need help with detonation at low boost

[sweetgn]

I was driving around one night and the car was running fine under boost. Later the same night while still driving the next time I got on the boost I had severe detonation over 10 Psi. I have been troubleshooting for a couple weeks now when I have had time and the problem seems to be getting worse. I can now just rev the car to 3-4 thousand rpms in park and the engine will detonate audibly. The key to this I think is the factoy boost gauge. It flutters now about 2-3 lbs of boost around the actual boost level. I have used an air pump to simulate boost while attached to the MAP sensor and the factory boost gauge is then rock steady. I have changed the fuel filter, put new fuel in, changed the oil, changed the plugs(AC43TS gapped to .34), changed wires, ignition module, and coil pack out from a know good running turbo buick, put in new chip and injectors, ran the car down the road with a fuel pressure gauge attached to the windshield with fuel pressures normal with no drops and increases under slight boost(didn't want to hurt the engine), changed several vacuum lines and checked the rest. The car has a translator plus and 3 or 3.5 inch LS1 MAF. I suspect a valvetrain component or cam issue, but I am hoping you all have some opinions of what could cause this scenario. I would appreciate any feedback.

Thanks.

 

[TurboBuRick]

Sound more to me like the cam is going flat. Is it stock? Do you know how to check it?

 

[sweetgn]

It is a Reed Cams 210/205 circa 1998. It has been in there since then and has about 30,000 miles at most. As far as testing it, I don't have a dial indicator so other than pulling the valve covers and watching the rocker arms I wouldn't know. Could this also be a bent pushrod?

Thanks

 

[BlackBandit]

Sounds allot like a cam going south.

 

[sweetgn]

Thanks to you both. So what is the popular cam these days. Should I go roller. Are they now reliable? I'll take any suggestions. Any suggestions on a shop in the Maryland area to do this work? The car has ported stock heads, bigger valves, TE60, bigger downpipe, etc.

Thanks for any advice.

 

[BlackBandit]

Don't get to carried away. First verify what you have. If you do need a cam I would go roller. They've been reliable for a long time. As for the shop I don't know. Maybe ask in the regional forums. Good luck.

edit: I say don't get to carried away because there's a chance it's aomething like an injector. Just verify the cam.

 

[sweetgn]

Thanks

 

[ttaowner]

contact this guy he is local to you.

Bill Anderson
Anderson Performance Automotive
8209D Rosebank Ave.
Baltimore, MD 21222
410-282-9335

 

[sweetgn]

Thank you,

I believe it is definitely the cam. I pulled the valve covers today and one rocker arm is moving about a 1/4 of normal travel and two others are at about 1/2 travel. I appreciate the help from everyone to narrow this down. As much as I didn't want this to be the problem, at least now I know what I have to deal with.



Thanks again,
Bryan