Truck won’t start normally

[Tomjohnson150]

1999 Dodge Ram 2500 4x4 5.9l automatic trans. Will not start until I drain the fuel filter for about a second. Then fires right off. I have tried the bumping the starter thing and the lift pump is working (brand new lift pump from Sep 2018). Even after bumping the starter several times to get the lift pump to run, it will still not start. Sometimes it will start if I crank it for about 10 seconds. It never fails to start if I drain the fuel filter for a second, even after sitting all night. Just changed fuel filter, which turned out to be clean since I just changed it in September 2018 and don’t drive much. Filled fuel filter with clean, fresh filtered diesel. There was no water in the fuel when I took out fuel filter. Still same symptoms after changing fuel filter and doing correct bump start procedure to prime fuel filter bowl. Drove it around all day yesterday, runs fine, not rough like if there was an air leak. No visible fuel leaks. Cracked port on top of fuel filter bowl while running to purge air. No air bubbles visible. Has a Blue Chip VP44 from 2012. Raptor lift pump installed 2012 and failed in 2018. Help!

 

[jghflys]

Not enough information on the fix, but a problem similar to yours here: https://mopar1973man.com/topic/6743-sucking-air/

 

[KATOOM]

The problem based on what you described is likely excessive fuel pressure during engine cranking... A question would be, does it do this with the engine both hot and cold, or just one or the other?
The Raptor should have come with and been installed with a new wire loom, which should also have an inline fuse somewhere accessible. Next time the engine wont start, open the hood and pull that fuse and try cranking again. If it starts then simply put the fuse back immediately or shut the engine off. Just dont run for more than a few seconds on no fuel pressure. If that solves the starting problem then there is a relay you can install.

 

[Tomjohnson150]

As stated in the first post, The Raptor pump was replaced Sep 2018. It lasted 6 yrs. back to a stock pump now, which is what is giving me these symptoms. The guy who helped me replace Raptor said to go back and check everything we touched to see if a connection may have loosened itself and is causing an air leak

 

[KATOOM]

An air leak will ONLY cause a cold engine starting problem. High fuel pressure during cranking will ONLY cause a hot engine starting problem. A slow dragging starter...and/or weak batteries...and/or bad corrosion, can cause a hard start problem for both cold and hot engine. A failing CPS can cause a random hard start problem. So again, does it do this with the engine both hot and cold, or just one or the other?

 

[DavidC]

On another post with hard starting the member finally changed out his starter that apparently was not turning the engine fast enough. He never noticed the gradual decline, anyway it starts the instant he turns on the key. Happy camper ending.

 

[DavidC]

The whole story here, coincidentally his is a 99
https://www.turbodieselregister.com/threads/hard-starting-after-engine-warms-up.266308/

 

[Tomjohnson150]

An air leak will ONLY cause a cold engine starting problem. High fuel pressure during cranking will ONLY cause a hot engine starting problem. A slow dragging starter...and/or weak batteries...and/or bad corrosion, can cause a hard start problem for both cold and hot engine. A failing CPS can cause a random hard start problem. So again, does it do this with the engine both hot and cold, or just one or the other?

Does it both cold and hot engine, batteries are fine cause they let me crank away many times, then finally when I drain the fuel bowl for a second it will start

 

[cerberusiam]

How long does the LP run when you turn the key on? There is flash to cut down the run time and keep the head pressure on the IP down so they start better. The VP-44 doesn't like too much pressure on startup and you will get a long crank. Quite frankly, the LP is probably on the way out but you can try the flash and a switch to cut out the LP to see if it will last longer. Usually when they started doing that the VP-44 was replaced in the near future.

 

[KATOOM]

Does it both cold and hot engine, batteries are fine cause they let me crank away many times, then finally when I drain the fuel bowl for a second it will start

Try this... Next time it doesnt want to start, dont open the fuel drain but rather open the fuel tank cap. If you hear any whooshing sound of air entering or escaping then thats a problem. What you could be experiencing is a pressurized or vacuumed fuel tank for a couple different reasons which we can determine by what you do or dont hear.
That said, I guess one way to know if its pressure or vacuum is...when you open the fuel drain does fuel come out?

