Hi: New to forum I have a 1990 jetta 1.6 n/a the car was just at the shop and had the injector set .095mm compression test all over 400 new glow plugs. The problem is in the summer when it's warm out the car starts fine, if the car is plugged in when it's cold it starts fine. When the temp is below 40 the car starts after a lot of cranking and if it's below 20 wouldn't start at all. I have talked to the vw mechanic no clue why it does this, I've contacted tech person for online vw parts he has no clue. Any help would be greatly appreciated
Have you tried glow plugging it twice before cracking? Although the plugs are new, have you tested for power at the plugs, to see if the timing circuit is running as long as it should?