looking for repair advice ( crank sensor )

triton

triton

Scarlet Fever
Joined
May 30, 2007
Messages
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as some may know, I recently assembled a new motor. Truck runs great unless I get into too hard and it will loose all power as if the fuel just shut off. Let off the peddle and all is good. Good rail psi and good lift psi.

if I connect the crank sensor, the truck won't start. Disconnect it and it starts up. I started out looking for a short in the harness. I believe I found one so I replaced the harness with a brand new one. Went to start and the same thing.... no start with the crank sensor connected.

new cam/crank sensors, new wire harness, grounds landed everywhere batteries are new.

Don't know where to go from here. Anyone know what the deal could be ?
 
what reference notch is the crank sensor looking for? it all it sees is |-|-|-|- without a starting break like |-|-|--|--|-|-| it won't know were TDC#1 or what ever reference cylinder its looking for, and may rely solely on the cam sensor as a secondary back up.

I see this often on older CAT engines, but i am unfamiliar with how the main crank to cam positions are seen by the ecm.
 
that's what it's doing, relying on the cam sensor. I thought the ring might be the case too but the thing is, it can only go on one way. It uses a pin in the crank for it's position. Nothing wrong with the ring either.

This is probably the route I need to look into more though. All that's left is the ecm and I doubt it's bad.
 
you have gone around the whole timing gear and seen that there is a break, or abnormal period (extra long single tooth, extra long gap, or combination of the two). or does this timing sensor pick up the pin as well as count teeth?
 
Nootch said:
you have gone around the whole timing gear and seen that there is a break, or abnormal period (extra long single tooth, extra long gap, or combination of the two). or does this timing sensor pick up the pin as well as count teeth?
Click to expand...

yes, there is a notch in the ring
 
do you have a meter than can read Hz? can you pick up a signal off of the sensor disconnected?
 
yes, but would be kinda difficult getting to the pins though, they face up. I have to do some shimming to my pumps anyway so I may just pull the damper while I'm in there. I know the stock crank gear has the pin but, I'm not positive this one did. Does the notch align to TDC thanks for the help.
 
i dont know if you remember my posts, but a few years ago mine did the same thing. i get the 0341 after the motor reaches about 1200 rpm.

new sensors, ohmed harness, checked AC circuit , crank ring etc etc. everything looks fine. i deleted the code with EFI, and i have been relying on the cam sensor ever since with no problems.

i have chocked it up to a bad ECU sector. i guess it will stay that way until something else forces me to get a new one.

good luck man
 
can anyone verify how the alignment pin on the crank for the tone ring relates to TDC ? I haven't got to it yet but, I don't believe the pin is there. It was a new crank gear so I'll have to get one but, I do remember 2 holes in the crank so I need to figure where to align the ring.
 
NP, you'd swear we're doing the same build weeks after the other guy. LOL
 
Fixed it. the tone ring was 180* out. I installed a new crank and new crank gear which didn't come with the alignment pin. I took a gamble when I installed it and lost. It sure starts and runs a lot smoother with both sensors working!
 
Glad to see ya found the issue, that stuff keeps me up at night.have any recent pics of the rig and engine bay...
 
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