best fuel pump

[PMMessina]

I sent an email to roadtrip with this question,because he says use the Bosch pump when you need to replace but I haven't heard from him.

He must be, on a roadtrip? I need to replace the fuel pump in my 78 spider. The IAP catalog shows two Bosch pumps. One is reasonable at $160 the other must be gold plated at almost $500. Which one is the right one? Thanks

[Roadtrip]

Phil - I sent you a PM answer on the 17th and it went to my outbox, so you may want to check your inbox again. In case it got deleted or something, here's a cut and past from the PM.


Phil -
I can't remember . . . . what were the symptoms that your car was exhibiting to make you think your fuel pump is bad? No sense in replacing an expensive part without knowing that's the problem for sure.

As far as replacement pumps go, I think the direct replacement is the 3 outlet pump. However, that pump costs almost $500 which is WAY too much, when the Bosch pump (IAP #90103) from the L-Jetronic Alfa's works just as well, costs much less, and lasts longer than the older style Bosch/SPICA supply pumps. A couple of years ago my 74's old-style Bosch supply pump quit and I replaced it with an L-Jetronic pump. Works great and is what Wes Ingram and a lot of other knowledgeable Alfisti recommend. However, to fit the newer pump you have to make three slight modifications to your year Spider.

1. Block off/remove the pressure relief port line from the old 3 port pump to the car's fuel return line. This is as simple as putting a bolt in the hose with a hose clamp, or removing the "T" fitting in the return line and replacing it with a straight-thru pipe.
2. The new L-Jetronic supply pumps are slightly smaller in diameter, so you have to use a piece of rubber or something about the thickness of belt leather to take up the space so the pump mount clamp will hold it tight.
3. The electrical connections are ring connectors vice the spade connectors on the old pump. Either replace the wire ends with rings, or install male spade connectors on the pump terminals.
4. Modify the injection pump outlet restrictor to 1/16" vice the present 3/32". To do this, just unscrew the front fuel fitting (the fuel outlet), solder up the hole with ordinary elecrical solder, then redrill with a 1/16" drill. The reason for this is the L-Jet supply pump is slightly lower in volume than the old-style pump. Narrowing the restrictor to 1/16" will ensure you get good line pressure (about 15 psi) with the alternator running and about 10 psi on the battery only. If you don't narrow the restrictor you may experience a low pressure fuel light on battery only and only about 10 psi with the alternator running.

Now that said, when you do this mod with a later 70s Spider, you're doing away with the pressure relief valve integral to the 3-port pump (although there is a high pressure relief built internally in the L-Jet supply pump). With the 1/16" restrictor, however, you won't be able to get more than 18 psi or so in the line anyway. The injection pump likes about a 15 psi feed.

These mods may sound like a lot, but they are really very quick and easy, and you won't have to worry about the fuel pump for probably the rest of the car's life. Of course, the rest of the fuel system is just as important, especially NOT having a rusty, dirty fuel tank.

Do you have the SPICA Fuel Supply System Guide that I wrote last summer? I've emailed it to quite a few guys on AlfaBB. It has a complete description of the fuel supply system and troubleshooting guide. Let me know if you'd like a copy and I'll email it to you if you send me your address. It's in MS Word format.

Cheers.

John