P1345 Help?
 

Hey guys, I swapped the 4.3 from my 99 Blazer into a Jeep and broke my original distributor in the process. I replaced it with an aftermarket unit and even though it seemed to be set right, I got a P1345 code. I had a mechanic check the cam retard and we tried time and time again to get it set right but couldn't make it happen. I swapped that unit for another new one, timing marks lined up perfect, tab on the rotor lined up way better with the mark on the dist. housing with this one but still got the P1345 immediately on startup. Any ideas on what could be causing this? The engine did sit for about 3 years before starting it last March.

What is your cam retard value?

George

I can't remember what it was with the old dist. and I haven't had a chance to check it since putting in the new dist. But as soon as I do I'll update. I think it was a few degrees advanced but not sure.

The spec for cam retard is +/- 2 degrees. The timing for spark advance is controlled by the computer but the cam and crank need to be synchronized. If your off by a few dgrees the you can modify the hold down and zero it out but you should not get a code. If your off by tens of degrees then you may be off by a tooth and trying one tooth either way may fix the problem. A new distr can also have the gear 180 out and it may need to be moved over. To double check you can drill a hole in an old distr cap and watch the spark alignment while the truck is running.

George

If it starts, it's off a tooth. Need to move it one way or the other. No other possibility as long as you remembered to plug in the cam sensor.

Do any of you guys know the PID formula for CMP retard? I'm trying to program it into my UltraGauge MX. I've got the header and the code entered but it's not displaying the data. I'm thinking there must be a formula I need to put in?
https://cimg1.ibsrv.net/gimg/blazerf...35e8d8aa50.jpg

Nope. They have been trying to do that in Torque Pro for years. Never seen it to work. If you want the supposed formula, go on the Torque Pro Forum. I tried it in Torque Pro - didn't work.

for a 1999 get Car Diagnostic Pro if you have an Android. Dash Command if you have I-phone and opt for enhanced PIDs from within the software.

Okay, thanks. My Bluetooth adapter **** the bed on me so when my new one comes in this week I'll get that app.

I reinstalled the new dist. this evening, following this guide to a T. How To Set Vortec Distributor Everything lined up exactly the way it's shown but when I fired up the engine, it ran like crap and 1345 was set immediately. So I tried it again with the old dist. and got the exact same result. I turned it back (counter-clockwise) one tooth and tried again, this time the code did not come back and it ran better but still stumbles badly under heavy throttle. What are the chances that the gear is 180 out on both distributors? Maybe 1/2 tooth off isn't enough to set 1345 but its making the spark gap too long?

I think it is certainly possible. 360/13/2=13.8 degrees. You need to read cam sensor retard to tell.

I'm too impatient to wait on the scanner lol the code came back this morning after a hard start. So on my lunch break just now I flipped the gear on the new dist. 180 and reinstalled according to that guide I linked yesterday. BAM! No code and it's running much better! Still falls on its face at WOT but that could be solved with a fine tune once I can read the CMP Ret. I also noticed my fuel trims were wayyyy better. I've been getting like 10-12mpg so a boost in fuel economy would be a welcome bonus to hopefully getting this solved. Here's a quick video of the UltraGauge screen while I'm running about 3/4 throttle.

Hey, Les I found one that works on Torque Pro! This is as close as I could get without modifying the hold down.
https://cimg2.ibsrv.net/gimg/blazerf...5fe6dec2d1.jpg

Cool! VERY interesting. Where did you find the formula? Good thing to know.

Please post the formula and how you entered it and I will check it for accuracy against other software on my vehicle. I never had any luck myself getting it to work at all in Torque Pro. I believe there are different formulas for V8 vs V6, but AFAIK they do converge readings at zero.

I actually found it on a Safari Van forum, I think this equation is for a V8 but I'm sure it's very close. I'm gonna have my friend check it against his Snap-On scan tool.
https://cimg3.ibsrv.net/gimg/blazerf...c5f507361a.jpg
https://cimg4.ibsrv.net/gimg/blazerf...d5c6ad9b77.jpg