Hard start when hot/sitting

[beautifulisblue]

Hey folks,

I've got a hard start issue that started when I pulled off the interstate in 115 degree heat.  Almost always has a hard start if the engine is warmed up and sits a couple minutes now.  Sometimes it will hard start if sitting overnight.  The first time was 1k miles after a fuel filter change on a road trip from Vegas to southern Idaho, but I did the standard bump the pump and it ran great after that. I can't see any fuel leaking anywhere.  I've always seen a little drip off the tank if I really top it off, but that's been the case since I bought it.

 

I just ordered a DDRP from FASS, but haven't installed it.  I'm driving a loop from Vegas>Oregon>Idaho.Vegas in a month with a small horse trailer and a couple pack llamas in it.  What's a good way to test the fuel system before hand?  Once I had a pump I could run off a battery and traced an air leak to a cracked pickup in the tank with a clear hose that way, but alas no more pump.

 

I know this truck has at least one stock style lift pumps and a upgraded VP44.  it normally runs 13psi at idle and 9 PSI cruising, can go down to 7 WOT, hence the DDRP.

 

Any chance I could be having an o-ring problem with the fuel filter that took a thousand miles to show up?  I snugged it down with a one and a quarter inch socket.

 

Thanks folks,

Edited July 20, 2020 by beautifulisblue

[Tractorman]

A couple of things you could try...

 

When parking the truck overnight, point the front end down hill.  It will reduce the amount of fuel leaking back to the tank if that is the problem.  It should start quickly in the morning.

 

If most of your hard starts are after the engine has reached full operating temperature, then the pump control module on the VP44 may be on its way out.   Some have tried pouring cold water on the module and if the hot module was the cause, the engine would start right up afterward.

 

- John

[beautifulisblue]

34 minutes ago, Tractorman said:

A couple of things you could try...

 

When parking the truck overnight, point the front end down hill.  It will reduce the amount of fuel leaking back to the tank if that is the problem.  It should start quickly in the morning.

 

If most of your hard starts are after the engine has reached full operating temperature, then the pump control module on the VP44 may be on its way out.   Some have tried pouring cold water on the module and if the hot module was the cause, the engine would start right up afterward.

 

- John

Thanks John I'll throw some paving stones under the rear wheels tonight.

 

seems like the hard start is becoming ubiquitous whether it's sitting or right after it's gotten hot.  Not sure if it would hard start after just sitting for a minute when it's not at full temp.

[CUMMINSDIESELPWR]

sounds like the vp has been murdered by the oem lift pump.  when you install the new lift pump set pressure at idle above 15psi. this keeps fuel flowing cooling the vp.

[beautifulisblue]

9 hours ago, CUMMINSDIESELPWR said:

sounds like the vp has been murdered by the oem lift pump.  when you install the new lift pump set pressure at idle above 15psi. this keeps fuel flowing cooling the vp.

Copy,

This likely has 200k on the vp44.  Has code P1693, I'll have to get it checked to see what the companion code is in the AM.

Anyone that's experienced a VP 44 going out know what kind of timeline it usually has?  I'm going on a trip Friday I need the truck probably about a 200 mi each way towing a light two horse trailer.

Edited July 20, 2020 by beautifulisblue

[NIsaacs]

Soon after I bought my used '01 in '03 with 34k miles on it, I had a hard hot start. I was towing a pickup on a real hot day and let my fuel tank drop down till the low light came on, I wanted to fuel at one of my favorite stops. I have since rarely let it get below 1/2 tank and when it is hot I do not let the pump run before start. I hit start instantly, never a problem after that, 346k miles on the same oem VP. 

 

Keep your fuel tank on the top half and do the quick start and see if that helps. 

[beautifulisblue]

4 hours ago, NIsaacs said:

Soon after I bought my used '01 in '03 with 34k miles on it, I had a hard hot start. I was towing a pickup on a real hot day and let my fuel tank drop down till the low light came on, I wanted to fuel at one of my favorite stops. I have since rarely let it get below 1/2 tank and when it is hot I do not let the pump run before start. I hit start instantly, never a problem after that, 346k miles on the same oem VP. 

 

Keep your fuel tank on the top half and do the quick start and see if that helps. 

I'll give this one a try this morning.  It's at a little below 3/4, which is more like 1/2 a tank.  I know because I once ran out of fuel with 1/8 in the tank and had to walk three miles to a ranch while elk hunting...

This morning with the rear wheels sitting on paving stoves it started up perfectly.

Edited July 20, 2020 by beautifulisblue

[Rotax3006]

I went through some hot hard start issues with my truck recently.  I ended up replacing the battery and starter. When it was cold it would crank over great and fire right up.  As everything got hot it wouldn't crank fast enough to build pressure and took longer to start.  It seemed like it was cranking fast enough at least until i put the new stuff on.  I would check the batteries and starter before you throw a VP at it, doesn't cost anything.  My starter actually passed the load tests at Orileys but you could hear that the bearings had failed.   

