Ip heat soak

[Cucvnut]

So. I think my IP is bad but has any one heard of them getting heat soaked like a starter? I searched and came up with nothing. The deal is when cold it starts great but when hot the truck just turns over and wont start. The gp's should not effect a warm motor or am I wrong?

 

[jdemaris]

So. I think my IP is bad but has any one heard of them getting heat soaked like a starter? I searched and came up with nothing. The deal is when cold it starts great but when hot the truck just turns over and wont start. The gp's should not effect a warm motor or am I wrong?

I've never heard the term "heat soak" and I've been a diesel mechanic for over 40 years. Regional or new term maybe?

With starters, if you mean when they crank well cold, but not hot - it's often caused by overheated solenoid too close to the exhaust manifold (on some Chevys), high-compression and/or over-advanced ignition, etc.

With Standyne injrection pumps? Yes, very common problem when the main part of the pump is worn-out (head & rotor assembly). It's been a big problem with military engines run on JP8 military fuel in hot weather. When warm. the pump can pass enough fuel to start when cold, because the parts fit tight enough. When hot, they expand, and the pump cannot overcome the internal leaks at cranking speed. It WILL often still run fine once it's going. Easy test. Turn the engine off (when warm). They douse the pump with cool water, but make sure you only do that with the engine OFF. Then, see if it starts. If it does, it's worn out.

Like I said, it's a BIG problem with military 6.2s and 6.5s. The Standadyne pump was a lousy choice for running on military fuel. That because it is a distributor pump and the distributor cannot handle low-lube diesel fuel. In-line pumps are MUCH more durabel and have no distributors.

If you look to buy a so-called "rebuilt" pump with an exhange price - read the small print very closely. Some shops will NOT give you your core-credit when they find out your head & rotor is bad. It is the most expensive part of the pump.

 

[nk14zp]

Sounds like its IP time.

 

[jdemaris]

One more thing . . .

So. I think my IP is bad but has any one heard of them getting heat soaked like a starter?

I forgot to mention that somtimes, with a worn head & rotor - you can work around the problem by #1 getting the engine cranking speed faster, and #2 turing the fuel adjustment up in the pump.

A 12 volt starter is designed to crank at 9 volts and a 24 volt starter at 18 volts. If you can raise cranking voltage by just one volt, it will spin MUCH faster. To do you, you need bigger batterys, cables, or maybe both.
6.2 normally cranks at 200 RPM and the injection pump only turns 100 RPM. Thus it only takes a little wear to render a hot pump useless at a slow cranking speed.

The 6.2 always goes to max fuel delivery when cranking. If you turn it up 1/16 or 1/8 a turn, it could make the difference from a no-start hot, to a good start hot. All depends on how worn.

 

[Cucvnut]

Thank you sir.

 

[MrBouncer]

So if you put cold water on it and it starts, the pump is worn out. If doesnt start anything special to get it started or just wait. What does the cold water do to the pump?