Fuel pump relocation questions, and other problems Options

[championgt1]

I finally got my car what I thought was running right. However after a half hour drive the car started to buck at around 3000 rpm. When I came to a stop the car just died. It would restart, but as soon as I gave it some gas it would just die. Acted like it was starved for fuel.

The TPS has been adjusted per the tech articale on pelican. The plugs look good, pump runs and is getting fuel to the cylinders. I thought it could be the fuel filter. This is where it gets strange. My car is a 74 which should have a small inlet and outlet. The filter is in its stock location but has a small inlet and a large outlet like the filters on a 75, 76.

The filter on the right is the replacement, the filter on the left came out of the car.



The fuel pump was relocated to the front at some point.

Couple of questions.

#1 Does anyone have pictures of a installation and did you leave the filter in the stock location?

#2 Should the filter be between the tank and the pump,not after the pump?

#3 The fuel filter that I removed was bulged outward. What could cause this?

I'm sure I will come up with more questions. Just a little tired right now.

[championgt1]

The lines coming out of the tunnel are in good shape. Another question is why are there two lines coming out of the tunnel? There is a small line and a bigger line. Is one of them a return line and if so which one is it?

This picture is of the lines coming out of the tunnel.



The big line had the filter on it. On the other side of the filter is a small line that goes into the engine compartment and feeds the #3 and 4 cylinders. The other line also goes into the engine compartment and feeds the #1 and 2 cylinders.

I pulled the carpet back in the passenger foot well to see if there was a acsess panel but I got not get the foam block out. I would have to break this into pieces to get it out. Any ideas on this?

[Cap'n Krusty]

The lines coming out of the tunnel are in good shape. Another question is why are there two lines coming out of the tunnel? There is a small line and a bigger line. Is one of them a return line and if so which one is it?

This picture is of the lines coming out of the tunnel.



The big line had the filter on it. On the other side of the filter is a small line that goes into the engine compartment and feeds the #3 and 4 cylinders. The other line also goes into the engine compartment and feeds the #1 and 2 cylinders.

I pulled the carpet back in the passenger foot well to see if there was a acsess panel but I got not get the foam block out. I would have to break this into pieces to get it out. Any ideas on this?

Let's clear this all up in one post. The filter is BEFORE the pump. ALWAYS. Metal ones, too. Metal filters from your FLAPS are not likely to be FI rated filters, so you want one from a BMW Tii. Dealer item, and readily available. The large line is supply to the pump, and there's a nice little step-down hose from the line to the filter. The 2-size fitting filter is larger on the outlet side (not the inlet), and isn't the same "larger" as the hard line anyway, so it won't work. The feed line goes from the filter to the pump, and from the pump the pressure line goes to the 3/4 injector rail. From there, it goes across the engine to the 1/2 side, ending at the fuel pressure regulator. On a 1.7 or 1.8, it goes through the cold start valve on its way across, right by the distributor. On a 2.0, the CSV is on a line from a tap on the 1/2 injector rail. From the FPR the return line goes across the engine on the rear side, down through the body and back to the tank. It's the smaller diameter hard line. On cars with the 3 fitting pump, the return line is joined by the pump return line in a "Y" fitting near the pump. There is no access panel from the interior to the fuel tank. That's probably a mandated safety rule.

On cars with a 2 fitting pump, the pump is located below the tank, behind a panel on the left side of the trunk firewall.. The tank has a smaller outlet than the earlier tanks, and has a 7.5mm line to the filter. From the filter, a 12mm hose goes to the pump, and a 7.5mm line goes from the pump to a 8mm hard line to the rear. Note that this is smaller than the same line on the earlier cars, so no adapter hose was used. They use a return line directly to the tank, with no "Y" from the pump.

Some people believe there is a vapor lock problem and move the 3 line pump to the front. That's OK, but you need to keep the order of parts intact, and run wires to the front from the existing plug under the car. I don't believe the problem exists, but what do I know.? I've only got 35 years experience on these cars ....

Good luck, The Cap'n

[zambezi]

The lines coming out of the tunnel are in good shape. Another question is why are there two lines coming out of the tunnel? There is a small line and a bigger line. Is one of them a return line and if so which one is it?

This picture is of the lines coming out of the tunnel.



The big line had the filter on it. On the other side of the filter is a small line that goes into the engine compartment and feeds the #3 and 4 cylinders. The other line also goes into the engine compartment and feeds the #1 and 2 cylinders.

I pulled the carpet back in the passenger foot well to see if there was a acsess panel but I got not get the foam block out. I would have to break this into pieces to get it out. Any ideas on this?

Let's clear this all up in one post. The filter is BEFORE the pump. ALWAYS. Metal ones, too. Metal filters from your FLAPS are not likely to be FI rated filters, so you want one from a BMW Tii. Dealer item, and readily available. The large line is supply to the pump, and there's a nice little step-down hose from the line to the filter. The 2-size fitting filter is larger on the outlet side (not the inlet), and isn't the same "larger" as the hard line anyway, so it won't work. The feed line goes from the filter to the pump, and from the pump the pressure line goes to the 3/4 injector rail. From there, it goes across the engine to the 1/2 side, ending at the fuel pressure regulator. On a 1.7 or 1.8, it goes through the cold start valve on its way across, right by the distributor. On a 2.0, the CSV is on a line from a tap on the 1/2 injector rail. From the FPR the return line goes across the engine on the rear side, down through the body and back to the tank. It's the smaller diameter hard line. On cars with the 3 fitting pump, the return line is joined by the pump return line in a "Y" fitting near the pump. There is no access panel from the interior to the fuel tank. That's probably a mandated safety rule.

On cars with a 2 fitting pump, the pump is located below the tank, behind a panel on the left side of the trunk firewall.. The tank has a smaller outlet than the earlier tanks, and has a 7.5mm line to the filter. From the filter, a 12mm hose goes to the pump, and a 7.5mm line goes from the pump to a 8mm hard line to the rear. Note that this is smaller than the same line on the earlier cars, so no adapter hose was used. They use a return line directly to the tank, with no "Y" from the pump.

Some people believe there is a vapor lock problem and move the 3 line pump to the front. That's OK, but you need to keep the order of parts intact, and run wires to the front from the existing plug under the car. I don't believe the problem exists, but what do I know.? I've only got 35 years experience on these cars ....

Good luck, The Cap'n

Not to be argumentative but why would the metal filter have to be FI rated. they are not under pressure in this arrangement. I could see them needing to be FI rated if they are like a GM vehicle mounted on the frame after the in tank pump and under 40 - 60 PSI, but mounted on our 914's they are under gravity feed from the tank. In my thinking you should be able to use any good quality filter, or am I not seeing something?
JIM