Injection Pump off by 2 degrees Is it worth it? - PeachParts Mercedes-Benz Forum

SGT John · #1 04-08-2007, 06:12 PM

About 2 weeks ago before I left on my road trip I took my car in for injection timing. The mechanic checked the timing and decided without even calling me that since it was only off by 2 degrees it wasn't worth my paying 270 dollars for the adjustment... so he just billed me 90 dollars for the diagnostic.

I was pretty pissed but it was after hours and I needed my car the next day anyway for the 2 week vacation.

My gut tells me to go back and give him the other 180 and tell him to finish the job, but what kind of difference in performance would I notice?

Will I finally get my 0-60 out of the 30's? Will I get noticeably better mileage?

Request all your comments and opinions

sedecrem · #2 04-08-2007, 06:19 PM

Some on this board claim with the fuel available today that 26 degrees is a better setting. So if the timeing is 2 degrees plus, keep your money and count your blessings. If it is 2 degrees minus see how it runs before making a dicision. Sounds like the mechanic is an honest guy that is trying to give you the best value for your money spent with him. I would tend to trust his judgement unless the drivability is a problem.

#3 04-08-2007, 06:27 PM

Yes, 2* WILL make a difference. However, if your 0-60 is that high you have other issues that need attention first.

TheDon · #4 04-08-2007, 06:40 PM

haha your timing is retarded

Like forced said... something else could be an issue.. sluggishness could be fuel filters

#5 04-08-2007, 06:42 PM

May also be a plugged TrapOx/OxCat if its a CA model.

P.E.Haiges · #6 04-08-2007, 07:20 PM

SGT John,

$270 for a timing adjustment? That doesn't sound too honest to me.

Most of the work was done. How hard would it have been to loosen the IP and bump it ahead 2 degrees?

BTW, how did he measure the timing? Did he check the cam timing? That usually changes twice the IP timing because of timing chain stretch.

P E H

300SD81 · #7 04-08-2007, 07:28 PM

If its retarded by 2*, advance it by 4, if its advanced by 2*, leave it.

#8 04-08-2007, 07:29 PM

Quote:

Originally Posted by P.E.Haiges

That usually changes twice the IP timing because of timing chain stretch.

Huh? IP timing changes the same as cam timing. They both run at 1/2 crank speed.

SGT John · #9 04-08-2007, 11:56 PM

Not a cali model. I am thinking about adjusting the ALDA soon, but there are a few things ahead of that... like fixing the radiator.. I broke off the nipple on top that goes to the coolant res, so I need to epoxy that... The army usually has me working pretty late these days... so who knows when I will get to it.

Hatterasguy · #10 04-09-2007, 12:01 AM

2 degrees on a 602/3/6 is a big deal, from what I have seen on the 617 not so.

How many miles, let me guess about 200k? The timing chain is probably stretched a bit.

Considering your 0-60 time I wouldn't worry so much about the timing at the moment.

SGT John · #11 04-09-2007, 03:49 PM

318K as a matter of fact

gsxr · #12 04-09-2007, 03:58 PM

Adjusting the timing may improve MPG slightly, but it won't do anything at all for the 0-60 time. Sounds like you have no boost signal to the ALDA, no boost pressure, a very lean ALDA setting, or some combination of the above. Your 0-60 time should be quicker than 15 seconds in an '85 sedan, below about 3000' elevation...

gsxr · #13 04-09-2007, 04:01 PM

Quote:

Originally Posted by ForcedInduction

Huh? IP timing changes the same as cam timing. They both run at 1/2 crank speed.

The pump is driven by the chain, roughly in the middle of the cam & crank sprockets. So if the chain is stretched by 4° as measured at the camshaft, the pump timing will generally be about half that much, or 2° out (retarded). For the OM617 you can adjust the cam timing with offset keys, on a 60 engine there is no adjustment - you replace the chain.

SGT John · #14 04-09-2007, 08:30 PM

What kind of project is it to replace the timing chain? What tools are needed?

What could I expect to pay a mechanic to do it?

Also, what *should* I expect to pay for injection timing?

P.E.Haiges · #15 04-09-2007, 11:37 PM

Forced,

THe cam is about twice as far away from the drive sprocket on the crankshaft as the IP is. Therefore the elongation of the chain is twice as much at the cam than at the IP.

Take a rubber band and put a mark in the middle. Then stretch the rubber band by attaching one end so it can't move and pull the other end. The mark in the middle will move 1/2 the distance that the pulled end moves. The length of the elongated timing chain works the same way. If it is elongated .010" at the IP, it will be elongated .020" at the cam. Therefore the cam will be retarded twice that of the IP.

Timing chains don't stretch like a rubber band. The bushing holes wear oblong on one side and the pins in the wear flat on one side where they contact the bushing holes. So actually the pitch of the chain changes and that's what makes the chain elongate.

P E H