Your vehicle has been exorcised!

My car has been blessed by both a Priest and a Rabbi (just in case). lol

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Paul,

It certainly sounds like your persistence and exorcism has been successful. I need to find the formula to exorcise mine!!!

My question to you is: has your gas mileage been affected by all these events? My headache is not too different from yours, but my mileage is down about 25%.

Mine is a 93 300E 2.8. A slightly different engine. Just before 95k mi. the CE light came on -- O2 sensor bad. I replaced it with a Bosch generic unit (after calling Bosch to make sure it was the right one -- 4 wire interface). In a couple of thousand mi., the CE light came back and would not go off. This time, to a dealer, who said the wiring harness was shot. The dealer replaced it at no cost. Since that day, the gas mileage has gone from about 25 mpg to 20. That has really has bothered me.

A few days later, the CE light came on again. The dealer said its the O2 sensor -- running too rich. This time, I had it replaced with an OEM O2 sensor. A little while later, another CE light -- this time, the EGR code. Got it fixed. Next time, the intake manifold length tuning flap. Got it replaced. None of these has brought the mileage back up. Now, it's giving the 26 code. After reading your thread, I'll check the vacuum on the tranny delay shift switch (and the switch). That should remove the 26 code, but won't account for the gas mileage drop.

Any ideas on what might cause the reduction in gas mileage on this car that runs perfectly -- now with 134k miles?

Thanks,

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Eric

With all the O2 sensor and egr codes, you may have a plugged hot inlet pipe to the intake manifold. The egr valve is on the exhaust manifold, and when the egr valve opens, it allows egr vapors to travel back to the intake manifold via this hot inlet pipe.

Steve Brotherton wrote an article in the DIY link at the top of the screen called Evaluating Electronic Engine Controls that shows this problem on a C280, which I think is the same engine as yours. The first half or so of this article is too technical for this shadetree mechanic, but this problem is explained at the end, with pictures. This condition seems to be systematic with all M104 engines (including mine).

This pipe gets coked up with carbon from these vapors, and triggers a code for low egr flow.

The fix is to ream out the pipe with a cable, like a speedometer cable, and a drill motor.

I've think I've read a post from Benzmac saying that he performs this every 30,000 miles on M104 engines as part of regular maintenance.

My mileage didn't really suffer through this process, only to the extent that it dropped while the mechanics kept the engine running so long diagnosing it.

My average mpg is about 21 - 21.5 consistently.

I have experienced in other cars significant drops in mpg when my O2 sensors were bad, though.

Don't give up on your problems, though. I had one indie mechanic give up and say he couldn't diagnose my CE light problems. Another indie mechanic blamed it on the car , you know "..sometimes these engines have CE light problems that have no real source...yada yada yada yada". He was wrong, and this website helped me diagnose the problem.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Paul,

Thanks for the suggestion on the hot inlet pipe. I'll have this checked out when I bring my car in for the next service next week.

I've not given up on bringing my gas mileage back up. I've seen a number of mechanics, including at Fletcher Jones Mercedes, regard a constant CE light as just normal on an old 124. But I have the same compulsiveness you noted in your earlier posts. Fixing a problem like this just takes time and patience, which is tough. But I know that, eventually, I will prevail. BTW, I've also found the help on this forum to be excellent.

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Eric

You're in Mission Viejo. I just came back from the Cheesecake Factory at the Mission Viejo Mall for a get together with my brother's family.

JCE (John) lives just across the freeway in San Juan Capistrano.

We had our last get together at the mall, where we looked at our cars, shared experiences on repairs, maintenance, upgrades, etc.

You should come to the next one.

John knows a great Mercedes independent mechanic in the area. You might e-mail him through the site to find out who it is.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Paul,

I'd be happy to come to the next meeting. John and I have talked about meeting, but never got it together to do so. Keep me posted.

I know of his mechanic, but it's not close for me since I work in Irvine. I have a fine mechanic in Newport Beach who does most of the work on my car.

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Eric

By the way, fwiw, you may have noticed that Arthur Dalton helped me a lot on this thread, and I've noticed he helps a lot of people with CE light problems.

He seems to know enough about these cars, that I'm willing to bet he either is or was a mechanic on these cars.

He also knows what each code number means for each car.

He may be able to provide insight / support for you, as well.

I also recommend you do what I did. I print out pages from this website when there's been a diagonsis that matches my problem and show it to my mechanic. He may be a little insulted, but it's your car, isn't it?

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

just some more feedback on those pesky "upshift delay" problems.

simple check out for function, unplug the hose leading to the bowden cable from the upshift delay swwitchover valve and apply a hand vacum of 20 hg or so, drive it, it should sift under very light throttle at 2400 or so for most 103's and 104's, if it dont, adjust the cable. Its the 5mm hex on the backside of the upshift delay actuator on the r'h side of the tranny. Not all models have 1-2 delay such as the 202.028 (c280, 1995), check the book for your model.

if it functions correctly, add in a vacum guage on the actuator side of the vacum line, with a stone cold motor (20c) drive it easy and your vacum guage should read about 16 to25 hg for 80 seconds or so and fall to zero after the 2-3 shift. If it dosen't start looking at electrical funtion of the switchover valve (activated by HFM/SFI) and put 12v and ground to the valve to make sure it works. (benz also says to add in a DVOM to see the votage provided by HFM).

I've recently had my butt kicked by a repeated upshift fault and am pretty familar with the players. HFM, ECT, bowden cable, vacum dist. block, DM and the swichover valve.


Joe

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Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.
Raleigh NC
919-881-0364

First of all, the 95 C280 does have the upshift delay. Secondly, it's the 2nd-3rd gear shift that is delayed.

Eric,
Would you mind telling me your mechanic in Newport? Thanks.

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2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)

David,

My mechanic in Newport is Strasse Automotive at 629 Ohms Way. They're actually on the Costa Mesa side of the border -- near Hoag Hospital. It's a small shop with 3 mechanics including the owner, Stan, who's a former racer.

I've used them on a Porsche, 2 Audis and 2 MBs for nearly 30 years. They're not magicians and don't always get everything right the first time (tough diagnoses sometimes take a few tries). But they're as stubborn as I am, stand behind the work, and usually come through. Unfortunately, Stan's just had a change in personnel on both other mechanics, including the one who works on MBs. So I'm watching the new guy carefully. I've had my diesel in there once under the new mechanic and it's too soon to know if he's up to Stan's standards. As Paul suggested, I've been known to print notes from this forum and bring them in. We'll see how the the new guy deals with that! This will happen first week in April. I'll keep you posted.

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Eric

"First of all, the 95 C280 does have the upshift delay. Secondly, it's the 2nd-3rd gear shift that is delayed. "

David, reread my post, I clearly stated the 95 c280 has no 1-2 upshift delay.

And just for yucks, the .6 of 96 up production has it as well, only it's software driven.

Joe

__________________
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.
Raleigh NC
919-881-0364

Ohhh I see now. Everyone always thinks that's it's the 1-2 upshift delay, so I thought that you were referring to the delay, and that my car does not have one.

Miscommunication.

__________________
2006 E350 w/ 155k miles (Daily Driver)

Previous:
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)