View Full Version : Still Detonating: can't figure it out

06-23-2003, 01:20 AM
Replaced fuel pump, EGR valve,(switch and transducer), suspect injectors, spark plugs and wires, sealed tubes and replaced vacuum lines that were bad, sealed blower top, new O2's and cats.
Pings at part throttle every time. And don't even think about mashing it. Ill blow it up for sure. I'll pull the battery terminal to reset the ECM. Then take off which seems to clear it a little but once the sucker relearns itself, same ol' thing. What's next? A shiny new sledge in think. Any thoughts?

Big Cat Davo
06-23-2003, 01:56 AM
What octane gas are you running? Anything less than 91 and you are asking for trouble.


06-23-2003, 02:14 AM
Dude, I've ran 100 octane from Unocal and still rattles like a mother. Like I was running 87 or 88 or something;no change in performance at all. And it idles rough too.

06-23-2003, 11:35 AM
It's either running way lean, or the timing is off. I'd try and track down if it's pinging in all cylinders or just one or two. Could have a bad injector that isn't opening all the way, or staying open long enough.

Joisey Jim
06-23-2003, 01:48 PM
Have you tried simply changing the fuel filter & checking the fuel pressure. To check the presssure at WOT you'll need a gauge and extension hose. I set mine up on the wiper arm (so I could see it on the highway) and found she was bogging down at about 52 psi and pinging like a bunch of marbles in any empty tin can. As soon as I changed the filter it rose to over 55psi and the pinging/detonation went away. Worth a try.

06-23-2003, 06:48 PM
CHeckthe EGR pipe. That tends to break or crack near the flex area. This would creating the part throttle pinging.

You might also removing the octane plug near the diagnostic connectors near the rear passenger engine area. This will retart the timing and help with detonation.

06-24-2003, 12:53 AM
Well I have replaced the fuel filter twice but have'nt checked the EGR pipe which will be soon. All new fuel injectors are going in as soon as payday comes around(InjectorPerfector - 150 for a set).
I've pulled the OCT plug and it really runs like crap but nary a rattle can be heard.

As for the timing, are our T Chains prone to stretching?

06-24-2003, 04:20 AM
I had the same problem a while back and the fix was a very inexpensive one. Perhaps this could also be your trouble as I did not read where you replaced the little devil which was driving me pinging nuts. Specifically, the PCV valve! Yes, in all my years I can say that I've never seen one go bad but it did on my SC and my engine pinged and it pinged and it pinged. My PCV valve was stuck open, which allowed vacuum to hold the EGR valve open at all times, which in turn allowed exhaust to enter the intake system at all times, which caused all my pinging problems! Also caused a rough idle in my car like you mention, as the EGR was being held open at idle. I replaced my PCV and whoalla! no more Ping!

Good luck, I hope your pinging trouble is as easy as mine turned out to be.

06-24-2003, 07:20 PM
Will check that out as soon as possible. Do think I have replaced that some time ago but with a Autozone unit. Will have to go to Ford for a SC PCV. We will C!