I started my plow truck the other day and it started up normally. It ran for about 30 seconds and died. I tried to start it back up with a jump pack and a then with a fully charged battery. It cranks fine but no start. I put a spark tester on one of the plugs, and took the air filter housing off to get a look at the injectors and I have spark and the injectors are firing like normal. Both injectors are working and I tried the spark tester on a second cylinder on the other side of the block and I had spark there as well. I changed the plugs out with ones that are used but had been cleaned in a plug cleaner. No start. I went and bought new plugs and put those in. No start. It turns over very smoothly. The timing should be the same as it was when it was running. I haven't removed the distributor cap or any of the plug wires at all other than when I was changing the plugs but I did them two at a time to not get the firing order mixed up. The truck started and ran a week ago. It's a yard truck but I use it for various projects a few times a summer and it ran fine all summer. I live in New England and it hasn't gotten super cold yet but it's been in the 20's a couple times so far this fall. other than when it ran for like 30 seconds last weekend it hasn't run since it was warmer out. The cold has been the only difference. My mind says, if I have fuel and spark it must be compression. What would cause me to lose compression randomly like that? Where do I go from here?

 

Check your cap and rotor; could also be your ignition control module. Try pouring a little gas down the throttle body, see if it fires/runs

 

The ICM is new as of last year. The one I replaced looked to be original.

 

I have spark at the plugs. I confirmed that with a spark tester. I did notice that the spark in the tester was yellow/orange. It's just a cheap Harbor Freight inline tester. The two cylinders that I tested were 3 and 4 mainly just because they're easy to reach. The tester was much brighter on cylinder 3 than it was on 4. I'm leaning towards it being a bad distributor cap and rotor but I figured if I had spark at the plugs it would at least try to start. When I crank the engine it doesn't sound like its even trying to fire. I had a similar problem to this when it got cold last year as well but that was a fuel issue. I wasn't getting anything from the injectors whereas now I am. I believe the problem there was the Ignition fuse. The one I had in there was one of the mini blade fuses and it wasn't making full contact in the fuse panel. I changed that out and cleaned up some of my grounds and it fired up and ran fine all last winter. It would periodically stall while I was plowing but it always fired right back up.