When I first try to start the my 2000 24 valve Cummins 3500 in the mornings it starts quickly. But when it warms up it won’t start again. Like if the intake manifold heater is not working correctly after it warms up. I was wondering what controls the heater? Also, has anyone else had this problem? Am I on the right track?

 

I fixed my hard start when hot with new batteries. Mine would still start, just slow doing it.

 

Thanks but it's not the batteries. It is cranking fast and strong.

 

If you had a fuel restriction as mentioned in the other thread it sounds like you just narrowed your problem down. probably your Injector Pump. This would be the same as your lift pump going out, not getting enough fuel through for lubrication and cooling.

 

I thought restriction could be the problem, so I already replaced my lift pump. I also installed a warning light that is set to turn on at 5 psi or less. The light turn off within 1/2 second of engine cranking. I also checked with a presure guage and I am getting 16 psi at and idle.

 

My truck would start real hard after it was warmed up, problem ended up being the injector pump. I had the fass kit on my rig at the time and had 22psi for fuel pressure. Have you check for any codes yet, cycle your key three times to the on position only, then on your odometer it flash some codes.

 

What would make the grid heaters not work AFTER its warm??? Its doubtful that the grid heaters are related you this issue.

You wont like this answer - "In most cases" when a 24V starts fine when its cold and then has hard starts when it hot - its the VP-44 (and probably the lift pump as well).

You should have it scanned for codes.

Do you have a fuel pressure guage??

 

My truck had hard starting problem when hot and it was the injection pump gone bad. Got it replaced under warranty. Hope this helps.

 

If you want to check it, when it's warm and hard to start pour a gallon of cold water over the pump. Bet it starts right up after that. The corrections you made were the right thing to do probably just to late for this pump.

 

Ok, I tried the cold water test when it was warm. It made no difference. It still had trouble starting. I had to use a touch of starting fluid. I checked the codes by performing the key on off test and no flashing code came up. What's next?

 

I'd still bet that is the problem. It's hard to get the water to the pump with all the stuff over the top of it, make sure you get it good and cooled off to get it to start. On the other side of this your pump may not just be bad but completely shot.

 

I still bet its the IP too...

BTW, starting fluid is really asking for trouble unless you unhook the grid heaters....its meant for trucks without grid heaters or glowplugs....

Kabooommmm

 

I have a friend who works at the VW dealership as there master mechanic and he gets sent a lot of the work dodge passes out and he had me buy a rebuild kit off ebay and rebuild my starter because i was getting hard starts when warm also... something having to do with the plunger i have no clue how it affects it but it was a 25 dollar fix... and the thing cranks on 1 revolution always now as before it never did.....

 

I hate to say it but Idle pressure isn't the main worry... I would check you cruising pressure and WOT pressure...

Mine: Starter Bump: 16.0-17.0 / Idle 14.0-15.5 / Cruise: 10.0-13.0 (load/slope related) / WOT: 6.0-8.0

I can suck mine down to 6 PSI at times... Which is below the 8 PSI limt which most here would hold too...

 

I agree with the Doc, I had the same issue this summer. I had plenty of fuel pressure so it was the baked electronics issue. Good Luck!