IP Timing does matter

[motomike33y]

I've been working with my rabbit diesels, vanagon diesels, jetta diesels for years and have always managed to put the IP back on so that vehicle would run.  I knew that there was adjustment in the IP, and had gotten the gauge, but thought it was more for fine-tuning than necessity.  My reading on this forum during the past several months seemed to follow that general thought.  Then.....my 91 jetta,1.6 NA, which I've been fiddling with for a couple years geting thing replaced/put back together was a difficult starting project.  I checked glow plugs, rebuilt injectors, etc. and got lots of smoke but no start.  Even tried the gauge and thought things were within acceptable tolerance.  Finally was able to get it started by towing, much smoke, worse running when cold start pulled out.  Wouldn't start w/starter.  I loosened the bolts and moved the IP as retarded as I could.  Lo and behold, it would start-still way too much smoke, so I used a bar to assist in moving it to the bolt limits.  started well, but now could clear it some w/cold start pull.  Finally experimented and advanced it until it seems to start well and run cleanly when warm w/cold start in.  Long way to say thanks for all the info on this forum that helped me accomplish what seemed like a miracle to me a couple months ag.

[8v-of-fury]

Timing is everything with these little monsters. When I got my 81 it smoked like a bugger, it was set to something like 0.85mm (stock settings) with a pump with over 700,000 kms on it.. I swapped pumps and bumped timing to 1.03mm and it starts and runs like a charm without use of the cold start lever.

Just for your information, the cold start lever only mechanically advances the pump about 3-5 hundredths of a millimeter at idle.. So if you have your static timing set to 1.00mm and you pull the cold start at idle it will bump timing to 1.03-1.05mm Useful piece of info for you lol

[rabbitman]

I don't think the bentley says it in mm, my memory says it was something like 5 degrees for mk1's and 10 degrees for the mk2's.........believe me at your own risk.......

[burn_your_money]

The amount that it advances it at idle will vary based on the shims and spring in the advance as well as your internal pump pressures.

[8v-of-fury]

The amount that it advances it at idle will vary based on the shims and spring in the advance as well as your internal pump pressures.

Right on, didn't know that. So how much does it advance a stock pump?

[motomike33y]

Haven't done anything about internal pressure-and don't know anything about it yet.  Still doing a little trial and error regarding starting ease and smoke-free running.  will probably try the gauge to see what I end up with.  pump is off an 82 rabbit after the one on the 91 quit for some reason a couple years ago.