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Not starting after warm

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15 minutes ago, jlbayes said:

I would suggest coming to terms with needing an ecm based on the 5v ref code. The lift pump running has be at odds but if the 5v ref is on the same bus bar in the ecm.....its done.

Anywhere you would suggest looking for a ecm? Thanks. 

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KATOOM

KATOOM

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Just to recap so I understand.....

Is your fuel pump wired utilizing the stock lift pump connector but using the aftermarket wire loom with relay?

Because I thought I read that it was wired direct to the key so that its running fuel time whenever the key is ON.....which would be bad.

Also, if thats how its wired up then correct the way the fuel pump is wired and it may possibly correct the starting issue.

If not then there's other suggestions but checking the most obvious and cheapest first is always best.

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1 minute ago, KATOOM said:

Just to recap so I understand.....

Is your fuel pump wired utilizing the stock lift pump connector but using the aftermarket wire loom with relay?

Because I thought I read that it was wired direct to the key so that its running fuel time whenever the key is ON.....which would be bad.

Also, if thats how its wired up then correct the way the fuel pump is wired and it may possibly correct the starting issue.

If not then there's other suggestions but checking the most obvious and cheapest first is always best.

The Air Dog runs as long as the key is on. I purchased the truck 2 years ago and that's how the previous owner had it. Never had a problem till about a month ago. 

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KATOOM

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Whats happening then is the AD is running at a full 18 psi (your setting) when the key is ON.  This means the VP is receiving fuel incoming pressure while the engine is cranking, which then increases the pressure load on the timing solenoid and fueling solenoid.  This can prevent starting of the engine until the fuel pressure is reduced internally in the VP.  And in your situation it sounds like its not allowed to bleed down.  A common problem with fuel pumps that are more aggressive than the stock lift pump.....which was rarely capable of putting out its regulated 15 psi.

 

Addressing this electronically as well, those solenoids require a minimum of 9 volts to function properly.  When you start the engine the load placed on the batteries is immense, and combine this with grid heaters and possibly batteries which arent great or corrosion or poor connections/grounds and you have a scenario where the solenoids arent getting 9 volts during engine cranking.  Same thing can happen during the hot summer heat too.

 

So again, I'd reconfigure the AD wiring setup, even though it did work.  And you might want even consider adding a delay relay so that the AD isnt running at all while the key is in the START position.  Very easy to do and it removes all pressure on the VP when engine starting.  Much better.....

 

Then check the batteries and all major connections, grounds, and cables for tightness and corrosion.  Especially since one of the codes is possibly coming from ground issues.

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JAG1

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In the morning I always bump the starter and wait for fuel pressure to get up to around 7-9 psi and then fire up the engine.

Works every time.

 

Need to find the ECM lift pump pig tail and have that control a relay that activates the lift pump connection to the batteries.

 

There is a lot more in articles in this forum that you have to consider, such as a protection relay to protect the ECM.

Edited by JAG1
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11 minutes ago, KATOOM said:

Whats happening then is the AD is running at a full 18 psi (your setting) when the key is ON.  This means the VP is receiving fuel incoming pressure while the engine is cranking, which then increases the pressure load on the timing solenoid and fueling solenoid.  This can prevent starting of the engine until the fuel pressure is reduced internally in the VP.  And in your situation it sounds like its not allowed to bleed down.  A common problem with fuel pumps that are more aggressive than the stock lift pump.....which was rarely capable of putting out its regulated 15 psi.

 

Addressing this electronically as well, those solenoids require a minimum of 9 volts to function properly.  When you start the engine the load placed on the batteries is immense, and combine this with grid heaters and possibly batteries which arent great or corrosion or poor connections/grounds and you have a scenario where the solenoids arent getting 9 volts during engine cranking.  Same thing can happen during the hot summer heat too.

 

So again, I'd reconfigure the AD wiring setup, even though it did work.  And you might want even consider adding a delay relay so that the AD isnt running at all while the key is in the START position.  Very easy to do and it removes all pressure on the VP when engine starting.  Much better.....

 

Then check the batteries and all major connections, grounds, and cables for tightness and corrosion.  Especially since one of the codes is possibly coming from ground issues.

This makes alot of since. Thanks! Any info on adding a delay relay for the AD that I can look up and read? I am going to be replacing my terminals on my batteries this weekend do to them being crack hence a possible bad ground somewhere.

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KATOOM

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34 minutes ago, Callsign said:

This makes alot of since. Thanks! Any info on adding a delay relay for the AD that I can look up and read? I am going to be replacing my terminals on my batteries this weekend do to them being crack hence a possible bad ground somewhere.

