Engine Guru needed

[litz]

87 GN with 60K miles, motor has 6 K on it, Comp Cam 218/218, 70MM throttle body and turbo, front mount intercooler, Terry Houston down pipe. Car had high boost/rpm iginition issues last week, sputtering/popping at boost of 13-15 psi, swapped coil packs did not help.
Below WOT all ok, seemingly.

yesterday started it up to move it in driveway, backfired once, then started and ran fine, moved it 30 feet, shut it down.

Wetn to move it back later, and after starting it, had loud, tapping or ticking sound coming from engine, 19 degrees of retard on scan master, at idle!

Where do I start looking???

When I was trying to solve the high rpm boost ignitionissues, I unplugged the Cam sensor and all was fine, so could this be a cam sensor issue??? I hope...
This is a daily driver, so it has to run Tuesday.

 

[V6 Beast]

SO are you saying that you had all these problems, unplugged the cam sensor and everything works fine, plug the cam sensor back in and everything goes to hell again?

I think you answered your own question. You can pull the cap off the cam sensor and see that the little interupter ring will move freely when it shouldn't.

Steve

 

[litz]

the tapping is new, and unplugging the cam sensor has no effect on the tapping sound. Unplugign the cam sensor eliminated my high end wot ignition issue. The Tappingt occurred after I tried to start the car in the driveway, and it backfired then fired up fine, moved it 30 feet parked it, all was fine. When I started it 4 hours later, it had the tapping sound.

I will look at the cam sensor first.

Thanks.

 

[litz]

pulled the cap off the cam sensor, and I see the silver interrupter ring, I guess. It does not move freely, it wiggles slightly left adn right but nothing to speak of. I guess I need to start looking under the valve covers?

 

[V6 Beast]

Check and make sure the little keyway is ok and that there are no little pieces of metal on the magnets inside the cap.

Steve

 

[litz]

no metal inside the cap but how do you check the keyway? Pull the entire sensor out?

 

[litz]

With regards to the interrupter ring, it is more of a cup rather then a ring correct? it looks like a flat circle with the edges turned up. the wall is not complete, meaning there is a square notch in it correct?

 

[V6 Beast]

right... it is a little ring with a window cut into. It is keyed to the shaft to keep it in position in addition to the screw on top. Sometimes the keyway will break off and it will seem like you can't turn it by hand but it will slip under force. Usually the broken pieces collect on the magnets in the cap though. You should be able to see the keyway on the shaft.


Steve

 

[litz]

Well, it seems the crank sensor is fine, the keyed part looks ok, as there is no pieces floating around. The keyed section is on the bottom of the flat washer type disc, correct? only a small notch. seems ok, can't spin it, but hard to get a good handle on it as well. I pulled both valve covers, all seems ok, but what should I be looking for besides the obvious spring material or buttons?

Also, Scanmaster shows 19 degrees of retard at idle so the tapping is pretty loud.

Any ideas???

 

[litz]

I let the car idle for about 15 minutes last night, still tapping, sounds like normal valve train but much much louder and 19 degrees of retar at idle. Oil pressure is fine or normal, 30lbs at 170 degrees and 800 rpm. going to get a stethoscope today to listen around.
Any other ideas???

 

[litz]

OK turns out, so far it is a collapsed lifter. Pulled the intake off after noticing the last rocker on the drivers side had some play in it. Pulled the lifter and it is squished. I am hoping this is all the problems I am going to have.

How do you know if the cam is OK?

Short of pulling it out.