350SDL, original owner, 147K miles.

I have a rough idle situation that started with a shop replacing the pressure valve seals on top of the injector pump.

In an attempt to cure the problem I am going to have another shop repeat the seal replacement process. I think it is possible that the first shop over tightened the pressure valve holders possibly damaging one or more of the pressure valves?

Is there any way to evaluate the condition of the pressure valves? Would it be a good idea to just replace them as part of the resealing process?

I am also considering having the injectors rebuilt or replacing them with rebuilt ones at the same time. With my mileage is this a good idea? Is it better to rebuild my injectors or replace them with rebuilt ones? What is the best source for rebuilt injectors?

Thank you.

ezrider:

My experience has been that the pressure valve holder are undertightened rather than overtightened, but there are always exceptions...

It will be obvious if they are broken -- the only thing that can happen to them is that they crack, and since the body of the pump is aluminum, I'd expect the holder to strip before the pressure valve cracked.

FastLane is as good a source of injectors as any, but any Bosch service center (diesel injection service) can rebuild them at the same price. Nozzle replacement is all that is required, along with setting the opening pressure.

I'm fairly certain that you can expect some wear on the nozzles by 325,000 miles!. However, trouble immediately after seal replacement makes me think they only replaced the 0-rings (you had a fuel leak around the pressure valve holders, right?), and the actual "copper" seals weren't replaced as well.

If the pressure valve seals are bad, you will have rough idle at all temps, not just cold. Rough idle cold only would more likely be bad glowplugs or injectors.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Peter,

Yes they were leaking and I can't get a straight answer if just the rubber o rings were replaced. Is it a good idea to repalce the copper seals too? One shop I talked to says they never replace the copper seals.

All glow plugs are new. Always rough idle and injector knock until it warms up.

After warm up rough idle is intermitttent and it is there more often than not. When it is not noticeably rough I can still hear a slight miss.

Thank you.

Copper seals are so cheap it is silly not to replace them, and since the holder rotates on them, unlike the older pump designs (those are under the pressure valve, not on top), good bet they are leaking a bit. Mine cost me $7.81 for both seals and o-rings.

If you have the same symptoms warm, get the seals replaced. Should solve the problem.

My brother said my 87 300D is dangerous, speed creeps up to fast and you can't tell! I love my 603!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

My 603 has been terrific.

Have you ever replaced your timing chain on your 603?

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87' 300sdl

How can you tell if the timing chain needs replacement?

My chain was severely stretched, by my first warning sign was when I would open the hood, and revv the engine, and hear a faint rattle at the front of the engine. It didn't sound like a knock or a valve, it sounded exactly like a chain vibrating around in there. You should probably have your chain stretch checked, especially with that engine.

well from what i've read, you remove the valve cover, roll the engine over to #1 tdc, line the mark up on the front of the cam ( the mark is between the gear and #1 cam bearing). When the mark is lined up with mark on the cam bearing cap. Look at the degrees on the damper if it is 4 degrees or more off from 0 that means the chain is streched too much.

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87' 300sdl

EZ:

I have a deep suspicion mine has a new chain, along with a new radiator and head -- suspicious, it went on eBay to an unsuspecting PO for a decent price, he was I think the fourth owner? Whatever. Ran terrible when I bought if from him, was expecting to do the head due to cracks (that new rad -- probably a busted hot side hose nipple....). New seals fixed the trouble, but I suspect, since there was oil in the coolant tank after I drove it a while, that the head was replaced due to cracks and that the timing chain was, too.

You may have to remove the front top cover to check the chain on the 603, I've not looked. The valve cover may not cover the cam gear. I know this is the case on the 103, and Benz tends to make the engines in classes.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!