Custom tunes with maf unplugged

[snow demon]

2000 a4 1.8t atw. When I was apr stage 3 and maf went out I could unplug and car would run decent enough to get me home and until the new maf arrived. Ecu went bad (water) and getting a local custom tune on used ecu. Supposedly now has base file for my gt28rs and 550cc but runs horrible idles 10:1afr fouls injectors and dies. Tuner said because of issue with maf. It runs the same with maf unplugged. I picked up car and diagnosing maf issue, but should it at least run better with the maf unplugged? Mafs don't last long on my car so I don't want to loose the ability to unplug it and have the car run temporarily. Is it normal for some big turbo tunes to not run ok with maf unplugged?

[Blazius]

Just dont remove the maf ...

[snow demon]

I'm not removing the maf its just that they they go bad and I don't want to loose the ability to unplug it to get home and not have to call a tow truck just because of a bad maf.

[MetalMan]

A MAF shouldn't go bad quickly... they should last years. Are you using cheap replacements or something?

Also I'd perform air leak testing. Air leaks are one of the big reasons why a car will run better with the MAF unplugged.

[snow demon]

I buy the expensive bosch mafs from ecs tuning. I read in this forum once somewhere that high boost and upgraded intakes significantly shortens the life of these mafs. In the 10 years I've had this car I think i went through 5 mafs. They start putting out low readings and car will run like crap untill replaced, I have always been able to unplug it temporarily while waiting for the new maf but seem to have lost this ability with the new tune. Car ran great untill water got in the ecu, recently replaced turbo and all vacuum lines and leak tested so 99% sure that's not the problem.

[ktsimp721]

2000 a4 1.8t atw. When I was apr stage 3 and maf went out I could unplug and car would run decent enough to get me home and until the new maf arrived. Ecu went bad (water) and getting a local custom tune on used ecu. Supposedly now has base file for my gt28rs and 550cc but runs horrible idles 10:1afr fouls injectors and dies. Tuner said because of issue with maf. It runs the same with maf unplugged. I picked up car and diagnosing maf issue, but should it at least run better with the maf unplugged? Mafs don't last long on my car so I don't want to loose the ability to unplug it and have the car run temporarily. Is it normal for some big turbo tunes to not run ok with maf unplugged?

Could get meastro and run awp file.... with maf unplugged it will run off alpha n (mafless)...... I know its expensive but hella worth it tho if you gonna be tuning


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[Blazius]

Dont touch the MAF on ME7 man, unless you rewrite it to Speed Density.. MAF is the ONLY and PRIMARY load ( cylinder charge) in Motronic 7, there is no maffless speed density nothing. There is only the secondary emergency load which is calculated via alpha N and it is LIMP mode.
If you get a mafless tune or anything, that means the ECU is constantly in LIMP mode, only they remove the DTC classes so you dont get check engine / epc light and no codes when you read the ecu. It is not recommended. If you really want no MAF in intake of the turbo ( absolutely no reason to do this ) is to get a blowthrough setup, even that works better than nothing.

If your MAF's are dying that fast then something is wrong with hardware. Revise your intake setup etc.


Not to mention a MAF setup always works better than SD or any other mode if you do not have leaks.

[snow demon]

I have no intention of removing the maf, I could ditch the apr intake for something else, I also used to get oil in the intake before I replaced the turbo and also put in catch can so maybe now my maf killing days are over. I just think its still important for alpha n limp mode to work. I'm trying to confirm or rule out a bad tune since everything was fine until I had to replace the ecu. Is it possible for the tuner to neglect writing in the alpha n limp mode?

[ktsimp721]

I have no intention of removing the maf, I could ditch the apr intake for something else, I also used to get oil in the intake before I replaced the turbo and also put in catch can so maybe now my maf killing days are over. I just think its still important for alpha n limp mode to work. I'm trying to confirm or rule out a bad tune since everything was fine until I had to replace the ecu. Is it possible for the tuner to neglect writing in the alpha n limp mode?

Idky we keep calling alpha n limp mode.... you cant do 100 mph on limp lol >:D


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[Blazius]

Coz it is lol. In me7 , alpha N is limp mode lol I told you. its classed as limp mode, doesnt matter what speed you are going, its still limp mode.

[snow demon]

Whatever it's called, what I'm trying to get at is if the tune is written correctly, it should run half decent with the maf unplugged providing everything else is in order.
So here is where I'm at now, maf wiring is good, voltages good at maf connector and continuity good from maf to ecu connector, tried 2 new mafs. Vagcom registering zero from the maf, at one point gave a very low reading but back to reading nothing.
No vacuum or boost leaks. Car runs stupid rich idle a/f 10:1. Any way I can confirm if tune or ecu is bad?

[00black1.8t]

A 2000 ATW can not run a MAF less tune unless you convert to a 2001 Awm ecu and add harness for wideband O2 sensor. The 2000 atw is narrow band. Will always run like crap without a maf. I did it I know. Are you running a oiled filter? The oil in K&n filters or any aftermarket filter with oil will screw your MAF up quick. Always run a oil free filter like Amsoil or similar. Try very gently with iso alcohol dipped q-tip to clean the wire inside the sensor. That can help sometimes.


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