pump timing cranked all the way

[rdodd]

I had my pump timed yesterday by a certified bosh injecter shop with a timing light. It was set at 10* which is close to 1. 25 lift. He set it to 15* but had to crank it to the very end of the curved slot to get there. The top of pump is now 1/4 in. from the motor. The motor seems quieter and more responsive now, but i am at the limit clockwise for advance. Do some pumps have to be turned all the way to get timing advanced over stock?

 

[Power Wagon]

The only way that could be, is if the drive gear is off a tooth. The only way THAT could happen, is if the pump were installed without being locked in time with the drive shaft lock.



I ran my pump way up there too, and found it snappy on the low end, no noiser than before, except under cruise conditions, where the metallic "clank" you could hear outside the truck was much worse.



I lost fuel economy there, though. It improved when I moved it back a bit. I don't know precisely what the timing is on my engine, but the top of the pump's about 1/2 - 5/8 inch from the block at the closest point.



Over 400 plus miles of twisting winding back roads - some of which were gravel - where you're on and off the throttle constantly I got just over 20. It runs very nicely now, with moderate noise, smooth response, and the exhaust sound better.

 

[paccool]

Did they set top dead center before timing the pump? Mine was off 2. 5 degrees and it moved the pump up about 3/8" from the original mark at TDC and 1. 7 pump timing.

 

[rdodd]

The shop didn,t check true tdc before timing pump. I mentioned it to them because i read about tdc being off on some of our trucks but they said they never heard of that. The pump was changed under recall back in 93 by chrysler so maybe they put it on wrong. Is there any good shops in eastern iowa that could check this thing out. Dubuque diesel injection that set the timing says everthing is fine.

 

[Power Wagon]

I learned it the hard way, that they often ARE off, and that checking it by hand results in a higher degree of confidence in the outcome.



I, and some of the guys I used to work with, put a LOT of hours into a truck trying to solve a seemingly unsolveable problem, until we invented a procedure for checking TDC and the pin position. Sadly, I would say that at least 1/3 of the engines people have complaints about (and at least some of the ones nobody complains about) are off enough to make a measurable, and some, a serious difference.



Yes, I know a LOT of shops know nothing about it, and would never question the pin position... But they don't read TDR, either. That puts you ahead of them. Too bad they wouldn't listen... they could learn from our mistakes and our efforts.



Heck, I know someone who has been to reputable TDR advertiser's shops who didn't get an inaccurate pin detected, and fixing that made a very noticeable improvement in performance, not to mention reduced smoke.



It IS real, it IS important, and it DOES happen way too often.