daking

Hello everyone,
yesterday I changed MAF sensor with new one.
My old MAF, was BOSCH F 00C 2G2 044.
Looking in internet it seems to be Alfa Romeo MAF, previous owner's mechanic mad ????
With old Maf sensor, car worked fine but sometimes, only in heavy traffic drive, I had PSM, ABS check light.

Now, with new MAF car goes worse!
First kilometers I had "on/off" fuel problem and when press gas pedal over 30% car seems to stop (like engine drown in fuel), obviusly PMS an ABS check light.
After 3 or 4 Kilometers, car went rather better, but still have some fuel/air ratio problem, expecially at low rpm "1.500 to 3.000 range".

Previous owner did a flash (ECU),probably with old MAF...


what can I do?

raineycd

May not be the MAF. These cars have a fuel pump line issue that may drop the pressure. Probably should start with getting the codes read and then find out what they are and go from there.

PAULUNM

Here's the correct Bosch p/n-

0 280 218 009

There's also a 996 p/n printed on the MAF I just bought- let me know if you need it.

Macster

Might be engine controller needs time to relearn with the new MAF.

Generally if the MAF is replaced an OBD2 code reader should be used to clear any OBD2 error codes. There won't be any if the check engine light is off but sending the clear error codes command resets the long term fuel trims (among other things) back to their defaults.

Thus when you start the engine the engine controller only has to deal with adapting to a new and properly functioning MAF. If the old MAF bad enough the engine controller may have adapted way the heck away from where it should be (with the new MAF) and the engine can run like crap until the engine controller adapts to the new MAF.

Even so the engine may not run as good initially as it will later on with some miles on it. Depending upon the condition of the engine, the weather (ambient temperature mainly) and some other factors even clearing the error codes when none are present and forcing the engine controller to relearn with a good MAF it had been learning from can have the engine sounding a bit sick.

But it should soon sound better.

If the previous owner fitted the wrong MAF the 'flash' has to be suspect as well. If possible you might go back to the stock flash and spend some time driving the car to develop a base line of behavior and performance. If the engine still acts up then it is easier to trouble shoot the engine with fewer unknowns to deal with.

Sincerely,

Macster.

Kevin

Caution, there are ALOT of wholesale internet parts housing replacing the factory 996TT MAF with the Boxster MAF or xyz.

Always order and check for the Bosch number which was posted, but more importantly> the Porsche part number 996.606.124.00 If you don't see this number it is NOT a Bosch MAF and a CLONE.

daking

Very many thanx.
Mechanic cleared all errors, but car still don't go.
Replace MAF unit is not original bosch, probably that's the problem. (like Kevin said)

But is it possible old turbo models mounts BOSCH F 00C 2G2 044 unit ??

daking

Every bosch MAF, have also 996.606..etc code???
Can it have only bosch number ??

Kevin

daking if you don't see the Porsche 996.606.124.00 part number>you have a reproduction MAF.

A original Porsche Bosch MAF that is correctly ordered WILL always have that number along with the Bosch number>>0 280 218 009

You car will not run correctly until you replace the MAF.

daking

Correct Maf installed.
Just plag and play.
Now car has a regular progression, no check lights.
Exhaust sounds lower.
Bar peak moves from 0.8 to 0.9 but car seems to be much less "aggressive", really much less!
Last track day, before changing maf, mixture was lean, exhaust double tailpipes was withe in the middle so I had to stop driving to prevent any damages.
Now, with new maf, I think mixture is ok, or a little rich and car "power" is less.
Possible I've lost so much power?

Kevin

AT this point you are just guessing. You need to datalog all the engine sensors to tell what is going on.

What is your boost request? What is the actual boost? Is timing getting pulled? Knock? AFR's??

daking

PSM ABS check light... AGAIN !!
2 code for Engine check light - lambda for cat bypass exhaust.
1 code p0102 "hot film maf sensor", but MAF is brand new.
Any ideas??

Kevin

Do you have the stock air filter or aftermarket?

