need advice on pinging

[Blackjack]

I've got this problem with Blackjack and can't seem to solve it.
The truck will ping (detonate) unless I run premium gas. I've adjusted the timing a bunch of times and can't get it to stop.
Will closing the gap on the plugs help? It has the TFI upgrade and I think I'm running .038 or .040 gap.

I seem to remember someone telling me about an adjustment by allen inside the the vacuum advance tube going to the distributor. Would this help and if so which way would I turn it?

TIA for your help.

[youngjeeper]

mine was the same way, but i only tryed the lowest instead of premium. then one day i just decided to try the middle one, and no ping. have you tryed all the gases?

[Blackjack]

yeah, I normally run 89(mid grade) and it does it with that.

[Jeep Craze]

Just a thought but check your total advance, at various RPM's. I noticed on mine that the mechanical advance is right on spec, and the vacuum advance is was over shooting on part throttle. Once floored at WOT the pinging goes away due to the vacuum advance loosing some of its vacuum (at full throttle there is little ported vacuum. Not sure about 83 but for 79 Total combined advance is to be between 27.5 and 37.0 degrees @ 2000RPM. That is straight from the 79 factory TSM. Mine is at 37degrees, I am just gonna keep adjusting the vacuum advance down until It is better.Unless it gets below the 27.5 degrees then I will have to look into other options. Just a thought...hope it helps Craig

[Blackjack]

sounds reasonable but how is that adjusted?

[Jeep Craze]

There is suppose to be(not all have them)an allen screw inside the nipple on the vacuum canister thats on the distributor. when you take the hose off the dist. its suppose to be inside that nipple. I have no idea what size allen wrench will fit it, and I can't locate in the book which way turns it less or more. so there is alot of words and not alot of help for ya......

[Chevelleguy]

I found the screw in mine but it had no affect. I think I will tear apart an old Motorcraft distributor to see how it works. My total advance at 2300 is 52 deg. and I don't have a detonation problem.

[ October 16, 2003, 09:54 PM: Message edited by: chevelleguy ]

[Don S]

..
GFD aka Blackjack

Sometimes when an engine is bored out or the heads are milled the compression ratio goes up and that can cause pinging with a stock tune set up. Over the years I have seen many engines pinging due to carbon build up.
... The carbon gets hot and it will glow igniting the fuel mixture causing pre ignition.
I’ve been using upper-lubes for over 50 years and will continue until they pry the bottle out of my cold dead hand…!!!
The idea described in the link below has worked wonders for me and others over the years. If you have short runs with a cold engine it may take a little longer for it to work. It doesn’t cost much…
FUEL TANK ADDITIVES

http://groups.msn.com/ATexasOklahomaJeepClub/ouraycotopic.msnw

http://www.ifsja.org/ubb/ultimatebb.php?ubb=get_topic;f=2;t=010756

Harsh treatments for removing carbon could create a problem with the rings. I have used the ‘sudden’ water and the sudden ATF treatments with no harm but never again. Once I learned all the benefits of using 2 cycle Out Board oil as an upper-lub I just don’t let the carbon form.

Good Luck.. and CUL.. Don S..

[Bob Barry]

Under what conditions is it pinging?

There are any number of possible causes, but knowing when it pings would help narrow it down.

[jode]

1BAD401 just recently solved his pinging prob after a check of total advance showed that he was WAYYYYY off. I bleev he jsut adjusted the size (or quanitity?) of the weights in the dist and is now a happy camper....you might try contacting him as he is very knowledgeable on the subject....

[Blackjack]

Don,
Thanks for the links. I'll try that.

Bob,
It does it under load, while accelerating with between 1/4 and 3/4 throttle. If I feather the throttle it won't do it and if I floor it it won't either.

Jode,
Thanks too, I'll contact him.

SO the gap has nothing to do with the detonation?

[1BAD401]

Yes I can help you with PING!!! I think I was the king of ping for a while!!! lol... Anyway I use to ping all the time, part-time throttle, WOT, hot days and on the 91 fuel. I tried big jets (flood the ping), 0* timing and nothing was right. Finally I found that my problem was that I was getting over 60* total timing at anything over 2,200rpm. So I striped down the dizzy to the spring/weights, stock springs are way wimpy, so I got a HEI curve kit and used a heavier spring. BINGO ping fixed! I can set my initial at 12* and my total is around 36* at 3,000!!! PERFECT!!! I advice you to get a timing gun with the total advance option, if you don't have one. Also I ALWAYS run 91 gas, if you have your compression up I'd suggest you always run it. A few more bucks at the pump is cheaper than a new ring/piston job from pinging....

[pdspeh]

so 2 ounces every 20 gallons. I use MMO every tank. I willin' to try it. Makes sense.

[Blackjack]

Originally posted by 1BAD401:
So I striped down the dizzy to the spring/weights, stock springs are way wimpy, so I got a HEI curve kit and used a heavier spring. BINGO ping fixed!

where'd you get this kit?

[letank]

Also to add more confusion...... if your CTO switch is defective (open or close at the wrong time or stuck partway) ... you may have too much advance when you start to move..... just disconnect the vacuum advance at the distributor and plug it..... you will only have the centrifugal advance. At this time you can connect a vacuum gauge and read vacuum for different speed... idle, part throttle and so on

Michel