Timeing with a cam

[cdbformula]

I beleive my tbi had a cam installed by he previous owner. If it does should the timeing be advanced some?

[dave89iroc]

I usually set them at 10* base and do everything else in the tune, don't go messing with it unless you are going to get a chip burned for it

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[Doober]

Even a stock TBI engine can use some extra base timing. That being said TBI handles timing different than a carbed engine, it's all controlled from the computer and base timing is set to x degrees in the programming, and ideally matches the base timing set by the distributor.

Why do you think it has a cam? Any cam, head, etc. changes should have compensation for more fuel... an actual tune with a wideband sensor is ideal of course.

[Customization]

can u adjust the timing by ear. and u just have to take out that electonic timing thing correct

[Doober]

You can get it kind of close but you really should use a timing light... it's not like the old school small blocks. Yes you do need to disconnect the EST connector, it's up near the fuel pump relay and terminal strip on the firewall.

[Customization]

ok and i think mine is connected right by the vaacum actuator on the intake manifold...

[Doober]

Vacuum actuator? Is this on the Yukon you posted about?

[Customization]

yes its the yukon...i watche a video of one getting set on youtube and it was online and the est connector was on the firewall.. i looked and i could find one....there is a bracket on the manifold that i think is it

[Doober]

It's a single tan wire with a black stripe. You didn't see it by where the fuel pump relay is?

It would be under or very near to this:
http://i228.photobucket.com/albums/ee137/greggmartucci/nonsense/P9040028.jpg

[dave89iroc]

Oobs is by the brake booster, this means pre 87 trucks, and through 91 suvs and 1 ton trucks

88-93 is by the fuel pump relay on the pass side firewall, taped to the harness originally

94-95 is taped to the harness by the blower motor under the dash, below the pcm

[Doober]

I didn't realize they moved it into the cab... I thought that was just on the S-Trucks.