is very possible.

Here's an exerpt from a Bosch EDC17 software document showing how MAF is compared to MAP calulated air flow to determine plausibilty, and hence which control method to use.

[Adieu]

Originally Posted by smassey321

Rock Auto has the Bosch one for $193. Did yours fail with a code or just lower than normal power?

thanks

There's actually a generic Evan Fischer (Chinese?) one for $65... well actually theres a ton of em, not sure if theyre the same one. But they only google up properly if you search the part number.

https://www.amazon.com/gp/aw/d/B077K...?ie=UTF8&psc=1




Housing is lighter and more brittle, chipped the edge of one end of the "pipe" installing it... however, power greatly improved once installed and like 3 MAF related codes went away (2 EGR / possibly CBU ones stayed).

Whatever....since its not a part expected to live super long anyway. Plus I'm really starting to hate on the usual Bosch and Siemens parts, theyre surprisingly likely to be the crappiest stuff in a car...