Hello, I just bought a '97 Crown Vic with a 4.6L engine and unless I use 93 octane fuel, it will ping upon heavy loading (going up hills, putting my foot in it to pass and etc.). Why pray tell is this and is this normal? I remember when I had a '79 Lincoln Town Car, it was the same way. Thanks.

 

Shouldn't happen, I have a '96 t-bird and a '97 Cougar with the 4.6L and they never ping. The MAF may be dirty.

There should be an "octane plug" somewhere under the hood. On my t-bird/cougar, it is in the harness running over the right shock tower, no idea where it is on a crown-vic. Removing the plug (grey) tells the computer to back off on the timing, usually enough to get it to stop pinging. It's a little grey plastic piece plugged into a connector.

However, it really should not do it at all. It could be the EGR valve is malfunctioning. This usually makes it ping on light to moderate throttle.

What happens if you really lay into the gas?

art k.

 

As long as there is 93 octane fuel in the gas tank, nothing but good power happens when I lay into the gase. Anything less though and pingin happens. With 93 octane fuel, I can burn all the rubber off the tires and no pinging, pull a house and no pinging. Thanks for the respoonse (working on 424 HP 390 for my F-100 tricl by the way, arrgh, arrgh, arrgh!).

 

Not to insult you but thought I'd ask...
How many miles on the motor? Do you know its history?
Could it be carbon deposits on piston tops increasing the compression ratio? (therefore requiring higher octane fuel)
Brian A

 

This isn't a police interceptor, or whatever it was called for '97 is it ?

I doubt the compression would be any different than standard even if it was. Is it possible it was chipped? My '96 t-bird 4.6L w/Superchips pinged without putting a lower temp thermostat into it.

Also, I wonder if it's possible the low-speed fan is not working and the car is getting far hotter than it should be?

art k.

 

My '98 Expedition 4.6 pings on 87 octane. With 89 it does not unless I am towing my 15' enclosed motorcycle trailer. I use 92 or 93 while towing. It has done this since 0 miles up to 99k.

 

Is it a Windsor or Romeo 4.6L ?

art k.

 

Not sure which one it is.

 

How many bolts on the valve covers? Does it say REP or WEP anywhere on the engine stickers?

F150's got the Windsor motor in '97 I think, so you're probably a Windsor. I've never seen a Romeo ping except when chipped/reprogrammed

ak

 

I will check tonight.

 

my 97 f150 supercab with the 4.6 also pings under acceleration or when the engine is under a load. with 93 octane, it doesn't. i always use just 87 octane since it's cheaper and there is no real benefit to using 93 octane gas on an engine programmed to run on 87. or is there? i have heard different stories on this subject. the only engine repair i have had done is to replace a sticky egr valve. other than that it's been very reliable. 147,300+ miles on the odo so far. mine has the windsor v8. date of manu: 4/96

Upper Case Edited out ...Again
Please refrain from its use

 

borderman, running high octane gas in a 87 octane vehicle is treating the symptoms but not the disease. if not already done, clean MAF, clean IAC, clean throttle body, clean EGR tube, check air filter, have you replaced plugs and spark plug wires. Possibly internal engine carbon buildup or fuel injection problem if above mentioned items dont help.

 

My '98 4.6 pinged on 87 octane the day I drove it off the lot. 89 cured it unless I am towing and then 92 takes care of it.