choking possible MAF failure (not sure)

[michel]

We have a problem with the car
We start and the car runs nice, when we pull the throttle it chokes completely and almost run dead. When we push the trottle harder it pulls trough
Running the computer gives a faillure (17) heating wire or something, strangly when we disconnect the MAF it makes no difference at all.

We cleaned the MAF and Trottle body with a special cleaner with no result, the thottle body is measured and is 2.5 degrees closed and around 56 degrees open. When we pull the throttle it opens correctly.

You would say why are you not sure it the MAF, well i have 1 spare MAF from a extra engine we bought in 2008. When we change them the problem stays.
In the video you can see and hear the problem, a new MAF here is 700 euro's.

[youtube]hJz5tGfm3Tc[/youtube]

 

[195910]

Connect it to HHT, and note the readings for MAF voltage, also note the intake pressure fluctuations.

 

[michel]

Sorry what is a HHT?

 

[gsxr]

HHT is the old MB scanner. It was replaced by the SDS / Compact scanners. Connect the car to the SDS and use the HHTWin program to view the live data from the computers. Then compare the data to another M119.

 

[michel]

Is it normal that the car runs the same with or without the maf connected

 

[gsxr]

Is it normal that the car runs the same with or without the maf connected

No idea - never tried that before. It should run with it disconnected though. Sounds like you may have some other problem, especially since the spare MAF did not change things.

Heating wire fault could be in the O2 sensor, but you'd need to tell us what module had code 17. I'd also want to see what the LH adaptation values are... again, need a digital scanner for that...

 

[Russell R Coe]

Check your distributor caps and rotors, sounds very similar to what was happening to my car. Cleaning up the cap and rotor just on the passenger side bank cleared up the issue.

15 minute job with the right tools.

 

[michel]

rotors are new and today new Bremi/Bosch caps are comming to elliminate these.

Thanks

 

[Jelmer]

MIchel, I still have my "old" MAF, which is most likely fine. You can come pick it up so you can try it.

 

[J-Sauce]

Your symptoms do sound very similar to what my M104 car was doing recently with it's bad MAF. When readings from the sensor become implausible, the system would ignore it all together. That meant I could remove the sensor entirely and note no change in performance. The funny thing is that I also replaced it with a used unit that was BAD as well. Took a second unit to finally cure the problem.

Now, I know they are different monsters than the LH systems and hot wires (vs hot plates) found in our M119, but I think they may behave similarly when the sensor misbehaves.

 

[Christian_K]

Is it normal that the car runs the same with or without the maf connected

Then the MAF is toast ;-)
Cheers.

 

[michel]

MIchel, I still have my "old" MAF, which is most likely fine. You can come pick it up so you can try it.

This where forum like these are briljant, hoping to pick up the MAF at Jelmers place.
Keep you posted

Today we put the new caps on no result (the old one looked worn) better save then sorry on this one

 

[michel]

Picked it up tonight, thank you for the warm welcome Jelmer.

Your car color and interior are amazing never seen this dark brown interior in combi with the bronze=zilver exterior, the condition of the car is also super.

Fingers crossed that the MAF fixes the problem i will film the first start.

 

[gerryvz]

Your car color and interior are amazing never seen this dark brown interior in combi with the bronze=zilver exterior, the condition of the car is also super.

Yes that's why he has the title here "I'm special" and his own smiley ....

 

[Christian_K]

Remove the airfilterbox, start the car, go veeeery close with your mouth to center of the mesh of MAF-cover and Blow-in as hard as you can into its middle area.
Car shouls stop immediately. If not , the MAF is toast. This is the most easy step to test MAFs of the early kind we have (LuftHitzdraht - LH ;-) )

 

[Jelmer]

Michel now has the MAF that my car ran fine with. Replacing it only takes a few minutes. Let's hope for the best!

Again, don't forget that it can take a while before the car "gets used" to the new MAF!

 

[gsxr]

Again, don't forget that it can take a while before the car "gets used" to the new MAF!

If the new MAF works and fixes the problem, the LH adaptation should be re-set. The adaptation could be all hosed up from the old/bad MAF readings.

