I hope this helps

[Frank87]

I have been trying to figure out what has been causing my detonation problem under hard acceleration on my 87 GN for a long time.( I rarely drive the car ) I hope I fixed the problem so I am going to share this with who ever needs it. My GN would detonate on pump gas but on 100 octane it was fine but as we all know that can get very expensive and I am waiting to purchase the alcohol injection for now. Well anyways a friend told me to try NGK plugs so I did ( part # UR4 6630) I gapped them at 0.35 and the detonation is gone and I have 93 octane in the tank. Each plug was under 2.50 but they made me buy 2 boxes of four plugs so I have 2 new plugs and next time I will only buy one box of 4. Now in the past I have replaced fuel pump ,sock, wires, plugs (AC Delco :frown: ) and fuel injectors and still no cure. Now just by replacing the spark plugs with the NGK's the car does not detonate. ( no I am not trying to sell plugs ) I hope this helps someone out.

 

[Dabigguy]

What plugs were you running before?

 

[TurboDave]

I have the same question.... What were the old plugs, and more importantly what were they gapped at???

BTW, for future reference, make your thread titles less meaningless. Makes searches easier. Your title could better have been "my detonation problem solved".

 

[Frank87]

My detonation problem solved

I was running AC Delco CR43TS and have been for a long time they were gapped at 0.35. My thing was that I ran them and they were fine at first then suddenely the car starts to detonate under hard acceleration and it makes you wonder what is going on. Although before the EPA or whoever had to add 10% ethanol to the gasoline the car was fine. I say that if you have detonation problems I would try the plugs to see. Now there are different listing numbers for the Turbo Buick so I would check it out first......



87 GN TA49 turbo 42.5 lb injectors upgraded fuel pump with hotwire kit and other minor tweaks ( chip K&N air filter) I have not been to the track in a long time but I believe it is a high 11 second car.