Van will not start when cold!

Questions #1

I have a 97 chev astro, 4.3l engine, new plugs, cables, cap, rotor, battery and coil. Fuel pressure is at 63lb when it pressurizes instantly, running is about 55lb. This morning it was cold (45 F) and the van would not start. Turn over great, no miss-fires also, just cranking away. I plugged in the block heater and about two hours later, I have ignition!!! It started instantly!!! Please help!!!

Could it be the fuel injection system? Runs great when warm.

Fuel pump is at the correct pressure, does not hesitate under load, same sound for the last 9 years

Water in the line?- the pump should cycle he water back to the tank?

Any suggestions would be greatly appreciated.

Answer #1

A faulty coolant temp sensor might cause this by not sending correct temperature information to the computer, which may not be enriching the mixture enough for a cold weather start.

Question #2

I changed the coolant sending unit, I get a better temp display, but the van does not start better at all. I plug it in at night, timer turns it on for about 3 hours before I start it. It starts better, (not first crank) what will I do when it gets to well below freezing? Is there a choke kind of mechanism within the fuel injection system? Could that be messed up? A mechanic told me that the pre-heating with block heater is warming up the gasoline and stated that the fuel pump needs to be replaced. ($750.00 I do not want to spend yet) I checked the fuel pressure when the van was warm, 55lb when engine was running. Could the pressure be that low when the engine is cold? The gas in the tank does not get warm when I plug the van in. Could it me a sensor of some sort? Air flow sensor? Throttle position senior? Please advise? Again once the engine is warm it runs great!


While I don’t believe 45F is a cold start I’d try changing the fuel filter first. Then run some dry gas or seafoam thru tank. Next I would try the “key dance”. Cycle key on and off without starting 2-3 times which will activate fuel pump and build pressure each time. If filter doen’t solve and key cycling does it may be the pump. I also think the astro has some other gizmo (pulsator or something) near tank after pump. A friend had similar trouble but don’t remember year or resolution.

Next time this happens, check to see if your getting any spark to the plugs. It could be a faulty ignition module that doesn’t like the cold.

You replaced the wrong temp sensor. There’s one for the display on the dash, and one for the computer. Replace the one for the computer, and I’ll bet she starts right up.


This morning it was below freezing, van did not want to start. Checked for spark with spark tester, looks good. Changed fuel filter first, still no good start. Can you tell me where the other temp sensor for the computer is?