Fuel problem

[siteunseen]

I haven't taken one apart but Blue has.  

 

http://atlanticz.ca/zclub/techtips/fuelpump/index.html

[EuroDat]

Here is my fuel pump. It will give you an idea what it looks like inside. Its a pretty simple design. Make sure you note the order the parts coma apart so you can rebuild it in that order.

The 2nd photo is a calulation for the o-rings I used on my pump. If you need new o-rings make sure you use Viton or NBR material.

I prefer NBR because of the hazards associated with viton if exposed to very high temperatures like fire. You never know...

Chas

[Zed Head]

Nice pictures.

 

I wouldn't be surprised though if he had an aftermarket pump.  Have to crawl under and see.  Running the pump backward might break it free if it's jammed.  Not sure if the stock pump does this, but the aftermarket pumps run fuel right over the electric motor.  So moisture and crud can screw that up also.

 

A new aftermarket pump is about $100 at the parts stores.  Looks like other places are having sales though.  The Airtex E8312 is a common one.

 

http://www.amazon.com/Airtex-E8312-Electric-Fuel-Pump/dp/B000DT7Y7K

[siteunseen]

I paid $250 for the Bosch replacement, wasted money because the that was on it was good. That was before I found this forum. Fastwoman & Z Train got me fixed up.

[FastWoman]

IMO there's nothing like the Bosch replacement.  I've read of too much trouble with aftermarket pumps.

 

And yes, the fuel flows right through the motor to cool it, so there is potential for it getting rusted/stuck.  Nice idea about trying to budge the thing with reverse polarity!

[Zed Head]

If you're on a budget, a wrecking yard Ford F150 pump might be an option.  They're factory issue Bosch pumps.  They have the long cylinder form though, like the Airtex.  Late 80's / early 90's BMW's use them also.  Many of the EFI sysems I've dinked with in the yards are still pressurized with fresh fuel, even though they drain the tanks.  I'd rank quality as new Bosch > used Bosch > parts store Airtex.  I wouldn't buy a new Airtex today although the one I have is still going strong, after about 5 years and maybe 50,000 miles.

[S30Driver]

The 77 has the fuel pump safety switch in the AFM, it was changed in 78 as Sarah has described.

 

You can jumper it temporarily to make sure the contacts are not the problem, & check for power at the pump with the starter solenoid disconnected and key at start.

[kjphilippona]

Ok, got up early before the south Alabama sun makes it unpleasent to be out! I made a jumper wire, removed rear wheel and discoved that the fuel pump looks like it has already been replaced with an aftermarket unit. I have attached a picture to get your opinion. I removed the nylon nuts so that i can access the terminals, being careful not to get them crossed so as to get them on the correct terminal. I could not tell what was ground and what was pos. both were black.I slipped the ring terminal on the rear post and touched the front post and it sparked, i assumed that was ground. i then attached the front terminal and touched the rear terminal "nothing" the pump did not spin. i take it that this indicates i need a new fuel pump. i also checked the pos. wire from the battery that goes along the firewall and it had 12v.

[Zed Head]

Hard to tell what exactly you jumped, and connected.  Did you jump the AFM switch, or did you run a jumper from the battery?  If you jumped the AFM switch, then you had power at the pump and grounding the negative terminal should have turned the pump.  If you ran a jumper from the battery, then you'd want to be sure you had a good circuit through the pump to ground.  You said you took both wires off of the pump but it's not clear what you reconnected after seeing sparks.

 

If you have a small mirror or can get your eye n the right place, I think that the + and - are molded in to the plastic by the pump terminals.  Also, one is smaller than the other, but I can't remember which is which.

[kjphilippona]

I jumped directly from the + of the battery. With both ring terminals on there original post, the treminal closest to the front of the car, sparked when i toched the jumper. I then touched the other post and nothing happened.

[kjphilippona]

Both terminals are the same size, too much crud to see any + or - marks.

[Zed Head]

Since you have a wire directly from the battery, you can test the pump separately from the rest of the harness.  Make another shorter jumper wire and connect it directly to the car body.  Then disconnect both wires from the pump, connect your positive wire from the battery to one of the terminals, doesn't really matter which one, then touch the wire that's connected to the body to the other pump terminal.  You should see a spark, showing that the circuit back the battery is complete, through the pump motor.  The pump will either spin or it won't.  If it doesn't, you might as well tap on it with the wires connected to see if you can break it loose.

 

I think that the ring terminals on the wires are different sizes.  Positive is small.