Power tapers off north of 4k rpm 97 E300 - PeachParts Mercedes-Benz Forum

spark3542 · #1 06-10-2010, 11:24 PM

P0400 code set. found cracked vac line on the intake manifold. Replaced all the lines at the flappers on the crossover pipe and intake manifold. Now have p0200 code every startup.

Also, when hitting the throttle, it will go to 4k and above, but be very anemic on power, when it finally upshifts down to 3k or so, it takes off. It very clearly has more hp at 3k than at 4k.

Both fuel filters are fresh, as I suspected them first, but it still holds back at above 4k.

I'm running B100, and have been for 72k miles. Adding Power Service white for the last 4 tanks seems to have helped somewhat, but its still anemic at high rpm.

What are your thoughts (on either P0200 or no power above 4k)?

Thanks

EdzBenz · #2 06-11-2010, 09:47 AM

-Any air in the fuel lines?
-Are any of the IP seals leaking?

vstech · #3 06-11-2010, 10:12 AM

are the 606 motors usually strong above 4000RPM?
cool!

spark3542 · #4 06-11-2010, 01:02 PM

Quote:

Originally Posted by EdzBenz

-Any air in the fuel lines?
-Are any of the IP seals leaking?

No leaks that I've seen. No fuel smell at all and not a drop of anything on the garage floor.

Wouldn't air in the lines show up in some form at lower rpms?

When I want to accelerate quickly now, I find myself hitting the throttle and watching the tach...as soon as it gets to 4k I feather the throttle to try and get it to upshift. Otherwise it will hang at high rpm with very little accelerating going on.

TMAllison · #5 06-11-2010, 02:27 PM

PO200 Inj Circut seems like a strange code on a diesel with mechanical inj's.

Have you tried a different code reader to confirm the code?

Has your crossover pipe been cleaned recently? Air flaps could be sticking limiting air supply at higher RPM.

KarTek · #6 06-11-2010, 03:09 PM

On my car, some codes will make it seem to "hang" on a gear until well above 4k and then stop pulling. On your NA model, it depends heavily on intake tuning to create good flow throughout the power band.

I would triple check that all the vacuum lines are connected properly and the resonance flaps free to move.

spark3542 · #7 06-11-2010, 09:45 PM

Quote:

Originally Posted by TMAllison

PO200 Inj Circut seems like a strange code on a diesel with mechanical inj's.

Have you tried a different code reader to confirm the code?

Has your crossover pipe been cleaned recently? Air flaps could be sticking limiting air supply at higher RPM.

I cleaned and "freed" up the flaps in both the crossover pipe and the IM. Confirmed that both vac actuators work with my MityVac.

What I haven't yet messed with are the vac lines and components that are adjacent to the air filter box. Does anyone have detail about their function?

I use a scangauge for a code reader.

pimpernell · #8 06-12-2010, 07:54 AM

Quote:

Originally Posted by spark3542

I cleaned and "freed" up the flaps in both the crossover pipe and the IM. Confirmed that both vac actuators work with my MityVac.

What I haven't yet messed with are the vac lines and components that are adjacent to the air filter box. Does anyone have detail about their function?

I use a scangauge for a code reader.

One of them controls the EGR valve, and the other controls the resonance flaps in the intake manifold. They are the same part number, and can be interchanged. The thread below gives some hints as to where to search.

P0200 in 96 e300

TMAllison · #9 06-12-2010, 11:20 AM

Make certain the "vacuum vents" are clear also. Do that first, all you have do is remove that line from the transducer (or the vent from the hose) and go for a drive to see if the code trips.

spark3542 · #10 06-13-2010, 05:33 PM

I confirmed that I have vacuum supply to both valves near the airbox, and confirmed that I have vacuum to both flappers.

Confirmed the vents work on both valves near the airbox (one vents to the airbox, the other to a paper filter...both clear). Swapped valve...still comes up with P0200.

Removed the crossover to confirm operation of the IM flapper. When I do this and start the car, P0400 code only shows up. When I return the crossover, P0400 disappears and P0200 returns.

Confirmed that the flapper on the intake pipe before the crossover is also working.

Everything I've checked so far is functional.

How about the MAF sensor? Is there a way to check it or clean it?

TMAllison · #11 06-13-2010, 07:39 PM

You can clean it with CRC MAF Cleaner (spray), no equal. If the MAF were bad you ought to get PO100.....

briandownunda · #12 11-13-2011, 05:12 PM

did you ever figure out what this problem was?

Zulfiqar · #13 11-13-2011, 08:29 PM

I just helped a guy today with a similar problem in a 95 E300D, he put in new filters, ran DP about 5 times, once MMO - all remained the same, no solid power above 4000 - 4200 rpm. Came out to be a partially blocked tank strainer. I had one lying with me, the car returned to normal power.