So I am from the Fullsize chevy and trucks and the thirdgens use somewhat the same stuff. Ok so I lurk a lot and I have read some great things. Here is my post from FSC. I hear you guys are gods over here.

 

places like www.summitracing.com sell timing tapes that stick on to your harmonic damper. Before ordering one, you need to measure the diameter of your damper. This is much cheaper, quicker and easier than trying the alternative, which is a dial-back timing light.

 

I have a HB that has the line. I am having a problem with timing it all together.

 

The line on the HB is where you put the zero mark of the timing tape.

 

What does your timing pointer look like? Does it have a few peaks/valleys? Just wondering if its the same as my stock 89 TPI motor's cover. It has a few different points on it with the biggest valley being 0 deg. The balancer had 1 line on it.

Timing tape would be ideal to measure total timing advance with RPM revs. I have a adjustable dial timing light that does pretty much the same thing but is able to use the single pointer position on the cover. Just dial in the degrees and line up the balancer mark with the 0 deg pointer spot.

Timing issues could cause your problems but then again it could be something else.

ECU should be controlling the timing once the EST is connected. You need to set base timing without the EST connected to whatever the ecu chip is set for. Stock is usually in the 6 deg range. After the EST is connected, the computer will add in more timing.

 

I know it's not what you want to hear, but ..... go back and check the very basics again.

1) Make sure your firing order is correct.
2) Make sure all spark plug wires are securely on their plugs - I had one that would pop itself off and I had to use needle nose pliers and slightly crimp the insides for a tighter fit on the plug.
3) Make sure each plug wire ohms out to almost zero resistance - can't tell you how many times I've bought new plug wires with shorts in them

On the timing tab - this is my guess ... most timing tabs I've seen from factory on chevy motors have 0 in the center of the tab, with BTDC being towrds the pass side, and ATDC being towards the driver side. If the tab is a zig-zag shape, each little peak is 1 degree, and each little valley is 1 degree - so from peak to peak is 2 degrees and from valley to valley is 2 degrees. Hope that makes sense.

AGAIN - I haven't seen your timing tab - this is a GUESS on my part!

Can you get us a pic of the timing tab?

The timing tape - like mentioned can be ordered from summit, or can order from any local parts store - I just got one from Oreilly last week. It's literally tape that sticks to the harmonic balancer, but it shows numbers up to 50 degrees rather than the factory tab that just shows up to 10 or 12 degrees. When the motor spins above idle rpms, the timing is advanced more and more until a point (usually around 3000 rpms) where it's advanced as far as it will go. The timing tape helps you see what the total timing is, and when it "comes in" (as in total timing is all in before 3000 rpms, or all in by 2400 rpms, etc.).

You need to measure the balancer - chevy balancers are either 6 in or 6 3/4 in in diameter, then order the correct tape. Mr. Gasket happens to be the brand that Oreilly's can order, several brands are avail - doesn't really matter, they are all the same.

Not sure a timing tape would really help you though since you are computer controlled - the computer is controlling it all with very little you can do to change it, other than changing the base timing which you don't need a tape for.

I'm using one because I'm non-cc carbed, and I needed to see where my total timing was at to better tune with - my total timing is only getting to 30 degrees and taking too long to get there - so now I know I need to change springs in my distributor to lighter springs so it advances quicker. But again, you are computer controlled, so you don't really have these options.

Go back and check your basics, and post a pic of your timing tab if you can, and maybe we can help further.

 

Yes I will try all that and snap a pic of my timing tab. Thanks guys

 

Was it a stock rebuild?

Here's a timing tab from a 305. Maybe yours looks like this.

And yes you have to disconnect the EST when setting the base timing.

 

Not quite but close. I will snap one when I get home.
thanks guys

 

Ok so I went home and check all those little things. I adjusted the timing to 0 then to 2 advanced. The truck runs ok at idle no coughing or anything. Stutters in reverse and then when try to go a little on the throttle it sputters and backfires through TB. I unhooked est wire and set timing hooked up and watched it advance. Im gonna check the valves maybe they are too tight. Maybe esc, dizzy, and the icm. Any other thoughts. This truck with a new motor shouldn't be running like complete dog S!@#$. Thanks
Brian

 

OK update time. I didn't take a pic of the timing tab becuase it is exactly like Doom was talking about. So I tried to time it. Well I timed it at 0 and -2. Still cuts out and bogs and chokes. Going to be getting a distributor because there is 300,000 plus miles on it so maybe the gear is on its way out. Also new ignition module and coil. Hopefully it will take care of the problem all together. I guess we will find out. Also going to swap out the ACCEL wires for a set of stock wires.

 

Was it a stock rebuild? And is it still backfiring after the timing adjust or just bogging out?

Hopefully it's just a tired distributor but if everything camaronewbie suggested checks out it sounds like a fuel or ECM problem.

 

Still backfiring through TB. So like I said I am getting a new dizzy and ign module and coil. Hopefully that will solve it. I will let you know.

 

Another consideration is that there are different balancers for different timing tabs. The two most common seem to be where 12 o'clock is 0 degrees and another where 2 o'clock is 0 degrees. If the balancer was replaced or if the timing cover was replaced it's possible that you have the timing tabs for one style and a balancer for another style.

Newer motors approx. 86+ seem to have the 12 postion marks. The balancer timing mark will be about 40 degrees off from the keyway slot. If the timing marks are at the 2 postion then the balancer mark and keyway will be almost straight with each other.

 

if you used the old balancer it could be worn out and it will move the timing mark Ive had that happen before

 

Well you guys are gods on here. Ok so a little update. Its running and running good. Timed at -2. OK here is what I did. I rplaced the coil, complete distributor with ignition module. New plug wires for stock ones instead of the Accel wires. The truck runs very good. One small slight problem. I notice the truck will seem to be loping and almost will die but doesn't. I checked batter and alternator with volt meter. Everything thing good there. I also notice when it warmed up the oil guage was all over the place. I got a new oil pressure switch so maybe it will help the guage and I heard its tied into the fuel somehow. The guage bounces around rapidly and goes to zero then the check guages light comes on everytime it bounces to zero. So I got a new switch just looking for the wire now. Thanks for everything.
Brian
89 K1500

 

Oh and just to let you all know. I used the original damper and timing cover from my old motor. Except for my issue above its is running really well!
Thanks for all the help, back to the FSC forum as soon as I fix the oil pressure switch.