removed injectors, now shaky idle? - PeachParts Mercedes-Benz Forum

cbjukraine · #1 02-27-2007, 08:51 PM

I did a compression test and removed all of the injectors to do so. I cleaned the soot off of the nozzle end of each injector with a brass brush, not aggressively, carefully. Reinstalled each injector (I didn't keep track of each injector so that I could put each one back into the cylinder it came from) with a new heat shield, and now my car has a shaky idle, as if one cylinder isn't firing. The shake smooths out at higher rpm, but sometimes I can feel it once or twice as the rpms pick up.

Any ideas? I knew I shouldn't have messed with the injectors! D'OH!!!

Thanks

vstech · #2 02-27-2007, 10:53 PM

I bet you have air in one of the lines. it's a real bugger to get the injectors to fire with air in them.
either that, or you have a bad one now.
John

aklim · #3 02-28-2007, 07:27 AM

I suggest you take them out and have someone professionally go thru them and check the pop off pressure and the spray pattern.

On my 606, there was a "washer" between the head and the injector that was replaced when the injectors came out. What about your's?

GRIESL · #4 02-28-2007, 08:59 PM

Quote:

Originally Posted by cbjukraine

I did a compression test and removed all of the injectors to do so. I cleaned the soot off of the nozzle end of each injector with a brass brush, not aggressively, carefully. Reinstalled each injector (I didn't keep track of each injector so that I could put each one back into the cylinder it came from) with a new heat shield, and now my car has a shaky idle, as if one cylinder isn't firing. The shake smooths out at higher rpm, but sometimes I can feel it once or twice as the rpms pick up.

Any ideas? I knew I shouldn't have messed with the injectors! D'OH!!!

Thanks

That's a total bummer. I assume the compression test went well? Anyway, I would crack the line at the injector with the car running and see how each injector affects the idle. If you find one that does not affect shaky idle, the switch it with the one next to it to see if it is in fact the injector causing the shakes. Good luck!

Old300D · #5 03-01-2007, 11:42 AM

Quote:

Originally Posted by vstech

I bet you have air in one of the lines. it's a real bugger to get the injectors to fire with air in them.
either that, or you have a bad one now.
John

I've not found that air in the hard lines is a problem. It will compress just fine and flow out the injector tip after a minute or so. More likely some debris has been introduced internal to the injector.

aklim · #6 03-01-2007, 11:45 AM

Quote:

Originally Posted by Old300D

I've not found that air in the hard lines is a problem. It will compress just fine and flow out the injector tip after a minute or so. More likely some debris has been introduced internal to the injector.

Well, he did clean off the tips so some debris could be clogging up the pintle.

cbjukraine · #7 03-01-2007, 12:13 PM

I think my problem was just air in the injector lines. I loosened each injector line at idle, and this experiment showed me that my problem was definitely not a cylinder missing. When a cylinder doesn't fire it is definitely much more violent than what I was experiencing. What I was experiencing was a small hiccup, not the heaving cough of a cylinder missing. But anyway, I borrowed a home-made injector testor from a friend and mine still spray great and all pop from 130-134 bar. A little off the mark, but within specs of the FSM. But bleeding the lines seems to have cured my case of the hiccups!

vstech · #8 03-01-2007, 12:19 PM

Glad I could help
John

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