View Full Version : detonation problems I can't resolve!!!

04-12-2002, 12:41 PM
hi all-
I'm having a problem w/ detonation I can't fix!!
I have checked fuel pressure under boost, timing, cleaned and balanced injectors, sensors, ect, and am running slightly rich over the entire power band.
could I have a "hot spot" on the cylinder head? the current head is stock (60k+ miles on it), and I have another w/ polished chambers (installing soon), so I hope this will fix it.

does anyone have any other ideas? I have wired the fuel pump to be 12v all the time (bypassed the boost voltage valve thingy), and it is a 190lph pump on a pretty much stock motor.


04-12-2002, 12:53 PM
You mentioned that you run a bit fat ( rich ) all the way through the power band....Im wondering if there is a build up of carbon in the chambers....

How many miles on the head..?

04-12-2002, 01:13 PM
There is about 60k miles on the head. I'm not blowing smoke, nor does it smell too rich.
I might just finish the additional head I have, slap that on, and see if my probs go away.

04-12-2002, 05:31 PM
Try this

Add a gallon of toluene or xylene to your gas tank next fill up. If the clatter disappears then you are not running a high enough octane fuel.

I have the same problems with my SVO, and toluene clears it right up.

04-12-2002, 10:30 PM
Run it and then pull the plugs to see which cylinder is running lean. I had the same problem and one of my cleaned and balanced injectors had gone bad.

I checked all of the sensors also but when I pulled the plugs three were tan and one was white...

04-13-2002, 12:18 AM
Is the stock head on the engine now???

If you are running a non-turbo head, it might make the compression ratio go up a bit, and that could cause some issues..

Also, what is your timing set at, and does retarding the timing (or running in unleaded mode) help??

Eric C