Stock GSX detonating like crazy

[sallystrothers]

A girl I work with has a bone stock 1998 GSX w/70,000 miles. She complained it has a problem. I took it out for a test drive and I am sure her problem is detonation/knock response. Why would a stock GSX have large amounts of detonation (happens almost every time turbo hits max boost)? I told her I would replace the spark plugs w/ colder ones, clean out carbon deposits w/ seafoam, and put 2 gal xylene in gas tank. I know this might help reduce detonation a little but there must be some underlying problem. Maybe air pocket in cooling system? Base timing off? What is the deal?

 

[Boosted 1.8]

check vaccuum lines going to fuel pressure regulator, if the fuel is wacked out then the car runs lean and so for detonates.

Originally posted by sallystrothers
A girl I work with has a bone stock 1998 GSX w/70,000 miles. She complained it has a problem. I took it out for a test drive and I am sure her problem is detonation/knock response. Why would a stock GSX have large amounts of detonation (happens almost every time turbo hits max boost)? I told her I would replace the spark plugs w/ colder ones, clean out carbon deposits w/ seafoam, and put 2 gal xylene in gas tank. I know this might help reduce detonation a little but there must be some underlying problem. Maybe air pocket in cooling system? Base timing off? What is the deal?

 

[sallystrothers]

Car has good idle so if a vacuum line were off the FPR it would have even worse performance than it is at now. Good idea and keep them coming!

 

[Boosted 1.8]

I wouldnt trust idle over my eyes, take a minute and look at the frp, the electrovane solonoid valve that it connects to and the hoses.