Where do I start? Numerous problems with my 606 - Page 2 - PeachParts Mercedes-Benz Forum

muleears · #1 11-25-2008, 11:06 AM

Quote:

Originally Posted by husk

P0100 is the MAF, check this first!!

Will do, I still have the old one, should I try that one again? My seller (********az) has a no return policy on electrical parts. Maybe I'll try a junkyard. Don't really want to spring for another new maf right now ($165)

The bad MAF would limit boost, wouldn't it?

TMAllison · #2 11-25-2008, 12:02 PM

Def would limit boost. Ought to be able to clear code and have instant power back until code sets again.

husk · #3 11-25-2008, 12:49 PM

Quote:

Originally Posted by muleears

Will do, I still have the old one, should I try that one again? My seller (********az) has a no return policy on electrical parts. Maybe I'll try a junkyard. Don't really want to spring for another new maf right now ($165)

The bad MAF would limit boost, wouldn't it?

IF its DOA they should replace it, I know Rusty will replace them if they are dead, I thought ********az had pretty good customer service. Thats good to know....I guess you could contact bosch and they will replace it if worst comes to worst. The symptoms you describe are very similiar to what would happen if you had a bad MAF.

muleears · #4 11-25-2008, 12:16 PM

Did that yesterday and the code poped up before I could drive anywhere.

Thanks Terry.

TMAllison · #5 11-25-2008, 12:54 PM

You've got a new or clean air filter installed? Not a K&N or other oil impregnated one right?

Assuming so, I'd check the electrical connections and make certain they're good, then spray clean the MAF again.

Does ******** sell OEM MAF's or inserts? MBDOC has said previously the VW inserts sold by some suppliers for use in MB's while similar are NOT the same, and that the Chinese parts should be avoided.

nhdoc · #6 11-25-2008, 01:00 PM

As for your problems - have you tried using an OBD scanner which has the ability to monitor the various sensor readings in real time or does yours just read and clear the fault codes? One as simple as the scangauge unit will provide you will MAF, MAP, temps, TPS, etc to be able to see if any of the readings is way off. Rather than shotgunning it that's where I'd look.

As an aside, apparently the MAF for the CDI which is part #6110940048 (MSRP $100) is supposed to work fine in our cars too. It is just the insert and you have to install it into the casing and for that you need a torx driver, IIRC.

KarTek · #7 11-25-2008, 12:57 PM

I may be wrong but as I understand it, the MAF only effects the EGR operation and doesn't effect fueling (unlike a gas engine EFI system). In this case, it may be setting codes but the codes are what puts the computer in limp mode, not the bad MAF.

The modulator for the wastegate is, as you say, the one behind the right hand headlight. There are 2 lines coming out of the top, one is the vacuum supply and the other goes to the wastegate. I was suggesting removing both of these top lines and connecting them together to keep the computer from limiting boost.

This will tell you a couple things. One, if the car doesn't respond and accelerate normally after bypassing the modulator, I'd next look at the MAP sensor (the one with a single vacuum line and a 3 wire electrical connector) on the left side "false" firewall next to the intake.

When you get to that stage, I can tell you how to test it with your MityVac.

I just want to take it one step at a time for organized troubleshooting. First just verify vacuum at the modulator and the wastegate.

husk · #8 11-25-2008, 01:05 PM

If he is getting a p0100 code it has to be the MAF/MAF Circuit etc? The other codes he was getting are now erased and never came back

THE Maf will effect Boost/Fueling etc the car will run like absolute crap with a bad MAF

KarTek · #9 11-25-2008, 01:18 PM

That's why I wanted him to try bypassing the boost control and see if performance comes back to any degree.

muleears · #10 11-25-2008, 04:33 PM

Quote:

Originally Posted by KarTek

That's why I wanted him to try bypassing the boost control and see if performance comes back to any degree.

Tested the vac. at the transducer on the fenderwell and the one for the turbo. Both had 29 inHG on the center line. Then I bypassed the turbo transducer and there was no change. Ran it up to @3K and 40 mph and it still ran like crap.

I haven't cleaned the MAF, that may have to wait for tomorrow, its getting dark here.

After all this was done I pulled the codes and all that came up was the P0100.

Could this possibly be my IP? I don't think so because it is so variable. Just thought I'd throw that out.

BTW no work had been done to the car to precipitate this.

Where do I go from here? I'll call ******** and see what they will do...

Thanks for the help.

Cal

muleears · #11 11-25-2008, 01:29 PM

Terry: Relatively new air cleaner, I'll install a new one tonite. ******** sells the entire unit, not the insert for $165. Mine was a Bosch unit.

Evan: I'll try the bypass tonite and report back.

Marty: My scanner is one of the simple ones, no monitoring ability. If the insert for the CDI is mounted like mine you will need the security torx (the ones with the hole in the middle).

Husk: The codes were erased yesterday and didn't come back yesterday. My wife drove the car about 25mi today, I'll see if the codes have come back. "absolute crap" is the perfect definition of how it is running.

Thanks again to you all, I think we'll get it eventually.

Cal

nhdoc · #12 11-25-2008, 02:18 PM

Quote:

Originally Posted by muleears

...Marty: My scanner is one of the simple ones, no monitoring ability. If the insert for the CDI is mounted like mine you will need the security torx (the ones with the hole in the middle).

Yep, now that you mention it I do recall they have a pin in the center so you would need that security torx bit or you'd have to grind off the little nub. I mention the alternative part because it is cheaper than the OE assembly and available from the dealers. I believe it is made by pierpoint.

A monitoring scanner will give you lots of good information and is cheap. I have one which interfaces with either a laptop or palm pilot and allows you to watch all of the sensors in real time. Sometimes one sensor is reading wrong and causes a code for another system so you can't always trust the OBD code reader to diagnose every fault by the simple code. I have one of the older scanners from these people:

http://www.scantool.net/products/index.php?cPath=8&osCsid=22ce7da42c94012d486d8fb6d4e6d228

F18 · #13 11-25-2008, 06:39 PM

Quote:

Originally Posted by muleears

If the insert for the CDI is mounted like mine you will need the security torx (the ones with the hole in the middle).

Cal

Muleears......just cut a slot in the torx security head with a dremel drill or hack saw blade so you can remove the MAF anywhere/anytime without a specialty torx security bit. Then you can use a flat head screw driver or a swiss army knife to remove it for cleaning. I have done that with all my vehicles

KarTek · #14 11-25-2008, 04:49 PM

OK, so no better with the vacuum routed directly to the wastegate?

Next, I would check and see if the line going to the MAP sensor is clear and not plugged with soot from the EGR. If the MAP doesn't see boost, the computer won't deliver any fuel. On my car, I can unhook the line going to the MAP and hook a long line to it and run it into the car. Then I hook it to the PRESSURE connection on the MityVac (the top one, just pull the cap off if it's there). I can get out on the road and floor the car and nothing happens but if I give a couple squeezes on the MityVac, the car will surge ahead because the computer is now allowing fuel. This test verifies that the MAP is working properly.

This might all be moot if something has happened like a mouse noshing on your wiring to the MAF. After all the sensor testing, The next thing I would do is start verifying the wire connections from the MAF to the computer. I can tell you which ones to trace if you get that far...

husk · #15 11-25-2008, 06:04 PM

The MAF does not cut boost at the boost pressure module, I think it interfaces directly to the ECU, if the MAF is bad I dont think there is anyway to get around it, other than emulating the MAF through other means or getting a new maf.

Thread Tools
Show Printable Version Email this Page
Display Modes
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode