Yep. Last summerish I posted a thread asking for help with a detonation problem in My 2003 S/C Harley F150. In-between then and yesterday only "2" guys chimed in! Lame. Yesterday at 5:01 PM I picked it back up since the detonation has returned with our hot air temps. As of right now, that post I did yesterday was the LAST POST Anybody did on that Forum! Of any kind. Unbelievable.

 

Hmm. I wonder if you have a bad CPS. that would run ignition timing up and cause detonation. Specially on a S/C engine.

 

what if anything have you done to it? I'm guessing no codes or anything related to the knock sensors? what octane fuel are you running and from where?

I've noticed in my Ranger that I have no issues running 87 from chevron or shell, but it knocks like crazy using 87 from arco or somewhere like that.

 

You might be on it 351. Last Monday I gave it to Service Dept to have them change the PCV hose while I was at work. It disappears somewhere back of the engine. We sell gobs of them here in Phoenix area. I told the tech I'm chasing detonation with no codes. He did something to the CPS. I think he said either adjusted it or calibrated. Still did it. Wednesday My battery went. Got a new one. Friday on my way home I didn't notice it. Hopefully either it took days for my PCM to catch up to what he did or the dead battery did something good with the Diablo programing. I guess I'll know when I drive home later today.

 

No codes. knock sensor is working and being read. Premium fuel. Tried different brands of gas. Best with Chevron but still did it. Thanks for your input.

 

let us know what you find out. good luck!

 

Gee whiz, no one at that Ford dealer you work at knows? Have you waltzed out to the service department and looked in the shop manual or seen if there were any TSB's on this problemo?

 

Mine was the intercooler pump

 

You do realize this post is 6yrs old.

 

Did you ever figure it out Jeff?


(PS, I cruise by your place daily now. Need to swing in sometime)

 

Welcome to FTE

I disagree. The 'puter will pull timing to prevent detonation when intercooler pump is not working (high IAT2), per lookup table. That said AZ fuel sucks and detonation may occur anyhow, and may be worse when hot.

 

That's what I was thinking too.

My '71 will ping on 87 gas. Sometimes on 89 too

The wife's 2013 Kia will throw a CEL on 87 it pings so bad. Even on 89 it's audible. 91 is better but way more expensive.


JEFFFAFA, have you ever tried running it on 93 or 100 octane? I know some of the Shell stations in Scottsdale have 93 octane at the pump. 100 octane is hard to find and over $7/gallon, but might be worth a couple gallons to test it.

 

As it ends up n it was intake manifold seals.

 

Vacuum leak and making it run lean or sucking up oil and causing it to knock?
Dave ----