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Igotboost
06-09-2005, 08:17 AM
I changed my after market chip back to the stock one, (emission related) I noticed the engine seems to be knocking. The previous ownwer did some bolt on mods, (walbro 307, adjustable fuel pressure set @ 37psi, boost set around 20) everything else is mostly stock. This is in park with a little rev, it starts knocking. This happened as soon as I put the stock chip in. Thanks for any help.
Frank :confused:
Keller
06-09-2005, 09:39 AM
If this is in park, it is not boost related.

Is it knocking at idle? What about in park at 2000-2500 RPM?

May not be chip related, either. How many miles on the motor?
Igotboost
06-09-2005, 09:55 AM
89,000 miles on the motor. Sounds like pinging on the upper half. It does not knock at idle. I never heard it until I put in the stock chip. Thanks for replying.
Keller
06-09-2005, 11:11 AM
What does "upper half" mean? 3000-5500? If you are running 20 PSI, I would expect it to knock. Especially on pump gas.

You initially were talking about idle.

These cars will not run 20 PSI on pump gas without alcohol/propane injection or an ultra low timing chip. Or with high octane fuel and just about any chip,
Igotboost
06-09-2005, 12:07 PM
What I mean by the "upper half" is around the heads. It is faint so I can't really detect where it is coming from. When I hold the rpm's (1500-3000) it doesn't do it. Does it more when I hit the throttle really quick. I will lower the boost. I purchased the car 3 months ago, and the previous owner did all the work, I'm learning as I go along. Thanks
Keller
06-09-2005, 04:40 PM
Well...gee...the combustion chamber is in the heads. Up by the spark plug. Where things tend to ignite (or pre-ignite, thus *knock*) when they get squished together as the piston makes that up-n-down motion. Yes, I guess that is where knock would tend to happen...

If you don't have any sort of scan tool, I suggest you get one. If you hear knock, it is already far too much knock. Knock is a big enemy of these cars. If you do not keep track of your state of tune (i.e. O2, knock, etc.) you may blow a head gasket. Then you may get to know your car inside and out - as you learn to fix damaged the motor.