Smog Fail and Code 42

[mistaake]

95 K1500 5.7L TBI... no codes no check engine light up until yesterday when we went to smog the truck to renew reg. They failed smog for timing being advanced 8*. On the way home check engine light came on. Scanned it with my OBD1 scanner and got a code 42 for timing control circuit fault.

My assumption without much research is this is like older Fords where there is a wire you disconnect to check the timing. I haven't actually looked for it on the truck but some googling and binging has lead me to think it could be in like 5 different places... anyone know for sure where it actually is? Perhaps the smog guy forgot to plug it back in... Anything else I need to check/worry about in regards to that?

As for the timing itself, we have not modified the timing or done anything with the distributor since the last smog 2 years ago. That said, I can borrow a timing light and test it myself. If it's off I am assuming spec is 0*? So I can try to play with the distributor. If I can't fix that I'm going to guess either distributor or timing chain... at 275K miles anything is possible but I've never had a timing chain issue on a SBC and it doesn't make any noises and always kept the oil full and at least somewhat clean-ish.

Thanks for your input in advance.

 

[smdk2500]

The wire you are looking for should be under the glovebox by the heater box unless for what ever reason yours is a odd ball. That is where my 95's is. It is brown with a black stripe. Yes timing is supposed to be set to 0 with that unplugged.

 

[Schurkey]

Sloppy timing chain doesn't ADVANCE the timing.

Did you use a scan tool, or a code-reader? Big difference.

Fix the Code 42 using the diagnostic procedure in the service manual. See what happens.