Anyone have an idea why my 93 W engine won't start when it's under 25 degrees. It fires right up and runs fine when the temperature is 30 or above.

This started when the weather turned cold about a week after I replaced a leaking water pump. The engine did peg the temp gauge before I realized the water pump was leaking and it was low on antifreeze. I replaced the fuel pump last year and the pressure checks 58 psi and holds the pressure. Recently replaced the fuel filter thinking maybe water was in it and freezing. Also replaced the rotor and distributor cap and the sensor just above the water pump, and the battery (although I never had any trouble with the old one and it checked good)

Thanks

Bill

 

Have you tried pushing/pulling on the two wire harness that exits the lower intake manifold below the throttle body? This is the harness that connects to the fuel injector inside the intake.

Have you checked for spark when the no-start is occurring?

 

Thanks Swartlkk
No, I had not messed with the red and blue wires or checked for spark. I just went out to check the red and blue wires and since the temperature is around 30, it fired up immediately and ran just fine. I did push and pull on the wires but it didn't do anything. I'll check for spark the first time it gets cold again. Thanks again

Bill

 

Last week I set up the engine with spark checker and fuel pressure gauge and this morning it was cold enough to check.

My wife turned the key to the on position and the fuel pressure gauge immediately went to 58 psi and stayed there. She then cranked the engine over and the spark gauge showed good spark but it refused to start.

This problem started the first time it got below 20 degrees after I had replaced the water pump. As noted above, the engine did overheat (gauge pegged) when the water pump went bad (leaked antifreeze out). I have replaced the fuel filter, the sensor just above and to the left of the water pump as well as distributor cap and rotor and pulled one spark plug which looked excellent.

Anyone have any ideas.

Thanks

Bill

 

Yeah try messing with those wires SKK mentioned. Inside the other end you cant see is a connector with TINY TINY little wires up inside it that contact the injector terminals. There is some slack in those wires and they will be stiff inside the engine, so you may have to pull more than an inch in either way to get the connector to move. You are trying to move something inside the engine that you cant see, but is on the end of those 2 wires.

Also, can you start it with a JUST A puff of ether (starting fluid) or a little squirt of raw gas in behind the throttle plates? I just use a straw with a finger on the end to hold gas in and use about an inch measurement, thats enough, and makes it easy to get inside the throttle.

 

There are a few temp sensors, one is the air charge/manifold temp sensor on the bottom of the intake hose right before the plenum. Or it could be a coolant sensor or even the idle air valve. Is your check engine light on? You said you replaced the cluster temp guage sensor that is located by the EGR, did you replace the lower temp sensor on the passenger lower side of the engine by the spark plugs?

 

Thanks everyone. No check engine light has come on. I'll start checking the other sensors mentioned.

 

i kno there is 1 module that is suseptible to temp even though its not a coolant sensor or anything like that, if that module is bad and temp is makin ur truck not start im guessing its probly that module cuz it will retard the timing wen the temp gets so low. im not sure exactly witch 1 it is but i will find out n post it on here. thats what it sounds like tho.