2002 Chevy 4.3 timing problem?

I have a 2002 AWD Astro I bought as an insurance wreck. So, I have no prior history on it. When I first got it all together - I had trouble with it stalling whenever I shifted from reverse to forward (or vice-versa). I pulled the engine-house off and found that the distributor was worn out. Worse I have ever seen. Near 1/4" of side-play on top. Bottom where the drive-gear is was fine. So I put in a new distributor. It started right up and runs great. No more stalling. Van absolutely runs great BUT . . check engine light keeps coming on with code P1345. I already took the distributor out once and did 2nd install putting the engine at TDC and following info in the book. It certainly seemed to go in correctly. This code indicates some sort of timing problem.

At the moment - engine has 187,000 miles and runs like new. No operating complaint. Just this light on. I have no idea if this is a new problem I caused or it was doing it long before I got it.

Two questions.
#1 -I am not sure how the crank-pulley indicator works to show TDC. Note the image I posted. I am not sure if the line on the pulley needs to point to the middle of the VEE I marked "A", or to an edge next to the VEE I marked "B."

#2 Has anyone ever verified a good running 4.3 engine with enough timing chain wear to keep throwing this code?

This code is basically telling you that the distributor is out of time. You are most likely off by one tooth in either direction. The engine will still run good, but the computer is not satisfied because the distributor is not in sync with the crankshaft.
I had the same problem on my neighbor's car a couple of years ago, and the fix was a replacement distributor and retiming it.
NOTE that the timing is NOT adjustable. Distributor must be installed and indexed correctly or the computer will generate a code.

You need to hook up a full function scan tool and see what the Cam Retard reading is. It is expressed in degrees. On the 4.3, it is technically not adjustable, but needs to be as close to plus or minus 5 as possible. It can be made adjustable by using a V8 distributor clamp. Reading becomes live above 1000 rpm, then you turn distributor back and forth until it is as close to 0 as possible.

First things first. Check your dist part number, and insure it is NOT for a Vortec engine. You must use the dist for the non-Vortec or you will never get the timing right, because the cam timing is different, and the dist is driven from the cam.

Next, the error has to do with the delta between the cam position sensor, and the crank position sensor. Has the cam chain been out? Have you checked the reluctor sensors for the crank and cam? Either of these being out of time(it could be just a too loose cam chain) will throw that code. I would check the two sensors, and plan on a new cam timing gear and chain very soon.

You need do do a re-learn procedure. Somebody who you can borrow a Tech II with current software can do it.

Had the same problem as previously stated . Distributor had to be rotated to get rid of the error code .

I know the V8 uses the same distributor as the 4.3,there is two timing marks on the base, 1 for the 8 and 1 for the 6.

V6 Vortec and V8 Vortec use the same distributor, just have to use the 6 or 8 mark. Never seen a chain fail in one of these, and I have
several customers nearing 300K on these.

Being a cam/crank correlation code, check the timing chain first. It could very well be worn out if the distributer was that bad. I just pull the dist. cap. With the cap off roll the engine clockwise past TDC #1 but stay on the timing indicator. I usually put them at 12 degrees. Then rotate the crank counterclockwise just until the rotor moves and count the degrees on the indicator. Over 8 degrees and it could use a chain, over 10-12 degrees and it needs a chain. I don't know how many degrees the computer needs to see to set the code. If the chain is ok cam/crank synch must be reset.

THIS!!! I've seen several with issue when we were running 4.3s in full size work trucks. After replacing the LIM at 50 to 70 thousand miles the timing chain (possibly with the worn distributor) would start throwing codes at 180 to 200 thousand miles. We usually sold them at that point rather than fix them.

If GM would have just put a decent lower intake manifold gasket in those engines they would have been a good bullet proof engine up to 200K. As it is you can expect a $1000 repair bill when they are in their prime - and many are ruined because the owner ignores the blown intake manifold and coolant becomes a main ingredient in the oil pan.

X2... This is the correct answer

I have the same problem in my '93 truck. I have replaced distributor, timing chain, coil, everything I can think of and still getting that stupid code. Seems to run well but, acts like the computer is "searching" for the correct timing while running as you can feel an ever so slight change in it while going down the road. Almost like what it feels like when the air conditioner compressor kicks in and out. Has been driving me crazy.

(quoted from post at 09:14:33 01/15/18) I have the same problem in my '93 truck. I have replaced distributor, timing chain, coil, everything I can think of and still getting that stupid code. Seems to run well but, acts like the computer is "searching" for the correct timing while running as you can feel an ever so slight change in it while going down the road. Almost like what it feels like when the air conditioner compressor kicks in and out. Has been driving me crazy.

Click to expand...

Missing/bad/weak reluctor sensor on crank or cam. The ECU is hunting for the right mixture to meet the RPM and mani pressure.

Some GM V6 had all metal cam drive gears, but some had metal hub with a plastic teeth. I can't recall which was the problem design. Doing a cam timing job in the van is a mess, but needs to be done most likely if the reluctor is working.

Update on my problem. I seem to have fixed it. I had the distributor back out and back in many times. No matter what I did, the rotor was never perfectly lined up with #1 pole in the distributor-cap when on TDC. I also checked the timing-chain for slop and there is very little. Barely 2 degrees of crank pulley slop, back and forth.

So - I took the steel hold-down plate that is normally non-adjustable. I made it slotted to give lots of adjustment. Just made it and now, swung all the way over to the end of the slot I made, it runs fine and no more "check engine light." Maybe the new distributor is not a perfect match for OEM? I cannot see any different but at this point, guess I don't care.

Maybe I am just too old-school, but it was nice to be able to mechanically adjust this thing.

"Maybe the new distributor is not a perfect match for OEM?"

Since timing is non-adjustable, I would suppose the factory exactly positions the gear on the shaft, then drills the pinhole.

Apparently the rebuilder isn't that particular!

I wonder what would have happen if you'd have knocked the pin out of the gear and turned it a half-turn, the put the pin back in.

Would probably depend on an odd or even tooth count, an the locations of the teeth in relation to the pinhole.