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Bad knock/ pinging problem

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Squid4life

Well-Known Member
Joined
Jul 5, 2004
Messages
6,275
Just installed my new motor, broke it in, etc and now I am having a severe knock/detonation problem under acceleration. I had the 85 ECM and a junk unknown chip that others told me was an extender. I swapped to 87 ECM, MAF, MAT, etc, and it has a stock chip. Fuel pressure is set correctly, and under even 1/4 acceleration it pings. Of course I let off and baby it home, but this is getting frustrating. I rebuilt the motor as soon as I got the car because it "needed a tune up", which turned out to be ate up valve guide, cracked header, etc.

I am waiting on a chip from Turbo tweak, but thought I could get this cured before it gets here. I am wondering if the cam sensor is set correctly, or if it is bad or good. When I set it I used the instructions from GNTTYPE.org and it fired up easily. But one thing I had an issue with was when it said "you should be at 7 volts, adjust it until you are at 0, then lock it down", mine went from 12v to 5v. (5v being in the "window".)

Any ideas? I will be bringing my laptop home and checking it on TLink, but it runs like crap. I am waiting on a poly drivers side mount because the aftermarket downpipe hits the bottom of the AC box, and maybe a few other places. With a slightly overstock cam it moves around a bit. This shouldn't create this big a problem. This isn't knock you "see" on TLink, this is the painful knock/ping you get with way too much timing.

Will the new chip help? Will the cam sensor being maladjusted do this? Any ideas would be greatly appreciated!!!

Squid
 
vacuum hoses crossed maybe?

Check out the thread "what kind of chip" since you just put the motor back in you might have the same problem. won't hurt to look.

Tim
 
Yeah, I looked at that post, and checked my stuff pretty thoroughly. My WG actuator only has one vac line on it. I replaced all the vac lines, and same problem. I found my battery during cranking went way, way down, so I have a new battery. I know if the cam sensor is out of adjustment it will fight the starter, dropping voltage but not to <3 volts. I am going to put the new battery in, adjust the cam sensor one more time, then try it again. I got my new chip in from Eric at Turbo tweak, made a big diff in the pinging, but still had a little due to the cam sensor being out of synch. Can't wait to get this thing running! I have owned the car for months and still have not really driven it. Was always running like crap, then pulled the motor, etc. Funny how things start with fixing an oil leak and repainting it, to what is in my sig! Gotta love it!

Squid
 
What about the hose/vac line between the turbo compressor and the throttle body? It is underneath... Any idea what purpose it serves? Mine is somewhat kinked, but due to the misalignment of the two barbs, I am not sure I'd be able to get it not to kink. I reset the cam sensor, and now it runs even worse than "setting it by ear". My battery was not holding a good voltage, and with a fully charged battery, the TLink shows the voltage drop to about 9v under load/revving.

Even when I set the cam sensor correctly it runs like crap. So I adjust it a little either way until it starts and runs smooth, but it stumbles under acceleration, like you are turning the key on and off.

I am waiting on the Caspers tool to set the cam sensor, but I should be able to get it damn close as I have been doing it. Although one place says 29 ATDC, and most say 25. I used 25, but it still runs like crap, idling really rough, motor shaking so bad the down pipe hits the AC firewall box. Xcounts at idle are constant 16, where as by ear the were 0.

Any other ideas to check???????
 
Well, I left the ECM power wire off overnight, went out and started it today and it idled pretty well. Drove pretty well too, unless you tried to give it more than 1/2 throttle. Then it pinged like crazy, about made me sick. It went to about 10 lbs of boost. Will a maladjusted cam sensor make a turbo buick ping/knock? I need to look for false knock as well because it had EXTREMELY high knock counts on the TLink, even at idle.

Slowly getting there...
Any other ideas???????

Squid
 
FYI, when I say high ESC, it starts at 15 at idle climbed slowly to 174!!!!!!!!!!!!!!!!!!!! Rev it and esc goes up 5 or 10, but stays. it creeps up no matter what. Why is this???
 
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