Engine/Transmission (1994 - 1998) P 7100 overflow valve

[Jeffrey Howes]

Does anyone know the drawbacks or danger/damage that may occur from removing an overflow valve and plugging it, has anyone ever tried this before?

 

[Missouri Mule]

If you plug the return fuel line coming out of the. p7100 the engine won't run. To much pressure. Do a fuel pressure test. .



The ofv regulates the pressure in.

P7100/fuel system.

 

[The patriot]

Your lift pump probably wont last long.



Edit:

I got one of these:

http://www.ebay.com/itm/Cummins-12V...Parts_Accessories&hash=item3385e3d5c3&vxp=mtr

 

[gtobey]

If you get it bled out, it will run, and you may or may not see much difference in performance unless you are running under full load with wide open throttle. The governor will work to keep the rpm's normal, but you will lunch the supply pump eventually. But the major damage to the injection pump will occur because of a heat buildup and pressure spikes in the gallery of the pump because there is no relief of that pressure out of the return. Most of the fuel pumped into the gallery of the P series pump is returned to the tank as cooling to the plungers & barrels. If they can't cool down they could seize or the excess pressure spikes can ruin the pump housing where you could have external fuel leaks or internal fuel leaks which means fuel dilution. Some old time drivers of Mack trucks with Bosch P pumps used to put vice grips on their return lines to increase fuel pressure within the pump. The pump housings would crack between the plungers and start fuel leaks all over the outside of the pump, and some cracked internally below the plungers and fuel got into their engine oil... not a good thing... .

 

[hsmith]

I like this^^^