2001 Bullitt GT Detonation/Spark Knock

[MCQEEN]

Hi guys.

Haven't posted on here in a long time.

I have a question about my 2001 Bullitt Mustang.

The only mods:
O/R H-pipe
K&N panel filter

When I first bought the car in 2006, I took it to GLD and heard some detonation spark knock in 3rd gear at WOT. I put 100 octane in it to calm it down. I later found the valve seals were worn as I had puffs of smoke after taking off from stop lights. I replaced the valve seals and the smoking stopped. I figured this was also the reason for the detonation.

Recently I started going back to GLD with it and bought some DR's for it. I also cleaned the k&n (lightly oiled) and cleaned the MAF. Traction was awesome, the air was cool and dense, but again I heard the detonation. Again I added some 100 octane and it went away. I always run 93 in it on the street.

I did a google search and found a Ford service bulletin for this exact problem and the cure was to have the PCM flashed with an updated tune. Rather than go back to the dealer, I brought it to the Bumper to Bumper auto parts store that I used to work at since they flash new PCM's using links from the manufacturer. They updated the PCM with a much newer revision then what was on the service bulletin.

I swear the car pulled harder on the street after the re-flash. Back to the track and I still hear detonation. Put in the 100 octane and it went away.

Has anyone else had a problem like this? It's annoying. Not sure what is causing it. The car has 140k miles. Doesn't smoke. Doesn't burn any oil. I was going to look into new spark plugs maybe trying a heat range cooler. I do have an SCT scanner for turning off the rear O2s but didn't really want to mess with anything engine related like timing in the tune.

Any help, theories or stories would be appreciated.

[Dynotune]

Originally Posted by MCQEEN

Hi guys.

Haven't posted on here in a long time.

I have a question about my 2001 Bullitt Mustang.

The only mods:
O/R H-pipe
K&N panel filter

When I first bought the car in 2006, I took it to GLD and heard some detonation spark knock in 3rd gear at WOT. I put 100 octane in it to calm it down. I later found the valve seals were worn as I had puffs of smoke after taking off from stop lights. I replaced the valve seals and the smoking stopped. I figured this was also the reason for the detonation.

Recently I started going back to GLD with it and bought some DR's for it. I also cleaned the k&n (lightly oiled) and cleaned the MAF. Traction was awesome, the air was cool and dense, but again I heard the detonation. Again I added some 100 octane and it went away. I always run 93 in it on the street.

I did a google search and found a Ford service bulletin for this exact problem and the cure was to have the PCM flashed with an updated tune. Rather than go back to the dealer, I brought it to the Bumper to Bumper auto parts store that I used to work at since they flash new PCM's using links from the manufacturer. They updated the PCM with a much newer revision then what was on the service bulletin.

I swear the car pulled harder on the street after the re-flash. Back to the track and I still hear detonation. Put in the 100 octane and it went away.

Has anyone else had a problem like this? It's annoying. Not sure what is causing it. The car has 140k miles. Doesn't smoke. Doesn't burn any oil. I was going to look into new spark plugs maybe trying a heat range cooler. I do have an SCT scanner for turning off the rear O2s but didn't really want to mess with anything engine related like timing in the tune.

Any help, theories or stories would be appreciated.

I would start with pulling some timing out with the handheld. If it goes away you know your on to something and it's free. If your not sure how call me and I'll walk you thru it.

[MCQEEN]

Thanks.

What would you recommend to start? -2 deg at a time?

[Greg@GLD]

Originally Posted by MCQEEN

Hi guys.

Haven't posted on here in a long time.

I have a question about my 2001 Bullitt Mustang.

The only mods:
O/R H-pipe
K&N panel filter

When I first bought the car in 2006, I took it to GLD and heard some detonation spark knock in 3rd gear at WOT. I put 100 octane in it to calm it down. I later found the valve seals were worn as I had puffs of smoke after taking off from stop lights. I replaced the valve seals and the smoking stopped. I figured this was also the reason for the detonation.

Recently I started going back to GLD with it and bought some DR's for it. I also cleaned the k&n (lightly oiled) and cleaned the MAF. Traction was awesome, the air was cool and dense, but again I heard the detonation. Again I added some 100 octane and it went away. I always run 93 in it on the street.

I did a google search and found a Ford service bulletin for this exact problem and the cure was to have the PCM flashed with an updated tune. Rather than go back to the dealer, I brought it to the Bumper to Bumper auto parts store that I used to work at since they flash new PCM's using links from the manufacturer. They updated the PCM with a much newer revision then what was on the service bulletin.

I swear the car pulled harder on the street after the re-flash. Back to the track and I still hear detonation. Put in the 100 octane and it went away.

Has anyone else had a problem like this? It's annoying. Not sure what is causing it. The car has 140k miles. Doesn't smoke. Doesn't burn any oil. I was going to look into new spark plugs maybe trying a heat range cooler. I do have an SCT scanner for turning off the rear O2s but didn't really want to mess with anything engine related like timing in the tune.

Any help, theories or stories would be appreciated.

Thanks for posting. It's been dead around here, nice to see some activity.
Mike Post can help you out for sure, get in touch with him.

The quality of pump gas has really gone down hill. Do you have 93 in your area? We still have it around here, but earlier this summer I went up to WIR and there were no stations with 93 anywhere, only 91. Just wondering if you are having this issue with 91 or 93?

[Dynotune]

Originally Posted by MCQEEN

Thanks.

What would you recommend to start? -2 deg at a time?

Always start by pulling out the max the handheld will allow. It's better to be testing with no detonation than to lower the timing and detonate then lower it agian and detonate and so on.

If pulling out the max timing makes it go away than just add 2* back in at a time until it comes back. Once the detonation returns pull the last 2* back out.

[MCQEEN]

Originally Posted by Greg@GLD

Thanks for posting. It's been dead around here, nice to see some activity.
Mike Post can help you out for sure, get in touch with him.

The quality of pump gas has really gone down hill. Do you have 93 in your area? We still have it around here, but earlier this summer I went up to WIR and there were no stations with 93 anywhere, only 91. Just wondering if you are having this issue with 91 or 93?

Here in Kenosha we have 93 according to what the pumps say.

I will try pulling timing with the SCT. Guess I will have to go back to the track and do some tuning soon.

Thanks.