89 Wrangler with 2.5, rebuilt the throttle body, it will crank right up & runs good, but when you turn the key off it will continue to run for about 3 seconds (sounds like runs out or gas) . Then it is hard to start (have to hold it wide open).
Engine keeps running for about 3 seconds after turning ignition off, then it is hard to crank
- Thread starter Chriswoodforge
- Start date
Flyer58
YJ Enthusiast
Wow. An initial concern is the ignition is still hot with ther key off and it's running out of gas because the fuel pump is off. Then it needs to re-prime the fuel rail to start
First place I'd look is your automatic shut down relay in the power distribution box. It sounds like it might be stuck on. As Flyer58 said, that would mean the rig would run until you lost fuel pressure.
Is the power distribution box located by the battery? If so all I have is 3 relays in a row, which I have replaced. Fuses are good except for the acc lps , which seems to no power on either side of fuse.
Steel City 06
Member
Does it sound somewhat normal when it keeps running? Or does it sound like it is dieseling?
Here is an example of dieseling:
Here is an example of dieseling:
Flyer58
YJ Enthusiast
I did some searching, and this is something that YJs occasionally do. No one had a solution, but the possibilities mentioned were something sticking in the steering column, ERG valve or EGR sensor, and the ASD (automatic shut down) relay. Since you've replaced the relay itself, looking at the circuit I'd say it has to be that the computer isn't sending the shut down signal to the ASD relay when the key is turned off. Here's one way to check that:
The computer keeps the rig running by supplying the ground for the coil side of both the fuel pump and ADS relays. When you turn the key off, it disconnects that ground, shutting off both relays at the same time. The wire that accomplishes this runs between the PCM (computer) and the power distribution box (by the battery), and is dark blue with a yellow stripe.
The easiest place to get at that wire will probably be the connector at the PCM, which is mounted low on the firewall on the driver's side. Hook up a test light to the positive terminal of your battery, and with the rig running, probe the connector at the end of that wire. Note: Be sure to get the correct wire! Your test light should light up. Have someone turn the ignition off. Your test light should go out immediately. If it doesn't, then keep the test light there and confirm that there's a correlation between the light going out and the rig shutting down. Once you know that the PCM is or isn't shutting down the ASD and fuel pump relays we can figure out where to look next. If the computer is keeping the rig running after the key is off, it's either not getting the message (sticky ignition switch?) or it is getting the message but not acting on it (sticky computer).
The computer keeps the rig running by supplying the ground for the coil side of both the fuel pump and ADS relays. When you turn the key off, it disconnects that ground, shutting off both relays at the same time. The wire that accomplishes this runs between the PCM (computer) and the power distribution box (by the battery), and is dark blue with a yellow stripe.
The easiest place to get at that wire will probably be the connector at the PCM, which is mounted low on the firewall on the driver's side. Hook up a test light to the positive terminal of your battery, and with the rig running, probe the connector at the end of that wire. Note: Be sure to get the correct wire! Your test light should light up. Have someone turn the ignition off. Your test light should go out immediately. If it doesn't, then keep the test light there and confirm that there's a correlation between the light going out and the rig shutting down. Once you know that the PCM is or isn't shutting down the ASD and fuel pump relays we can figure out where to look next. If the computer is keeping the rig running after the key is off, it's either not getting the message (sticky ignition switch?) or it is getting the message but not acting on it (sticky computer).
I see a lot of technical advise to your issue. I am very old school and sounds like your timing may be a little too far advanced. Just a thought.
Stoopid Jeep
YJ Enthusiast
I have a buddy [Dennis] with a 1885 C10 that does the same thing. It has a carbureted 350 and no ecm. What it does have is the exact same steering column 
Dennis doesn't worry about it, he just turns it off, jumps out, walks around to the front of the truck Then ...at the perfect moment, he smacks the hood and says "off"
Dennis doesn't worry about it, he just turns it off, jumps out, walks around to the front of the truck Then ...at the perfect moment, he smacks the hood and says "off"