Injector #6 shuts off @ 5000RPM on ML320
 

Driving normally - all is ok.
Press the pedal to kick down in gears and reach approx. 5000 RPM, I have determined that the injector for cylinder #6 closes.
Under normal driving, I have determined the injector works fine.
did all the things like:
replacing crank shaft sensor
replacing MAF sensor,
replacing spark plug and lead and coil pack
checked wiring loom
PLEASE.... any solutions?

How about excessive exhaust back-pressure 0n the left side catalyst?...

Also that system doesn't have fuel return, if there is a "pocket" of non-fuel like water then it will stay at the rear of the fuel rail..no place to go.

Thank you, M.B.Doc.

Sorry to query but I am a novice here....

If there was water in the injector line, would the problem be there more constantly?
Also, would a blocked cat. cause a more consistent rough idle/halted injector in all rev ranges?

Well this beats all....
Just spoke to the mechanic who advised there was no apparent fault with the engine - when he drove it cold 1st thing in the morning.
Cylinder/injector reverted to faulty after the car's initial warm up.

PLEASE.... any clues here??????????????????

During warm-up the fuel mixture is RICH, as the engine warms-up the mixture goes very lean..any weakness will show up.

Checking the exhaust back-pressure is a somewhat simple task..I would want to rule out that problem first.

Also contamination in the fuel rail is common, possibly removing the fuel rail & marking & moving that injector to a different location.

has a compression test been done?

First let me thank you very much for your interest n my problem. I am so glad I discovered this excellent forum.

Compression test has been done and readings are excelent.
Not sure if fuel rail has been cleaned out but I do know a fuel pressure test has been done.
Don't know if exhaust back pressure test has been done but do know that exhaust emissions test has been done and readings are ok.

Is exhaust back pressure test difficult? ... much involved ?

A back-pressure test requires an adaptor & gauge w/hose to screw into the front O2 sensor fitting(s).

why two posts for same topic?

http://www.peachparts.com/shopforum/showthread.php?t=165342

My apology. It was an error on my part.

any luck with the crank sensor?

No luck unfortunately. Fitted a new sensor and cleared computer values. Then took it for a drive. Kicked down the transmission to reach high revs... same ol same ol !!!!!

were you able to get a code when they reset it?

i just read about the Pocket of non fuel also, do you have a product in your country called dry Gas? i have heard of this working

Don't recall exactly. But something about Injector 6 malfunctioning.

Needless to say, we replaced the injector several times with no improvement.

Don't know about Dry Gas but I will, for sure, look into it. Thank you.