Fuel Pump and Filter

[cutchaguy]

I'm assuming that fuel pumps are all different and all pump fuel at different pressures, correct? On the underside of my car, I noticed one shiny part and that it was not anywhere close to OEM or replacement part.

If you don't have a tool to measure pressure in the fuel line, it is just better to replace it with something you know should work?

Pic below...check out the AWESOME wire connectors.





The fuel filter looks like it is held in place with a bracket and some hose clamps. This should be an easy fix, but I'd appreciate advice before I get the tools out. (Probably should order a new fuel pump and do all at once.)

[launieg]

I have an '81 FI spider too.

It is a little hard to tell from your photos, but I think you might be missing the entire bracket that holds both the filter and the fuel pump (in a line). It also looks like they are in the wrong order (if I see the photo correctly). The line should come from the tank, go into the pump first, and then into the filter, then up to the engine compartment. I know, it seems wierd, but that is the correct order.

Edit: No, I change my mind; the order looks correct, now that I look more closely at the photos.

Another edit: I think I see part of the original bracket just above the pump in the first pic. So if you get the correct pump, it should mount onto that bracket, much like the filter does. A short and straight piece of hose connects the two items.

The filter looks stock. It's cheap to replace. Get one. The pump (which looks like it is not mounted to anything in your photo) might be an okay substitute. If you are not having fuel issues, then it is probably okay. If it has make and model number on it, look it up online and see if it has the volume and pressure you need. I've found that many pumps will work fine. I have four different bosch pumps and they all produce enough volume and pressure. If you look hard, there are some bosch pump tables that show the various specs.

Edit: your pump is very small - almost half the size of a stock (bosch) pump. Probably puts out less than needed.

I suspect you also might have a kink in that hose between the pump and filter. But that will go away when you rectify things.

Ideally, you should buy a replacement pump (search this forum for advice - people have bought good ones, new, under $100). Absolutely, buy a new (proper) filter, and also try to get a bracket. If you can't get a bracket (used), you can fabricate something quite easily. Someone might have a photo handy, or I could take one. It is a simple setup.

You don't like those connectors? You won't want to see mine!

[cutchaguy]

It is kinda hard to see, but it does go from Tank, to pump, to filter. The filter has something like a "c" clamp with only one bolt attached. I have the replacement filter on stand-by. I look at things like the wire caps and I start scratching my head.

I've yet to come across a procedure for replacing the filter itself, but I have a guess:
1. pinch off fuel lines before and after filter.
2. unscrew old clamps and throw away.
3. pull off fuel lines from filter
4. put on new filter, making sure the arrow points the correct direction and secure with new hose clamps
5. unpinch fuel line

Do similar with the fuel pump? It has been suggested to me that I use a vice-grip to pinch the fuel line. That just seems like a bad idea...maybe have a plug of some sort on standby and use that instead? Also, have a pan to catch fuel and wear protective eyewear, gloves, and mask in place.

[launieg]

I just relieve the fuel pressure (in my car it drops to zero overnight anyway). There is a prescribed process for this, but the concept is essentially to slowly relieve the pressure. (Be careful.) I don't like to pinch the hoses. The rest of your steps are correct.

The "c" style clamp around the filter should have a mount at each side (two bolts, that is) and the same for the fuel pump.
A rubber sleeve fits around both items to reduce vibration, etc. I lost one and replaced it with a section from an inner tube, wrapped around the pump.

[launieg]

I should add that you don't want these pumps to run dry. they rely on fuel for lubrication and cool running. There is an uphill turn from the tank to the pump, so it takes a bit of running to prime the pump. That is the danger period (running dry). So I'm thinking it might be wise to pinch off the line just before the pump, so that fuel remains in that line. But I've not had a problem drawing that first flush of fuel into the pump. Someone else might have a suggestion on this point.

[launieg]

It's a terrible picture (sorry) but you can see the fuel pump on the left and the filter on the right, and you might be able to make out the two clamps, which mount to the single bracket that holds them both.

[cutchaguy]

If I would have just waited a couple of hours, the new manual I ordered had the procedure outlined. The Haynes book didn't have it, but I got the shop manual from Brooklake Books (ISBN 1855200791) and a lot of my questions are being answered and most of the pictures in it are recognizable! It is the 9th ed. published in 1991.

It's the first book I've seen that shows the Throttle Plate Heater in a diagram!