 

[michel]

If the new MAF works and fixes the problem, the LH adaptation should be re-set. The adaptation could be all hosed up from the old/bad MAF readings.

you mean hook the car on the computer and reset the MAF fault code ?

 

[195910]

you mean hook the car on the computer and reset the MAF fault code ?

Not only clear the fault code, but you need to reset your engine adaptation (see under LH control unit in HHT)

 

[195910]

Remove the airfilterbox, start the car, go veeeery close with your mouth to center of the mesh of MAF-cover and Blow-in as hard as you can into its middle area.
Car shouls stop immediately. If not , the MAF is toast. This is the most easy step to test MAFs of the early kind we have (LuftHitzdraht - LH ;-) )

Really ?! I never tried that. will try this one

 

[gsxr]

Not only clear the fault code, but you need to reset your engine adaptation (see under LH control unit in HHT)

Correct. The adaptation is reset on the LH module using SDS / HHTWin (or a Snap-On digital scanner). Ideally you'd check to see what the values are prior to the reset; to see if they were near the maximum limit, which would usually indicate a problem with the MAF or O2 sensor.

A hand-held blink code reader can also reset the adaptation but of course the blinker box cannot tell you what the adaptation values were prior to reset, nor can it confirm the reset was successful.

 

[michel]

Very frustrating, didn't work so we can exclude the MAF, we tried another "nokkenas" sensor because there was a fault code in the memory. This had no result as well, mondag we will start from the beginning and start measuring the fuel pressure (we changed the fueltank 2 weeks ago) and from there on start looking into the system.

Current the car is running beautiful at 550rpm but when we push the trottle in N or P it chokes when we push the trottle a little more it comes over this point and runs better, in D it drives terrible and we smell a lot of fuel.
Measurement from the exhaust gives us CO between 0.5 and 7

 

[J-Sauce]

My next hypothesis would be to check the harness going to the maf and look for shorted wires. Also, the upper harness in general if you have not replaced it.

 

[michel]

Gonna search step by step now the most simpel hardware replacement is not working
Starting with the fuel pressure and then probaly measuring wiring
Upper harnas is replaced 4 years ago.
Gonna reset it al and see what codes come back as fault

Keep you posted and thanks for all the help my 500 family

 

[Jelmer]

FYI: I have moved Roberto's post and its replies to a new thread: http://www.500eboard.com/forums/showthread.php?3013-Rough-idle-smoothes-out-gt-3k-rpm

 

[michel]

Fuel preasure is checked and ok

We have 2 maesure boxes launch and a snap-on

Which coils are the best BERU, BOSCH or MAPCO?

replaced or new
upper harnas
caps
rotors
spark plugs and wiring

 

[michel]

The story is getting weird
The third MAF (the one i piched up at Jelmer) was not doing the job.
I decided the bring the car to Cor de Jong (advice Jelmer), he has a HHT.
When we put it on the car ambulance the car was running 100% oke (very frustrating), the car was delivered at Cor and still was running 100%.
The next day the problem was back again, and measurement give MAF faillure, he changed it to his own MAF comming from his 500e and it run well.
After measuremenys all 3 MAF's have not the good values so we decided to order a new one.

Its comming tomorrow then we will see if its is fixed or not.

 

[195910]

Wait, Maybe you have a shorting that is burning the MAF ?!
Also what about the ETA ? are you getting correct throttle angle, other readings

 

[michel]

Its all measured and oke according to Cor de Jong.

 

[Jelmer]

Wait, Maybe you have a shorting that is burning the MAF ?!
Also what about the ETA ? are you getting correct throttle angle, other readings

Ouch, that might even be the case. My MAF was OK, or at least it seemed like it. It just sat upstairs. I spoke with Cor about this, and he claims a MAF won't suddenly go bad when lying around... So either it fell somewhere down the road, it was broken and I didn't notice it, or Michel's car burned it and might be busy burning Cor's MAF?

Well, since Cor is measuring everything, let's hope he notices this, too... *fingers crossed*

 

[195910]

It seems like its burning everyone MAF's ! Michel, do check again before installing the new MAF.
I don't have a 500E now, or I would have compared HHT values with you. Can you switch complete MAF+ETA with someone and compare?

