I brought the truck in for CA smog check today and it passed emissions really well, but failed for timing.
It was 7º btdc instead of 14º btdc.
I never really paid much attention to the timing before because it is electronic ignition and the distributor has been frozen in place for 20 years or so.
I looked at my smog check paperwork from 2 years ago, and see that I have only driven the truck about 400 miles. The timing in 2012 was 14º.
What could cause the timing to change in such a few number of miles?
I put less than 1,000 miles a year on it because I only use if for picking things up.
I went back through my previous smog checks and see that the timing has varied, though since it never failed smog for timing I didn't pay attention to it.
Year Mileage Timing RPM
2014 65723 7º doesn't say but I saw him measure it at idle
2012 65382 14º
2012 65376 14º it failed this test because EGR passed was plugged with carbon
2008 63357 14º
2006 62367 16
2004 60664 12º It was sitting on the rollers and didn't even move from the pretest yet changed
2004 60664 8º I did a pre test that year, but it passed timing even though off 6º
The truck is a Federal vehicle, not California.
I got it in 1985 with about 38,000 miles. It has always run well and no symptom of timing chain jumping.
Since I suspect it will be difficult to get the distributor unstuck, is there some component that might have worn to cause the timing variation?
If not, any suggestion for unsticking the distributor, or methods not to try because they will break something?
I have a timing light to check it.
have the same problem?
Friday, January 31st, 2014 AT 4:32 PM