Hard starting 4 clanger.

[BIGTRUX]

Ok guys let me start off by stating I have a 97 TJ with a 2.5/5 speed. this started over night and has been this way for about 3 months now. If I try and just start it she turns over and over and then fires up and runs fine. BUT, If I just hit the key and let it sit and then start it, then it fires right up and is good. what can this be? I was told that it could be my Crank sensor?But that advice was from a 20 year old kid at autozone so what do you guys think?

[Ricky Booby]

CEL on?

[airforce26yrs]

What kind of fuel system? Injected or what?

Have you tried just turning on the key for a few seconds with out hitting the starter? Does it start right up then?

What I am trying to see is if it might be a fuel pressure problem.

[hobbyshopass]

What kind of fuel system? Injected or what?

Have you tried just turning on the key for a few seconds with out hitting the starter? Does it start right up then?

What I am trying to see is if it might be a fuel pressure problem.

My 97 ZJ starts the same. I have leaking injectors.
If turning the key on and waiting a few seconds helps then you have a fuel leak. either injector or fuel pump by-passing.

put a fuel pressure gauge on it and turn key on. when fuel pressure builds (normally around 40psi, on mine) turn key off and watch fuel pressure gauge. You will know something within about 5-10 minutes.

[stud_man50]

i would def. say it is the fuel system because once you turn the key to "bat" you can hear the fuel pump kick on and since you let it sit like he said it builds up. you may be losing pressure from somewhere or the fuel pump is slowly going out. like you said its been doing this for a while. so it could be that.

[BIGTRUX]

Tried leaving the key on for almost 10 minutes and it still started the same way I have to turn the motor over just once and then it is good to go. Trully baffled? it is throttle body injection. on a 2.5 177K miles.

[hobbyshopass]

I think it is fuel injectors. after about 5 sec the fuel pump turns off unless motor is running or trying to start. Since pump turns off, the injectors are leaking into cylinder. turning key over and then trying again clears the cylinder so it not acting as if it was flooded.

Put a fuel pressure gauge on it and then watch it. as i said mine is doing the same thing. and thats my problem.

[irish1371]

there is a leak down valve at the end of the fuel rail. this valve keeps fuel up in the rail while the engine is off. It sounds like that valve is letting the fuel leak back out of the rails and then your waiting for the fuel to build back up giving you the trouble starting.

[airforce26yrs]

I think it is fuel injectors. after about 5 sec the fuel pump turns off unless motor is running or trying to start. Since pump turns off, the injectors are leaking into cylinder. turning key over and then trying again clears the cylinder so it not acting as if it was flooded.

Put a fuel pressure gauge on it and then watch it. as i said mine is doing the same thing. and thats my problem.

there is a leak down valve at the end of the fuel rail. this valve keeps fuel up in the rail while the engine is off. It sounds like that valve is letting the fuel leak back out of the rails and then your waiting for the fuel to build back up giving you the trouble starting.

He said it is throttle body, so I do not think there are any cyclinder injectors or fuel rail.

[hobbyshopass]

Is there an injector in the throttle body. my truck was TBI and had 2 injectors.

could still be an injector or bypassing fuel pump or fuel pressure regulator