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How to cure pre-detonation??

4K views 30 replies 20 participants last post by  1995 cougar xr7 
#1 ·
My car pings, rattles, pre-detonates, etc. when I stomp on the throttle on the highway, or around town.

In old cars, this is caused by the timing being too far advanced. I had a `69 Torino GT with the 351W 4bbl. It had 10.7:1 compression, and I had to carefully check the timing when using lower octane fuel due to the pinging.

However, with my Cougar, I have no idea how to retard the timing. I also don't want to run premium in it since I will be using it for commuting 120 miles a day and the extra cost will really add up.

I think I've heard that some engines with higher mileage will develop the pinging due to carbon build up in the combustion chamber, which creates hot spots that can ignite the air/fuel mixture before its suppose to.

Anyone heard of that with the 4.6?

Any other ideas how to fix this? Could my free-flowing intake and filter contribute to the problem by leaning out the mixture?
 
#2 ·
Duh...

I did a search AFTER I posted and found plenty of good info.

I'll try the SeaFoam treatment, and clean the MAF to see if that helps.

Sorry for the unnecessary thread:(
 
#5 ·
I have the same pinging under higher RPM load such as full throttle runs up to 80+ MPH. I have been reluctant to try carbon removal stuff as I have over 170 K miles on my 96 and can't afford potential damage to my engine. I have a 100 mile r/t to work each day (from New River to Mesa, AZ) and have been just running premium fuel to help out with the pinging. I am very interested in your results with the Seafoam before I try it. THANKS !!!

John
96 LX 4.6
Mods: Pure stock except for a K&N filter.
(Been running Castrol Synthetic 5W50 since 46 K miles)
 
#7 ·
I've been seafoaming mine every oil change, (the day before the oil change) and am going to keep doing it until it quits helping; I have 210k on this one...
 
#9 ·
Well, I did the Seafoam routine and got a lot of smoke, seems to run a little better, but the pinging didn't go away.

It's fine when I'm down in Phoenix, but when I'm home up in Prescott, at 5000' above sea level, it pings really bad.

Coming up the mountain to go home is limited to 70 mph since any time the tranny shifts down, I get a bunch of pinging:rolleyes:.

I drove my wife's car to work the other day, and it did the same thing.

It's a 2001 Mercury GM with the 4.6 and 70k miles on it.

Both cars were purchased new at, and spent most of their lives at, low altitudes.

:confused::confused::confused:
 
#10 ·
Silly thought, but have you cleared the computer, to let it relearn the mix and stuff while at the higher altitude?

Pull the eec fuse in the underhood fusebox (#15?), and try to start the car, which won't start, and then put it back, and everything's clear...

I'd say 5000 feet is probably outside the normal adjustment range...
 
#12 ·
colder plugs can sometimes help too. i used to have a toyota that pinged like crazy w/ bosch plugs but was perfect w/ the recommended NGK's, just a thought. If you're not using the recommended plugs, i'd try getting those and see what happens.
 
#13 ·
Mine pings at low RPM, High load. (like if I try to accelerate in town, and the car doesn't downshift). But I have PI heads, and an SCT tune. I do run it on 91 Octane. I mixed about 3 gal of 110 Octane in it and (of course that fixed theh problem for that tank). but I can't do that all the time.

I'll put new plugs in tomorrow and see if that helps, but I don't think the current ones are that bad.
 
#15 ·
I'll try changing plugs, cleaning the MAF, and resetting the computer. I always use NGK plugs, but I can't remember if I've changed the plugs in this car. With 6 vehicles, it's hard to keep track of what I've done:confused:.

Anybody know which fuse is the EEC one that Grog6 spoke of?
 
#16 ·
4th big blue square one on the passenger side of the black power distribution box in the engine bay
 
#18 ·
I reset the computer.

I don't know what prompted the reply by DirtyDog regarding the burning of oil, but, ironically, I just noticed this today.

I use Mobil 1 10/30 full synthetic. I have no oil leaks and no smoke. After putting about 2k miles on this oil change, I checked the oil on Wednesday and was down 3 quarts!

I filled it up and then checked it again today. Down another quart!

Where is the oil going??
 
#19 ·
out the exhaust
 
#22 ·
something maybe vacumm related.



check if the vacumm fitting have been broken off. on mine i have done everything but i can't find the missed when the engine under load and when i pull my engine i found this have broken off at the top fitting. so this may cause it.
 
#23 ·
I reset the computer at home at 5000' and the car seemed to run a little better, but still pinged when coming up the mountain.

I then reset the computer at work while at 2000' elevation. No difference.

I filled the tank tonight with premium, and at $3.09 a gallon, that will not do:(.

I guess I'll try a colder heat range on the plugs and make sure gap is good.
 
#24 ·
clean the maf , it cured my pinging when I fist got my car .
 
#25 ·
sometimes a clean MAF isnt always a good MAF. Im suffering from pinging myself, but I have a bad O2 sensor, so ya know....
 
#26 ·
One of my '97 Birds pings like crazy too. I have two. Only has 32,000 miles on it so high mileage is not the cause. Also cleaned the MAF and had no effect. Still has the factory plugs, so I doubt if it's that. Seafoam does absolutly nothing, neither does Chevron with Techron additives. I currently run a 50/50 mix of premium in it. I plan to water inject it next with an atomizer. Who knows??? My other '97 doesn't ping but is hard starting when hot and have never been able to cure that one either. Phil Swanson
 
#28 ·
it sounds like its running very lean. You may have a fuel system prob. have youve done simple maintanace like fuel filter???
 
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