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Old 05-05-2002, 01:14 PM
Whb Whb is offline
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I recently installed a TFI upgrade on my '79 Wagoneer, except for regapping the plugs. It ran fine, but not exceptionally better than before. Then I regapped the plugs to .045". Now it misses, especially at idle. Anybody have any suggestions, other than setting the gap back to .035"?

--Bill
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Old 05-05-2002, 01:31 PM
thos thos is offline
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Bill-

Did you replace the wires w/ 8mm? How about the cap and rotor? Use copper? What's your timing doing? When I did the upgrade last month I had no pbms whatsoever and it runs like a champ.

As far as gapping the plugs, I used regular bosch (not plats) gapped at 40. I figure they will widen w/ time.
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Old 05-05-2002, 01:32 PM
Gladi8r Gladi8r is offline
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Double check and make sure you dont have the positive and negative to the coil backwards. I have heard that someone on here had theirs backwards and the rig ran but not with any noticeable difference. Once they corrected the wiring it ran better. just a thought
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Old 05-05-2002, 02:49 PM
Whb Whb is offline
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thos:
Replaced the wires with 8mm, cap & rotor are both copper. I'm using regular Bosch plugs. I haven't checked the timing, but since it ran fine with the gap at .035", I assume it's ok. I'll check it tomorrow. Maybe .045" is just too wide and it should be .040". I'll do the timing first, as I do hate removing/installing the plugs. There has to be a special spot in hell reserved for the guy who located the heater core and the power-brake diaphragm right in front of the four rear plugs.


Gladi8r:
I'm surprised that the thing would run at all if + & - were reversed. Still, I think I have it right. The tfi coil isn't marked + & -, but the instructions said the red was positive, so I hooked it up red to red, green to green. Also, my tach works when attached to the green wire just as it did with the old coil. I don't think it would if things were backwards. I'll check it again anyway.

Thanks for the suggestions, guys.
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Old 05-05-2002, 02:58 PM
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Michael Michael is offline
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Is it a subtle miss????

Gap them @ .42.... Mine had a little miss @ .45 also... it went away at .42

Also make sure all you wires are "snapped" on the end of the plug....

Good luck to you.
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  #6  
Old 05-05-2002, 03:21 PM
Whb Whb is offline
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Michael: Actually, the miss is not too subtle. I had another thought though. I'm wondering if the resistor wire to the coil is limiting its output? If it is, that could account for a miss with a .045" gap. I had thought that the resistor wire was a hold-over from points style ignitions, where it was necessary to keep the points from burning up in relatively short order. Do you know if the resistor wire is really necessary? Now that I think about it, though, by limiting the current to the coil, it probably serves to limit the current draw on the ignition module; removing it might fry the module. Or do I have this wrong?
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Old 05-06-2002, 01:57 PM
thos thos is offline
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I seem to recall that resistor wire is a red herring. I simply snipped the pigtail wire (extra pos wire) off and haven't had any pbms. I like Mike's suggestion re: snapping all plug wires on tight. Mine were hard to snap on - had to use extra elbow grease.
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  #8  
Old 05-11-2002, 05:00 PM
Whb Whb is offline
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Well, I checked the timing, replaced all the vacuum lines, and made sure the plug wires snapped on smartly. No joy. I Finally regapped the plugs to .040" and then it ran pretty good. Idle still isn't as smooth as with a .035" gap but it's not bad and it has more power; think I'll leave it like that for a while.

Still investigating the necessity of a resistor wire. I contacted the mfg. of my tfi coil, Regitar, and was told by a tech. guy that it won't hurt the coil to remove it, but might overload the ignition module, depending on its design. Surprisingly, he didn't have the details of a 23 year old Motorcraft i.m. at his fingertips and it wasn't listed in his cross-reference charts, but he is researching it now and should have a definitive answer on the subject next week. I may have to buy something else from him whether I need it or not just because he's being so amazingly helpful with this.

--Bill
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  #9  
Old 05-11-2002, 05:11 PM
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RustyJeep RustyJeep is offline
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Seems to me there were posts soon after the whole TFI thing started about the significance of the resistor wire. I believe some ran without it and smoked their coils and ignition modules. I am going by memory here, but the major concensus was to leave it in there. Besides...everyone else running TFI, including me, probably didn't worry about the resistor wire, and mine runs at .045 with very smooth idle. I'd jsut double check everything, maybe your idle mix is a little off now...I know some people had to readjust timing and idle mix after the TFI...I'd check the mix.
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Old 05-11-2002, 05:14 PM
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When I did mine I had to retune the entire rig....I.E. Carb and timing. It is very possible you need to set the timing and also the mixture and idle screws.... May be a good idea to buy a vaccum gauge and tune the carb...I did that and my miss is gone now. Good luck to you. Do you have any vaccum leaks?
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  #11  
Old 05-11-2002, 08:27 PM
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a great tool my dad gave to me was a champion plug ratchet it flip flops at the end a truly wonderfull tool . as for the resister if it was in line then it is still there on mine .because all i did was rig the coil up to bolt into the stock spot for it and swaped the wires to the little harness cliped it in ran the wires hooked up vacum gauge set fuel timing and let er buck
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Old 05-12-2002, 01:00 AM
SandHog SandHog is offline
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Angry

As far as getting the back plugs by the heater core and brake booster, I came up with a trick. The spark plug socket I used has a 3/4 inch hex on the end, so I slid it over the back plugs, then put a shallow 3/4 inch socket on my ratchet and slid that over the top of the plug socket. Perfect length and still had clearance on the booster and heater core. A stupid thing, but it worked, and allowed me to use my torque wrench to tighten the plugs to spec.

My thoughts, my own, and rarely are they good ones. [img]tongue.gif[/img]
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  #13  
Old 05-12-2002, 08:02 AM
jeepbob jeepbob is offline
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There is a timing difference between the caps going from the stock to the TFI cap, you must reset the timing. The resistor wire is a must or you will fry the coil from too much voltage. They are made to run 9 volts most of the time, withstanding short bursts of 12 volts for easier starting. You should also retune the carb for optimum performance.
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  #14  
Old 05-13-2002, 04:23 PM
Whb Whb is offline
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Thanks for all the advice and suggestions. I have a long-standing appointment in the Panamint mountains and Death Valley starting tomorrow morning. I'll be out there for a week--the truck is running well enough for that--and if both it and I survive I'll try them when I get back.

--Bill
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