1975 and 1976 electric fuel pump poll

[westy64]

Hello,
could the owners of 1975 or 1976 cars with stock wiring tell us how (and when) the pump runs ?
is it when key is on ?
when key on start ?

regards
jean

[donerehart]

I have a 76 and my fuel pump comes on when I turn the ignition on before starting.
Don

[westy64]

Thanks !

[fergarelli]

Yep, my 76 does the exact same thing. Pump turns on when the key is moved to "on"

[gionetz]

My 75' Pump turns on with ignition

[rjkoop]

My 75' Pump turns on with ignition

I have an '81. Is it supposed to stop pumping once the pressure gets to 30 PSI? Mine slows but doesn't seem to completely stop. If it's supposed to stop what does the stopping? Does the pump internal know when it's at 30 PSI or is it a component at the engine end? I just want to ensure that the pressure isn't getting too high.

[redcars]

On a 81 FI the pump should not run unless the engine is running or the starter is running. The fuel pump on FI cars does not stop running with high pressure. There is a pressure regulator that regulates the pressure and the pump runs all the time the engine is running, but does not run if the engine is not running. If you fuel pump runs with the ignition on but the engine off then a PO has change the wiring,

[rjkoop]

On a 81 FI the pump should not run unless the engine is running or the starter is running. The fuel pump on FI cars does not stop running with high pressure. There is a pressure regulator that regulates the pressure and the pump runs all the time the engine is running, but does not run if the engine is not running. If you fuel pump runs with the ignition on but the engine off then a PO has change the wiring,

Ok. I'll check the wiring. I'd like it to be wired right. I read that the air flow sensor is what activates the pump. But I guess that isn't correct.

So the pressure regulator ensures that the pressure going into the fuel line is at the 39 PSI correct? So if the pump is going then where does the extra pressure it generates go? Does the fuel flow back through the return line to the fuel tank?

[rjkoop]

On a 81 FI the pump should not run unless the engine is running or the starter is running. The fuel pump on FI cars does not stop running with high pressure. There is a pressure regulator that regulates the pressure and the pump runs all the time the engine is running, but does not run if the engine is not running. If you fuel pump runs with the ignition on but the engine off then a PO has change the wiring,

Ok. I'll check the wiring. I'd like it to be wired right. I read that the air flow sensor is what activates the pump. But I guess that isn't correct.

So the pressure regulator ensures that the pressure going into the fuel line is at the 39 PSI correct? So if the pump is going then where does the extra pressure it generates go? Does the fuel flow back through the return line to the fuel tank?

Just to follow up the pump runs with the key in the 'on' position and the engine not running. I tried disconnecting the wide cable at the air flow sensor and the pump stopped. So I guess the wiring still goes to that area but either internally in the cable or internal to the relay/unit the PO changed something. Do you think it's worth trying to put this back to the way it was for safety reasons?

[redcars]

Being as the pump stopped when you removed the plug from the AFM I would think that it is wired as per factory. Most likely your switch in the AFM is not opening. It may be from your flapper sticking and not closing all the way or your switch is out of adjustment. Take the top off of the AFM and you will be able to see what is going on. Others have posted pictures of the switch in the AFM with nice labeling and everything. If you do a search you should find some posts that cover this very well.

[rjkoop]

Being as the pump stopped when you removed the plug from the AFM I would think that it is wired as per factory. Most likely your switch in the AFM is not opening. It may be from your flapper sticking and not closing all the way or your switch is out of adjustment. Take the top off of the AFM and you will be able to see what is going on. Others have posted pictures of the switch in the AFM with nice labeling and everything. If you do a search you should find some posts that cover this very well.

Wow! That makes sense for sure. I'll take a look at the posts and see if I can figure it out. Thanks for the info.

[rjkoop]

Being as the pump stopped when you removed the plug from the AFM I would think that it is wired as per factory. Most likely your switch in the AFM is not opening. It may be from your flapper sticking and not closing all the way or your switch is out of adjustment. Take the top off of the AFM and you will be able to see what is going on. Others have posted pictures of the switch in the AFM with nice labeling and everything. If you do a search you should find some posts that cover this very well.

Wow! That makes sense for sure. I'll take a look at the posts and see if I can figure it out. Thanks for the info.

Took cover off AFM and... sure enough... the contacts were touching even when the flap was closed. So I adjusted it so that the contact is open when the flap is closed and when the flap moves a bit it makes contact again. Also the flap opens and closes fine (no binding at all). That should work great... Thanks for the help!

[darrenj99]

hello
just got a 76 124, ignition switch is a replacement lada, the wiring is wrong on it. when i connect battery the fuel pump turns on and fuel pump relay clicks. the car will start but i can turn key to off and take it out and car still runs? any ideas? I have six wires on term # 30, which has two posts, i have brown wire on one and green/black and gray on other. red on term #50, black on 30/1, pink and blue/blk on term # 15 and blue and blue and red on int. driving me crazy

thnx

[westy64]

hello
just got a 76 124, ignition switch is a replacement lada, the wiring is wrong on it. when i connect battery the fuel pump turns on and fuel pump relay clicks. the car will start but i can turn key to off and take it out and car still runs? any ideas? I have six wires on term # 30, which has two posts, i have brown wire on one and green/black and gray on other. red on term #50, black on 30/1, pink and blue/blk on term # 15 and blue and blue and red on int. driving me crazy

thnx

maybe your wiring have other troubles
maybe your switch is worn,
but as a start, green/black and gray should not be on 30.
it should be on 16 terminal.

OEM used (and working) switches are not very expensive, easy to replace and worth the expense!!

[darrenj99]

ok thnx, i will look into oem switch( any suggestions ebay? bayless?????). i dont think there is a 16 on my switch? i will take a look( with a mirror and flashlight on my back ) and report back.