Long start : will quick start once fuel pump stops

[CajunRC]

I"ve done alot of research here and other places but havn't found anyone with the same issue. It's my wifes 97 wrangler Sport 4.0 automatic.
Problem mostly exists in weather below 70deg. I found out about the turning igniton on and off a few times and that works when the weather
is above 70 no problem. But now that it's cold that doesn't work at all. I've narrowed it down to it "will not start unless the fuel pump turns off".
Brought it to a reputable shop and the spent 2 days on it and said it was the computer. Some times the Battery and Fuel gauge wont come on.
But today it started fine without the gauges still off, as long as the fuel pump turns off, starts fine. Also the computer wont send ignition to the
plugs or injectors till the pump stops. Is there something the computer is looking for to activate the ignition/injectors? I"ve got a new crank sensor
and fuel pump sitting her, but don't think they are the problems. My diagnosis has come down to the "Fuel Pump has to Turn Off". Fuel preasure does
bleed off fast once the ignition is off. But when the fuel pump turns off, the pressure drops to 0, but will still start in one second. Any help would
be appreciated.

 

[CajunRC]

I've seen your replies about this before. I've checked all that you sugested. I can start her jeep right now, but only if the fuel pump shuts down. It seem there is something going to the computer to tell it it's " time to turn on ingectors and ignition" . If the pump doesn't turn off there is nothing going to those. Is why my mechanic couldn't find the problem "said computer isn't sending ingector and ignition signals" . I"ve started it all day today no problem, never stalls, runs and drives fine. But will not start until fuel pump stops running. Is there a relay the computer is looking for?

 

[AndyG]

Buddy I'm not the most knowledgeable guy here... But if you'll stay here and also do some searching... There is an issue where the fuel bleeds down out of the line back into the tank in some cases.

Keep an eye on your thread and use the search feature fuel draining back into the tank.

You will find the best TJ knowledge in the country right here.

 

[Goatman]

I've always rotated the key to "run", wait a second or two, then to "start". Even with magneto for an ignition. Making sure the gauges are doing what they a re supposed to do. If that is all it takes for the engine to fire up easily it seems easy enough.
I'm assuming the computer is waiting for proper fuel pressure before it signals the ignition to power on. But this is just a guess.

 

[CajunRC]

we've been doing the same and it works fine until outside temp gets to below 70 deg. Then the pump keeps on running. When the pump stops it will always start. Even when my Fuel and Battery gauge don't move.

 

[CajunRC]

Changed the Crank shaft position sensor, old one wasn't reading any ohms. But would still start when it is warm. New sensor didn't help. Mechanic shop said it was computer, but once it starts it stays running, and restart over and over. Computer wont send signal to injectors or plugs and a diagnostic scanner wont read the computer except when the fuel pump stops. Then everything works fine.