ion sensor code P1312

[aaacardoctor1]

I recently replaced the timing belt on this vehicle and I used an aftermarket gates brand belt at first and could not get timing set right due to what they say is a peoblem with using aftermarket belts because they are not marked correctly. I then used a factory belt all the marks matched up perfect and the cam and crank marks are in the proper position the truck starts right away when you crank it and idles smooth but when you put it under load it backfires.It ran fine before the belt replacement and the belt was only replaced due to maintenance recommendations not because it broke. I keep getting code P1312 ion sensing sec circuit 2 open or short but nothing was touched during belt replacement to cause this. Anybody got any answers? I ran a compression test all cylinders on the driver side bank are within spec it is got good spark from coild to plugs and injectors are working properly but the 2/4/6 cylinders are on this circuit and they are cool to the touch after running the engine a few minutes but the 1/3/5 cyls are getting hot and they are firing normally.

[rodeo02]

Did you move one of the cam sprockets by chance? Almost sounds like you are 360deg off on one of them. The ion sensing crap might be just picking up the no fire.
G/luck
Joel

[aaacardoctor1]

Originally Posted by rodeo02

Did you move one of the cam sprockets by chance? Almost sounds like you are 360deg off on one of them. The ion sensing crap might be just picking up the no fire.
G/luck
Joel

yes both of them actually have been spun several times due to the aftermarket belt. I have never worked on one of these but all 3 marks are in the correct place on the belt and according to instructions. Have you ever heard of anyone having this problem and causing an open or short circuit code for the sensor?

[rodeo02]

Originally Posted by aaacardoctor1

yes both of them actually have been spun several times due to the aftermarket belt....

That's most likely your problem. When the T-belt was off, if you messed up the orientation of the cam sprockets with respect to the crankshaft sprocket, your valve timing will be off. You can't move anything once the T-belt is off. You can line up all the timing marks, but still be off 360deg or more at that point. As far as I know, the ion sensing system wont cause your truck to NOT run, it's just a 'sensor' that helps tweak ignition timing.

Joel

[aaacardoctor1]

Originally Posted by rodeo02

That's most likely your problem. When the T-belt was off, if you messed up the orientation of the cam sprockets with respect to the crankshaft sprocket, your valve timing will be off. You can't move anything once the T-belt is off. You can line up all the timing marks, but still be off 360deg or more at that point. As far as I know, the ion sensing system wont cause your truck to NOT run, it's just a 'sensor' that helps tweak ignition timing.

Joel

yea thats what I thought but wasnt sure if you could do that. It starts right up and idles perfect until you put it in gear and step on the pedal then it sputters and misfires.Any tricks you know of other than spinning the right side came gear again until it comes back up to the mark?

[rodeo02]

If the valve timing is off, the only way to reset it is pull the valve covers so you can eye-ball the camshafts, you match the cam lobes to a cylinder at TDC. I don't have a manual for the specifics, hopefully someone can chime in!
G/luck
Joel

[aaacardoctor1]

Originally Posted by rodeo02

If the valve timing is off, the only way to reset it is pull the valve covers so you can eye-ball the camshafts, you match the cam lobes to a cylinder at TDC. I don't have a manual for the specifics, hopefully someone can chime in!
G/luck
Joel

Ok. Thanks! I'll let you know how it goes tomorrow I will be back at the shop and giving that one a try as we have tried everything else except to start to throw expensive parts at it.