Hello everyone.... Just found this forum and I look forward to helping others as well.

The truck is a 93 Ranger XLT 4.0 manual trans..... something has caused 2 brand new oem coil packs to crack on the bottom within a hours of installation... needles to say, the truck won't run right after it occurs.....

2 garages have looked at it... no codes...

first one replaced the coil pack & wires.... that lasted 1.5 hours until it occured again....

second one said ecu needed to be replaced as well as the coil.... that lasted about the same 1.5 hours of running wonderful before the coil cracked on the bottom again....

Please Help.... Thanks in advance

 

Could there be something underneath them not allowing them to sit proper when bolting them down? Maybe they are not sitting square to where they bolt down and stress cracking! They should not have to be forced to bolt down. This was just a thought hope it helps!

Goon

 

Hi Goon.... I thought the same thing after it happened the second time so I removed the screws and checked it as soon as I got it home.... It was definitely sitting flush and not forced in any way.....

Thanks for the reply....any other ideas?

 

Welcome to FTE!!!

Was the original one cracked when it was removed??

 

yes it was... that's whats making me think it has to be something electrical...

 

Have you made changes or mods in that area lately, like a new or different manufacturer for the intake manafold????

Are you having any indications of engine cooling problems????

 

no changes or mods and the engine cools fine....

 

OK, good input.

Is the land area the coilpack is mounted to, square, level & flat, end to end, side to side & oblquely, corner to corner.

Does the coilpack "rock" any at all, when it is just laying on it's mounting surface, BEFORE it's fastened down????

If it sits flat, with no rocking or wobbling, before it's fastened down, then it sounds like a coeficient of thermal expansion problem, between the material the coilpack is made from & it's mounting surface.

The coilpack being plastic or composite & epoxy encapsulant, will expand & contract more & faster with temperature. than the metal surface it's fastened to, so that expansion/contraction force, has to be borne by something, when the coilpack is restrained by it's fasteners.

I've not heard of this kind of problem being common on Fords, but if it is, or is becoming so, then I'd suspect a manufacturing processing control problem at the coilpacks facility!!!!

Anything from improper epoxy curing temp control, to lack of internal stress relief, to maybe improper or out of date encapsulating material.

The thing that bothers me about it being a new product problem, is that you said the origional coilpack was cracked too, so that would suggest to me that the problem is with the mounting surface, or with the item the coilpack is mounted to, is warping & overstressing things!!!!

Have you recently installed new intake manafold gaskets, or done any kind of maintenance, or underhood cleaning , or changed your drive cycle habits just before this began happening????

 

Haven't changed anything at all.... It was running fine and then not.... if the first coil wasn't cracked after running fine for years I'd say maybe a mounting problem. The fact that the one on the truck ran fine for years... then cracked... then 2 subsequent coils cracked makes me think something electrical is frying them but all the voltages are fine and there's no codes being thrown before or after the last 2 coils cracked in such a short time.... Is there anything you can thing of like a surge or something that could possibly cause this?..... I've never been this stumped and not havin g the truck is creating big problems....


Thanks everyone for your help

 

Well on the electrical side, the only thing I can think of, that could maybe cause it to overheat, is a poor ground connection.

This could cause a voltage drop to the coilpack & cause it to want to draw more current to do it's work & that could cause it to overheat, but I can't imagine it drawing so much wattage to cause enough heat to crack it.

Seems to me if it were to draw that much power it would pop a fuse or fry some wiring someplace.

If you are thinking a overvoltage situation, you should have other signs of it too. like blowing lamps in the dash or lights, or maybe doing in some other solid state things, like the radio .

To satisfy your self you could do a voltage test with some heavy loads on, like the headlights, bower motor on "high" & see what the alternators votage regulator does, or take it, or the alternator, to your favorite autoparts store & have them load test the system & see how it behaves.

Still i just can't imagine an electrical problem that would get the coilpack hot enough to crack it, without there being other signs of problems too.

Lets see, did all the coilpacks crack in the same place????

Did they show any visual signs of being hot or smelling like they had been hot????

 

they don't "smell burnt" but they all cracked on the bottom.... changed the ground cable and cleaned everything good.... tried yet another new coil, this time aftermarket with the same result...

I'm seriously stumped here

 

I am stumped along with you, but have a guess, is it staying dry? High temperatures then some sort of rather cool liquid gets on it, could per chance crack the plastic/epoxy. Random, maybe will help some.

 

Good grief, thats what, 4 coilacks now, 3 were OEM (including the OEM one delivered with the truck) & one aftermarket coilpack!!!

Well then, it seems to me we have maybe two things to consider, the coilpack, or it's mounting surface is being mechanically over stressed some how, or over heated & causing it or it's mounting surface to warp somehow.

You say you've not done anything too, or around the the coilpack, or the surface it's mounted too, so seems to me we need to look at some kind of temperature problem in that area, as you say it takes an hour or two for it to happen.
I'm not sure if the 93's coilpack mouning configuration is like my 99 or not, but I wonder if something like the EGR valves plumbing, or some other kind of exhaust manafold leak of some kind, close enough to the coil pack or it's mounting surface, that's causing a over heat/over stress condition, to the coilpack itself, or it's mounting surface & causing it to stress crack???

The description you've given of the cracks, sound like a overstress condition of some kind.

Have you taken any thermal heat readings around that area, to see if anything is WAY out of whack????

A leak in something like that, is about the only thing I can think of temp wise, that could over heat things badly enough, to cause that kind of thermal stress, to the coilpack or it's mounting surface.

 

The coil pack does not have a ground connection. One side of the primaries is tied to 12V when the ignition is on, and the other side it taken to ground to create the Di/Dt from open collector drivers in the PCM.

 

Bob.... so what do YOU think I should be looking at???

PawPaw... your correct....4 coilpacks.... I'm going crazy here