Silly truck keeps dying

[Dechion]

Good morning folks, been kinda quiet here for a while for me. Mostly because i'm eyeball deep in my XJ getting it back on the road. Just havn't had much time for the interwebs. Anyhow, I'm back and starting back in on the MJ now.

 

The question of the day is what would cause the MJ to die just when it's first starting out?

 

It starts up just fine, and idles just fine.

 

If I leave it idle for a few minutes then it's fine.

 

Once it's actually moving it's fine, even if I have to stop after a block or so.

 

If it's still warm from running everything's fine.

 

The problem is when first shifting into gear (drive or reverse) after a fresh startup it will die. :hmm:

 

Generally once it starts back up it usually runs fine. :dunno:

 

I'm sure it's something simple, but I just can't seem to figure it out. Wondering if anyone else had a similar problem.

 

The MJ in question is an '89 4.0 2WD automatic.

[comanche12]

try TPS and IAC?

[Eagle]

Good morning folks, been kinda quiet here for a while for me. Mostly because i'm eyeball deep in my XJ getting it back on the road. Just havn't had much time for the interwebs. Anyhow, I'm back and starting back in on the MJ now.

 

The question of the day is what would cause the MJ to die just when it's first starting out?

 

It starts up just fine, and idles just fine.

 

If I leave it idle for a few minutes then it's fine.

 

Once it's actually moving it's fine, even if I have to stop after a block or so.

 

If it's still warm from running everything's fine.

 

The problem is when first shifting into gear (drive or reverse) after a fresh startup it will die. :hmm:

 

Generally once it starts back up it usually runs fine. :dunno:

 

I'm sure it's something simple, but I just can't seem to figure it out. Wondering if anyone else had a similar problem.

 

The MJ in question is an '89 4.0 2WD automatic.

I bought my '88 Cherokee new. About six months after I bought it, the dealership was sold and the new owners immediately laid off my racing buddy, who had worked there his entire life, from an oil change monkey at the age of 16 all the way up to service manager. So I started having service done at a different dealership (that was actually a bit closer to home). At one point, they talked me into having a TSB job done (not a recall, so I paid for it) to cut out the C101 connector on the firewall and hard-connect each pair of wires. They claimed this would improve fuel economy, improve performance, save me money, have beautiful women begging me for dates ... just about anything they could think of, this TSB was supposed to fix. All lies, of course, but ...

 

One of the things they said it would fix was a syndrome chronic to the Renix XJs and MJs called "early morning drive-off stall." What you describe sounds exactly like that. The engine starts right up in the morning, idles fine in the driveway ... and stalls (ONCE) when you start to drive. Start it up again, and it's fine for the rest of the day. The next day ... rinse and repeat.

 

Needless to say, the $500 TSB to remove the C101 connector did NOT cure the "early morning drive-off stall," and when I later confronted the service manager about it he flat out denied that he had ever said that.

 

If that's what you have ... there is no real fix for it. It either goes away on its own ... or it doesn't.

[comanche12]

That's part reason how dirty business those dealerships are.

 

 

Maybe it's all from ecu? Like some cars have to get reflash the ecu? Or maybe PCM?

[Dechion]

Thanks for the input folks, I'll keep poking at it.

 

Who knows, maybe i'll get lucky.