"12.something"? 12.24v = 50% charged while 12.65v = 100% charge.
Nothing wrong with the stock ignition system as long as the parts are healthy.
"loud gurgling from the fuel tank" may be related to your check valve allowing fuel to drain back into the tank which would also explain the slow to start condition on occasion.
I suggest you replace the battery if it is weak and live with the occasional slow start (remember tjwalker's "poor man's prime" on the 1st page). Or if it really bothers you, replace the fuel pump with a quality unit.

 

It's just how the renix computer is when you turn off the jeep the computer whipes the fireing order so when you go to crank it it has to re find the fireing order there's nothing wrong with it

 

thanks DaddyCat for posting that video and giving me some info to work with.

@limegreenxj- I thought renix was 1987- 1990?

 

You're welcome, I do hope you get it working as well as you want. As the saying goes "it's a work in progress."

Correct, 1987-1990 are the years with the RENIX 4.0s

 

my fault your correct

 

No biggie man.

I did go and buy new plugs, wires, cap, rotor, and an accel super coil. and a lower temp thermo and gasket.

I almost bought a fuel pressure tester, but I had already spent too much on a whim already.

 

Lower temp thermostat? the inline 4.0 really wants that 195 degree t-stat.

 

X2

 

the reason I wanted a lower t stat, is because mine runs 210 all the time. its not even hot out in IL yet. but I did in fact get a 195 t stat for a replacement. gonna flush the jeep and see if it helps any too...

 

It starts on the first crank usually

 

Well just rub it in why dontcha? this thread is a help me fix this problem thread, not a post ***** thread...

 

My 2000 4.0 starts right up -cold -hot whatever. I changed ALL ignition parts ,CPS 3 yrs ago.

Still change the plugs every year but the last 2 years they looked like new.

 

do people even read the thread before they post???

 

before fuel pump crapped out, 8-10 revolutions, and it would start rough

after replacing fuel pump, IAC, TPS, CPS, plugs, cap&rotor, 12-17 revolutions, it would idle more smoothly

went to flush/backflush injectors, and found one that wasn't firing at all. replaced all 6 with JY 703's. now she fires up at 3-4 revolutions and purrs

 

Well I cleaned the ground cables up real good and the jeep "seems" to start better... But am still going to do a full up-graded/ tune-up ignition setup. thanks to all that tried to help.