Hard warm start
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Joined: May 2012
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Hard warm start
I don't know if there is already a thread on this matter if so could you direct me to it. 86 F150 5.0 V8 2WD, two fuel tanks, auto trans, fuel injected, starts fine when cold but is getting harder and harder to start when hot. This isn't something that happened over night it has been steadily getting worse, it has compression, fuel pump is running, starter is turning it strong and at normal RPM. I've since replaced cap, rotor, plugs and wire with no improvement, new air filter. I've had the truck for 6 months and I don't know what was done prior other then a new battery, I know it was new because I went with him to get it but aside from that nothing. Any information would be appreciated.
FTE Legend
Joined: Jul 2010
Posts: 32,875
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From: Northeast, OK
I don't know that much about EFI, but I can think of one thing that might cause a problem - injector leakage. I think the system is supposed to hold pressure when off for a length of time, but don't have any info on that because my manuals don't cover the EFI'd trucks. But, if you have an injector leaking then it could cause flooding that would require cranking to clear out. You might try a fuel injector cleaner in the system to see if it helps. And, there is a way to test the system pressure, which would allow you to watch to see if it drops quickly after turning the key off, which would indicate a leaking injector. But, again, I don't have a manual that covers EFI so can't tell you how.
Having said all that, you should pull the codes to see if the computer is trying to tell you what the problem is. Here's how to do that: Link
Having said all that, you should pull the codes to see if the computer is trying to tell you what the problem is. Here's how to do that: Link
Posting Guru
Joined: Feb 2011
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From: Princeton MN
Also check the range on the ECT or engine coolant temp sender. It could be like the issue I had in where the ECT was always reading cold, therefore on a hot start it would imediately flood. The sender is just above the thermostat and has 2 wires going to it.
Posting Guru
Joined: Jan 2012
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From: Dallas, GA
Just to be clear...in your first post you stated it is actually cranking by the starter good, then later you refer to hard to crank when it's cold??
So I'm assuming this is for sure not a cranking issue but rather it just won's start correct?
If it's steadily getting worse as you say, that would almost lead me to believe it's something mechanical. Not for sure but seems like it. Something electrical would "normally" be good or bad...but those can fade as well.
Would definately get your codes pulled. That will tell you if you have something wrong with a sensor, voltage or position of something.
Have you checked fuel/pressure? Might be something getting clogged, maybe a filter or in tank LP Pump?
So I'm assuming this is for sure not a cranking issue but rather it just won's start correct?
If it's steadily getting worse as you say, that would almost lead me to believe it's something mechanical. Not for sure but seems like it. Something electrical would "normally" be good or bad...but those can fade as well.
Would definately get your codes pulled. That will tell you if you have something wrong with a sensor, voltage or position of something.
Have you checked fuel/pressure? Might be something getting clogged, maybe a filter or in tank LP Pump?
Senior User
Joined: Nov 2002
Posts: 486
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From: Cochranville, PA
Just a thought:
I had this same scenario a few years back. Turned out I had a 'bad' Ground cable coming from the battery. It would start fine when cold, but barely start when hot. You could try connecting a jumper cable from the (-) Batt post directly to a chassis ground. If your truck starts good when hot, then check your GRD cable for replacement. They can look good from the outside, yet be damaged inside. Good luck.
I had this same scenario a few years back. Turned out I had a 'bad' Ground cable coming from the battery. It would start fine when cold, but barely start when hot. You could try connecting a jumper cable from the (-) Batt post directly to a chassis ground. If your truck starts good when hot, then check your GRD cable for replacement. They can look good from the outside, yet be damaged inside. Good luck.
Last edited by Coneynew; May 25, 2012 at 11:32 AM. Reason: typo
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