Lost Prime

[Barry Rooker]

Just a reminder about something I forgot and it cost me $500.

We'd been parked in Indio for nearly four months and it was time to head for home. But the engine wouldn't fire. It would crank but not fire. Having had the same situation some years before I quickly diagnosed this as crank position sensor failure.

I had watched the tech change the sensors years before & I had a set of spares. but I couldn't find one of them on the engine. I even took pictures to help look behind the engine air compressor to look where I couldn't see. After failiing to find a local mechanic who could come & install my parts, I located a road service mechanic. He came, saw that there wasn't fuel visible in the filter, he loosened the air tubing, shot in some ether & fired it right up! I had failed to check the filter and too quickly came up with my incorrect diagnosis.

Then I had also failed to recall that our wonderful Newells are equipped with a priming pump at the fuel tank. I could have re-primed the filter on my own. What a dummy!

Don't forget that priming pump.

[rheavn]

That is a good reminder Barry.

Thanks................

[RussWhite]

I would like to understand the priming pump in more detail. My Detroit Manual indicates that the fuel filter is between the tank and the fuel pump. That means that the filter is normally under vacuum as the fuel pump pulls fuel from the tank and on through the filter. Is it correct to assume that all the fuel passes through the priming pump? If that is the case, then when one pumps the priming pump it will pressurize the fuel downstream of it and push the fuel toward the engine. For fuel to flow it must displace air or fuel. If the cap is off the filter then fuel would be pumped into the filter. I have tried that, and I am able to see the fuel level rise in the filter.
What happens if the fuel pump has pulled air into the lines between the filter and the pump, or even moved air past the pump and onward to the injector? Is there a place you let this air escape as you pump the priming pump? Thanks to anyone that knows..... Russ

[tuga]

Russ,

I am a long way from being a diesel mechanic, but I have air locked my generator when I changed the fuel filters. I was told to "crack" the last injector from the fuel filter while cranking the generator. As diesel fuel starts to spue out I tightened down the injector with a crescent wrench.

I would assume that the same thing would have to be done on the series 60. I would think that instead of cranking the engine you could just pump the priming pump until diesel spued out of the last injector that was "cracked".

I know that all air has to be removed from the system.

Running a diesel engine out of fuel and air locking it is a big deal! Don't ever let your fuel gauge get too low. It's a real mess!

Hope this helps!

[rheavn]

Tuga,
My genset has a priming switch in the genset compartment to prime the system after changing the fuel filters. Mine is on the right side, mounted toward the front, down low and marked with the typical black Newell signage. If you don't have one it will again reinforce that no two Newells are alike.

[encantotom]

my genset has the priming switch as well on the 2002. on the 90 it does not have it.

my handle is missing from the primer on the fuel tank.

i have to find or make one. forgot to ask when i was at newell.

exactly how do you use the primer knob?

tom

[RussWhite]

Tom,

My questions does concern the priming pump for the series 60. What little I know I learned from Tuga. Once you get your knob, screw on in like a nut, then while truning the other way, but not enough to loosen it and turn it off again, wiggle on the knob and pull. When you get lucky it will pop out a few inches and when you push it in, it will spring back out. It pumps fuel to the Davo fuel filter and if it is closed, will try to pump it farther if there is a path for flow. I am looking for how/where to open the fule circuit to let the air out as you pump in the fuel. You may be able to source the knob locally when you get back home. I figure it is better to have a plan for how to prime the S60 just in case. Russ

[rheavn]

Russ,
I'm not a diesel mechanic. In reading my DD series 60 service manual the only thing that I have seen that would remove air after the Davco fuel filter is the Pro-Chek check valve. It is installed on the right side of the motor between the fuel pump & the injectors.

From the manual: "An optional PRO-CHEK check valve that removes air from the fuel supply line may be installed between the secondary filter and the cylinder head. The fuel flows to the injectors in the cylinder head through passages intregal with the head. Surplus fuel exits at the rear of the head just above the inlet, through a restrictive return fitting which maintains fuel pressure in the system and returns back to the fuel tank."

[RussWhite]

Steve,

I also have the Davo Pro-Chek installed. I found the same information you quoted, but nothing more. Even the Davo website is silent on the product. There are a few mentions of the product on the web, but nothing about how it might actually work. There are even some comments from "diesel mechanics" suggesting it does not work and they just remove it if ever a hose leaks or there is a fuel issue. I think I will send an email to Davo and ask for additional information - it can't hurt. If I get anything I will post it in our new files section. It may be invovled with the removal of the tiny fuel bubbles that Davo says are normal in any fuel filter that operates under a vacuum. More later.... Russ

[Richard and Rhonda]

The pro check works. I learned this when I tore into my engine. It will self prime. On the Davco filters, pour some new ATF in through the top hole and you may have to crank it three or four times but it should start right up.

On the gennie's, do as Tuga said, crack an injector banjo bolt, hit the toggle until you make a diesel mess, tighten the bolt, and crank it. Well do as he said, but I use the right wrench, not a Crescent. Just messing with you Tuga.