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Primevci 08-14-2004 09:06 PM

1989 Chevy 350 TBI Timing
Hey hopefully someone can help me out with this. I am working on my friends 1989 Chevrolet caprice which has a 350 with TBI. I was wondering what the timing needs to be set at and if this thing has a timing advance anyone know were to look for the wire to unplug. Also I was curious as to what the firing order was for the engine and the cap, not sure if they are hooked up correctly and of course most of the books I have found suck. Thanks for any help you can offer...

Neophyte 08-14-2004 09:31 PM

I am also eager to see the answer to the timing question as I've got a 1991 TBI myself that still needs to be stripped down for replacement of rings, bearings gaskets and so on.

The firing order you will see on the intake manifold just in front of the throttle body.

docvette 08-14-2004 10:10 PM

Fire Order
1 Attachment(s)
[color=yellow]Doc Here:pimp:

1 8 4 3 6 5 7 2.....Direction of rotation is Clockwise , # 1 plug (at stock location ) Is about 5 O'clock.

As far as the timing, I think it's controlled by the Computer on that car.

Photo to help you locate the F.O. Below...#1 is at 5 O'clock (wire with Black tape on it) The power & Tach plug on the cap faces left, Between wires 7 & 2.

Doc :pimp:

TurboS10 08-15-2004 08:21 AM

Timing is controlled by the ECU I believe. If this is the case, you have to set the idle timing to match what the ECU thinks timing is. This is likely ~10, but you will need to know exactly what it is so that the ECU can properly control total timing. Once you find what it needs to be set at, just set the timing at idle just as you would normally would.


syclone 08-15-2004 09:07 AM

firing order is just as doc vette stated. As far as timing you need to unplug the interupter wire. not sure where it is on a caprice. On my 92 silverado it is under the panel on the firewall to the left. Most tbi's are set at 0 base timing(wire unplugged). this is a factory setting. I currently am running at 8 degrees advanced with no issues

firechicken383 08-15-2004 11:00 AM

Just as syclone said the factory spec is 0. However alomst all TBI's can be timing from 4-8 degrees with better power. I'd start with 4 and go from there.:thumbup:

Primevci 08-15-2004 11:05 AM

OK thanks for all the info i got one other question is the notvs " they look like v's cut out" is the first one 0 then sencond 2, 4 and so on?

ratman33 01-29-2009 08:09 PM

first notch[the bottom of valley] the one at bottom as looking at it is 0,next valley 4,8 and 12.the pointed parts are 2,6,10.

UR50SLO 01-30-2009 04:31 PM

Yes.. as others have said... 0deg. with the wire

The wire would be in several spots..

back of the firewall on the harness

Inside the car where the harness comes through the firewall taped to the harness.

It will be a single pin connector tan and black or tan and white.

I agree that a few more degrees of timing would help... Keep your ear open for knock/ping.
Good luck,

peterr jurd 01-31-2009 05:13 PM

1989 Chevy 350 Timing
Thank you docorvette I am now cruzin in my 454 BB thanks to your photo, it solved my dilemma!

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