Hot start problems
Tuned
Joined: Jan 2009
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From: Carmichael, CA
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
The way I understand it they are saying when the engine is Hot the fuel is too rich to start the engine.
So they (Ford) are trying to make the engine run cooler with the modifications so it will start with the rich fuel mix.
I would think you could do the same thing by going to wide open throttle just after it starts to crank. This would turn off the fuel injectors and it should start. It of course is just a guess.
So they (Ford) are trying to make the engine run cooler with the modifications so it will start with the rich fuel mix.
I would think you could do the same thing by going to wide open throttle just after it starts to crank. This would turn off the fuel injectors and it should start. It of course is just a guess.
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New User
Joined: Apr 2009
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I'm in the middle of moving houses, so I won't have a chance to play with this too much for a while, but I'll definitely update the thread as I do things.
I have the TSB from AllDataDIY.com. Pretty handy site. I'll replace the IAT sensor first, then the computer if the problem is still there. I'll also try going WOT while starting it to see if that helps.
My thermactor (smog pump, right?) isn't even hooked up to the cat, since the tubes didn't reach the inlets on the replacement cat. Do I still need the new silencer? Is running it unhooked like this damaging anything?
I have the TSB from AllDataDIY.com. Pretty handy site. I'll replace the IAT sensor first, then the computer if the problem is still there. I'll also try going WOT while starting it to see if that helps.
My thermactor (smog pump, right?) isn't even hooked up to the cat, since the tubes didn't reach the inlets on the replacement cat. Do I still need the new silencer? Is running it unhooked like this damaging anything?
Elder User
Joined: Aug 2006
Posts: 813
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From: foristell, missouri
i would look at you battery cables and starter and selenoid. i know it sounds goofy but mine did the same thing and it was the starter and cables. this is cause it takes more juice to turn over a hot motor cause everythings expanded when t heats up.
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New User
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I replaced the IAT and TPS today. Did seem to help a little with a slight bog I'd have when I just cracked the throttle after idling for a bit. No change on the hot start.
I did notice when I took out the old IAT that it was coated in fuel-smelling gunk, and it looked like the whole intake was too. I'll probably try to figure out how to clean that, since I'm sure it's not good for performance.
I'll order the computer next and see if that fixes anything.
Thanks,
Chris
I did notice when I took out the old IAT that it was coated in fuel-smelling gunk, and it looked like the whole intake was too. I'll probably try to figure out how to clean that, since I'm sure it's not good for performance.
I'll order the computer next and see if that fixes anything.
Thanks,
Chris
Cargo Master
Joined: Jul 2009
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From: Des Moines
I get that you're getting the code 34, but check your ignition coil- this sounds to me like that's a potential problem as well.
*Edit- I'm kinda tired right now so I posted that after only reading the first page- after reading thru the whole thread I still think you should check out the coil. The fact that it has difficulty starting when hot sounds like the coil is getting close to overheating.
And if running with the smog pump unhooked from the cat hurts something, I don't know what it is- my truck's been running with it unhooked for almost 6 months just because I've been too occupied with other things to properly repair the connection- no problems to date.
*Edit- I'm kinda tired right now so I posted that after only reading the first page- after reading thru the whole thread I still think you should check out the coil. The fact that it has difficulty starting when hot sounds like the coil is getting close to overheating.
And if running with the smog pump unhooked from the cat hurts something, I don't know what it is- my truck's been running with it unhooked for almost 6 months just because I've been too occupied with other things to properly repair the connection- no problems to date.
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I haven't given up yet, but I'm trying to sell my 2008 F150. Since I paid it off early to get the title, I'm a little short on cash to buy parts until it sells. I'll update as soon as I start on the 250 again.
Also, I may not have mentioned it in this thread, but I did replace the coil already, and nothing changed.
And while helping a friend move last week, I discovered that I'd gone through about 3qts of oil in ~500 miles. I don't think I'm burning it, since there's no smoke and I had a good compression test a few months ago, and I don't have puddles under the truck, so I must be losing it on the highway? One more thing to figure out.... yay old vehicles!
*edit* I've also replaced the starter, which I think is in this thread somewhere. It turns over real hard, just doesn't catch, so I don't think it's related to the starting/charging systems.
Also, I may not have mentioned it in this thread, but I did replace the coil already, and nothing changed.
And while helping a friend move last week, I discovered that I'd gone through about 3qts of oil in ~500 miles. I don't think I'm burning it, since there's no smoke and I had a good compression test a few months ago, and I don't have puddles under the truck, so I must be losing it on the highway? One more thing to figure out.... yay old vehicles!
*edit* I've also replaced the starter, which I think is in this thread somewhere. It turns over real hard, just doesn't catch, so I don't think it's related to the starting/charging systems.
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New User
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The Ford dealer looked at the truck twice and couldn't give me any answers. They're pretty sure that TSB isn't the issue, but all they could offer was that my EGR valve didn't hold vaccuum. I'm assuming this couldn't affect a hot-start or even running rough at idle until it warms up for a minute, right?
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Nope, the dealer was pretty sure it wasn't the TSB, which was what said to get the computer. I'm tired of throwing money at it and not getting anything in return. That TSB was just the last-ditch effort from the last shop that couldn't figure it out either.
Fleet Owner
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From: Easton,Ks
Still sounds like the EGR valve is sticking open when hot.
Try removing the EGR valve and cut out a a thin block off device and bolting the EGR back on and see out it runs then. If it fixes it then just replace the EGR valve or the EGR solenoid.
This will not cost you anything to try.
OR unscrew the big tubing nut at the bottom of the EGR valve, drop a penny in the tube and had tighten the tube back on to the EGR valve. Then see how it runs, if OK then take the penny out and replace the valve or the EGR solenoid.
Try removing the EGR valve and cut out a a thin block off device and bolting the EGR back on and see out it runs then. If it fixes it then just replace the EGR valve or the EGR solenoid.
This will not cost you anything to try.
OR unscrew the big tubing nut at the bottom of the EGR valve, drop a penny in the tube and had tighten the tube back on to the EGR valve. Then see how it runs, if OK then take the penny out and replace the valve or the EGR solenoid.
Hotshot
Joined: Sep 2001
Posts: 11,958
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The IAT goes in the air filter box on mass air trucks. If you have a speed density truck, I don't believe you have this. I think it was only on mass air trucks. Seeing as how you have a MAP, your truck is speed density. I believe all the 460 trucks were speed density. Where is the IAT located on the 460?
Hotshot
Joined: Sep 2001
Posts: 11,958
Likes: 228
I had a similar hot start condition that a few shops and 2 Ford dealers could not figure out. An SVT mechanic even looked at it. It turned out to be the injectors. They would leak fuel into the engine and flood it out when the engine was shut off. I just replaced all of them.
The problem my F150 had was it would start fine when cold, but after being driven it would be very hard to start unless you started it back up within a few minutes. It would normally have to sit for a few hours or longer before it would start normally.
The problem my F150 had was it would start fine when cold, but after being driven it would be very hard to start unless you started it back up within a few minutes. It would normally have to sit for a few hours or longer before it would start normally.