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1986 Ford E-150 Malfunction - Ignition System
Question: At first, engine would start only if hot or cold, but not when "luke warm, " i.e., if it was run until hot and then allowed to sit for a couple of hours. Now, it usually won't start at all, or if it does, after long periods of cranking. There is spark to the cylinders, the fuel filter was changed a year ago, and the throttle body valve has been replaced.
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Technican: If there is spark to L cylinders and the engine has compression (not worn out), you'll need to check fuel pressure. You can spray a small amount of carb cleaner down the throttle body and see if the engine will start this way. Only a small amount and follow all safety precautions with highly flammabe products- especially in confined engine compartments found in vans.
Does it smoke when it does start, black smoke by any chance?
If you need more help, please confirm that you have a fuel injected engine and not one with a carburetor (I know you indicated a throttle body valve but I need to make sure)."
Owner: Hi Doug,
No, the van doesn't smoke that I've seen, and yes, it is indeed a fuel injected 302. I assume that ether will work as well as carb cleaner (since I don't have a carb, I don't have any) for this test?
Reading the archives on, some similar trucks had the temperature sensor as the problem. Could this be mine as well?
John
Technican: Yes, ether is a just a little more potent than carb cleaner.
If you unplugged the temp sensor the problem would likely disappear, if the sensor itself is the problem. I don't think it is. The sensor conveys coolant temp to the computer. If the sensor is bad and falsely reports the engine to be hot on a cold morning it can cause a no start or hard start condition. This is because, as you probably already know, a cold engine needs more fuel to start than a hot engine (the computer won't enrich the fuel mixture on a hot engine). Conversely if the coolant sensor always reports a cold engine the computer will make the mixture richer than it needs to be. This potentially (but rare) could be rich enough to wash oil from the rings and make starting difficult (do you smell gas in the oil?). Or simply foul the plugs or create a common flooded condition.
Another thing to try besides the starting fluid, is to hold the accelerator to the floor and attempt starting. This will put the engine in 'clear flood mode' (yes it's the same for carbs and EFI). If the engine starts better this way there can be a few causes. Chances are it won't, unless you have noticed a strong fuel smell (or black smoke). Here's How To Get Guaranteed Solutions In Minutes
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