7.3 idi no start when warm
- Thread starter Mtew2000
- Start date
79jasper
Chickenhawk
Yeah, sure, it's new. From?
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SebastIDIan
Full Access Member
Pour cold water on it, see if it starts. New to you maybe
chicken bones
Docker
My truck was very difficult to start when warm,but would start cold with glow plugs no problem. Replaced the starter Motor ,problem solved . Engine was cranking over so much quicker with the new Starter.
Macrobb
Full Access Member
Exactly.
You want to pour the cold water on the back of the IP, where the lines come out of it. This shrinks the "head" by a microscopic amount, just enough to reduce the clearance to the "rotor" inside it and let the IP build enough pressure to start it.
This, of course, means the IP is 'bad' - head to rotor clearance cannot be fixed except with a new head/rotor assembly - a $400 part, by itself.
We run into this issue on cheap reman parts because they aren't about to replace said $400 part on a $500 IP. It's just not worth it.
This is actually a symptom of the same issue - you still have some(possibly excessive) clearance between the "head" and "rotor", but increasing the cranking speed was enough to overcome the fuel leaking past it and start.
Chances are, it's nothing to worry about, except that it *could* someday have the same issue again as it wears more.
The other factor in this is the Injector pop pressure. New, 1800 PSI. Worn... they will wear all the way down to 1000. The higher the pressure, the harder the IP has to work to build that pressure.
This is why you might put a new set of injectors in it, and suddenly run into hot start issues when you didn't have it before - the wear on the IP wasn't enough to keep it building, say, 1400 PSI at cranking speed... 1800 was too much for it.
What he said. But head and rotor isn’t a $400 part, try $700. The ones being marketed for $400 range are not new but have been reground, most pump builders try to avoid them, I’ve had no luck with reground head and rotors.
Same exact issue with my truck when I bought it. Cold water on the back of the pump allowed it to start hot. I'd start saving your pennies for an injection pump from a reputable rebuilder.
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adamsanders
Full Access Member
Having been down this road last summer, I'll give my thoughts. The truck started cold and ran flawlessly but would not start well when hot at all.
First off, I tried messing with the timing, both ways, to no avail. Even tried skipping a tooth on the IP gear itself. Eventually, I bought a Mini Moose injection pump from Mel for around $700. For the record, when I called and talked to him he said that most of the time with these pumps its not the head/rotor but rather the calibration of the many fuel adjustments these pumps have. Either way, I put the Moose pump on and the truck really ran great. However it still took, in my opinion, excessive turning to crank when warm.
So after much frustration, I bought a brand new Nippo-Denso style starter and replaced ALL battery cables (grounds too) with 2/0 cable with properly crimped ends. Truck began starting very fast cold and warm. It was a noticeable difference.
I say all that to say this. If you think there is a chance your starting speed has began to diminish over time, replace the starter/cables/batteries and see what happens. It's hard to say if that would have fixed my problem originally or if it would have bought me more time. I don't know. Either way, I now have a high-end pump, great starter and a quick-starting truck.
First off, I tried messing with the timing, both ways, to no avail. Even tried skipping a tooth on the IP gear itself. Eventually, I bought a Mini Moose injection pump from Mel for around $700. For the record, when I called and talked to him he said that most of the time with these pumps its not the head/rotor but rather the calibration of the many fuel adjustments these pumps have. Either way, I put the Moose pump on and the truck really ran great. However it still took, in my opinion, excessive turning to crank when warm.
So after much frustration, I bought a brand new Nippo-Denso style starter and replaced ALL battery cables (grounds too) with 2/0 cable with properly crimped ends. Truck began starting very fast cold and warm. It was a noticeable difference.
I say all that to say this. If you think there is a chance your starting speed has began to diminish over time, replace the starter/cables/batteries and see what happens. It's hard to say if that would have fixed my problem originally or if it would have bought me more time. I don't know. Either way, I now have a high-end pump, great starter and a quick-starting truck.
Joseph Davis
Full Access Member
When starting try to put a wire on positive side battery to (fuel on the IP) if it starts then bad power line to IP.
I think there was another (weirdo thing) that could cause this and it had something to do with a weak fuel line going to injection pump..... After warming up and engine then shut-off, the line would suck or collapse shut... Someone more familiar may recall this and explain in better detail. I think it's the soft line this guy is pointing toward. If you don't use a ridge fuel line type hose, it can collapse.
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79jasper
Chickenhawk
Well, that's a return line, but it could.
The one between the frame and lift pump should be the one you're thinking of.
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The one between the frame and lift pump should be the one you're thinking of.
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Haha alrighty then
Hydro-idi
Full Access Member
Invest in a bike and helmet along with the water for when the truck leaves you stranded somewhere.
