Wonky start/idle issue

I have a slow crank that I need to push the gas pedal during to get the engine to catch. Then, I need to keep my foot on the accelerator to keep it from stalling. After several seconds, the engine will start to idle on it's own at about 900-1000 rpm.

I took the throttle body off and cleaned it out and cleaned out the IAC. When I did, I noticed a wet look inside the exhaust manifold. I touched it and it was sticky and had the smell of fuel.

After cleaning and replacing the IAC the situation remains. So, could there be a bad fuel injector leaking into the manifold causing it? Could there be an issue with the starting/charging/battery system? There are no codes so I can't figure it out that way.

Thanks

For 1996+ Jeeps, the OBD-II engine computer (ECU/PCM) re-boots, and the idle settings are deleted, when you: (1) let the battery run down by leaving the lights or radio on, (2) disconnect the battery for an extended period of time, (3) when the battery goes bad and needs replacing, (4) when the alternator is not properly charging the battery, (5) or when poor battery connections result in a voltage drop at the PCM or poor battery charging.

Loose, corroded, or damaged battery cables or ground wires may also cause or contribute to the problem.

Your symptoms are: (1) having difficulties starting the engine without depressing the gas pedal, and (2) the engine will have a low idle and probably stall unless you keep your foot on the gas pedal. (3) The ECU will relearn the idle settings after a short period of driving and the engine will start and idle normally.

Begin with basic trouble shooting of the start and charge systems. Remove, clean, and firmly reconnect all the wires and cables to the battery, starter, and alternator. Look for corroded or damaged cables or connectors and replace as needed. Copper wires should be copper color, not black or green. Do the same for the grounding wires from the starter to engine block, the ground wires at the coil, and the ground wires from the battery and engine to the Jeep's frame/body. You must remove, scrape, and clean until shiny, the cable/wire ends, and whatever they bolt to. Jeeps do not tolerate low voltage, bad connections, or poor grounds.

If the symptoms reoccur, you need to have your battery and/or the alternator load tested at a repair shop or auto parts store. This is usually a free service they offer to bring in potential customers. Even with low battery voltage, the engine will start, but the ECU can re-boot multiple times and a new battery may be required.

After cleaning up all the connections (they needed it) and cleaning the IAC (it needed it, too), the symptoms were still there.

I swapped the good battery from another Jeep and she started right up with no issues. When I pulled the suspect battery out there was a sloshing around sound. The guy at the store said it busted a cell.

So, free battery under warranty and all three Jeeps are currently running under their own power (knock on wood with my fingers crossed while rubbing a rabbits foot and standing under an upturned horseshoe in a field of 4 leaf clovers).

I had the exact same symptoms on mine, 99 with 4.0, try resetting the computer:
Remove the positive battery terminal, leave the negative connected.
Ground the positive terminal to the negative for 30 seconds to discharge any capacitor.
Turn ignition on without starting the engine.
Turn on headlights
Turn off headlights
Start the engine

This procedure fixed my issue.

Of course, a bad battery would do exactly what Tim said, in my case the battery was good.

Prom3theus said:

I had the exact same symptoms on mine, 99 with 4.0, try resetting the computer:
Remove the positive battery terminal, leave the negative connected.
Ground the positive terminal to the negative for 30 seconds to discharge any capacitor.
Turn ignition on without starting the engine.
Turn on headlights
Turn off headlights
Start the engine

This procedure fixed my issue.

Of course, a bad battery would do exactly what Tim said, in my case the battery was good.

Click to expand...

I already replaced the bad battery with a good one and that took care of it! Thanks for the idea though. With 3 Jeeps in my garage, my only reliable vehicle is my John Deere garden tractor!