Ticking - PeachParts Mercedes-Benz Forum

psaboic · #1 09-03-2014, 10:08 PM

Hey folks,

Any idea what would cause a ticking that sounds like nails being dropped on a chalkboard sound coming from the engine bay? It just started a couple days ago (and now for the weird part) it only occurs in gear at 1200 RPM. If the car is in park or neutral there is no ticking, but once warmed up it will tick only at 1200 RPM in gear.

If it was a gasser I would say it was spark knock/pinging. No bad vacuum pump symptoms (brakes, locks, etc work fine)

Glenn

psaboic · #2 09-04-2014, 08:45 AM

Could it be fuel related I wonder? I started using some B-50 two tankfuls ago, but why only tick at 1200 RPM?

barry12345 · #3 09-04-2014, 08:54 AM

My thoughts exactly. Add some additive to the current fuel perhaps. I think this item has to be eliminated as a suspect before moving on anyways.

At least pull the filler cap off and smell the contents of the tank. I was wondering even if some gas in the fuel might enable this issue. It pays in my experience only to fuel up at truck stops when possible and practical.

TX76513 · #4 09-04-2014, 09:11 AM

Try to eliminate the non engine related possibilities like heat shield, alternator bracket, air filter housing, idler pulley, etc. A wooden broom handle is a good way to put some pressure on these items.

vstech · #5 09-04-2014, 09:35 AM

1200 rpm idle is completely different from in gear to the engine. Can you replicate it parked in gear? If so you might be able to park against a wall or tree and hold car under load and loosen an injector line nut at a time and isolate it then swap two and see if it moves or not.

Diesel911 · #6 09-04-2014, 10:44 AM

It could be Fuel Injectin Pump Timing or worn Injector Nozzles.

I had the upper Timing Chain Rail on My Year and Model loose and it rattled; it is right there on the left if the Valve Cover is removed.

If it goes away after you add a Fuel Addative that raises the Cetane of the Fuel then you know it is related to the Fuel itsef, Injectors or Timing.

How long has it been since a Valve Adjustment was done?

psaboic · #7 09-04-2014, 11:03 PM

Well, I doubt it is worn injector nozzles, as I just had Greazzer do a set of Monarks for me about 7K ago. The last valve adjustment was done at the same time.

Today I went to the local station and diluted the Bio that was in the tank with some fresh D2, so now it is running roughly B50. It had roughly B75 in it before. Anyway, I drove it around and could not get it to tick no matter how I tried.

Is it fixed? Maybe, I guess time will tell.

Glenn

barry12345 · #8 09-04-2014, 11:57 PM

Sounds like there is a possibility some of your local biodiesel percentage fuels may have issues. We have less diesel fuel issues generally up here in eastern Canada than parts of the states have. Especially in the last year or so.

Still there are some. Biodiesel here is no longer available here for many years as they really messed it up.

Injection pump sales locally went through the roof with the stuff. It was so bad I suspect the oil companies got tagged with a lot of the costs of the injector pump replacements.

Since the newer diesel engines arrived. Bills of 7-9 thousand dollars now to fix the fuel system are not unknown with a dose of bad fuel.

I am not paranoid about fuels but have over the decades experienced some issues I could have lived without. Anyways I hope your issue was only fuel related.

In the modern diesel engine warranties you void them with any percentage of biodiesel above 5 percent was established years ago here.

Especially when travelling long distance I am really picky about where I buy fuel. Only large busy truck stops have proved flawless in comparison to small volume outlets. If the truck stop is not busy I also pass them by.

The truckers would have stopped buying fuel at them if bad is my thought. Or perhaps the price is wrong. Also you usually get good miles per gallon with what the busy ones sell. Locally we had a brand that only gave you about 1/2 your normal fuel milage at one time.

WVOPWRD! · #9 09-05-2014, 03:48 AM

Run the undiluted "sick" dose of diesel purge, certainly can't hurt...

leathermang · #10 09-06-2014, 08:57 AM

The Diesel purge can't hurt..
to do undiluted.... put in new filter fuel cartridge filled with the Diesel Purge.. put rest of can into tank when level is low...

this other suggestion may seem strange.... but I had it happen to me...
check your TACH cable... if you have one... some are electrical...some are actual cables like the speedometer....