Fuel Pump Zombie

I never wanted to have to ditch the 2.0L Type4 engine in the bus. But the scarcity situation for the Type4 engine does not make it easy to keep it: buckets of NLA parts, astronomical prices for those that remain, and a wide market of grifters who will pass a piece of junk off on the unsuspecting.

So the first order of business, with the Bus safely stored under a weather-proof cover, is to discover whether I actually have an engine...or a boat anchor. If I have a running engine, then I can at least shove the body around under its own power while I get other portions of its refurbishment dealt with, and at some point, sell the engine and Engine Management System complete, 'as running' to offset the cost of conversion. Does it run, is question #1.

But first, there are protocols for restarting an engine which has sat, unmoved, for over a decade. In this case, the whole vehicle has sat since Clinton was in office.

Here's the planned procedure for just such a circumstance:

1. Disconnect the Fuel pump from primary harness, drain-o the insides with Carb Cleaner, then give it a drink from a jerry can, and finally give it power to see if it will even turn.
2. If the fuel pump will run, connect a battery and pull the spark plugs.
3. Replace the oil in the case, and put in a new filter.
4. Use the starter to turn the engine while performing compression and leakdown tests. (If the valves or the rings are junk, it will show here.)
5. If I don't completely fail the compression and leakdown tests, disconnect the Fuel Pressure Regulator, and purge the fuel ring, possibly leaving it full of solvent for a while to loosen the fuel varnish.
6. Reconnect the FPR and the fuel pump, rig the pump to drink from the jerry can of clean gas rather than the goopy horror in the fuel tank.
7. Set the fire extinguisher within reach of my assistant.
8. Say my "Hail Marys" reconnect the coil, and turn the key.
9. Rejoice or diagnose, as required.

So, Procedure #1: I jacked up the left rear, pulled the LRr wheel, clamped off the outlet from the fuel tank and got the fuel pump out. A lot of standing on my head and finding sockets I haven't used since my Beetle left town 18 months ago.

Considering how long Old Ferd' has been sitting and growing varnish in the tank, I expected the fuel pump to be a gummed up total loss. Depending on who's selling and whether it is genuine Bosch, this pump style can run from $100-$250 for a replacement. So I darn well went through the exercise of testing and cleaning the pump.

I was given an AGM 12v battery for a wheelchair from my father (who uses one) and it is only 20 months old. Just right for kicking around while bench testing components. And it sure beats dropping $100 on an SLI battery !

A little bit of horrible smelling gas came out of the pump, and I've been reeking of it all day. I set it up with the outlet down and the inlet up, filled the body with carb cleaner, and left it to cook for about 90 minutes. I came back out and applied power to it...nothing.

Well, nuts. ~$150 for a fuel pump? I started to monkey with it, assuming I couldn't do any damage to what was already 'broke.' I swapped the polarity and got...nothing. And again,and again.

Then I saw a lazy .burp. at the inlet. (the outlet was pointing down into a funnel to a catch can.) Either there was movement in there or some spaces were just now getting the solvent. I dumped it out. And got chunks of varnish. Refilled, I did the polarity swap back and forth again, same thing, occasional burps at the top inlet. Body of the pump was quite hot now. I tickled the outlet with the end of a nail and got a dribble with no power.

The Bosch 'roller cell' pump, used by Volkswagen from 1975 through the late 1980s.

I kept changing solvent and polarities for about 20 minutes. Sudden the pump gave a gurgle and spat out the outlet all of the solvent in the body. Up until then, there had been nothing come from the outlet with power applied. I loaded it up with solvent again, reapplied power, FOOSH! empty again! Success!

I set it up with inlet and outlet hoses to 1 gallon of clean gas, and ran that in a loop for about 90 minutes. I think the patient is going to pull through!

So just in diagnostic costs, I've already dodged $250 worth of expense, only going in so far for $25 in 2 meters of ethanol resistant SAE J30r9 fuel injection hose and $4 of Carb Cleaner.