Confession: MFI pump not correctly stored

[Scott Clarke]

Time to fess up. My MFI pump has been left sitting for three years now. I thought my motor would be down for just three or four months. Ha! Anyway, it's time to get it going again. So, how bad is it? Should I run some calibration fluid through it? Do I just have to bite the bullet and send it to Gus? The PO had the pump rebuilt about 5 years ago (and almost no miles since). The MFI worked perfectly when the car last ran following my CMA diligence. Any thoughts?
-Scott

[Tyson Schmidt]

Check to see if the main rack moves freely. If not, try filling the pump with some ATF. The high detergent content in the ATF may help free things up.

[Scott Clarke]

Tyson-
Thanks for the tip. I operated the control lever last night, and it seems to move pretty well. The return spring moves the lever back to within 10% of rest position quickly, and the rest of the way MOST of the time (but slowly). After operating the lever repeatedly it seemed to free up a little. Should I put some ATF through it? Do I pour it in the fuel intake and then rotate the pump drive cog clockwise?
Thanks again,
-Scott

[Rot 911]

MFI pumps which have been allowed to stand idle for long periods with oil and fuel in side them often suffer from binding or sticking control racks and gumming up of fuel galleries, as well as possible seizing of internal components of the pump and regulator. To overhaul such pumps, fill fuel inlet with carburetor cleaner (or methyl alcohol), Remove plastic plug above driving cog (back of pump housing) and insert the blunt end of a plastic biro or similar non-metallic object into the hole to contact the control rack. Using slight pressure, gently push against the control rack while turning the drive cog clockwise. This is best done if the MFI pump is clamped to a work bench. Push and release the biro as you rotate the cog. Repeat this procedure until the rack moves freely with the MFI camshaft using very little pressure on the biro. You may have to add more cleaning fluid and repeat the steps several times. If, after several attempts, the control rack is still stuck, it is time to send the pump off for a rebuild.

[svandamme]

mine was stored just like that for say 20 months
it wasn't stuck, still worked, but picked up a habit for beeing overly rich to the point the engine wouldn't rev no more... the idle circuit had gone dead and the only way to make it work was with main open wide, whicn meant to rich in upper revs... uncurable, had to have it revised by Koller...

[BURN-BROS]

What Tyson said...If ATF doesn't work try Diesel fuel.

Best of Luck!

[Early_S_Man]

Scott,

B-12 is the preferred solvent for cleaning a gummed pump ... check the Pelican MFI Tips page!

Drain all gas, oil, or ATF out ...

Tape up all of the fittings and clean the external areas of the pump with acid brushes, spray carb or brake cleaner ... blow off with compressed air!

Then, remove all of the solenoids [and thermostat] and fittings and bag, along with sealing rings ... and remove all three cover plates, and bag them with hardware and the rubber gaskets. Next, find an appropriate-sized metal pan at least 6" deep so it can be completely submerged in Berryman's B-12 Chemtool. Completely cover pump with B-12 ... while wearing HD solvent proof gloves ... turn over pulley several times to get solvent into all passages

Allow to soak for at least 24 hours with the pan covered by a larger pan or cardboard box ... raise pump up, and work the pump rack and turn the cogged pulley over a few times. If the rack return movement has improved, submerge again and allow to sit for another 24 hours. If solvent is discolored & dark, or dirty ... drain and refill with clean B-12.

When rack movement is free and ready to finish cleaning ... blow off/out with compressed air.

[Randy W]

So how do you correctly store an MFI pump?

[Lukesportsman]

I'm glad you asked, Randy.

Is there a way to correctly store if mounted to an engine? I'll be removing my 2.7 MFI down the road and it may sit for sometime before it goes into the next running project. Can this be done safely...I really don't look foward to an engine swap just to keep her lubed

[pwd72s]

Originally posted by Randy W
So how do you correctly store an MFI pump?

Darned good question. I've heard a good way to store some parts is in a bucket of motor oil. Don't know about MFI pumps though.

[svandamme]

it's in the mfi docs section somewhere
not motor oil though

[Rot 911]

Storage — pumps which have been removed for the car should be flushed and sealed prior to storage. Kerosene is suitable for flushing out the pump and regulator housing. Pour in through the fuel and oil inlets while rotating the drive shaft (cam) clockwise and turning upside down. You may also remove the side cover and governor cover to add more kerosene. Wipe down housing with a clean lint-free cloth when finished. The pump and governor must now be treated with calibration fluid in order to preserve the delicate internal parts. Calibration fluid (eg. Bosch # 5 701 301 725 or equivalent) is only available from specialist fuel injection shops and is expensive. About 1/2 litre should be sufficient. Repeat the sequence as per the kerosene cleaning and drain well. Replace all covers and ensure a coating of calibration fluid remains on the outer casing as well. All hose and fuel line vents should be plugged (plugs available from fuel injection shops) and the pump stored in a sealed plastic bag in a moist free environment at room temperature. Quarterly inspection and clockwise rotation of the drive shaft cam is advisable.

[304065]

Excellent description Kurt. The storage instructions are in the back of CMA.

If it were me I would pickle the thing in a bucket of Marvel Mystery oil.

[Randy W]

Thanks, Kurt and John!

[Scott Clarke]

Thanks to everyone for the input. Last night I removed the plastic plug and operated the rack using the blunt end of a plastic pen as described by Kurt above. The rack moves about 1cm before coming to a positive stop. The rack returns to its rest position promptly by itself. The amount of pressure needed to move the rack seemed to be solely a function of the return spring pressure. We have seen a variety of remedies for disused pumps. Is the rack movement I'm seeing indicative that my pump is OK, or should I not take any chances and do the full-boat treatment Warren describes, or a more moderate approach?
-Scott

[Rot 911]

If it was me, I would do a thorough cleaning now rather than hoping everything works ok once you get it back on the car. And once it is on the car and assuming it doesn't work ok, the only way to clean the MFI will be to remove it. Nice thing about a thorough cleaning is there is a much better chance that the MFI pump will be working 100%! It really is quite simple to open up and clean per Warren's instructions. I would also take the time to remove the thermostat disks and clean the disks and rod. Just make sure you reinstall the disks in the correct order and orientation. Taking a picture before disassembly is never a bad idea.

[bavaria911]

Kurt and Warren,

Thanks for the great post. I have a beginners question. Last month I bought two MFI 2.4 systems, Pump #015 w/ T-bodies and stacks and pump # 013 w/ T-bodies and stacks. Iwant to use the 2.4S system on my car but had a good deal on both...figured the twinparts will help.
My question is while I inspected the rack for both pumps I pushed the rack in and both returned nicely, but on the 015 pump I could push the rack in further than the 013 pump. Maybe twice the distance. Is this due to calibration or difference in pumps or is there a hidden issue...dirty or sticky parts?
I plan to clean both as you two have recommended, but wonder why the difference.
TIA
Bavaria

[bavaria911]

Anyone answer please?

[elflamo]

Like asked by Lukesportsman on the 23rd, I'm very interested to know how to 'store' the MFI pump while it's still on the engine/in the car. Any thoughts?

Thanks

Dennis