Down on power, detonation, burning pistons - NEED HELP

[Jerryl]

Incorrect. The voltage should drop from 7.5-8v to 0 volts. That's how you set the sensor. When the window is open you have voltage when the sensor moves past the window no voltage thus voltage drop. Don't waste your money on a sensor just yet....those things are expensive. Double check your double check.

I agree.
Not sure if the cam sensor was the problem, here is why. . . .
If the car started, and idled/ran ok, the cam sensor was fine since "No cam signal = no start".

If the cam sensor signal get lost while running, the ECM will go into batch fire mode, untill you shut it off.

 

[TurboBuRick]

I agree.
Not sure if the cam sensor was the problem, here is why. . . .
If the car started, and idled/ran ok, the cam sensor was fine since "No cam signal = no start".

If the cam sensor signal get lost while running, the ECM will go into batch fire mode, untill you shut it off.

Right! BUT if it's intermittent I think it can cause issues.

 

[phvrod]

phvrod

On my 85 had a similar problem....Found that a shop had replaced the heads and actually crossed the injector wiring..I.E. wrong signal going to the wrong plug at the wrong time....X2...Triple check the harness and or just replace with new caspers....PHVROD

 

[phvrod]

phvrod

On my 85 had a similar problem....Found that a shop had replaced the heads and actually crossed the injector wiring..I.E. wrong signal going to the wrong plug at the wrong time....X2...Triple check the harness and or just replace with new caspers....PHVROD

 

[boostmaster]

Right! BUT if it's intermittent I think it can cause issues.

Let me tell you what happens when you have an intermittent cam signal phsing in and out while the engine is running...........pow!!!! Backfire!!! So check elsewhere or find someone local in your area that can help you solve the issue. Repeat tear downs are time consuming and expensive, so is parts chasing.

 

[edmonds27]

Thanks for all the input guys. When we ran the diag tree it lead to a bad hall effect switch. We ordered a new Caspers from full throttle and she runs like a dream. I have to confess that we did change several things at once (87 ECM, New chip from TT, new knock sensor, new hall effect switch) so I don't really know which was causing the timing and detonation problems, but she runs great now. Idles smooth and quiet, smooth hard pulling acceleration, PLENTY of boost, and best of all NO RATTLING VALVES OR DETONATION- at least none I can hear with my ears. We still plan to get a PowerLogger and that will be the true test but for now we (this is my 16 year old son's car) can't stop smiling. I'm thinking about getting myself one. A GREAT BIG THANK YOU TO THE GUYS OF TURBOBUICK.COM. I appreciate all the help!

 

[Boost231]

Hall switch?

 

[edmonds27]

I'm not sure if your asking what I mean by hall switch or if your asking if I think that's what caused the problem so I'll answer both:
1-What I'm calling a hall effect switch is the cap on the cam position sensor. Please correct me if that's not correct. We bought the Caspers with the slotted ears and LED indicator light. I like it MUCH better than the stock.

2-I'm certain the hall effect switch (cam position sensor) was bad, because that's the only thing we replaced to get the car to start and run after the tear down. But we had a timing/detonation problem that caused the tear down and that's when we replaced the ECM, chip, and knock sensor. It seems logical to me that the sensor might have been the problem all along but since we changed those other things to I can't be certain.

 

[Boost231]

gotcha. was wondering what you where calling the hall switch. Cam sensor and cap eh..