I own a '96 Jeep Cherokee with a 4.0 inline 6, fuel injected. Here's the problem...Went to start the jeep, and had a dead battery. No big deal. Charged the battery. Went to start the engine, engine turned over but would not start without pumping the gas. Also wont stay running if I take my foot off the gas pedal. What is the problem? If it is something I can avoid going to a mechanic for, then I will do it myself, but I dont know where to start. HELP!!!!!

 

From what i am understanding, as you describe it, it sounds like it may be a fuel pump or your injectors to start off with. Also, did you update you idler and tensioner. Sounds like it may be the fuel pump or injectors tho if it runs when you push the pedal. Is you check engine light on?

 

Hmmm... pumping the gas on an FI engine really doesn't do much unless the engine is running. All it does is open the throttle plate and the computer figures out how much fuel to squirt based on air flow through a MAP or throttle position sensor.
I would check your cold start valve. It's the enrichment circuit (like a choke) for the FI cars. Also make sure that your battery is actually good and supplying full voltage, and all grounds are good. FI and electronic ignition needs almost a full 12V to work correctly.
You'll need a shop manual to diagnose the cold start circuit. You will need to measure resistance of the various components to see if they are working and the manual will tell you what and how to measure. It's actually not that hard, you just need to be patient and follow the troubleshooting steps in the shop manual.

Good luck.

 

Sorry, I should clarify. Pumping the gas is the wrong word. I have to step on the gas pedal to get the engine to start. Then to keep it running, I have to keep my foot on the gas. As soon as I take my foot off the gas, the engine dies. No check engine light. Aside from having to keep pressure on the gas pedal, it starts and runs fine. I asked a friend who told me to disconnect the battery for 10-15 minutes, then re-connect it and try to start the engine. Something needing to reset. Any further info for me? Thanks

 

Sounds like the cold start circuit is bad, or the throttle position sensor is bad. If you let it run until it warms up does it still die? If so it's probably the TPS. They aren't very expensive and usually easy to replace. Basically the TPS tells the computer where the throttle poisiton is and how much gas to give it. When the TPS goes bad, it doesn't send the correct signal to the computer telling it to go into idle mode. So it just quits opening the injectors and the gas in the fuel rail is passed back into the tank. Of course it's a bit strange that it ran fine until the battery died?
BTW Pulling power from the battery won't do anything. Nothing will be "reset" by doing this.

 

Put plugs in it. Seen it a million times. Also stick a new battery in it.
The ECM holds the injectors wide open when the battery voltage drops below 8VDC (It's cold start thing)... Anyhow... The plugs may look good but they're not.... the porcelin cracks. And at low RPM it will shake rattle and stall.
Typical 4.0

 

90% of the time when it runs fine but stalls at idle, the IAC (idle air control valve... may go by other names for other brands, I work on Fords. They all do the same thing though). They get stuck and the solenoid can't adjust the amount of air bypassing the throttle plate to control the idle. If you can find it and give it a few lights whacks with a hammer they'll usually break loose and work right for awile (not saying it'll stay working), but it'll at least tell you if it's the culprit or not. I could too though be a bad TPS or other problems... with modern cars it can be anything and everything.

Was it stalling before the battery thing? I don't know why it would be related to the dead battery but anythings possible. Did the battery hold a charge? Sometimes with a really dead battery the modules won't get enough voltage to operate properly. I've had cars with weak batteries cause a no power steering assist condition with a "check steering assist" on the message display. This is because during cranking the voltage drop is so low that the VDM module would shut down and throw a battery voltage out of range code, and it'll stay turned off as a fail safe type of thing to keep from frying the module and won't reset until you shut the car off and back on again. The VDM controls the VAPS solenoid on the PS rack thus causing the no power assist. Not exactly the same thing but just an example.

So I'd make sure you're battery is actually good, and if it is I'd first look into the IAC (or whatever Jeep calls it) for the problem. You may want to try disconnecting the battery for several minutes and try again, that could be all it is. Believe me cars to weird things!!

 

If i were u i would buy a manual to find out but from what u are describing i would agree with the popluar vote and say tps or fuel pump. Those jeeps are known for the tps going bad and causing the car not to run. The cool thing is on those the tps is fully adjustable so i would fool with that first before i go out and buy anthing. As for what some people are suggesting the cold start valve and so on the newer cars dont have that it works the cold starting fuel enrichment works is off the intake air temp coolant temp sensor and the o2 sensors. So just loosen the two Torx bits on the tps and have someone in the car giving it gas and letting off while u move it a lil at a time and see if it runs on its own. One other thing to check is the idle controll valve in am not sure if the jeeps have them or not but if you see a lil electronic device next to the the throttle cable that it looks like it should be hitting the eccentric for the throttle cable and it is not touching that would be it

 

This dude knows whats up.