Where do I start? Numerous problems with my 606 - Page 3 - PeachParts Mercedes-Benz Forum

muleears · #31 11-25-2008, 06:50 PM

Evan, I have replaced that particular vac. line so I know it isn't plugged. Could it be plugged behind the nipple? I'll have to try the other test tomorrow.

Husk, I have emailed ******** about warranty replacement of the MAF. I can't find one in a junkyard either.

Does anyone have a part number for the CDI MAF?

Thanks again for all the help.

muleears · #32 11-25-2008, 07:50 PM

"Husk, I have emailed ******** about warranty replacement of the MAF. I can't find one in a junkyard either."

It appears ******** is going to take it back as a warranty claim. I'll keep you posted.

KarTek · #33 11-25-2008, 09:00 PM

Cal,

Right now, don't fool with trying to test the MAP. That code that's set now will probably just trump any further testing. For fun, you could go ahead and take the MAP hose off and run a pipe cleaner through the nipple on the EGR and make sure it's clear.

We'll wait and see what happens when you get the replacement MAF. I have the pin numbers and wire colors so you can do a continuity check on the MAF circuit if need be.

Once the code is eliminated, we can look at any remaining issues.

Quote:

Originally Posted by husk

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.

You are correct sir... Another project I'm working on is the EGR eliminator. It's pretty much perfected now but I want to try and develop something to get rid of the MAF as well.

TMAllison · #34 11-25-2008, 10:30 PM

Quote:

Originally Posted by muleears

Does anyone have a part number for the CDI MAF?

See post #22.

muleears · #35 11-26-2008, 04:04 PM

Well today I swapped MAF's, the old one is back in the car. Drove it 3 miles (to the post office) it ran like it did before, smooth but only at 75%. Thought I could feel some boost but it still hesitates. shut it off, in Post office 10 min. Upon return it started right up and idled ok. When I started to drive it began to misfire horribly, as it was before. The same hot start symptoms I had before. The trip back peaked at 30mph. There are times when it seems to be missing on two or three cylinders. Its very rough. What could make an instant change like this? Any way, got home and pulled the codes and a new one popped up, P0300 (there's a surprise) and the standard P0100. "Multiple cylinder misfire" according to M.B. Doc there are only three things that can cause this. Heat, new plugs and always wait past time to start. Compression, it runs ok sometimes and really bad others, don't think its compression. Lastly, injectors, a poor spray pattern will trip the code. Hmmmm. But why only after a hot start? I am thoroughly confused and confounded. Any more suggestions guys (and gals)?
Some random thoughts: CPS? Injector timing (is it variable?)

KarTek · #36 11-26-2008, 04:27 PM

This is just a theory but I'm wondering how the ECU determines that the engine is "mis-firing".

Just thinking out loud but my questions are:

If you continue to drive, does the performance deterorate or is it an instant change after shutdown and restart?

Does the ECU measure the engine speed and detect an un-even pattern in the RPMs?

Cound the output from this speed sensor be erratic causing the ECU to "hunt" and surge, attempting to control the RPMs?

Is heat causing the engine speed sensor to fail?

Or... Is all of this a heat related mechanical problem with the injection system? I read back through your postings but I didn't see where you've done any injection work. Are all the fuel lines good? No air leaks? Bubbles?

I'm still wondering about the integrity of the sensor wiring, particularly the MAF. If you want to do continuity testing on it, I can post the instructions later this evening.

Also, I'd sure love to get hold of a data log of your sensor readings...

muleears · #37 11-26-2008, 04:52 PM

Quote:

Originally Posted by KarTek

This is just a theory but I'm wondering how the ECU determines that the engine is "mis-firing".

Just thinking out loud but my questions are:

If you continue to drive, does the performance deterorate or is it an instant change after shutdown and restart?

It idles well in both "conditions" hot start and cold start. It is when I put a load on it that the problem presents itself. With the hot start it seems to be instant, as soon as I step on the pedal I know. It also seems to run the same, not get worse or improve. I have never driven it over three miles in this condition, it can't be good for it. No known injector work.

Something else I should point out; it seems that it will run in the "cold start" mode indefinetly, until shut off. I have driven it 40 mi. in the cold start condition, only to have it act up instantly after a stop at a fuel station.

KarTek · #38 11-26-2008, 05:45 PM

Quote:

Originally Posted by muleears

Something else I should point out; it seems that it will run in the "cold start" mode indefinetly, until shut off. I have driven it 40 mi. in the cold start condition, only to have it act up instantly after a stop at a fuel station.

That seems significant to me... (scratches head...

) So, If it's allowed to cool to a certain point, it will behave somewhat normally upon restart?

notfarnow · #39 11-26-2008, 05:54 PM

$20 says you are getting air past the o-rings when you are under load.

Check the vacuum on the fuel lines pre-lift pump.

muleears · #40 11-26-2008, 06:30 PM

Quote:

Originally Posted by KarTek

That seems significant to me... (scratches head...

) So, If it's allowed to cool to a certain point, it will behave somewhat normally upon restart?

Yes, I don't know how long it must sit to cool. The shortest period I have tried is 7 hrs. Then as long as it is not shut off it will run at 75% (limited boost it seems) until shut down again. Today it sat for no more than 10 min and when restarted and accelerated above idle at all it misses badly. I can't drive above what it creeps at without problems. What happens at a hot restart to cause this transformation... I too am scratching my head

husk · #41 11-27-2008, 02:02 PM

This problem is very weird, I am wondering what will happen once you do get the new MAF, to see if anything changes. I too have had the P0300 code, once we switched over to ULSD. I have been running B100 and it has not come back. My best is still on the MAF.

muleears · #42 11-28-2008, 06:28 PM

********az is going to cover the MAF under warranty, I should have another new one late next week. I'm coming to the conclusion that I have more than one problem and no one part is going to fix it. I think there are at least a couple gremlins in there that need exorcising.

I am still confused as to why/what the shutoff/hotstart changes.

KarTek · #43 11-28-2008, 06:50 PM

Well, I was thinking about you as I was working on my car today. It's been off the road for 3 months now and it sure shows!

Look at how dusty she is! And how rusty the rotors are!

It started right up after I finished but it has some kind of code and it's running with no boost like your car does when you cold start it. It looks like if there's a code, it'll only run so hard...

The first place I went was the car wash...

One other thing occured to me. Have you ever replaced or serviced the K40 relay? I think it supplies power to all the sensors but I'll have to double check the wiring to be sure. If it's sending jittery or intermittant power, it's sure to cause trouble...

muleears · #44 11-28-2008, 07:18 PM

Terry was kind enough to loan me a known good k40. So we tried that a few weeks ago. No change. Good thought though. Right now I'm waiting for my new MAF to see what that does.

KarTek · #45 11-28-2008, 07:42 PM

I guess we'll see what happens when you get the new MAF. I think getting rid of that code should be job 1 then work from there.