No start when hot
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Elder User
Joined: Jul 2011
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From: Stockholm, NJ
No start when hot
My '78 F250 has a 1984 351W in it (with headers) Lately, I've noticed that it is harder and harder to start when hot. It has a brand-new battery. Today, it started on the first crank after sitting for two weeks. I drove it around and went to get gas. It turned over very slow (rrrr...rrrr...rrrr) then nothing. I was able to bump-start it. I then drove it 50 miles, and again as son as I shut it off I couldn't restart it. I'm confident that if I try to go start it later tonight, it will fire right up. Should I replace the starter, and if so, how do I know which starter to get? I'm not sure what vehicle the engine came from. Should I also replace the solenoid and the cables as well? Thanks.
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From: Virginia
I have had the same problem, before. If it does start right up when it's cool, then a couple things come to mind.
1. What ignition are you running? The original Ford duraspark II ignition has a spark retard feature when cranking the engine. That makes the engine easier to crank when it's hot.
2. Headers are notorious for this. They overheat the starter, and then it doesn't want to crank over. What I did was take some thin cheap aluminum from Lowes and wrapped the starter with it, and tied it on with some wire. The only thing you need to be careful with is the large lug on the starter from the solenoid. Put something around this lug if you need to to keep the aluminum from touching it. This really helped my truck, I had a 351w I had swapped into a 1980 and had used headers.
1. What ignition are you running? The original Ford duraspark II ignition has a spark retard feature when cranking the engine. That makes the engine easier to crank when it's hot.
2. Headers are notorious for this. They overheat the starter, and then it doesn't want to crank over. What I did was take some thin cheap aluminum from Lowes and wrapped the starter with it, and tied it on with some wire. The only thing you need to be careful with is the large lug on the starter from the solenoid. Put something around this lug if you need to to keep the aluminum from touching it. This really helped my truck, I had a 351w I had swapped into a 1980 and had used headers.
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Elder User
Joined: Jul 2011
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From: Stockholm, NJ
Thanks Dave. I will definitely give this a go. The truck started fine this morning, and then, on my way to work I had to stop at a 7-11 to pick up oil (the truck is suddenly leaking oil out of the passenger front of engine very bad. I just had a shop do a cam swap and add GT40 heads, and somehting tells me they didn't tighten everything, or used a bad gasket) and I parked the truck on a hill because I knew I would probably have to do a bump start. Much to my surprise, it started up when I came out of the store. I am still going to wrap the starter and replace the ground cable (it looks a little frayed where it bolts to the block).
Frank
Frank
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From: Virginia
You can turn the timing back a little bit and that will help. But I never like doing that too much because it kills the power the engine has.
When I was fighting this same problem, I stumbled onto something that helped me when I was desperately trying to get it to start. Take the gas pedal and pump it a few times. Then start cranking the engine. This actually floods the engine in the beginning, and it will spin faster, giving it a little momentum so when it clears up it can have a head start and keep cranking. It helped some, but it's a little iffy sometimes trying to get it going. Having the best possible battery, cables and starter helps some, but it won't make the problem go away.
When I was fighting this same problem, I stumbled onto something that helped me when I was desperately trying to get it to start. Take the gas pedal and pump it a few times. Then start cranking the engine. This actually floods the engine in the beginning, and it will spin faster, giving it a little momentum so when it clears up it can have a head start and keep cranking. It helped some, but it's a little iffy sometimes trying to get it going. Having the best possible battery, cables and starter helps some, but it won't make the problem go away.
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You may want to verify your base timing- running too far advanced can cause hard-start problems, as well.
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From: Franklin, GA
A little diagnostic trick I learned when my father's Lincoln was having the same issue was to get the car up to operating temp, then go back to the house and park near the hose pipe. Try to start the car and if it was doing the straining starter thing you describe, squirt the starter with the water hose to cool it down then immediately attempt to re-start the car. Worked every time with that car. Exhaust manifold heat was killing the starter. I ended up having to replace the starter because the heat had cooked it for too long, and add insulating between the manifold piping and the starter.
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From: Franklin, GA
Forgot to add the other suggestion: If cooling the hot starter doesn't produce any positive results, check all of you grounds in the starting circuit wiring conditions. I'm sure all the grunting slow starting attempts is heating up your primary wiring circuit. Faulty and corroded connections are greatly exaggerated when under hood temps are high. New cables might be in order or connections may need cleaning up to get good grounds.
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Elder User
Joined: Jul 2011
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From: Stockholm, NJ
Thanks for all the feedback! I am definitely going to do some diagnostic work this weekend. I have a very bad oil leak as well and can't seem to locate wheremits coming from. Will update on Sat.
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