Replaced intake manifold gasket and now won't start - 300 SDL - PeachParts Mercedes-Benz Forum

tstarr · #1 11-04-2003, 08:47 PM

To the august group,

I'm a bit perplexed at the moment. I needed to replace the shutoff valve since I really got tired of popping the hood and hitting the shutoff switch every time I wanted to stop. I pulled the intake manifold and crossover pipe, replaced the shutoff valve and a couple of glow plugs. I put everything back together, torqued it down and the car won't start. I'm getting blow out of the spot where the crossover pipe connects to the turbo, but everything else seems to be OK. I don't see any leaking around the intake manifold gasket. Any ideas? I was wondering if I needed to bang down on the crossover pipe to get a better seat into the turbo, but I'm hesitant to bang too much. Any help greatly appreciated.

- Ted

turbodiesel · #2 11-04-2003, 09:43 PM

Sounds like something is messed up with the shutoff valve. If you hold the STOP lever down, the car won't start.

tstarr · #3 11-04-2003, 09:45 PM

Turbodiesel,

I was wondering about that. After I replaced the shutoff valve, I pulled vacuum on it and it depressed. When I released vacuum, the lever came back up. I assumed that was OK. Also, I am getting diesel fuel (there's lots of smoke coming out the exhaust), so I thought that the stop lever was functioning OK.

- Ted

kerry · #4 11-04-2003, 10:49 PM

This may be a blessing in disguise. Have you read the threads about the engine running away after replacing a shut off valve? If not, read them and be prepared to take the necessary action to stop your engine should there be a malfunction in the newly installed shut off valve.

Somebody lost an engine in the recent past when it ran away after installing a shut off valve. (Larry Bible???)

tstarr · #5 11-04-2003, 11:11 PM

Kerry,

Yes, I read those threads and was prepared to pull the fuel line if necessary. I guess it could be the shutoff valve, but I'm not sure since I'm smelling a lot of fuel and seeing a bunch of smoke out the exhaust. Also, there's something blowing out of where the crossover pipe plugs into the turbo. I'm thinking that may not be down as far as it needs to be and isn't sealing. I've put a new O-ring on it. Well, I'll look at it tomorrow...

- Ted

sixto · #6 11-05-2003, 12:16 AM

MB Diesels are fuel throttled, not air throttled so the crossover pipe has nothing to do with starting or running. It's only there to serve as a source of filtered and pressurized air.

Did you pull the fuel lines when you replaced the intake manifold gasket? If so, did you bleed the fuel system before getting the car to start? On the 603 it'll self bleed if you crank for a minute straight. I can't see letting the starter get that hot so I crack the injector lines and give it 2 or 3 cranks of 10 seconds each, closing the lines that show fuel along the way.

The trouble I had when I replaced my shut-off valve was that the stop lever stayed down. I had to wire it in the up position to start the car. After one start it stayed up on its own. I figure there's something not right with the key switch such as the vent being clogged. It hasn't happened again so I haven't looked into it further.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

tstarr · #7 11-05-2003, 06:31 AM

sixto,

Thanks. I'm going to look elsewhere than the crossover pipe. I didn't pull the fuel lines when I replaced the intake manifold. And the lever is up at rest. If I pull a vacuum on the shutoff valve, the lever goes down. Release the vacuum and it goes back up. That leads me to believe the shutoff valve is hooked up correctly.
But I want to get out there today with a fresh look at the hoses, etc., and I'll bleed the fuel lines anyway.

- Ted

Ken300D · #8 11-05-2003, 07:28 AM

My suggestion will be the glow plugs. These engines seem more cold natured with their aluminum heads than the older diesels. My 1987 needs the glow plugs to start even in warm weather.

So, check your glow plug wiring again, and make sure you are actually sending voltage to them. Got a voltmeter?

Ken300D

tstarr · #9 11-05-2003, 03:16 PM

Ken,

The big fuse is blown on the glow plug relay. Actually, it was blown before and the car started. I stopped by my parts place and she was out of the 80A, so she gave me a 50A, but it has already blown. I went through the first couple of checks, bulb goes on, voltage getting to the box, etc. and everything has checked out. The next check I need to do (according to the CD) requires the fuse to be there, so I'm on hold for now. Also, I ran the battery down this morning cranking it and am recharging. It did seem to TRY to start up several times, giving me some hope here. But I won't be able to go get the fuse until tomorrow, so I'll pick it up again then.

- Ted

Ken300D · #10 11-05-2003, 05:25 PM

If it were something I needed to start and had carefully confirmed no pinched glow plug wires, then I'd jumper the two fuse bolts with a pair of needle nose pliars and get the car started.

Also would consider using two of the 50-amp fuses together under the bolts.

Ken300D

tstarr · #11 11-06-2003, 09:04 PM

The saga continues. I replaced the 80A fuse, charged up the battery, but I get nothing now. THe glow plug light comes on, but the starter doesn't turn at all. The car has been in the driveway all day and, with it raining all day, I'm hoping that some wiring just got wet. The rain has stopped, so it should dry out overnight and (fingers and toes crossed...), hopefully it will start.

- Ted

turbodiesel · #12 11-06-2003, 09:07 PM

Tap on the starter casing with a hammer a few times.

tstarr · #13 11-06-2003, 09:11 PM

Thanks. I'll try that in the morning. The glow plug light stays on about 10 seconds or so, and the fuse hasn't blown, so everything looks good there. Also, I discovered the proverbial "extra" part when at the bench which turned out to be a rubber washer type thing which fits over the turbo intake from the crossover pipe. Duh! That would explain the extra blast of air out of there. Hopefully all will be cool tomorrow.

- Ted

tstarr · #14 11-11-2003, 11:22 PM

Problem is solved. I tapped on the starter many times to no avail, so figured it must be the starter. Replaced it and I'm back in business. All I can figure is the starter must have been on its last legs and the strain I put on it trying to start it after replacing the gasket did it in. Now I also notice that I have a leaky injector as well. It's always something, but replacing that should be much easier. The starter wasn't too bad, but I had the car in the driveway on a slight slope. Coming at it from underneath with plenty of clearance would have made it a much faster job. But it's good to have the car starting and quckly turning off now. Woo hoo!

- Ted