Searching the site about info on the ever aparent missing or hesitation problem on our cars I found a TSB number. I have a connection on another board that works at a dealership and I have them the TSB # and this is what came up.

She said it doesn't pertain to f-bodies in general, but it might shed new light on the hesitiation problems many of us have here is the info.

ENG. MISS, HESITATION & ROUGH PIERCED SEC. IGN. COMPONENTS #93-35-6D - (10/01/1992)
SUBJECT: ENGINE MISS HESITATION OR ROUGHNESS DUE TO PIERCED SECONDARY IGNITION COMPONENTS

MODEL and YEAR: 1980-93 ALL PASSENGER CARS AND TRUCKS

THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 87-121, DATED MAY 1987. THE 1989-93 MODEL YEARS HAVE BEEN ADDED. ALL COPIES OF 87-121 SHOULD BE DISCARDED.

During the diagnosis procedure for an engine miss, hesitation or roughness, a spark plug or spark plug wire condition may be suspected. Several types of commercial or homemade diagnostic equipment required the secondary ignition boots or wire to be pierced. This is normally done to check for spark plug firing or to perform a cylinder balance test. Similarly, the use of pliers or other such tools to disengage a spark plug boot may pierce or damage the boot or wire. Secondary ignition components should not be pierced for any reason.

Piercing a spark plug wire and/or distributor boot may create a condition that will not be immediately apparent. Over time, the hole in the pierced boot may allow a ground path to develop creating a plug misfire condition. Heavily moisture laden air in the vicinity of the pierced boot may accelerate this effect.

Piercing a secondary ignition wire creates a gap in the wire's conductive core. This gap is a point of high resistance. The current flow in the wire will increase to compensate for the higher wire resistance. Over time, the wire may fail creating a plug misfire condition. The time required for the condition to appear depends upon the extent of damage to the conductive core.

To help prevent future condition that are spark plug wire related, do not pierce or otherwise damage any secondary ignition component. Only use diagnostic equipment containing an inductive pick-up to check for spark plug firing or to perform cylinder balance tests. When disengaging a spark plug boot from the spark plug, twist the flanged boot 1/2 turn then pull on the boot only to remove the wire.

 

Thanks for the heads-up

 

n/p, I myself have that missing problem and would like to get as much info on it as possible and pass as much info as I can find also. Like I said the model years on the TSB don't match up but it can give us new ideas on where to start looking when trying to find the problem.

 

So basically it just says check for broken or incorrectly installed plug wires. Cool. Thanks for the help.

 

Basicaly yea, espically near the boots.

 

I'm not trying to be an a$$ or anything, but duh.....

Good Info though, that's what this board is all about

 

Heh I didn't say it was good info, I just saw that TSB # come up and didn't find the actual bulliten for it, thought it might be helpful.

 

Well, no, it is good info. If you mess with the wrapping of a wire, eventually with the heat that they are subjected to, you're gonna have failure. Just to me seems like common sense. Don't poke holes in your wires....

 

Good info. I own a piercing probe but not for Ignition wires though... However it brings up a good point.


The information is not completely correct though. Or at least I think it should be re-worded. this is what I am talking about.



When I read this part it makes no electronic sense to me because in any electronic circuit where you increase the resistance... the current flow drops acordingly. the exact oposite of whats stated here. the part where it says the current will compansate makes no sense either. The ignition coil fires at its maximum voltage each time....so where the higher voltage needed to increase the current on a higher resistance will come from? it just make no sense to me.


I think what they mean to say is that the reduced surface area will generate more heat when the same voltage/current attemps to pass through it... with such area degeneratin quicker than the rest of the part... or something like that... also the contact to air will probable allow corrosion and I dunno what else.

Thanks for the post... even if for some is a duh.... not everyone is as knowlegable the other one..


Thanks.