HOrnbrod Posted June 28, 2012 Share Posted June 28, 2012 Come to think of it, I have NEVER had to change out a coil on any of my vehicles. Not even my then 29 years old F100 with 230K when I wrecked it. Coil going bad at 100K would mean bad quality craftsmanship. Have to agree with this. I had to change only one coil that I can recall ever, through many many different vehicles. It was an aftermarket MSD coil on my 91 HO. It only lasted about 10K miles. Glad I kept the original as it's back enjoying life again. Lesson learned. Link to comment Share on other sites More sharing options...
mountainman Posted June 28, 2012 Share Posted June 28, 2012 Well...lol. I'm not really here to argue but i will say this. What your experience may be with your personal vehicle, i can assure you does not apply to the rest of the world in all cases. remember you may live where its nice and cool all the time, or you may just have good parts. There are a lot of solid items out there in the automotive world, this much I'm aware of. (they are tested to the max here in the dry HOT desert) But doing this for a living every day now since about 1995, i can say that ive had my hands on a ton of vehicles, 10s of thousands. I am a drivability and diag tech. Had my smog license for a decade in CA, and I'm still at it. Ive seen every manner of ignition failure you can imagine. The coil is the part that goes first. spark plug sparks ONE cylinder.. that wire sparks ONE cylinder. A coil has to spark them all.. over and over and over. 100k miles is a $#!& load of sparks for that particular piece of equipment. Coil on plug should last longer right? except that it is subject to twice as much heat thereby negating any longevity you could have gained by having one coil per plug over having 1 coil for 6 plugs. Quality IS a big factor though, so if your getting a bajillion miles out of a part, thats awesome but remember that is not going to be everyones experience. My point was, at 10 years or longer, and 100k miles, if you have to buy a part thats only 125 bucks... you shouldnt let that ruin your day. thats quite cheap when other cars need entire transmissions or engines at 100k. I understand being spoiled on parts. I build old vws, and i have the original gearbox from 1957 in my bus. God knows how many miles are on it, and I'm putting 3 times the factory horsepower through it and it doesnt miss a beat. lol. Link to comment Share on other sites More sharing options...
COFFMAN Posted June 28, 2012 Share Posted June 28, 2012 Hey fellows can i please chime in here as i have a similer problem with my 99 XJ It has a miss & sounds fluffey out the exhaust. Engine also has a viberation in it when driving but not all the time. Pretty sure the L/H engine mount is U/S though. So the first thing was check the plugs, # 6 was wet fueled up so i think this is my problem cyclinder, regaped plugs & refit still the same. As i,m old school, point,s etc i was thinking she burnt out a valve or worn a cam lobe. The next thing i was going to do was compression test The motor done 270 000 km As i work away i was planning on swaping motors with my donna XJ done around the same Km, when i get home in 2 weeks, after compression test, which will take up a lot of me time ( MJ time ) if i had to swap motors So it was great to stumbel on to this As i only have one coil that would rule that out ? Any input by you guys would be great :wavey: Link to comment Share on other sites More sharing options...
COFFMAN Posted June 28, 2012 Share Posted June 28, 2012 P.S no check engine light comes on :wrench: Link to comment Share on other sites More sharing options...
Eagle Posted June 28, 2012 Author Share Posted June 28, 2012 Hey fellows can i please chime in here as i have a similer problem with my 99 XJIt has a miss & sounds fluffey out the exhaust. Engine also has a viberation in it when driving but not all the time. Pretty sure the L/H engine mount is U/S though. So the first thing was check the plugs, # 6 was wet fueled up so i think this is my problem cyclinder, regaped plugs & refit still the same. As i,m old school, point,s etc i was thinking she burnt out a valve or worn a cam lobe. The next thing i was going to do was compression test The motor done 270 000 km As i work away i was planning on swaping motors with my donna XJ done around the same Km, when i get home in 2 weeks, after compression test, which will take up a lot of me time ( MJ time ) if i had to swap motors So it was great to stumbel on to this As i only have one coil that would rule that out ? Any input by you guys would be great :wavey: Not sure how the '99 would react. Have you tried testing the spark plug wires? If the #6 plug is wet, you have fuel but it isn't firing. Firing requires three things: air, fuel, and spark. A burned valve is usually an exhaust valve, which would typically allow firing but with low compression, and you should be hearing some backfiring if that's the case. The wife's 2000 didn't throw a check engine light when the rough running first started. In fact, I drove it with the skip for two or three days before the CEL finally came un. Once the light came on, I got a code for #6 misfire. With separate circuitry for each cylinder I guess the coil-on-rail system can be that precise -- the cap-and-wires system probably has no way of knowing. So I would start by checking the ignition wires. You test test them with an ohmmeter. Link to comment Share on other sites More sharing options...
COFFMAN Posted June 29, 2012 Share Posted June 29, 2012 Hi Eagle when i checked the plugs i also change the spark plug leads from my donna XJ. :( Link to comment Share on other sites More sharing options...
Eagle Posted June 29, 2012 Author Share Posted June 29, 2012 Hi Eagle when i checked the plugs i also change the spark plug leads from my donna XJ. :( Well, then, I guess you should run a compression test. Link to comment Share on other sites More sharing options...
COFFMAN Posted June 29, 2012 Share Posted June 29, 2012 Hi Eagle when i checked the plugs i also change the spark plug leads from my donna XJ. :( Well, then, I guess you should run a compression test. Thats my plan, just wanted to gather as much info on possible causes before i get home, so i don't use up all my MJ time Just hope i don't have to swap motors :dunno: Link to comment Share on other sites More sharing options...
carnuck Posted July 19, 2012 Share Posted July 19, 2012 I think that even newer models (on WJs) went back to single coil per plug setup. Might want to check into that. Link to comment Share on other sites More sharing options...
terrawombat Posted July 19, 2012 Share Posted July 19, 2012 I think that even newer models (on WJs) went back to single coil per plug setup. Might want to check into that. Only on the V8. Link to comment Share on other sites More sharing options...
carnuck Posted July 20, 2012 Share Posted July 20, 2012 It's still pretty easily done if you can solder. Link to comment Share on other sites More sharing options...
terrawombat Posted July 20, 2012 Share Posted July 20, 2012 Considering the OP didn't want to line up the timing mark on the crank pulley to determine if the #1 cylinder was at top dead center, I highly suspect that he would not want to convert the 4.0L coil rail to a coil-on-plug setup. Link to comment Share on other sites More sharing options...
COFFMAN Posted July 21, 2012 Share Posted July 21, 2012 Well after getting home from work with the fuel & A/C disconnect tools ( purchased while away at work ) and hopening i didnt have to do a motor change. First thing was compression test, and YEA my problem cvyclinded cum up trumps 180psi Next step was change injector rail and now she gose like a cut cat :banana: Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now