88-98 FAQ's "Is your truck running weird? Check here it could help"

[speedygonzales]

If you remove and replace the distributor in a generation I Vortec engine, it's correct position must be checked by scanning the cam retard number. According to GM it's referred to as the Camshaft Retard Offset Adjustment.

Here is the shop manual page for it.

http://carphotos3.cardomain.com/imag...arge.jpg?modal

The timing of a Vortec is not adjustable but the position of the distributor must be at a reference point of 0 degrees +- 2. This will have an effect on idle quality and fuel economy at least.

We know without doubt that a Snap-on Solus, Solus-Pro and Modis will show the cam retard value. Others may, but I'm not aware of them.

Just to let you know, mine was reinstalled without checking the cam retard going back as far as 2005. I was careful to reinstall it each of 3 times doing the intake gaskets. It never gave a code after the install. The last time a week ago after a complete rebuild, it was at -13*. Never had a code.

Now here's one thing you won't read in any shop manual.

Once I got it to 0, in no time it threw a code 1345. Let me repeat that. I was off for over 6 years and never threw a code. After I set it to 0, it threw a code.

My recommendation comes from others that have experienced the same thing. Set it slightly negative. The spec is +-2 away from 0.

Again I want to repeat for people using "google" looking for this information. If you remove and replace the distributor in a generation I Vortec engine, it must be checked by scanning the cam retard number.

[mountie]

Uh, and what years is a Generation 1 Vortec??

[tommie]

Originally Posted by mountie

Uh, and what years is a Generation 1 Vortec??

Vortec SBC 1996- 1998 in the trucks, went to 1999 in the suv (suburban)

IIRC

[68C15]

Originally Posted by speedygonzales

If you remove and replace the distributor in a generation I Vortec engine, it's correct position must be checked by scanning the cam retard number. According to GM it's referred to as the Camshaft Retard Offset Adjustment.

Here is the shop manual page for it.

http://carphotos3.cardomain.com/imag...arge.jpg?modal

The timing of a Vortec is not adjustable but the position of the distributor must be at a reference point of 0 degrees +- 2. This will have an effect on idle quality and fuel economy at least.

We know without doubt that a Snap-on Solus, Solus-Pro and Modis will show the cam retard value. Others may, but I'm not aware of them.

Just to let you know, mine was reinstalled without checking the cam retard going back as far as 2005. I was careful to reinstall it each of 3 times doing the intake gaskets. It never gave a code after the install. The last time a week ago after a complete rebuild, it was at -13*. Never had a code.

Now here's one thing you won't read in any shop manual.

Once I got it to 0, in no time it threw a code 1345. Let me repeat that. I was off for over 6 years and never threw a code. After I set it to 0, it threw a code.

My recommendation comes from others that have experienced the same thing. Set it slightly negative. The spec is +-2 away from 0.

Again I want to repeat for people using "google" looking for this information. If you remove and replace the distributor in a generation I Vortec engine, it must be checked by scanning the cam retard number.

A crank position relearn should have taken care of that. But I find they run best with -4 degrees