Hey all,
I have a 94 4x4 with the 4.0 and I am finding it really hard to restart right now. If I have the car running and I shut it down and try to restart it anywhere from 0 to 10 minutes after shut down it fights me tooth and nail and I end up having to hold the gas pedal to the floor to get it to fire.

In normal situations where it has been turned off for more than 10 minutes it fires up in about 2 seconds and requires no extra gas pedal from me at all.

I have new plugs, wires, coil and fuel injectors. Fuel pressure tests out perfect so I am not sure what to look for next.

Any ideas?

 

I've experienced the same situation on my '95. The first few times it did it, I replaced the fuel pressure regulator on the front of the rail, and it seemed to work well. Recently, it has started to do it again, and after replacing the fuel pressure regulator, nothing. Still does it. I've done a lot of research, and some said it was the idle air sensor, but after another expense, it is new and shiny, however, nothing is changed. I did find some obscure information on this on a site, and they mentioned the engine air temp sensor might cause this. I have purchased one (of course), and intend to install in a few days to see if it makes any difference. When I posted a similar problem, nobody could figure it out either. Good luck. If the temp sensor helps, I'll let you know.

 

my jeep is having the same issues. i too have replaced just about everything. however speaking with the guys at work, there was a TSB in the late 90's that was on the vent line in the gas tank. its stateing that with a full tank of gas you hear a gurgling sound comeing from the gas tank. i guess there is a lil spring and ball device inside the gas tank right beside the filler neck. after speaking with the dodge dealer here in town. that part number in which the TSB is refering to is no longer aval.. go figure. and the only option at this time is to replace the tank.. so at this point in time i need to figure out what size hose that is (vent line) going back to the tank and somehow put an antiflow back check valve to hold pressure in the lines.. hopefully this is helpfull.. thanks.

 

Thanks, definetely keep me updated on the air temp sensor. I have done some more research and read a couple things saying the CPS might be bad. I guess the signal gets messed up sometimes and maybe when it is really hot just doesn't work since it is original. Not sure if I think that is true or not but it is probably worth a shot since those are supposed to be trouble anyway.

I have also noticed that when cruising about 30 mph and letting off the gas the motor is having trouble finding an "idle" rpm. It kinda goes up and down for like 10 seconds and then settles into an RPM. I wonder if the two issues are linked.

 

My ZJ does this anytime I shut it off it cranks hard (like if there is a loss of pressure in the fuel system)

I think I should change my FPR!

 

x2 on the FPR. Go rent yourself a Fuel pressure tester and start ruling stuff out

 

I have tested my fuel pressure and its perfect. This has got to be some sort of sensor issue, I just can't figure out why giving a quick push of the gas pedal would take care of it.

Are any of the sensors attached to the throttle body responsible for helping the car start? Maybe one of those is having issues and opening the throttle is helping it?

 

My 1989 cherokee limited does the same thing, will start great for months, then all the sudden decide not to. I have to dump a little fuel in her and she`ll usually fire right up. If it didn`t I would take a small stick and lightly poke my cps then it would start.. I have replaced all that stuff so let me know about the engine air temp sensor please because to be honest here, I was about to put it in cl and just sell it and buy something else,,
Still might, as long as I have my wrangler but I really like those cherokees.

 

coolant temp sensor (for the computer)
or
fuel pressure regulator.

those are my guesses

 

OK I am going to replace my coolant temp sensor today... its gonna cost me 7.50 and well it is cheaper then the regulator.. who knows this may fix my hard start.. we shall see!

 

ok I went out to the JEEP.. here is something to check.. on my 5.2L there is a small service port (kinda looks like a service port on an air conditioning hose) I pushed the shrader valve down and NO FUEL, NO PRESSURE..

so it is not my ECTS... it is something fuel pressure related