Problems after motor swap

[LakeRat32]

Hello people, I have a couple of issues after having replaced the 300k motor in my 96 tahoe. The motor went in fine, and runs, but it feels gutless. I have a check engine light on, keep getting a code for cam/crank position senser, and a buddy of mine said that means I am running off the proper timing. Now I have hooked my truck up to a Solus and am sitting at 0 knock retard, and am running 18 degrees retarded on timing. I dont think I should be at that degree. Have any of you come up against this issue, and if so, what can i do to fix it?

 

[willxfs]

I would like to hear more about this as I am having similar issues on my 98 2 door. A year ago I had the 350 rebuilt and made into a 383 stroker motor. Currently the motor runs ok now but just doesn't feel quite up to par. I had my computer reflashed with a mail order tune from Brian Harris of TBI chips. Maybe the tune is too conservative. I'm thinking of having a local tuner take a look at some live engine data.

LakeRat, did you have the computer reflashed? Also are you running the original knock sensor? I've read somewhere that a bad knock sensor can cause timing related problems.

 

[LakeRat32]

I did not have the computer flashed, now that you mention it, that might make a bit of difference. I have however replaced every sensor on the motor and off it. The first time I got the correlation code, I replaced the knock sensor, cam sensor and crank sensor all as one unit, rather all at one time. So I do not think that could be the issue. I did however have a buddy of mine take a look at the tune recently, and that might be a factor as well. I just want to get the most out of the truck before I start having issues as a result from not having it properly built.

 

[HeliMatt]

I had an issue similar to this last year after my distributor gear sheared. I put a new distributor in, and it had no power, it got ****** gas mileage, and my check engine light was on, the code it threw was the same that you said, the cam and crank position sensors were misaligned. Try putting your engine at TDC on the #1 cyl and then take the cap off of your distributor and make sure the rotor point is lined up exactly with a little embossed 8 on the distributor body. If it's not, I'd bet that's your issue.

 

[east302]

What code are you getting? Is it P1345--camshaft/crankshaft position sensor correlation?

If so, and pretty much whenever the distributor is removed, you need to set the camshaft position sensor offset (CMP retard). It needs to be at zero degrees, plus or minus two degrees, at 1000-rpm. Use either a scan tool to read the offset or use a Bluetooth OBD adapter and an app (DashCommand or CarGaugePro) to read it while holding it at around 1000-1100 rpm.

Loosen the distributor hold down screw and rotate the distributor until you get the value close to zero. If it is too far out of range, it'll throw DTC P1345.

As a ballpark, the tab on the distributor cap screw will be nearly touching the intake manifold...maybe 1/16" or less.

http://www.gmt400.com/threads/car-gauge-pro-can-read-cmp.35275/


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[LakeRat32]

What code are you getting? Is it P1345--camshaft/crankshaft position sensor correlation?

If so, and pretty much whenever the distributor is removed, you need to set the camshaft position sensor offset (CMP retard). It needs to be at zero degrees, plus or minus two degrees, at 1000-rpm. Use either a scan tool to read the offset or use a Bluetooth OBD adapter and an app (DashCommand or CarGaugePro) to read it while holding it at around 1000-1100 rpm.

Loosen the distributor hold down screw and rotate the distributor until you get the value close to zero. If it is too far out of range, it'll throw DTC P1345.

As a ballpark, the tab on the distributor cap screw will be nearly touching the intake manifold...maybe 1/16" or less.

http://www.gmt400.com/threads/car-gauge-pro-can-read-cmp.35275/


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The timing retard is set dead zero, I had it hooked up to a Solus when reading, and was at a constant 1000 rpm throughout. But that is the code i am reading, still.

 

[LakeRat32]

I had an issue similar to this last year after my distributor gear sheared. I put a new distributor in, and it had no power, it got ****** gas mileage, and my check engine light was on, the code it threw was the same that you said, the cam and crank position sensors were misaligned. Try putting your engine at TDC on the #1 cyl and then take the cap off of your distributor and make sure the rotor point is lined up exactly with a little embossed 8 on the distributor body. If it's not, I'd bet that's your issue.

I will give this a try. I've tried just about everything else I've seen posted here and elsewhere, and I'm still getting the same code.

 

[east302]

Distributor could be off a tooth or maybe worn timing gear/chain set. Here is the diagnostic for P1345 for a 98 350, maybe it will help...






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