Your tune might be now in question.

How many miles do you have on your car?

Macster

My info is in the event of a P0102 (mass air flow sensor -- below limit) the PSM is switched off. This probably accounts for the PSM warning light, and perhaps ABS too since the ABS and PSM systems are 'connected' in a way I won't cover here.

IIRC you're running a car that has had an Ecu reflash. I know nothing about these other than what I've read here and other places and that is some work beautifully and some can cause more trouble than they are worth. Your car may have a reflash that falls into the second category.

Also, the car has had its exhaust modified. Again I know nothing about these but what I've read here and other places: Some work just fine, while others are chrome headaches.

These latter exhaust systems may have a good sound, sell for an attractive price, they may even boost hp and torque but check engine light events due to 'sensor' issues is an unpleasant side effect.

These check engine light events may be due to the stock (or aftermarket) Ecu being unable to adapt/work with the different exhaust flow characsteristics of the engine with this aftermarket exhaust.

The position of the sensors in the exhaust gas flow is critical to their proper operation. Furthermore the performance of the converters is important too, because the #2 sensor is there to measure/monitor the converter's performance.

Some aftermarket converters simply may not have ability to provide a more open or freer exhaust gas flow and yet completely process the exhaust gases. The metals used in the converters are very very expensive so the natural tendency is to use less of them to keep costs down.

But a high flow converter almost has to have more of these metals since to be a high flow converter it would have a larger diameter or longer converter section which means a larger surface area whch of course must be coated with necessary metals to do the converting so I would hazard a guess all other things being equal a high flow converter would be more expensive since it should have more surface and thus a hgher content by weight of the expensive catalytic metals.

So, where does that leave you? Well, with too many unknowns. Questionable flash. Questionable exhaust system. And questionable any other mods that have been done to the engine.

Kevin's comments I think are spot on the money. You need to stop guessing and look at the engine data: MAF, O2 sensor, and so on and so forth. It is hard to say at this time what data will prove to be the most useful.

The times I've tried to track down problems with stock engines I've jumped from one set of sensor or derived data to another set and back again comparing and trying to understand the results to make an accurate diagnosis.

Sometimes I'm succesful. However at least once I made the wrong diagnosis (diagnosed a MAF when a leaking oil filler tube cap was the real cause of the error codes). But it was a mistake I paid for out of my own pocket.

Anyhow, without any sensor data any guess as to what is the problem is just that, a guess. But one you're not likely to know is the correct guess without spending a lot of time and money, your time or some mechanic's time (your money though) and money for parts.

As much as I would like to come up with an answer for you I'm unable to offer anything but to 2nd Kevin's recommendation/advice and get you to start looking at the sensor/derived data and post this and perhaps Kevin or someone else will spot something that they can pass on to you that proves directly helpful.

Sincerely,

Macster.

jury_ca

There are 2 MAF sensors available, the BOSCH part 996.606.124.00 that Kevin mentioned and a Porsche branded part, which is much more expensive. I assume(d) they are the exact same part produced by Bosch.

My car was throwing PASM/ABS warning lights and the Durametric suggested it was the MAF sensor. I replaced the unit myself with a brand new BOSCH unit purchased from Pelican parts. The car ran a little better but was still throwing the PASM/ABS lights, after which it would run like crap until the computer was reset. The problem was driving me nuts, because the Durametric was still showing the MAF as the source of the problem. I replaced a bunch of other parts in the intake system and even the turbo boost controller but the problem was still there. My mechanic convinced me to replace the MAF again with the Porsche branded part, which I did. The problem went away.

I don't know if they are indeed 2 different parts, or I was just unlucky and received a defective part (or some dishonest customer returned a defective to Pelican, which was restocked and resold). However, if the Durametric is telling you it is a MAF, it is very likely to be the MAF.

jury_ca

BTW, agree with Macster, that if you are trying to diagnose a difficult condition, it is better to bring the car back to stock tune by reflashing the ECU to see if the problem with the MAF still exists.