RwChevy967

I have a 1996 Tahoe that sets a P1345. In using a scanner the ign/adv at idle reads -18.5/-22.0. In checking the harnesses at the crank and cam sensors the only reading not correct is the 5Vac. The reading is 1.8Vac, but the engine starts fine. I noticed the distributer was loose. I tightened it but do not know if it is set right. Using a timing light the line is left of the mark about 1 1/2 inches. I cannot find the tan wire with a black stripe to disconnect to check it properly. Can anyone tell me where this wire to disconnect is located on a 1996 Tahoe. Or does anyone know what the ign/adv timing reading should be on the scanner at idle?

MDTAHOE

You can not use a timing light to set the timing in this truck. The distributor does not set "ignition timing" as it did in TBI engines. There is not a tan wire with a black strip. The distributor is the cam sensor, and it distributes spark that is it. Turning it sets the correlation ( relationship) between the cam and crank sensor.

P1345 has nothing to do with ignition advance. You need to look at cam retard (not all scan tools have it) The spec is read at idle. 0 + or - 2. Anything out of that window is going to set p1345. Every time an adjustment is made you must snap the throttle over 1000rpm for the data to update. You can get more info off this site if you put p1345 in the search at the top of this page, it has been discussed hundreds of times (or at least it seems).
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RwChevy967

Thanks a lot for the info. I slowly turned the distributer, removing the code after each attempt and did eventually get the lite out and this stopped the code from being set anymore. I do have one question, I noticed while turning the distributor till the engine began to stall and to where the distributor position put the check engine lite out and the mark on the Harmonic balancer never appeared to move. At the position that put the lite out the timing marks never lined up? Is this normal for this 1996 5.7.

MDTAHOE

Consider the mark on the balacer irrelavant. It does not work like that. The dis. does not set ignition timing so it has 0 effect on the balancer. You can not use a timing light

RwChevy967

That is very interesting. Just one more thing. When I retarded the distributer the adjustment resolved the 1345 code. Before retarding the dist. the engine started on the first revolution. Now the check engine lite is out and setting no codes, it is the 2nd or 3rd revolution before the engine starts. If I advance it a tiny bit do you think the lite would stay off and this would be better? Thanks again for all the help.

MDTAHOE

You need to see what the spec is now. It is a guessing game until then. Maybe turning it will help maybe not depends where it is now. Maybe turning will bring back p1345 maybe it will not. Since you have no idea where it is you can not even be sure which way you need to turn it now. If your scan tool does not show you what you need to see then you need to buy one that does or pay someone to set it. Any shop that has a Snap - On scan tool can do it. It should not be all that expensive.

RwChevy967

Thanks for your assistance.