88 300E M-103 auto. turns over, won't start... - Page 4 - PeachParts Mercedes-Benz Forum

400Eric · #46 03-05-2009, 05:52 AM

Prepping the M-119 car for it's day at the strip (03/07/09). After that, have to move the turbo 740 wagon, after that, it's back to work on this one. Regards, Eric

sportline7 · #47 05-09-2009, 12:10 PM

Keep looking, when you find the problem let us know.

400Eric · #48 05-12-2009, 07:06 AM

Sorry guys. I hate it when a thread starter doesn't wrap up a thread properly so I always try to do the right thing and not leave a thread hanging. I just simply haven't gotten back to work on this car yet but I will get to it and when I do, I will report back here what it took to get it running again. I fear that by the time I get to it, the gas will be bad after all so now I'll be trying to chase down more than one problem. Regards, Eric

tinypanzer · #49 05-12-2009, 04:48 PM

The air meter plate not having much resistance when you push on it could be a stuck plunger, but it could also be a bad fuel pump or just lack of fuel pressure. When the system is up to proper fuel pressure, the air meter plate will be noticeably stiffer than when it isn't.

The proper thing to do would be to test your fuel pressure. I think it's supposed to be in the neighborhood of 85 psi. Might wanna verify that.

Do you have a mechanics stethoscope? If so, with the ignition in the ON position, place the steth on one of the injectors. Push the air meter plate down. You should hear the injector squirt, and if it is working well, it should chatter slightly. If that all checks out, then indeed you are getting fuel to your engine and pressure would seem to be adequate.

At that point, I would start checking for vacuum leaks, and possibly the coolant temp sensors. If they are way off, it can make starting near impossible.

Pull out your plugs and clean/gap them. All of these failed starting attempts could have fouled them.

Good luck!

400Eric · #50 07-04-2009, 02:33 AM

"All of these failed starting attempts could have fouled them."
I'm thinking that last sentence may hit it on the head. Got the car running today! All I did was a couple squirts of ether a couple times and it was off to the races! Well, not exactly the races but it did run good enough to drive. I wasn't even really trying to make it run....the ether was just the next step in my diagnostic plan. The gas in there NOW IS old so it probably won't be running at it's best until all that old gas is out of there. So it's running...that's the good news. The bad news is that we still don't know why the car wouldn't start in the first place and we also don't know if this problem is gonna re-visit me again. Thanks though to all who posted! I will update again if and when there are any developments.
Regards, Eric

pawoSD · #51 07-04-2009, 11:48 AM

It may be a combination of temperature sensor failure, idle control valve issues, or fouled spark plugs.....what RPM does it run at once you got it started? If its like 500ish then its running on mechanical injection and the computer is not involved. (Hence the rough running)

400Eric · #52 07-04-2009, 05:12 PM

It was idling normally and it would rev normally with no load but it won't rev normally with a load....seems to be starving for fuel. Don't know if that is what's happening but that's what it seems like.
Regards, Eric

400Eric · #53 07-09-2009, 06:15 AM

Drove it some more today.... as long as I'm driving like a granny, it runs great but any attempt at anything resembling acceleration and it either bucks or just bogs until I let back up on the pedal. And it's still hard to start.... had to squirt it again once with ether to start it today but at least now it tries to start without it so that's progress I guess. BTW, this car ran fabulous before it got parked for that extended period of time. Any ideas what I should be looking at now? Or do I just need to run all this old gas out of it?
Regards, Eric

mak · #54 07-09-2009, 09:02 AM

it should fire up with starting fluid sprayed down the throttle bore, acc pedal fully depressed to keep the throttle plate open .That is if the ignition and plugs are ok.
mak
300se

JayRash · #55 07-09-2009, 01:00 PM

if the fuel is old man flush it out. Get some fresh fuel in and add a bottle of injection cleaners and drive . If that solves it add another one once u have to refuel. Should clean the fuel head.

gsxr · #56 07-09-2009, 01:39 PM

Sounds like the acceleration enrichment isn't working, and/or the EHA isn't working right. I'd try some heavy-duty fuel system cleaner like BG-44K before throwing parts at it.

pentoman · #57 07-09-2009, 04:51 PM

Quote:

Originally Posted by 400Eric

Is that the plate over the throttle body? It's not stuck---it is funny you would mention that. It actually seems to me that there is not enough resistance---the plate seems to move too freely. How much resistance should there be? Maybe something has failed (a diaphragm? Maybe it got chewed?) If it's not getting sucked open when it should be, that would be the same as it being stuck closed. I need to check the one on the '89. I also need to watch how that plate is supposed to behave when starting/running. Thanks. Regards, Eric

THe air flap will have resistance when there is fuel pressure, but it dies away over time.
If you remove your fuel distributor completely, the flap becomes floppy, almost so that it moves under its own weight. But connect to car and turn on the ignition, it becomes much more resistant. The resistance doesn't seem to go away even if the car is left overnight etc.

I don't think you need any acceleration enrichment for the car to drive alright. No way it should stutter and completely bog down, but maybe a bit of bogging is 'acceptable' with an EHA not-functioning problem. Try disconnecting the EHA just to be sure the computer isn't making things worse instead of better.

I once had a major problem of idling but refusing to rev up, when I had put the OVP relay in wonky. It was misaligned by a couple of pins and it completely screwed the engine - luckily I figured it out but even with the relay being the only thing I changed before the problem, I was stumped for a bit. (that may be my stupidity though).

400Eric · #58 07-10-2009, 04:22 AM

Thanks big time guys.

So my marching orders for now are to get all that old gas out of there and run some FI cleaner through it to eliminate those variables, then I will try disconnecting the EHA and see what that does.

It might be a few weeks.... I'm juggling a lot of stuff right now. But I will stay on this.
Regards, Eric

gsxr · #59 07-10-2009, 01:14 PM

Acceleration enrichment is required for the car to drive properly. Otherwise it will stumble whenever you press on the gas. The pedal is snapping open the throttle plate, there has to be a squirt of fuel at the same time otherwise you get - a lean stumble.

Eric, you may need to use a heavy-duty cleaner like BG-44k (it's expensive, but worth it - Google for info) so if you try the cheap stuff from McParts and it doesn't work, move up to the big boy's cleaner next.

400Eric · #60 07-13-2009, 02:25 AM

So I guess the stuff from Big Lots/99cent store/Dollar Tree might not do it? Oh darn.

OK, I'll report when I have news. Thanks again.
Regards, Eric