I've had problems with excessive fuel consumption for a while now. But today it went absolutely haywire..!

It is smoking like crazy (brown/black unburnt fuel-smoke) whenever i touch the gas pedal. And i used almost half a tank driving only 120 miles!

From reading other posts, i suspect the fuel pressure regulator, but don't know how to check it..?

Any ideas to what might be wrong?

Freestyler

__________________
Never criticize someone until you've walked a mile in his shoes. That way, when you do, you're a mile away -and you have his shoes!


'86 300E optically converted to '95 E300 (Sold)
-Blauschwarz on silver
-Black leather
-17" AMG & 15" AMG for winter

Fuel pressure would be a good start. You check it by teeing a gauge into the system and reading it.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Unfortunately i haven't got a service manual yet.

What kind of pressure should i be reading from the fuel pressure regulator?

Freestyler

__________________
Never criticize someone until you've walked a mile in his shoes. That way, when you do, you're a mile away -and you have his shoes!


'86 300E optically converted to '95 E300 (Sold)
-Blauschwarz on silver
-Black leather
-17" AMG & 15" AMG for winter

Something i have forgotten to mention:

Around the same time this fuel-hell started, i noticed a distinct rhythmic clicking (sounds like a relay going on and off) inside the drivers door.
When it clicks on -or off? every 3 secs. the engine surges for a second when idling..!?

Do i have a relay, controlling engine functions inside my door?

Freestyler

__________________
Never criticize someone until you've walked a mile in his shoes. That way, when you do, you're a mile away -and you have his shoes!


'86 300E optically converted to '95 E300 (Sold)
-Blauschwarz on silver
-Black leather
-17" AMG & 15" AMG for winter

Update:

I replaced the fuel regulator. And the extraordinary heavy fuel consumption and clouds of black smoke went back to "normal".

By normal, i mean ~10 mpg and black smoke whenever the revs above 4000 rpm.

Another problem has arised (it'll never stop). When i touch the gas pedal from a full stop, the engine surges and half of the times completely dies. -Very annoying!

The only thing i can think of is the little microswitch that is released when activating the gas pedal. Could this switch cause a surge like this if it's bad?

__________________
Never criticize someone until you've walked a mile in his shoes. That way, when you do, you're a mile away -and you have his shoes!


'86 300E optically converted to '95 E300 (Sold)
-Blauschwarz on silver
-Black leather
-17" AMG & 15" AMG for winter

Last week I finally had enough of this and sent the Benz to a highly recommended shop that almost exclusively is reparing Mercedes-Benz'es.

It took the mech almost 4 working days to come up with the conclusion that he couldn't pinpoint the exact problem..

What he DID find was several corroded electrical connections at various relays and at the ignition coil. And one of the pins on the relay that says "Kickdwn..something" on it, was corroded entirely away! -This took care of the hesitation-from-standstill problem, but fuel was still pouring through.

Finally he replaced the ENTIRE injection system with a used one from a wrecked 300E.
He also replaced the cat, since it was shot after having been soaked in unburned fuel for so long.
Now he could adjust the mixture to spec.

I was there when he made the final adjustmens and i was happy as can be. Finally my Benz were running smooth again. -Or so i thought..

Yesterday morning i went to start the car. (first cold start since repair). It started fine -and immediately died.
This repeated a couple of times until it barely kept itself running with a very rough idle at 500 rpm. -Also after warming up.
The car runs perfect now exept for this rough idle and an occasional stall after breaking to a standstill. And gas milage has improved drastically

But we're going to the shop again..

This is going to be REALLY expensive i'm afraid..

Freestyler

__________________
Never criticize someone until you've walked a mile in his shoes. That way, when you do, you're a mile away -and you have his shoes!


'86 300E optically converted to '95 E300 (Sold)
-Blauschwarz on silver
-Black leather
-17" AMG & 15" AMG for winter

I know that several of us are following your saga. I know I am, since I am having similar problems. We hope the best of luck for you!! Hang in there!!

Yeah, hang in there, you'll suddenly find what it is and be running like new again

__________________
190E's:
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black 2nd owner
http://www.maylane.demon.co.uk/190esmall.jpghttp://www.maylane.demon.co.uk/190esmall2.jpg

And then tell us what fixed it!

Can you briefly describe how you changed a '86 300E to a '95 E300?

Well.. After a last adjustment of the little hex-screw (fuel/air mix) it now runs perfect! CO was WAY down. -Couldn't even measure it on a CO-meter.

So the remedy is this..

Replace the following:

-The entire injection system.
-The cat.
-The ignition coil.
-ALL the vacuum hoses.
-All the ignition wires.
-The ingnition distributor and rotor.
-A handfull of relays.

-Pay the $3000 (on top of the $4000 you already spent on repairs the last year) and be happy the mechanic was able to use used parts. -otherwise it would have cost 3 times as much!

-Put this never ending money pit up for sale and never look at a Benz for the rest of your life..

Peace out..

Freestyler

__________________
Never criticize someone until you've walked a mile in his shoes. That way, when you do, you're a mile away -and you have his shoes!


'86 300E optically converted to '95 E300 (Sold)
-Blauschwarz on silver
-Black leather
-17" AMG & 15" AMG for winter

Wow!!!!

What a horror story. In the trade we call it a radiator cap kit. Remove the radiator and slide a new car under it. I'm really surprised that anyone so inept at diagnosing would be able to assemble all that and have it run at all.

I guess that should be the standard for a good tech: the ability to get the car running after replacing every part on it.

How does he deal with the complicated models?

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Too much! Thanks ..... I'm still laughing.

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)

He doesn't. The shop specializes in older MB's.
And while it seems a bit overkill to replace all this, mind you that 2 different MB dealerships gave up finding the defect! -Or rather they told me the only way was to start replacing parts from one end of the engine bay until faulty part was found..! (mucho $$$)

This guy just did it for far less money..

stevebfl I love the "radiator cap kit".
I have heard another version of that 'fix'. -Gently unscrew both front and rear licencense plates.. -Replace whatever was between them.. -Then screw license plates back on. -Car runs like new!

Freestyler

__________________
Never criticize someone until you've walked a mile in his shoes. That way, when you do, you're a mile away -and you have his shoes!


'86 300E optically converted to '95 E300 (Sold)
-Blauschwarz on silver
-Black leather
-17" AMG & 15" AMG for winter

I refuse to do that! I have reached the point that my desire to diagonse and repair my challenge has faded away. I intend to take mine to a pro and say "please don't hurt me!", but at the same time I'll tell them "when you get to the point where you're guessing, just pull it out and start selling parts off it".