IP Timing: Need Some Advice - Page 2 - PeachParts Mercedes-Benz Forum

79Mercy · #16 07-08-2014, 10:26 PM

Do you have a ip locking device? It is to be installed in place of the 17mm plug in the side of the drivers side of the injection pump. When the lock is installed it presses against a notch in the cam in the injection pump which is only seen at 15' degrees ATDC. I would set the motor at 15 degrees ATDC and remove the plug and using a mirror look inside the pump and see if you can see the notch on the cam in the pump. Sometimes i haven't had good luck with drip timing, everyone has a different idea of whats correct and whats not correct with drip timing.

npretnar · #17 07-08-2014, 10:30 PM

Quote:

Originally Posted by 79Mercy

Do you have a ip locking device? It is to be installed in place of the 17mm plug in the side of the drivers side of the injection pump. When the lock is installed it presses against a notch in the cam in the injection pump which is only seen at 15' degrees ATDC. I would set the motor at 15 degrees ATDC and remove the plug and using a mirror look inside the pump and see if you can see the notch on the cam in the pump. Sometimes i haven't had good luck with drip timing, everyone has a different idea of whats correct and whats not correct with drip timing.

Thanks, I may try this tomorrow if I have time. I plan on just moving the pump around anyway to see if I can find a sweet spot somewhere. The wobble is what is concerning me most though, and the resistance I encountered on the pump shaft. Any thoughts there?

79Mercy · #18 07-08-2014, 10:34 PM

The cam in the pump is going to hit resistance as the cam lobes press on the plungers. When turning the cam on the pump when you hit resistance it will probably spring back counter clockwise depending where the lobes are at. I highly doubt the cam is bent or warped in the pump.

btw, the oil filter housing doesn't need to come off to remove the pump, nor does the oil cooler hoses.

npretnar · #19 07-08-2014, 10:36 PM

Quote:

Originally Posted by 79Mercy

The cam in the pump is going to hit resistance as the cam lobes press on the plungers. When turning the cam on the pump when you hit resistance it will probably spring back counter clockwise depending where the lobes are at. I highly doubt the cam is bent or warped in the pump.

btw, the oil filter housing doesn't need to come off to remove the pump, nor does the oil cooler hoses.

Yeah, I know. I notched the top of the bracket the last time I went through this fiasco. Hell of a lot easier.

cooljjay · #20 07-08-2014, 11:30 PM

You can use a lug bolt if you don't have the timing lock tool....

npretnar · #21 07-08-2014, 11:32 PM

But doesn't the pump still have to be drip timed even after using the locking tool?

scottmcphee · #22 07-09-2014, 09:10 AM

I've only ever timed by ear and butt dyno, for the style of driving I do and have been totally happy with the smoke to noise to power ratio I've dialed in. Dripping for precision gains you what...? The knowledge that something is technically perfect.. But you still may prefer a little more advance if you're like me with heavy foot. And the precision setting is for a new engine when everything is tight and perfect.

I used locking tool only for IP removal to keep its rotational position.

Do you have a really sloppy chain, like is it old? How much do you have left on the chain tensioner... Maybe your cam and crank are too far out of phase because of old chain.

npretnar · #23 07-09-2014, 09:26 AM

The car only has 177k on it. I don't care enough about it to mess with the chain. I barely use it except for the occasional trip to STL and back, and it leaks when it rains. I'd say 177k is too early for a new chain anyway don't you think?

barry12345 · #24 07-09-2014, 10:48 AM

Never hurts to check chain stretch. Not that bad of a job.

I would make sure fuel is coming out the return line on the injection pump. I would not want to see any air with it. Then I would also close that line off temporarily for a test.

If no fuel is coming out the return? The fuel supply system is weak.

Any major improvement with the close off and the fuel system should be checked. Specifically the fuel pressure present in the base of the injection pump. Age more than miles for example can weaken the fuel relief valve spring.

Cadin · #25 07-09-2014, 12:43 PM

FWIW: As far as a timing pin, I have even used 7/16 oak dowel with great success. The advantage is that it's pretty snug, and you can tap the dowel groove onto the tab inside the ip and get it to stay snug very easily. If it is slightly loose, dunk the dowel in warm water and try again. Bolts and bits work as well, but they are harder to work, and don't deform to match the shape of the IP tab to grab it snugly.

My motor has around ~180k, and she was very close to spot on after using the dowel and at 14-15 atc; before this I had tried to keep everything aligned, and the timing was way off (Shaking, stalling, etc.)

Cheapest solution I've found! (Of course the real tool is nice too!)

Like these fine folk mention as well, the fuel relief spring gets tired with time, and that lowers the lift pump fuel pressure to the IP. I certainly noticed an improvement in take-off response when I adjusted mine, as well as the idle getting a bit smoother.

spock505 · #26 07-09-2014, 12:44 PM

Quote:

Originally Posted by npretnar

The injectors were rebuilt by Greazzer with new nozzles last year. I don't think they're the problem.

..ahh ok, try undoing each pipe line at the injector when the engine is running rough. You may find one makes no difference in which case it's a bit more isolated.

npretnar · #27 07-09-2014, 01:25 PM

Quote:

Originally Posted by Cadin

FWIW: As far as a timing pin, I have even used 7/16 oak dowel with great success. The advantage is that it's pretty snug, and you can tap the dowel groove onto the tab inside the ip and get it to stay snug very easily. If it is slightly loose, dunk the dowel in warm water and try again. Bolts and bits work as well, but they are harder to work, and don't deform to match the shape of the IP tab to grab it snugly.

My motor has around ~180k, and she was very close to spot on after using the dowel and at 14-15 atc; before this I had tried to keep everything aligned, and the timing was way off (Shaking, stalling, etc.)

Cheapest solution I've found! (Of course the real tool is nice too!)

Like these fine folk mention as well, the fuel relief spring gets tired with time, and that lowers the lift pump fuel pressure to the IP. I certainly noticed an improvement in take-off response when I adjusted mine, as well as the idle getting a bit smoother.

What's the procedure for adjusting this spring? Should it be pushed back in or pulled out further?

Cadin · #28 07-09-2014, 03:41 PM

Quote:

Originally Posted by npretnar

What's the procedure for adjusting this spring? Should it be pushed back in or pulled out further?

Here is the thread with a pic I took of the spring unstretched, at maybe 20.5. I stretched it to 27mm, and reinstalled.

Adjusted - Fuel Bypass Spring

npretnar · #29 07-09-2014, 08:02 PM

Well I did the fuel bypass spring to 28 mm. Retarded the timing a little (black smoke, too advanced I figured), started it up and it still ran very rough, and wouldn't hold idle below 1000rpm. I shut it off for a second and my neighbor came over. I then fired it up again and it missed like three or four times in a row and made a very bad clanking noise and then died. I think it might've skipped a tooth (the misses were successive and bad).

...

I'm now considering parting it out because I don't really need it and I don't really need to spend two hours a day messing with it. Any last resort suggestions?

Cadin · #30 07-09-2014, 08:12 PM

Mine was grumpy when I didn't have the IP right. Are you sure you aren't 180 out?