1997 TJ wrangler check engine light

Jakob McElhaney

Jakob McElhaney

New Member
Joined
Oct 3, 2017
Messages
13
Location
Zanesville, OH, United States
I am new to this jeep forum and I am seeking help. I own a 1997 TJ wrangler Sport. Inline 6 with an auto trans. I recently had tube fenders installed along with a 20" light bar. When I went to pick up my jeep after everything was all said and done, it would not start. Turn the key over, none of the gauges would even move. I was very confused with what was going on. After 2 days of brainstorming what could be wrong with it, I get a text saying it is running fine now, but nothing was changed. It just randomly started. After driving it for around 2 days, my CEL came on. NOTHING, mechanically is acting weird with the jeep. I had the codes come up 12,43,43,43,43,43. I know 43 is for a misfire but the jeep is running fine. I drive it daily with no problems. Recently the CEL has been flashing at random times. I am just wondering what could be causing this? I personally feel like it is electrical since the jeep is running fine. I am just looking for opinions? The only electrical stuff that had been done to it was getting the light bar installed, I had LED lights placed under the dash and for the dome light for my sound bar, and a fuel pump spliced in. Thanks for the input and help
 
I would assume that the 12 popped up due to the battery being unhooked while the electrical work was being done. Have the same codes come back after it was cleared? Why did you have a fuel pump spliced in??
 
Sounds to me like maybe it was indeed just the battery connections.

I would try clearing the check engine light codes and seeing if they come back. I'm also curious as to why you had a fuel pump "spliced in"?
 
BTW, here is a quote from Jerry Bransford regarding the code 43 misfire issue:

There is an official Jeep TSB (technical service bulletin) specifically for this problem, though there's no guarantee of a complete fix if you perform the TSB. Some early 4.0L engines in '97 and early '98 came with a bad (weak) set of valve springs from a bad batch which is what causes the misfire for a good percentage of those getting the 43 DTC. The TSB instructs that the valve springs be replaced and the engine be de-carbonized afterwards.

My '97 often even had multiple 43 codes at once (like 12 43 43 43 55) and before Jeep came up with the TSB, I fought the problem for years to the point that Jeep engineering actually contacted me after reading of my pleas for help on the various Jeep forums. The engineer who called me (none other than THE Jim Repp, "father" of the Jeep Rubicon) sent me a care package of components to swap into the Jeep one-by-one but none of them helped. The kit had all new fuel injectors, fuel injector wiring harness, PCM (engine computer), clockspring, and a few other odds & ends. I had already replaced everything in the ignition system including the plugs, ignition wiring, distributor cap, and rotor.

Then later, the TSB was issued and I replaced the springs which cut my repeated 43 codes by probably 80%. I suspect I had the 43 code occurring for so many years that the valves or valve seats might have burned a bit which is why I still get a very occasional 43 code code but it's rare compared to how it was before I replaced the valve springs. A friend had the same issue and a complete valve job with new valve springs completely cured his TJ and he hasn't had a 43 code in probably five years now.

Note that a TSB is not the same as a Recall so you will have to pay for any work performed under a TSB. Good luck with it.
 
Having your own scanner will allow you to read a CEL anytime you want and allow you to clear the codes when you have fixed the problem. If you take it to a parts store they sometimes will not clear them.
 
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