Fuel feed pump issue OR not?

[esarratt]

Thanks again for the help! This has been an adventure.

I have been reading my Volvo workshop manual and it mentioned making sure the fuel feed pump (aka lift pump) "squeaked" when you press the manual lever (the bleeding lever).

Mine does not squeak. At all.

Squeaking indicates that the diaphragm inside is in good working order.

First of all, I am going to ignore it (for now) and not rebuild/disassemble it.

What I want to know is has anyone recently rebuilt their MD7A fuel feed pump? The pump for the MD7A (and many of the older Volvos) is a Pierburg, model number 15672.

The reason I ask is because they don't make parts anymore for this model and I have been unable to locate a rebuild kit, or anything, for the fuel feed pump.

[model 10]

Toss it in the garbage. Get a modern electric pump. Even if it ever did fail, it would still be way more dependable than the stupid mechanical pump.

[Shawn67]

My life pump doesn't squeak when you press the lever but it works fine. You can see if it is flowing by trying to bleed your system. The pump has a fairly long throw, if you aren't getting that turn the engine a quarter of a turn or so and try again. Open the bleed screw on the engine filter and see if you get any fuel out of that. Screw 1 on the injector pump is will also freely flow fuel from the lift pump.

On my engine the lift pump was only leaking fuel out the injector pump screw 1. However it turned out that my fuel pickup had stainless steel wool mesh in it that was very clogged up. Taking that out made the lift pump flow much more fuel.

Shawn

[Doug Brown]

They do make a rebuild kit but it costs more than the pump.

They also make a new design of pump which costs $$$ (it is a Volvo after all).

To get it to work on the engine, you either need to buy the "specially formed" fuel pipe to get everything to hook up (fuel pump to fuel filter), or buy some pipe fittings so you can install fuel line hose.

The special fuel line costs nearly as much as the fuel pump - ie $$$

You'll have to hunt around, but you can usually find used fuel pumps. They are all the same from the MD-7 thru the 2000 series of engines (2001, 2002, 2003). Early VW's used the same fuel pump as the Volvo, but again getting hard to find.

Having a small 12vdc electric fuel pump (as mentioned in another post) is another possibility. It's big advantage is that it will reprime the entire fuel system in less than a minute after changing fuel filters.

If you go electric, make sure that you have a fuel filter installed BEFORE the electric pump to strain out junk. Plump the pump so it feeds into the original fuel filter on the engine - helps keep even more junk out of the injectors.

You can use a cross reference chart and find non-Volvo fuel filters that will replace the Volvo filter on the engine. Much cheaper.

And wire it correctly so turning off the key kills the electric fuel pump in case of fire.

[DougR]

Repair kits for the fuel feed pump are #834255. Check around on line....

Replacement pump is #21134777, and requires a longer fuel hose # 840001, or make your own hose.

Because your engine wasn't fitted with a primary filter the pump is probably full of junk and that's why it doesn't "squeek".

DougR

[a64pilot]

One issue with mechanical fuel pumps is sometimes if the diaphragm ruptures, it starts leaking fuel into the oil. If you regularly check your oil level if it starts increasing, suspect the fuel pump.
Oil diluted with fuel isn't as good a lubricant of course, but a very real danger is if you get enough fuel in the oil, the engine will run away and the only way to stop it is to choke it off by blocking the air intake. Do not use a body part like your hand to do this though.
I'd can the mechanical fuel pump, go electric and carry a spare. I think about $50 for a decent electrical fuel pump.

[DougR]

One issue with electric pumps is that when your battery dies, so does your engine. You can't even hand crank it to start. At least with an MD7 you can easily start it with the hand crank, even if the battery is toast. (Assuming you have a mechanical fuel pump)

DougR

[model 10]

Originally Posted by DougR

One issue with electric pumps is that when your battery dies, so does your engine. You can't even hand crank it to start. At least with an MD7 you can easily start it with the hand crank, even if the battery is toast. (Assuming you have a mechanical fuel pump)

DougR

They use so little power that even a trickle from solar will keep it running.

[GrahamHO]

Any reason to not fit an electric pump before the mechanical? Naturally both after a filter.
Then there would be electric to prime with. Not specifically Volvo as Yanmar is similar in. That department.

[model 10]

Originally Posted by GrahamHO

Any reason to not fit an electric pump before the mechanical? Naturally both after a filter.
Then there would be electric to prime with. Not specifically Volvo as Yanmar is similar in. That department.

Sure but if you have a leak in the mechanical pump, you are still screwed. Another reason to ditch it.

[DougR]

Electrical or mechanical, both have potential pitfalls. Pick your poison....

DougR

[NCSailor]

I had a fuel leak from my lift pump so replaced it with a new one. Biggest issue was getting access. Cut a access under my chart table. All is good now.

[esarratt]

Originally Posted by Shawn67

My life pump doesn't squeak when you press the lever but it works fine.

Yeah. That's what I figured. I know not to take things apart like that just because the manual says so.

Thanks to everyone for the information.

[esarratt]

Originally Posted by Doug Brown

They also make a new design of pump which costs $$$ (it is a Volvo after all).

Thanks for the information.

Originally Posted by Doug Brown

The special fuel line costs nearly as much as the fuel pump - ie $$$

Yeah. I'm starting to see this theme with Volvo.

Originally Posted by Doug Brown

You'll have to hunt around, but you can usually find used fuel pumps. They are all the same from the MD-7 thru the 2000 series of engines (2001, 2002, 2003). Early VW's used the same fuel pump as the Volvo, but again getting hard to find.

Having a small 12vdc electric fuel pump (as mentioned in another post) is another possibility. It's big advantage is that it will reprime the entire fuel system in less than a minute after changing fuel filters.

If you go electric, make sure that you have a fuel filter installed BEFORE the electric pump to strain out junk. Plump the pump so it feeds into the original fuel filter on the engine - helps keep even more junk out of the injectors.

You can use a cross reference chart and find non-Volvo fuel filters that will replace the Volvo filter on the engine. Much cheaper.

And wire it correctly so turning off the key kills the electric fuel pump in case of fire.

Thanks for the information. I saw the marked resemblance between my pump and the VW, Porsche and Mercedes pumps. At this point I am going to clean out the filter and use the pump as is, but if she won't run I will look into other electric options.

I know that the pump is not that big of a deal from Nigel Chandler who noted that you can "limp home" with a gravity fed diesel system if your pump fails.

[esarratt]

Originally Posted by DougR

Repair kits for the fuel feed pump are #834255. Check around on line....
DougR

$150. OW! That won't be happening if I can help it. Thanks for the info though. It is saved in case I need it in the future.