 

[Tomjohnson150]

Try this... Next time it doesnt want to start, dont open the fuel drain but rather open the fuel tank cap. If you hear any whooshing sound of air entering or escaping then thats a problem. What you could be experiencing is a pressurized or vacuumed fuel tank for a couple different reasons which we can determine by what you do or dont hear.
That said, I guess one way to know if its pressure or vacuum is...when you open the fuel drain does fuel come out?

Yes, fuel comes out of drain, then truck will start

 

[KATOOM]

Did you check and see if any air whooshing noise comes from the fuel tank cap when you remove it? That would indicate that there's pressure in the tank.
I say this because...the fuel system maintains a "prime" which simply means that there's always fuel in the lines and those lines are not under pressure when the engine is off. Therefore if the system is working normal then opening the fuel drain would result in nothing coming out. Just like your finger over the end of a drinking straw. So if fuel is coming out then somethings up...

 

[Tomjohnson150]

Did you check and see if any air whooshing noise comes from the fuel tank cap when you remove it? That would indicate that there's pressure in the tank.
I say this because...the fuel system maintains a "prime" which simply means that there's always fuel in the lines and those lines are not under pressure when the engine is off. Therefore if the system is working normal then opening the fuel drain would result in nothing coming out. Just like your finger over the end of a drinking straw. So if fuel is coming out then somethings up...

I’m not so sure about that, doesn’t it say in the owners manual to drain some fuel from the fuel bowl at every fill up? Do they want you to drain it while the engine is running? I will go out and check fuel cap now

 

[Tomjohnson150]

How long does the LP run when you turn the key on? There is flash to cut down the run time and keep the head pressure on the IP down so they start better. The VP-44 doesn't like too much pressure on startup and you will get a long crank. Quite frankly, the LP is probably on the way out but you can try the flash and a switch to cut out the LP to see if it will last longer. Usually when they started doing that the VP-44 was replaced in the near future.

LP only runs for max 2 sec for normal tries at a start. When I bump it to get it to run, it runs for about 30 sec. neither of these situations will give me a start. But I can drain fuel bowl for a second, even on a cold engine with the 2 sec LP run time, and the engine will fire right up. Otherwise, no start, no matter how many bumps to get LP to run for 30 sec.

 

[DavidC]

Fuel Pressure gauge ?

 

[KATOOM]

I will go out and check fuel cap now

What did you find out? Because the more I read what you're describing, the more I think your fuel system is being pressurized.

 

[Tomjohnson150]

What did you find out? Because the more I read what you're describing, the more I think your fuel system is being pressurized.

Fuel cap not pressurized, truck started right up cold...weird. Let it warm up, d and over it a little, shut it off. Fuel cap still not pressurized

 

[Tomjohnson150]

Fuel Pressure gauge ?

I installed a low pressure light when I installed the blue chip vp44 and raptor 6 yrs ago. Low pressure light working properly (on when ignition on and engine off, off when engine running) no light when engine running. No fuel pressure gauge

 

[Joe Mc]

I got a set of Larry B's (<-pretty sure) from Geno's Garage when my started started acting up a bit, back in 2003, and it has operated flawlessly since.

 

[Tomjohnson150]

SO i drive the truck about once a week or so and it has been fine for the last few months, don’t know why, but it did this starting hesitation to me again this weekend. Started up cold just fine (10 deg F that day). Idled for a bit while loading up supplies, then drove for about an hour. Did just fine, no hesitation, no low pressure fuel light. Shut it down and it sat at 10 deg F for about an hour, then did the start hesitation thing again when I went to start it. Then drove for about 20 minutes, shut it off for about 30 minutes, then hesitation on start again. Drove for 20 minutes, shut off for 10 minutes, then hesitation on starting again. When it does the hesitation on starting, it cranks really fast for a few seconds longer than normal and then it finally starts.