troubleshooting stalling when idling hot, idle/mixture adjustment? Options

[timofly]

'74 2.0 with .010 oversize cylinders, original Jetronic fuel injection intact and works great 95% of the time. However, engine idles very slowly (almost off the bottom of the tach scale) and will eventually stall unless throttle is "goosed". Condition only occurs in high ambient temps after 15-20 minutes driving. Then hard to start without a bit of throttle, but starts fine with that little bit of throttle, so I don't think it's fuel vaporization. (Fuel pump has been moved forward and fuel lines are all SS.)

Runs normally otherwise. Cylinder head temp sensor? Idle adjustment? What? Any ideas would be appreciated.

Tim

[914werke]

On top of the AFM is a recessed screw to adjust idle mix.
it will have IDK 12 or 14 discernible detent's. Verify where its currently set and
increase adjustment as necessary 1 at a time

[emerygt350]

Is this ljet or djet?

Sounds like your idle mixture is a bit thin.
If it is djet
You can use the throttle body's idle screw to raise the idle and the pot on the ECU to richen it. Make sure the motor is hot and misbehaving before you try. I would start with the ECU pot first. Turn it clockwise a few clicks to richen. See if the idle stabilizes and comes up.

Is this a new behavior or something that it's always done?

[emerygt350]

Is this ljet or djet?

Sounds like your idle mixture is a bit thin.
If it is djet
You can use the throttle body's idle screw to raise the idle and the pot on the ECU to richen it. Make sure the motor is hot and misbehaving before you try. I would start with the ECU pot first. Turn it clockwise a few clicks to richen. See if the idle stabilizes and comes up.

Is this a new behavior or something that it's always done?

Do you have the retard on this distributor hooked up? Is it the stock distributor?

[fiacra]

On top of the AFM is a recessed screw to adjust idle mix.
it will have IDK 12 or 14 discernible detent's. Verify where its currently set and
increase adjustment as necessary 1 at a time

AFM is L-jet. Confusing because the OP says L-Jet, but a '74 2.0 should be D-Jet. Idle speed adjustment on D-Jet is on the throttle body. The knob on the ECU adjusts the idle fuel mixture, and I think that's what may need to be adjusted.

[timofly]

Is this ljet or djet?

Sounds like your idle mixture is a bit thin.
If it is djet
You can use the throttle body's idle screw to raise the idle and the pot on the ECU to richen it. Make sure the motor is hot and misbehaving before you try. I would start with the ECU pot first. Turn it clockwise a few clicks to richen. See if the idle stabilizes and comes up.

Is this a new behavior or something that it's always done?

It's a D-Jet. I've owned the car for 20 years but this is the first time I've had this problem. Thanks for your reply. I'll give it a try.

[timofly]

Is this ljet or djet?

Sounds like your idle mixture is a bit thin.
If it is djet
You can use the throttle body's idle screw to raise the idle and the pot on the ECU to richen it. Make sure the motor is hot and misbehaving before you try. I would start with the ECU pot first. Turn it clockwise a few clicks to richen. See if the idle stabilizes and comes up.

Is this a new behavior or something that it's always done?

Do you have the retard on this distributor hooked up? Is it the stock distributor?

I assume it is, since its been with the car at least since 2006.

[timofly]

Is this ljet or djet?

Sounds like your idle mixture is a bit thin.
If it is djet
You can use the throttle body's idle screw to raise the idle and the pot on the ECU to richen it. Make sure the motor is hot and misbehaving before you try. I would start with the ECU pot first. Turn it clockwise a few clicks to richen. See if the idle stabilizes and comes up.

Is this a new behavior or something that it's always done?

It's new. I've owned the car since 2006. I'll give that a try. Thanks.

[timofly]

On top of the AFM is a recessed screw to adjust idle mix.
it will have IDK 12 or 14 discernible detent's. Verify where its currently set and
increase adjustment as necessary 1 at a time

I'll try that. Thanks

[timofly]

On top of the AFM is a recessed screw to adjust idle mix.
it will have IDK 12 or 14 discernible detent's. Verify where its currently set and
increase adjustment as necessary 1 at a time

AFM is L-jet. Confusing because the OP says L-Jet, but a '74 2.0 should be D-Jet. Idle speed adjustment on D-Jet is on the throttle body. The knob on the ECU adjusts the idle fuel mixture, and I think that's what may need to be adjusted.

My bad, it's a D-Jet. Thanks for the reply, I'll give it a try.

[914werke]

Whoops OP used "Jetronic" My mind went to L-Jet

[emerygt350]

If this is new, I might not try to correct it with the adjustments. That will just mask the underlying issue.

Anything altered before this started?