 

Thanks...  Glad I explained it decent enough since I know I can get a little wordy.  It makes sense to me when I'm typing but that doesnt mean anyone reading is following my logic. :think:

 

Anyways, yes this is a problem for most people with aftermarket fuel pumps.  Doesnt have to be a problem immediately either, but it will eventually most of the time.  Understanding that the factory ECM fuel system circuit is even programmed to alternate ON/OFF voltage to the lift pump during engine cranking in order to reduce the cranking fuel pressure to about half delivered to the VP before the engine starts.  So thinking about that...  If the OEM Carter lift pump was hardly capable of 15 psi while engine running, the factory fuel pressure should have been no more than about 7 psi while engine cranking.  Your VP is receiving 18 psi no matter if the engine is cranking or running.

 

All that said, after you get the AD connected to the factory lift pump pigtail connection with a relay to remove any additional amperage to the ECM, you can add a 5 pin relay which when wired into the hot lead and triggered by the starter solenoid circuit, the fuel pump is prevented from pumping at all when the ignition key is in the START position.  But all other fuel pump function is retained.  If you want I can upload a wiring diagram Moparman created years ago showing how to wire this relay in.

 

Lastly, what you could potential find out when trying to rewire your AD is that the previous owner wired it up direct to key ON because the ECM fuel system circuit has been burned out or is no longer working.  This sometimes happens when people wire their new aftermarket fuel pumps directly to the lift pump pigtail unknowing that without a relay removing the additional amperage placed on the ECM the circuit cant take the additional load.  Especially when the AD 150 pulls something like 6+ amps over the factory lift pump.  So what happens is when that circuit no longer functions they'll wire their fuel pump directly to a keyed source and there ya go.....  The option of wiring directly while using an additional keyed relay is still something they can do but they either fail to know or forget that they can go that route too.

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4 minutes ago, KATOOM said:

 

Thanks...  Glad I explained it decent enough since I know I can get a little wordy.  It makes sense to me when I'm typing but that doesnt mean anyone reading is following my logic. :think:

 

Anyways, yes this is a problem for most people with aftermarket fuel pumps.  Doesnt have to be a problem immediately either, but it will eventually most of the time.  Understanding that the factory ECM fuel system circuit is even programmed to alternate ON/OFF voltage to the lift pump during engine cranking in order to reduce the cranking fuel pressure to about half delivered to the VP before the engine starts.  So thinking about that...  If the OEM Carter lift pump was hardly capable of 15 psi while engine running, the factory fuel pressure should have been no more than about 7 psi while engine cranking.  Your VP is receiving 18 psi no matter if the engine is cranking or running.

 

All that said, after you get the AD connected to the factory lift pump pigtail connection with a relay to remove any additional amperage to the ECM, you can add a 5 pin relay which when wired into the hot lead and triggered by the starter solenoid circuit, the fuel pump is prevented from pumping at all when the ignition key is in the START position.  But all other fuel pump function is retained.  If you want I can upload a wiring diagram Moparman created years ago showing how to wire this relay in.

 

Lastly, what you could potential find out when trying to rewire your AD is that the previous owner wired it up direct to key ON because the ECM fuel system circuit has been burned out or is no longer working.  This sometimes happens when people wire their new aftermarket fuel pumps directly to the lift pump pigtail unknowing that without a relay removing the additional amperage placed on the ECM the circuit cant take the additional load.  Especially when the AD 150 pulls something like 6+ amps over the factory lift pump.  So what happens is when that circuit no longer functions they'll wire their fuel pump directly to a keyed source and there ya go.....  The option of wiring directly while using an additional keyed relay is still something they can do but they either fail to know or forget that they can go that route too.

Awesome, thanks a lot! And yes if you can upload the diagram that would be great or if there is a link that too. Thanks alot all of you for your help. Hopefully I can get this figured out this weekend.

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Dieselfuture

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So who is using this mod, I've just been relying on a relay that came with fass that uses ecm plug to energies it only, but my truck starts with half a crank so I'm not even sure if pressure even starts to rise while it starts. I can see it would be more important if it took at least couple of revolutions to start, where pressure may be higher by then. 

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KATOOM

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I've had this additional "delay" relay setup on my truck for a long time.  Around a decade if I'm remembering correctly.....  I chalk it up there with one of the most important changes/upgrades I've done to the truck since I know its beneficial to have very low to zero fuel pressure placed on the VP during engine cranking, as long as fuel supply and prime is intact.

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JAG1

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On ‎2‎/‎12‎/‎2018 at 6:57 AM, jlbayes said:

Fuel pump relay is ONLY for the vp44 in these trucks. It looks like the ecm 5v ref is shorted based on the P1475.

Are you still powering your lift pump off the factory ECM lead? Jlbayes I like old technology..... water wheels for electricity and old covered wagons, but you need to get up to speed bud. Not poking here :punish:

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