Author Topic: Start me up! (Read 1996 times)

ontariovw · « **on:** February 16, 2008, 12:59:13 pm »

1994 VW golf, 1.9TD AAZ. Perhaps someone can help diagnose my starting problem. I have read through most if not all of the starting posts here, and elsewhere, but I am still stumped. Also, I'm kind of *cheap* so I don't want to randomly change parts until I find the source of the problem.

Here is the problem: I have to crank the engine for about 5 seconds or more after a long, hard, run, but not immediately after shutting down the engine.

Starting a cold engine (longer than 30 minutes) after running hot (operating temps)= difficult to start.
Starting a cold engine after running cool (for example starting it up, and then shutting it down and waiting for a few hrs)= starts easily enough.
Hot engine after running hot = starts immediately.

I was thinking the problem might be air in the fuel, but I often get white smoke in the exhaust during hard starts. There are a few bubbles that appear in the input fuel line under load (if I blip the accelerator), and a few bubbles the pump appears to be holding prime (I can see no leaks on the pump, and only a bubble or two in the input line. Could these bubbles be causing my problems somehow? Why then would the pump be able to hold prime if it was primed while cold?

Thanks for any suggestions

bert · « **Reply #1 on:** February 16, 2008, 01:32:16 pm »

My AAZ was exactly the same,i had advice from these lot on here :wink: set my static pump timing to 0.95mm from 0.8mm and its 100% better,dont need the cold start lever anymore

Bert

ontariovw · « **Reply #2 on:** February 16, 2008, 03:27:43 pm »

Would the timing affect the engine at different temperatures/conditions? My particular IP has both a cold start lever AND an electronic cold start device (KSB). As I understand it, the KSB affects timing at cold temps. However, when I unplug the wire to the KSB while the engine is running I cannot hear a difference in engine speed or sound. I wonder if the KSB is sticking open/closed after hot runs...?

Cheers,
Curt

ontariovw · « **Reply #3 on:** February 16, 2008, 09:58:50 pm »

Ok, so I have a small update. I tested the KSB using a test lamp shortly after firing up the old AAZ. I was not getting 12v at the terminal. Could this be a problem? As I understand it, it should show 12v when the engine is cold (which it is because it's about -8 degrees C tonight.). Maybe I will try to jumper a wire from the fuel stop switch to the KSB and see what happens...

ontariovw · « **Reply #4 on:** February 21, 2008, 09:08:00 am »

I think I have solved the problem (knock on wood). The small amount of air getting in may have been the problem. There are two places on the IP that can potentially leak under suction - the input banjo and the pressure regulator. As I understand it, any other seal on the IP will leak diesel instead of suck air. I put grease around the pressure regulator to seal it from above and that did not solve the problem, so I sprayed wd40 around the banjo fitting and that did help. Subsequently, I re-annealed the copper crush washers at the banjo fitting by heating them using a propane torch until the glowed orange and then let them cool to room temperature slowly. Absolutely no bubbles now. Still starts at -13 degrees C with 440k on the clock :-)