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Advancing Pump Timing - quick n dirty?
by
rs899
on 31 Jan, 2010 04:16
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OK- I have the formerly trashed 91 Jetta running reasonably well now, but I am sure the IP timing is retarded because it runs sluglike compared to my Caddy and when I pull the cold start it picks right up and sounds nice.
So, I tried to advance it, but the IP has run out of room towards the block.
I need to advance the pump by one tooth, then go from there. I think this means holding the belt in its current position, then rotating the pump clockwise one tooth, correct?
How do you guys do such a thing without upsetting cam and crank timing?
Rick
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#1
by
theman53
on 31 Jan, 2010 06:31
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I don't believe that you can. Best would be to retime with the dial indicator. Unless someone else knows better.
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#2
by
Rabbit on Roids
on 31 Jan, 2010 09:04
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i would advise AGAINST doing what you said. if you do one whole tooth, you probably wont be able to retard it enough to run right.
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#3
by
rs899
on 31 Jan, 2010 15:33
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Ok, technique aside, for the time being. There has to be a way for this thing to run with the "proper" advance. I used a dial indicator on it and it's right around 1mm right now, but it obviously needs more advance. Maybe I didn't read it right ?( I have done it countless times, but never on this car).
What's wrong with advancing a tooth and then pulling the pump towards me?
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#4
by
dennis
on 31 Jan, 2010 16:16
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Might want to check internal pump pressure.
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#5
by
rs899
on 01 Feb, 2010 10:14
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Thanks Andrew-
In fooling around for 16 years with my Caddy, I never have had to deviate from using the dial indicator reading as gospel. But this time with this Jetta, I am going to have to do more of a seat of the pants setting to get it running better.
I am a little nervous doing it this way, but am I correct in thinking that as long as my cam and crank are dead on with each other, having timing a tooth off one way or the other (until I dial it in by feel) will not damage anything?
Rick
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#6
by
rs899
on 01 Feb, 2010 11:02
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OK, so thinking ahead, if I fudge it this way and get it to run better, I presume I will end up with more lift than the book says I should have, but what?
That complicates my future timing belt changes ( if I use the same IP). I guess I will need to eventually record what the dial indicator "sweet spot" reading is for this pump. Any better ideas?
Rick
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#7
by
Vincent Waldon
on 01 Feb, 2010 11:53
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I guess I will need to eventually record what the dial indicator "sweet spot" reading is for this pump. Any better ideas?
I think that's a very reasonable approach. The dial indicator method doesn't account for cam wear, injector pressures etc, so sometimes needs a bit of tweaking... but its advantage is that it's reproducable. If you manually find where your engine runs best and then measure it you'll have dialed in your specific pump/injectors/etc in a reproducible way.
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#8
by
rs899
on 02 Feb, 2010 04:14
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It occurs to me that I just need to remember to record the lift with the dial indicator on the old belt when I go to change it 3-4 years from now. Now, the problem is trying to figure a fail-safe way to do that- perhaps a yellow sticky in the Bentley? Except that having done this so often, I may not even look at the Bentley....getting old sucks.
Rick
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#9
by
Rabbit on Roids
on 03 Feb, 2010 07:52
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write it on the wall of your shop. thats where i write stuff that i dont wanna lose.
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#10
by
8v-of-fury
on 03 Feb, 2010 20:09
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write it on the wall of your shop. thats where i write stuff that i dont wanna lose.
I keep a notebook in my tool box
I'm only 20.. but i still have a memory like sieve sometimes lol
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#11
by
rs899
on 04 Feb, 2010 03:50
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Maybe I'll put a note on the strut tower. If I use a permanent marker, though, it might eventually fade due to diesel and solvents- probably have to use paint.
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#12
by
ein bora
on 07 Feb, 2010 06:50
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The flywheel on my 1.9 IDI has two TDC marks, apparently the same flywheel is used on some gassers so the second mark is 6 degrees BTDC. When I first set the timing up of coarse I had the wrong TDC. The car ran but I had to run the pump all the way up to advance it as far as I could - and had issues like you described. When I finally figured it out, now it sits where it should and runs as it should. Not saying you have the same issue, but maybe worth checking out.
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#13
by
rs899
on 07 Feb, 2010 15:04
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I think my flywheel is OK, since I had the head off a few weeks ago and it looked like TDC was where I expected it (but I know the gasser flywheel you are talking about and I agree it is confusing). I slipped the IP one cog advanced and now it runs better- and I used up almost that whole cog. I haven't measured it with a dial indicator- I am curious to find out what it is.
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#14
by
Rabbit on Roids
on 07 Feb, 2010 19:19
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i had that problem too, as i used a gasser flywheel, and it had only gasser timing marks.