Runs Bad when Cold

[hogelectra]

Ok realize I live in Arizona and here getting cold is down in the 50's. I have had no running problems for weeks but now the temperature has started to drop I noticed that it runs real rough and hesitates at any speed.

 

Any thoughts - 86 MJ 2.5L

 

Need to add that earlier I did a complete tuneup. New plugs, emission devices, vacuum hoses. Cleaned all around the carb with cleaner. Almost foregot that I installed a new thermostat

 

Did that the first thing - it was still hot and ran fine

[Randy in Maine]

If it were me, I would try rebuilding the carb paying careful attention on adjusting the choke correctly.

 

I am not a carb guy though.

[Pete M]

The truck should have a TBI fuel injection, not a carb.

[Rockyrider367]

yeah your motor would be a TBI setup. its the only way the 2.5l 4 cylinders came. hey and if someone knows why it does this mine does the same thing. :D but up here it just dropped to 3 degrese today and thats when it does it for me.

[Pete M]

Just to avoid confusion, export 2.5L trucks could be found with a carb, as well as the 84-85 2.5L XJs.

[Rockyrider367]

ohh haha i did not know that. thats kinda cool though.

[manche]

i live in chandler ,az i have the same prob it runs rough now that its getting colder and my gas milage droped i think maybe i got a vacumm leak causing the gas prob cause i idle like 1000rpm

[hogelectra]

Here is what my research has shown me - still have problem - but have been researching what to look at.

 

It seems the fuel injection system/Carb is not reaching an operating temperature or the system is not responding correctly to the cold.

 

1. The choke could not be staying closed long enough or at all.

2. The engine may not be reaching a working temperature - thermostat opening to soon

3. The fuel injectors could be bad

 

If anyone else knows of a potential cause please add.

 

My approach:

1. Check the thermostat first - it's easy. Pull it and put into some water and start heating it until it open and record the temperature of the water - my question what temperature thermostat is best?

 

2. I had already cleaned the whole area with carb cleaner - what I'll guess I'l do is see from the outside what indicates the choke is closed. Start the engine and watch what happens.

 

3. Now the injector - don't know what to do there except maybe replace it.

[hogelectra]

Here is what my research has shown me - still have problem - but have been researching what to look at.

 

It seems the fuel injection system/Carb is not reaching an operating temperature or the system is not responding correctly to the cold.

 

1. The choke could not be staying closed long enough or at all.

2. The engine may not be reaching a working temperature - thermostat opening to soon

3. The fuel injectors could be bad

 

If anyone else knows of a potential cause please add.

 

My approach:

1. Check the thermostat first - it's easy. Pull it and put into some water and start heating it until it open and record the temperature of the water - my question what temperature thermostat is best?

 

2. I had already cleaned the whole area with carb cleaner - what I'll guess I'l do is see from the outside what indicates the choke is closed. Start the engine and watch what happens.

 

3. Now the injector - don't know what to do there except maybe replace it.

[hogelectra]

Looks like my current thermostat was 160 degrees. The OE was 195 degrees. Will put a new thermostat this weekend. This might be a positive path to better health

[hogelectra]

New 195 degree thermostat fixed the problem - runs great now

[Pete M]

:clapping: