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88 xj slow starting

rattler43

NAXJA Forum User
Hi Fellers: Just a simple question. Have an 88xj 4wd 4.0, BA15, Command trax. Ever since I've had it, it takes about 5 seconds to fire up after I engage the starter. Hot, cold, same thing. I thought maybe valve in fuel pump, but does the same thing if you turn key on and wait several seconds. My parts man here in town used to own an xj w/auto trannie, and said his did the same thing and don't worry about it. He said they all do it. The xj runs like a sewing machine, but I don't agree with his advice. Looks to me like that would tax the battery and starter needlessly. Would like to hear from some of you on this matter, and if its not right, any suggestions to the cause? Thanks Don
 
oops, my bad. I have a bad habit of skimming. My 91 cranks pretty fast (maybe 2 secs), but my 90 always had trouble like yours(at least 5 secs). I didn't worry about it. It could just be age finally catching up.
 
Thanks fellers. I was just curious because it runs perfectly, uses no oil, but has a Gazillion miles on it. I'll just count my blessings that it runs as good as it does, and not sweat the slow start....Thanks for quick response. Don
 
Yup, just age catching up to it. Mine takes awhile to crank, especially when its cold. I have found that if I crank it and stop after a sec. Then crank again it fires right up. Less time the starter is spinning anyway.
 
I think it's pretty normal. My '89 Laredo has always been a slow starter! 3-4 seconds at least...and I've had the Jeep for 9 years.
 
Had my 90 since new. Always takes longer than I think it should. My 92 is much faster.

I think the difference came in 91 when the ECU changed. I would be interested in what changed exactly. Maybe the tone ring for the CPS?
 
The CPS on the Renix computer will take a couple rotations before ignition; you can sometimes speed it up a bit more by turning the key until the fuel pump primes before starting it.
 
This is normal operation for the '87-'90 Renix systems. I agree that it's hard on the batt and starter but there's not much you can do about it. There is a CPS adjustment technique that is supposed to reduce the start time. Basically you bend the CPS bracket to get the sensor closer to the flywheel. Get it too close and it destroys the CPS.
 
Thanks again fellows.....As long as it is normal, I will not worry about it..Just thought there might be something I could adjust to get it to fire up a little quicker..No problems other than that. Been lucky so far, I guess. Now for some rock rails, bigger tires, and maybe a rear locker.
 
At that age how old are the main power cables ?? Original maybe ?? Might want to consider pulling and cleaning all the grounds and even putting in newer and bigger main cables.
 
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