Dodge/Ram Diesel Tech Discussions on all generations of Cummins Diesel powered Rams plus the new Eco Diesel

Hard starting when engine is warm.

Thread Tools
 
Search this Thread
 
Old Jul 2, 2009 | 12:30 AM
  #1  
pcman's Avatar
pcman
Thread Starter
|
Amateur
Joined: Mar 2007
Posts: 32
Likes: 0
From:
Default Hard starting when engine is warm.

My 1999 24V (125k miles) is difficult to start when the engine is hot. When I first get in the truck in the mornings it fires right up, but after driving a bit if I turn it off and then try to start it, it just turns over fine but no starting. After cranking 10~20 seconds it does start. If I let the truck sit 4 hours or longer after driving it always starts right up. There are no codes. My VP44 is a little over a year old, as well as Edge Jammer injector tips. As for the lift pump replacement I'm running the FASS system. I'm showing plenty of fuel pressure (idle 15+ psi) before the VP44. Anyone have a idea as to what is causing my problem?

Thanks.
 
Reply
Old Jul 3, 2009 | 01:24 AM
  #2  
rabbler's Avatar
rabbler
Record Breaker
Joined: Jul 2007
Posts: 1,488
Likes: 3
From:
Default

Have your batteries and starter tested.
If you don't have good cranking rpm you get hard or no starts.
 
Reply
Old Jul 5, 2009 | 09:57 PM
  #3  
pcman's Avatar
pcman
Thread Starter
|
Amateur
Joined: Mar 2007
Posts: 32
Likes: 0
From:
Default

Batteries were just replaced less than 4 months ago and the starter is about 2-3 years old.
 
Reply
Old Aug 14, 2009 | 03:08 PM
  #4  
Mr. Jimmy's Avatar
Mr. Jimmy
Registered User
Joined: Mar 2009
Posts: 10
Likes: 0
Default Fuel Pump

The fuel pump might be going bad. It might have a leaky check valve.
 
Reply
Old Aug 16, 2009 | 05:35 PM
  #5  
hounds's Avatar
hounds
Rookie
Joined: Jun 2009
Posts: 62
Likes: 0
Default

My '01 is doing the same thing. I have noticed where the lines are going to the injectors some are leaking (leaking from inside or behind where it screws in) . I am thinking seals inside the injectors (IF there is any) after warming up they swell and allow fuel to leak?
Does this sound plausible?
Thats what I'm thinking. If it was the injectors themselves, it would do it all the time I think?
Its really pissing me off though.
FYI, I have replaced my IP and lift pump assembly less than a yr ago.
 
Reply
Old Aug 17, 2009 | 07:41 AM
  #6  
Coal Train's Avatar
Coal Train
All Star
Joined: Dec 2008
Posts: 863
Likes: 0
From: East Alabama
Default

That sounds to me like you're getting some air in the lines.

Check all your fuel lines and make sure you don't have any cracks or leaks anywhere.

When the VP44 loses prime, it's a PITA to re-start.

Other things I'd look at is a clogged fuel filter / water seperator.
 
Reply
Old Aug 19, 2009 | 08:33 PM
  #7  
hounds's Avatar
hounds
Rookie
Joined: Jun 2009
Posts: 62
Likes: 0
Default

It DOES appear that leaking or broken fuel lines would be the obvious culprit but why only when its warm? Why not all the time?

In MY situation I DO see a little bit of fuel and its leaking from where the fuel lines go into the injectors (and they are TIGHT). Not pouring out but seems to be leaking. I don't see any leaks anywhere else from the tank all the way up to the filter, into the IP, etc.

thanks
 
Reply
Old Aug 21, 2009 | 12:25 AM
  #8  
rabbler's Avatar
rabbler
Record Breaker
Joined: Jul 2007
Posts: 1,488
Likes: 3
From:
Default

It's possible for a leak between the lift pump and tank to suck in air and not have a fuel drip. Splice in a section of clear hose and look for bubbles or foam. bubbles = air leak
 
Reply
Old Aug 21, 2009 | 12:47 AM
  #9  
pizzo's Avatar
pizzo
All Star
Joined: Aug 2009
Posts: 876
Likes: 0
From: Chicago
Default

injection pump is going bad
dam you VP 44
 
Reply
Old Aug 21, 2009 | 07:36 AM
  #10  
Coal Train's Avatar
Coal Train
All Star
Joined: Dec 2008
Posts: 863
Likes: 0
From: East Alabama
Default

Originally Posted by hounds
It DOES appear that leaking or broken fuel lines would be the obvious culprit but why only when its warm? Why not all the time?

In MY situation I DO see a little bit of fuel and its leaking from where the fuel lines go into the injectors (and they are TIGHT). Not pouring out but seems to be leaking. I don't see any leaks anywhere else from the tank all the way up to the filter, into the IP, etc.

thanks
Hounds,

That sounds to me like the fuel line nut got overtightened and the compression fitting is shot.

The fitting between the HP fuel line and the connector tube is a compression fitting and, really, it's only suppossed to be used once. Can you get away with removing an installing it multiple times? Yes, but you need to ber very careful not to damage the head of the fuel line, otherwise a leak develops.

This can either leak fuel under pressure or it can allow air in when the system is off.
 
Reply



All times are GMT -4. The time now is 04:08 PM.