Last week I bought a 2003 GC with the 4.0L. It has 92K miles. When I got it the previous owner said it needed a new alternator, I had it tested and I replaced it. Before the replacement the Jeep started quickly and had no check engine light. After the alternator replace I drove it a couple of times that evening and it started just fine and on the third start it was very hesitant to start and the engine light came on. I hook up my code reader and it said the TPS was the problem. I replaced it and the code went away. It will start now but if the engine is cold it still takes a while for it to start. Once it starts the idle is fine and it drives good. I just can't figure out why the long start. Any ideas?

 

One thing to try first when cold is to turn the key to on for about 5-10 seconds before turning to the start position and see if that makes a difference in it starting.

 

Thanks.

 

I've been turning the key on and letting it sit a few seconds before starting. Sometimes I get a quick start and other times it just turns over and over without starting. If I try cranking it a couple of more times it will fire right off.

 

I have a theory. I think you've got a sticky fuel injector that's bleeding the fuel rail when sitting overnight. Sometimes it does and sometimes it doesn't. On cold startup, try cycling the key on 3 or 4 times for about 3 seconds each. This will give the fuel pump multiple shots to charge the fuel rail. If this works, it's either a sticky fuel injector or the check valve in the fuel pump. The pressure regulator is in the filter, but IDK if the check valve is or not.

 

Well it is pretty consistent now. I am to the point where I have to cycle the ignition switch 2-3 times before it will start.

 

Check fuel pressure with a guage, I just had 2 vehicles do the same and it was the pump or regulator.