Shel155

Man I've been around the block with this thing lately here's the story, will try to make it short. Was having fuel starvation issue replaced bent tank and strainer. Ran good for the summer, then started having similar issues. At the moment it will start hard, and run poorly for 15 seconds and then you can only keep it running by PUMPING ACCELERATOR (that's got to be a clue), pumps are working (new). Have replaced following parts, nothing crappy- OEM or MB parts; coil, cap/rotor/plugs/wires, fpr, fuel distributor, bosch pumps and filter, coolant sensors, tank/strainer, fuel injectors, OVP. None of this has changed the situation significantly... the EHA is not leaking, getting 80lbs or so of FP on the top side of FD. A local shop that works on these futzed with it and said it needed fuel injectors which didn't help a bit. If I don't get this solved I'll have to tow it to Benz and have them try and diagnose the issue, would rather not. I admit to being a bit of a "parts thrower" but can do some basic trouble shooting if I know where to start. Any informed suggestions greatly appreciated!

Shel155

Changed out the plugs, looked really rich. Runs now at say 3k but won't rev up, not sure if rich or lean because... BUT, was wrong one (rearward) pump still makes a shrieking sound indicating fuel obstruction? Will do some sort of volume test.

Pintoo

[QUOTE=Shel155;7709035]Changed out the plugs, looked really rich. Runs now at say 3k but won't rev up, not sure if rich or lean because... BUT, was wrong one (rearward) pump still makes a shrieking sound indicating fuel obstruction? Will do some

If engine won't rev over 3k then it's a good chance the catalyst are plugged

Shel155

[QUOTE=Pintoo;
If engine won't rev over 3k then it's a good chance the catalyst are plugged[/QUOTE]

It's a possibility, thanks. A more competent shop has it now, word is that the "altitude sensor" (never heard of it and was hard to find one) was inop, infamous potentiometer on the MAF was fubar, new temp sensor for eng. management (Behr) was off by 20 degrees. They have the parts, waiting to hear from them, hoping all that is what was actually causing the problem, will advise when I get word.

mikkelrev69

Idle control valve? What about rubber parts? MAF rubber boot, ICV hoses., crank vent hoses. All of those rubbers cracks and mess up the air metering. Injector casings and seals. Remember the injector plastic casings has vent openings drawing air from the crank vent channal thus the injector casings must be posisioned correctly.
Vacuum hoses leaking?
Also clogged tank ventilation valves?
When renewimg the ignition and distributor cap you need to check distributor back plate for cracks. If only a little tired this cause arking to the head. It's evident if you spot tiny pittings in the head alu behind the plate
Edit: additional info. Almost nobody is aware of the small fuel filter on the fuel pipe connectimg to fuel distributor. If tvis is clogged it can reduse fuel pressure. You got good fuel pressure BTW? Pressure regulator ok?

Shel155

Well, all those rubber items have either been checked and found good or replaced, vacuum test is good. Has new backing plate, FP checked twice (new pumps cuz old and noisy) regulator new. Verifying those fuel vents was the first thing I mentioned to them so I surely hope they did that will definitely ask again. Yes was vaguely aware of that filter... will mention it when I give them the rebuilt fuel dist that's arriving Friday, along with STI wires (cheap wires were not up to snuff) and new fuel injectors because they tested them, because 3 were plugged and the rest sub par spray patterns and I know why Ah, this car is too early to have those plastic whatever they are, this is just a grommet/seal... right? Darn thing better run like a German Swiss watch. Thanks for the reply.