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majestic
10-01-2017, 10:45 AM
Having this issue. Car will detonate at WOT up until about 3000rpm, then boost hits full. Then runs fine and makes plenty of power. Replaced plugs and plug wires and set base timing to 10 btdc with SPOUT unplugged. Still having the issue. Any suggestions on what else to check? Car funs fine otherwise. Also, distributor and all components are new other than the coil.
Meotchh
10-01-2017, 04:39 PM
Are you sure you are experiencing detonation?
Your post is a little confusing. Detonate at WOT up until about 3krpm?

Are you sure you aren't having miss fire or stumbling issues? If you were experiencing detonation you would likely be replacing the headgasket by now.
majestic
10-01-2017, 05:09 PM
Are you sure you are experiencing detonation?
Your post is a little confusing. Detonate at WOT up until about 3krpm?

Are you sure you aren't having miss fire or stumbling issues? If you were experiencing detonation you would likely be replacing the headgasket by now.

It pings/knocks when you floor it until it gets full boost and then stops. It's not bad, but noticeable.
MikeFleming
10-01-2017, 05:46 PM
As a first step in diagnosing detonation issues, add more octane and retest.

What fuel are you using?
majestic
10-01-2017, 05:51 PM
Shell 91, which is the highest we can get around here. I guess I could add some octane booster and see if that helps.
MikeFleming
10-02-2017, 10:10 AM
Add 1/4-1/2 gallon of paint store quality Toluene to 10 gallons of pump 91.

The next question [after we ID 's the petrol quality is the issue] is what to do next?

NOTE: I have not purchased small qntys of Toluene in many, many years. There may be some ID requests, etc. to prove you're "not one of them". Be sure to get your nitrogen fertilizer at a different store.
NY eric
10-02-2017, 06:09 PM
Add 1/4-1/2 gallon of paint store quality Toluene to 10 gallons of pump 91.

The next question [after we ID 's the petrol quality is the issue] is what to do next?

NOTE: I have not purchased small qntys of Toluene in many, many years. There may be some ID requests, etc. to prove you're "not one of them". Be sure to get your nitrogen fertilizer at a different store.
ok thats funny.

serious note what type of stuff did you use (wires, plugs and what not).
Laredo
10-02-2017, 10:20 PM
Shell 91, which is the highest we can get around here. I guess I could add some octane booster and see if that helps.

Is there any leftover old fuel in the tank, or is it all fresh? Old, stale fuel will detonate more easily.
Do you still have stock boost control and knock sensor?
majestic
10-03-2017, 10:07 AM
Fuel is fresh. All Motorcraft parts. Boost control and knock sensor are stock.
Mike S
10-03-2017, 10:31 AM
Have someone follow you and report what they see coming out of the tailpipe when this occurs.
majestic
10-03-2017, 01:07 PM
I've actually followed the car and don't notice any smoke after the initial puff at startup.
Mike S
10-04-2017, 08:56 AM
I've actually followed the car and don't notice any smoke after the initial puff at startup.

The puff at start up indicates valve stem seals are going bad, but oil in the combustion chamber would have more of an effect under high rpm boost conditions.

Are you sure it is detonation and not a rattle under the hood?
Laredo
10-04-2017, 09:15 PM
Are you sure it is detonation and not a rattle under the hood?

^^ Loose intercooler brackets...?
majestic
10-05-2017, 10:47 AM
Nope. I removed the brackets. I drove it yesterday in cooler weather and it was not nearly as bad.