[beautifulisblue]

Thanks,

I rebuilt the starter solenoid with a LarryB's Dodge Cummins Denso Starter solenoid kit 4 years ago.  Batteries were new AGMs, but my kid turned on the interior light and when I took them in to get charged, they just gave me new ones 6 months ago.  I will check that stuff though, maybe the starter needs a full overhaul. Also did new battery cables recently.

 

Ran the codes, got P1693 last night, P0380 and P0382 using my EDGE.  Ran it on the scanner at Orielly's this morning and got two codes each for P0380 and P0382.  

 

Filled the tank, no big difference.  Can still turn off hot truck, let it sit 15 seconds and then get hard start.  

[Rotax3006]

The good news is that those are not the VP death codes, of course that doesn't mean much.  It does not sound like a fuel leak to me.  It would have to be a major leak for a hard start immediately after shut off.  Here is pretty good link to hot start trouble shooting  https://www.bluechipdiesel.com/troubleshooting-quick-reference.  This is what I used along with the advice on here.  They definitely emphasize making sure the starting system is 100%. Good luck it can be frustrating. 

 

 

[beautifulisblue]

4 minutes ago, Rotax3006 said:

The good news is that those are not the VP death codes, of course that doesn't mean much.  It does not sound like a fuel leak to me.  It would have to be a major leak for a hard start immediately after shut off.  Here is pretty good link to hot start trouble shooting  https://www.bluechipdiesel.com/troubleshooting-quick-reference.  This is what I used along with the advice on here.  They definitely emphasize making sure the starting system is 100%. Good luck it can be frustrating. 

 

 

Yeah appreciate the info.  Definitely frustrating as I need the truck Friday for a packing trip I've already paid for.  That link is great.

[beautifulisblue]

4 hours ago, Rotax3006 said:

The good news is that those are not the VP death codes, of course that doesn't mean much.  It does not sound like a fuel leak to me.  It would have to be a major leak for a hard start immediately after shut off.  Here is pretty good link to hot start trouble shooting  https://www.bluechipdiesel.com/troubleshooting-quick-reference.  This is what I used along with the advice on here.  They definitely emphasize making sure the starting system is 100%. Good luck it can be frustrating. 

 

 

Pulled the starter figured out how to work the bench tester at O'Reilly since the staff couldn't.  Worked but sounded like bad bearings, got a new one at NAPA, and now can't replicate the hard start.  I wish I had time to rebuild mine, but needed it solid as we are going packing in central Nevada Friday.

 

Thanks for the advice!

Edited July 20, 2020 by beautifulisblue

[Rotax3006]

So if I understand you correctly, truck is starting fine now?  Hope that fixed your problem.  Enjoy the pack trip. 

[beautifulisblue]

13 minutes ago, Rotax3006 said:

So if I understand you correctly, truck is starting fine now?  Hope that fixed your problem.  Enjoy the pack trip. 

Yep starting well, can't replicate the problem.  

 

Need to get it nice and hot tonight and double check.

[Rotax3006]

Any updates?

 

[beautifulisblue]

Seems pretty good,

We had a little fire pop up on the forest I work on, so had to postpone our pack trip till we get it under wraps, but so far so good.  Definitely fires up real quick with the new starter.

[CUMMINSDIESELPWR]

i think the OP wasnt clear as to which hard start he was referring to.

 

will the engine crank over but not fire when hot (vp44 failure)

 

or

 

will the engine just not crank over (or very slow cranking) at all when hot (starter failure)

 

we all thought it was the vp44 when you mentioned it but i think clarity on the exact style of no hot start is needed.

Edited July 22, 2020 by CUMMINSDIESELPWR

[Rotax3006]

To be fair, i went through the exact same situation.  My truck would start quickly when cold but crank for a long time when hot.  I think as the starter started to fail i didnt notice the cranking speed slowing down.  I definitely noticed once I installed the new starter though.  Mine had bad bearings, easy to spot once you bench tested it.  I think the heat sink would tighten them up and cause excessive draw and slow cranking when hot.  I noticed with the scanner that once the cranking speed hit 300 RPM the truck would start.  It just took longer to build pressure with the initial slower cranking.  The VPs on these trucks are so fragile that its the go to anytime you have starting issues.

 

[beautifulisblue]

5 hours ago, CUMMINSDIESELPWR said:

i think the OP wasnt clear as to which hard start he was referring to.

 

will the engine crank over but not fire when hot (vp44 failure)

 

or

 

will the engine just not crank over (or very slow cranking) at all when hot (starter failure)

 

we all thought it was the vp44 when you mentioned it but i think clarity on the exact style of no hot start is needed.

The engine would turn over and crank and didn't even seem that slow when it was hot and eventually start.  That's why I originally assumed it was VP44.  It wasn't until I put on a new starter that I realized how much zippier it was than the old wore out one.

[Rotax3006]

Yep same for me. New one seems twice as fast. Glad you are up and running.