How do you measure the air gap of these sensors to rule out a possible "to small or to big" air gap?

 

sorry, define ckp and cmp

 

crankshaft position sensor and camshaft position sensor

What can I use as a .030 shim so I can set the cmp air gap correctly. Or should I just find a thin washer and use that for a spacer.

 

Neither have an "air gap". You unscrew them, replace them and torque them. The crankshaft positioning sensor goes to 105in lbs on the 5.7 and 205in lbs on the 4.7.

The camshaft positioning sensor is 105in lbs on the 5.7 and 106in lbs on the 4.7

What year truck and size engine? Are you getting any CELs or DTC codes?

 

Its the 4.7 engine.

 

I the vehicle I have is the 99 4.7 wj, the only time I get answers are when I come here ask questions. So that is why I just say 4.7. Here is a tsb on what I am talking about and this is why I think I have a p1391 check engine light on. http://wjjeeps.com/tsb/tsb_wj_082200a.pdf I remember when I took one of the senors out the metal tip looked like it had been scapped on something and at the time I didn't think anything about it. What do you think?

 

Here is all the info I have on P1391

 

im guessing its a no start?
Unplug the TCM and see if the engine will start. It is quite possible that the TCM can pull down the CKP signal thus causing a no start.

 

Last night I went to home depot and bought .032 thick fiber washer and used the washer as a spacer for the cam sensor. Well after I got done putting in the sensor with the spacer and started it up I could till right awat that the vehicle had more hp and ran better. The fuel trims actually looked normal for once. But the studder or hesitation is still there so I think am gonna do the same with crank sensor and see what happens. Hope it works, if not I am gonnna go buy two new sensors and put them in with spacers and see what happens.

I have wiggled the wires quite a few times hopping that would cause it to act up but it never did so I think the wiring is fine. So I put new sensors in hoping it would fix the problem no help. So I then started to try and fix the symptoms of my fuel trims which is how I found out I had a clogged fuel filter, I put that in which helped the fuel trims to quit reading so lean. But then the trims looked like they were a little rich so I was gonna start checking injectors. When I came across the link I posted earlier about adding a spacer to the sensors which increased the air gap which fixed problems of a p1391 in some vehicles. The new sensors never came with the paper spacer on the end of the sensor for proper air gap when installing the new sensors. So I gave it a try and it seems to have helped the timing and fuel trims to finally be normal. But I still have the check engine light on, I will say every time I put a new sensor in it seemed to fix the problem for a short time then the symptoms would come back. So I think the air gap on the crank sensor is to small also, which will cause the check engine light to come on as a p1391. So I am hoping this will fix the problem, I am about ready to drive the thing into a lake.


Thanks for all the help!!

 

Very good to know. I have never heard of that making contact with the tone wheel before. Have you thought of replacing them since it is said sensor damage could occur from contact?