W115 Pulsing After Valve Adjustment and Injection Pump Re-Timing.

[bipolardave]

Hey folks.

I finally got a replacement for the lost delivery valve spring and took it out for a drive today.

Just a few weeks ago, I adjusted the valves and, with your help, got the injection pump dialed in.

Anyway, the idle felt weird after starting it up but I took it for a 20 mile spin, regardless.

The first thing that I noticed was more black smoke. It's running a lot richer than it did before the adjustments.

At idle and low speeds, I feel a pulsing that propagates throughout the car. The engine noticeably shakes but at highway speeds it's smooth as ever and my butt dyno indicates more power.

I stopped by my local mechanic and the first thing he said was, "Your Mercedes isn't as smooth as it normally is. It's pulsing," Funny that we'd independently arrive at the same word to describe it.

However, I felt it whereas he could hear it from the tail pipe.

My mechanic friend seems to think that I might have misadjusted a valve which could cause the pulsing as well as too much fuel. He's not a diesel guy, but he thinks that's more likely than a slightly mistimed injection pump.

Anyway, is that were I should look first?

[Diesel911]

When I was a Kid a mechanically inclined neighbor told me when you work on your Car do one proceedure at a time and then test drive the Car. He said if you do several preccedures at one time you won't know which one of the proceedures fixed the problem.

In your case you don't know which of 2 procceured caused the problem.

You can re-check the valves.

Getting the Fuel Injection Pump too advanced can also cause it to smoke. But the valve clearence are easier to check.

[bipolardave]

Checked the valve clearance - two intake and one exhaust valve were ever so slightly loose. Adjusted accordingly.

On a hunch, I replaced the crush washer and o ring around #1 delivery valve.

I buttoned up and restarted to no avail. It still pulses. Think Harley Davidson, but nowhere near as loud - just a mild thud-thud-thud from the exhaust with a shaking engine. It goes away at higher RPMs.

No other unusual engines sounds.

No champagne bubbles in the pre filter.

The only thing different is #1 delivery valve spring. I ordered a few replacements from a local Bosch shop. I could be mistaken, but I thought they were all replaced when the IP was rebuilt. If so, they should all be the same part # and not too far apart in age.

If they weren't replaced, would having one new spring (or possibly incorrect part number) alongside three old be an issue?

[danken]

Originally Posted by Diesel911

When I was a Kid a mechanically inclined neighbor told me when you work on your Car do one proceedure at a time and then test drive the Car. He said if you do several preccedures at one time you won't know which one of the proceedures fixed the problem.

I am saving this...

[Diesel911]

If the Fuel Injection Pump has a pneumatic governor a vacuum leak causes the governor pump to give more fuel.

[Diesel911]

Originally Posted by danken

I am saving this...

Also, if you did say 3 things and test and find out your problem is worse which one of the 3 caused the problem to get worse?