 

[michel]

Don't think thats the case the MAF of jelmer didn'd do the job for 1 second and the MAF of Cor is doing it for a day now.
Values a diferent on the MAF's, I asume that Cor knows what he is doing.

i will call him today with this question.

 

[gsxr]

Weeeeiiiiiiird.

 

[michel]

Job done

New MAF, cleaning of the contact points (wiring MAF)
Reset all codes and no codes came back.

The car runs beatifull

Cor and Jelmer thanks till now

 

[195910]

That's good to know. But weird as well.

Let us know how things are after some time.

 

[Christian_K]

Really ?! I never tried that. will try this one

Do i have the reputation to be a guy that talks non-true things? ;-)
Yes, please go ahead and try it. What i say is true and a fact. Cheers.

P.S. Like i said in the beginning, it was a toast MAF.
Now for the future, if you disconnect a MAF and you find NO change in running behavior of the engine, your MAF is toast already.
Then there is the easy test method i described above. Only then, if you are still uncertain you need a computer to read fault codes.

P.P.S Someone should add my knowledge about this into the WIKI

 

[195910]

Do i have the reputation to be a guy that talks non-true things? ;-)
Yes, please go ahead and try it. What i say is true and a fact. Cheers.

I was misunderstood. I wasn't questioning our dear member, but rather was surprised

Just to add on the MAF discussion, in newer MB cars the MAF is replaced every few years (more frequent than old MB), it is much cheaper about 1/3 the price of the M119 MAF. You know its faulty in the engine switches off while turning left/right on the road ! and also by hesitation of acceleration.

 

[Christian_K]

I was misunderstood. I wasn't questioning our dear member, but rather was surprised

Just to add on the MAF discussion, in newer MB cars the MAF is replaced every few years (more frequent than old MB), it is much cheaper about 1/3 the price of the M119 MAF. You know its faulty in the engine switches off while turning left/right on the road ! and also by hesitation of acceleration.

Yes, as MAFs are chosen as yet another cash-cow by the car industry and especially its supplying industry. The old type we use (Hot-Wire type) last muuuuch longer than the modern film-types. Many M119 MAFs live up as long as 15 years, some guys even have the FIRST MAF in the 500Es, thanks to its implemented burn-off technology. They are even the ones that can be cleaned with electronic-oxidization cleaners, followed by electronic spray-washes until their platinum-wire is glossly again.
I recovered a few M119 MAFs that way already, whos wires were already matte/tarnished and the MAFs not working properly anymore.

 

[michel]

Regarding the cash cow thing.
In the Netherlands Bosch is not allowed any more to deliver to the customer (under pressure off MB)
So you can only purchase it trough the dealer for 680 euro ex VAT and you get 80 euro return on the old one.

I also heard a roumor that there are no upper wiring harnas available any more, this is gonna be a custom made item.
If so the price will go up dramaticly.

Going to get my car now and hopefully enjoy it for a long time.

 

[borring]

Hmmm... Upper wiring harness, I got one from Mercedes in Denmark two months ago, the price was ~5000 DKK that's $833,33.

 

[michel]

Runs beatyfull so far, looks like its realy solved.

 

[195910]

Yes, as MAFs are chosen as yet another cash-cow by the car industry and especially its supplying industry. The old type we use (Hot-Wire type) last muuuuch longer than the modern film-types. Many M119 MAFs live up as long as 15 years, some guys even have the FIRST MAF in the 500Es, thanks to its implemented burn-off technology. They are even the ones that can be cleaned with electronic-oxidization cleaners, followed by electronic spray-washes until their platinum-wire is glossly again.
I recovered a few M119 MAFs that way already, whos wires were already matte/tarnished and the MAFs not working properly anymore.

Also a tip here: use the burn off function in the HHT. this will clean up the wire. The 500E I had still has its original MAF ! just clean with burn off function.

 

[Jelmer]

For the next time, if anyone wants to test their MAF, here is the result described by Christians' trick
[youtube]ghBoMT4PKLU[/youtube]