1992 300TE just purchased. 3.0 6-cylinder
My first Mercy. Mercy ME! Beauty wagon. Replaced fuel filtr because of stall and long starts. Appears to be rich. THEN started easy but still no "real power" ( 20 seconds to 60 mph) thn after hot it took 10 seconds plus to start, and wouldn't rev above 4-5K rpm. I am new to Mercedes. The problem is intermittent!! M thoughts are that it is fuel related. PLEASE any ideas???

I would seriously look for computer codes, another thing you should check is your air filter and if your car has them the Air sensors both before the engine and after it. any one of those can cause problems. if your service engine or check engine light is on (I dont know if MBZ has these) read the codes, there should be a writeup on how to check them on the site here.

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hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

I would test for fuel pressure to confirm it is within specs. If not, then I would start off by checking out the fuel pressure regulator. Also, a weak fuel accumulator will cause longer crank times when the engine is warm or hot. What is the condition of the ignition system components?

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1989 300CE

Wow , thanks for the fast responses. Has new air filter, but headed to a bone yard today and going to see if I can pull a box full of parts to replace. It is weirdly intermittent...possibly caused by heat..the poor performance may or may not be associated IMHO. I mean , when it starts easy and revs easy, it is still very weak engine. No smoke.
I'll check air sensors. Dont have a computer code tester...no service engine lights are on.
Fuel pressure reg, and accumulator sound suspect to me. I appreciate those pointers.
Haven't removed the distributor cap but cant see how that would effect it intermittently.

Also, I would like to test the fuel pressure, but not sure how to do that.

Fuel pressure regulator and accumulator were replaced today from thwe boneyard , but made little difference. The engine revs so slow, wether in drive in park. Has been idleing a little better, but wont get going . afraid I'm gonn aget ran over.

i think that the ovp relay is bad and the fuel injection computer is not getting power so that you are driving in limp mode.first check the fuses in the top of the relay,they sometimes blow when a car is jump started and the battery not allowed to charge up some.

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David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg

OVP relay? OK where's that baby located? Sounds like a good one!
Also I rented a fuel-pressure tester from AutoZone for $165 , use it , return and they give you full refund. Keep it for 10 days and it's yours.
ANYWAY, Before I hook it up, what pressure reading am I suppose to have??
Thanks a bunch!

the OVP relay is generally near the battery, it may have a clear cover, it'll be square and look simular to this one On the TE's it should be in the same general area, I could be wrong

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hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

Check the coolant temperature sensors, there is a thread here I posted with the correct values; you can search for it. The sensors that feed the engine and fuel computers are separate from the one that feeds the display on your instrument cluster, so you can't go by that alone.

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-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition

YEP, Found it and pulled the OVP, but fuse is still good. ...fwiw the SRS light is on...(is that the check engine light ?? as I don't see one labeled otherwise)
I'll search for the coolant temp sensors. I did read where you posted that info TinyPanzer.

found the info. Tested the fuel line pressure at the filter using the banjo adapter with the kit. Book said 46-52 psi . It reads 40 then leaks down top 38psi. There's 2 pumps on this car. Anyway to test which is bad or assume they are both bad?
Please,. thanks.
Les

Isn't the M103 motor rev-limited to 4K in park or neutral? That's by design.

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1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't

May ba a rev limiter, but it revs very slow...and does occasionally jump above the 4K to 5 or 6 . Somethings still not right.

I don't know if this makes logical sense for your symptoms, but maybe you should consider that the fuel pump relay is malfunctioning, inasmuch as the FPR is where the rev limiter function comes from. If you can rev above the established 4K limit, maybe that's an indication that the relay isn't good anymore, and might be contributing to the anemic performance symptoms you described. Just a thought.

__________________
1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't