All was fine till I changed the heater core. Now at 3500-4000 wot it detonates. Runs rich all the time but detonates only at wot. I replaced map sensor and ect with no luck. It is a 88 gt tfs intake edelbrock heads msd ignition and a paxton sn-92. Yes I checked for vacume leaks holds 17 pds at idle. Can't find a leak anywhere and I checked all the maf conversion wiring and still nothing. pulls no codes except for typical egr stuff. Please help!!!
need a guru's help with detonation PLEASE!!
- Thread starter rich9521
- Start date
When i first got my car, its timing was way off and it would detonate as well, even with 91 octane. I just set it back a few degrees and it fixed the problem. Could be as simnple as that. But I dont see how a heater core could mess with your timing. Just throwing that out incase you havnt checked 
since the core is in the region of the puter and harnesses for the puter, any chance wiring was messed with?
otherwise, back off timing and see what happens. might want to put a fuel pressure gauge in to see if you are losing pressure at WOT and running lean...
good luck.
otherwise, back off timing and see what happens. might want to put a fuel pressure gauge in to see if you are losing pressure at WOT and running lean...
good luck.
Michael Yount
Mustang Master
"Typical egr stuff" -- very common side effect of malfunctioning egr is detonation. The engine runs hotter in the chamber than the computer designers expected (egr cools the chamber during combustion), often with too much timing added by the computer when the exhaust it expects to be present in the intake mixture isn't present because the egr's not working. The result is often detonation.
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