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-   -   Fuel Pump Issue (https://www.yotatech.com/forums/f116/fuel-pump-issue-318082/)

Boogeyman Dec 17, 2023 02:26 PM

Fuel Pump Issue
 
I have a 1986 Pickup and when I turn the key on I don't hear the fuel pump prime..Its also hard to start..I have to pump the gas a bunch of times while I crank..usually takes a minute depending on how cold it is.

I started by checking power to the pump and there was none...so for fun I jumped the fuel pump with an extra battery just to make sure it works. It does.

I go up the line to the "Open Circuit Relay" right behind the passenger dash speaker. I pull that off and check the resistance per the service manual. Everything checks out. So then I check the actual plug that the relay plugs into. There's 5 ports
https://cimg9.ibsrv.net/gimg/www.yot...afe8defc39.png
I get power to the B port, but I don't have power on STA port..I hot wired the relay and in order for it to work I need power from both sources..The next stop up the line is the "Air Valve Connector"

Has anyone had this issue before? Am I overthinking this? I was gonna wire a manual switch to the fuel pump until I figured out what was wrong..

Thanks for the help

wallytoo Dec 17, 2023 04:01 PM


Originally Posted by Boogeyman (Post 52491349)
I have a 1986 Pickup and when I turn the key on I don't hear the fuel pump prime..Its also hard to start..I have to pump the gas a bunch of times while I crank..usually takes a minute depending on how cold it is.

the fuel pump doesn't run when you turn the key "on". toyotas don't prime ahead of start. if things are functioning correctly, the pump only runs when the key is in the "start" position, and when the engine is actually running. pumping the gas in an efi makes no difference for starting. it doesn't add fuel or air to the charge; doing so only makes you feel better, but it has no effect.

verify the CSI is operating during "start". if it isn't, cold-weather cold starts will be difficult.

Boogeyman Dec 18, 2023 06:31 PM


Originally Posted by wallytoo (Post 52491353)
the fuel pump doesn't run when you turn the key "on". toyotas don't prime ahead of start. if things are functioning correctly, the pump only runs when the key is in the "start" position, and when the engine is actually running. pumping the gas in an efi makes no difference for starting. it doesn't add fuel or air to the charge; doing so only makes you feel better, but it has no effect.

verify the CSI is operating during "start". if it isn't, cold-weather cold starts will be difficult.

I checked the cold start injector. Pulled it out, cleaned it, checked the resistance. It appears to be working..Still need like 4-5 times turning the key to get it to start. When I get a buddy I'll pull the injector out and see if fuel actually shoots out of it.

Jimkola Dec 21, 2023 08:40 PM

If the cold start injector looks ok then test the sender that controls it.
#89462
https://cimg0.ibsrv.net/gimg/www.yot...b43eaaa385.png



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