Ignition woes..

[YJBLUE]

I have a 1988 YJ with the 4.2L engine. It was "nuttered" last year. A couple of weeks ago I did the TFI ignition upgrade. I used the "juicebox" from CRT Performance. The jeep ran great for about 2 weeks before it started stalling and finally died. I did all of the testing in the Chilton manual and I'm sure the ignition module is fried. Did this happen because of the upgrade? During testing I found that I had 12V to the + Coil with both the key "on" , and with the engine cranking. I'm told that the module can't handle 12V - is this true? The 1988 YJ should have a resistance wire to lower the voltage but I can't find it. Anyone know where it is? Chilton also recommends testing the resistance between the + coil and the dash connector. I've pulled the dash apart but I can't find the connector. Anyone have experience with this problem. Any suggestions are sincerely appreciated. Thanks....

Mike

 

[jay79cj7]

It is likely your module. I have had the same problem on my CJ. Do yourself a favor and take your upgrade one step further with the HEI/TFI hybrid upgrade. It uses the same coil and other components that you just bought for the TFI, but you get rid of the ignition module and use the HEI one. It's about $20 and can handle 12V, so you don't have to worry about ballasts or resistance wire. I found this online about 2 months or so ago and its been going well for me. Just do a google search and there will be a few pages with info. Just make sure to use a heat sink of some sort for the new module. I used a heat sink off an old computer, other people used the old module case. Also, another side benefit is that you can have your key in the run position with the engine off (to listen to the radio) and not risk killing your coil/module. I had that problem with the TFI/Duraspark once too.

 

[YJBLUE]

Thanks! I'll definetly look into this option. Where did you buy yours?

 

[jay79cj7]

I picked it up at Autozone. I actually spliced the HEI module into the harness with the stock module disconnected so if anything goes wrong, I can just switch it back over. Not needed yet... I can't find the bookmarks I had when I was looking into this to share with you. One guy had the module attached to a computer heat sink like I did. Other guys had torched the guts out of the old module to get the aluminum case and used that to mount it.

By the way, for about 2 years before I did this HEI module upgrade, I used resistors from RadioShack to reduce the voltage for the TFI coil/module. I never had a problem after doing that either. I think there were four 8 Ohm 20 Watt resistors wired in parallel. (As I was guided to do here on Jeepz.)

 

[YJBLUE]

Thanks for the info...There is an AUTOZONE very close to me but I don't know what year or model to ask for since they aren't for a Jeep. I'll look around for some writeups on the internet. Replacing the resistor is another option I guess, though I would love to have a bigger spark (12V). I heard that the resistor wire I need is part # ICR22 at NAPA. I'll work on it tonight. Thanks......

 

[jay79cj7]

Here's a good site:

http://www.geocities.com/cantwait_forviolence/cj_tfi.html