How do you test your fuel pump?

batmmannn · 05-16-2010, 12:38 AM

Is there an easy way to test the fuel pump? My Red Supra has died. I hear no humming from the tank at all when the ignition is turned on even though I have my ear pressed to the tank. I found the thread on replacing it but I am wondering where is the best place to open up the system to see if it is pumping anything. My plugs are dry after a lot of cranking car suddenly died after sitting 6 years and on it's first test drive after a starter replacement.

Is it best to disconnect the fuel line before the filter and see if it can pump through on cranking? Can you open up the fuel regulator and see if it pumps and if so where is the fuel regulator on the car and what does it look like? I hear that is hard to get to. Please chime in and let me know.

Thanks so much, Scott

cre · 05-16-2010, 12:49 AM

I PMed you on how to bypass the ignition circuit to test the fuel pump... jumper the +B and FP connectors in the diagnostic box. If you can't hear it try actually measuring for pressure.

batmmannn · 05-16-2010, 12:59 AM

I see in the manual where they say to do the bypass but how can I tell if I am getting fuel I need to see it coming out like out of a hose or something correct? I would have to get the tool to measure the pressure I was just hoping to find a way to see if it is working at all. Or are you saying do the jump and then go see if I can hear it running back at the tank? Oh and I take it there is no access panel under the seat for the pump like there is on the celica? Could it be a bad fuel relay? Thanks Scott

cre · 05-16-2010, 01:17 AM

Generally, you'll hear it flowing through the fuel rail. To really test it you should get a fuel compatible pressure gauge, disconnect the fuel pressure damper and connect the gauge to the rail there and see what the pressure is. I can't remember if you said this car was turbo or N/A, if it's N/A you need to have the AFM plugged in and you'll need to prop open the vane, otherwise the emergency fuel cut switch will prevent the fuel pump from getting power. You should also test the fuel pump relay and resistor.

Most of the trouble shooting proceedures you need to go though are located here:
http://www.cygnusx1.net/Supra/Librar....aspx?S=FI&P=1
Give it a thorough read.

cre · 05-16-2010, 01:22 AM

http://www.cygnusx1.net/Supra/Librar...aspx?S=FI&P=72

Here they recommend using the cold start injector's connection.

What manual are you using? Haynes?

batmmannn · 05-16-2010, 01:52 AM

Ok thanks I just read through the instructions. I am looking for the small box with the jumper to made in it. I found the box next to the fuse box. Since I don't have the tools to measure the pressure can I just open up the cold start line and then make the jump to see if it pumps fuel? Or should I disconnect the fuel line from the regulator and see if fuel pumps out of fuel line 2? Or as you said if I don't hear any return fuel passing then something is broke.
Thanks for your patience with me. I am not a pro at this by any means.

cre · 05-16-2010, 02:18 AM

Quote:

Originally Posted by batmmannn

Since I don't have the tools to measure the pressure can I just open up the cold start line and then make the jump to see if it pumps fuel? Or should I disconnect the fuel line from the regulator and see if fuel pumps out of fuel line 2?

I really wouldn't advise that. You shouldn't have to crank either, just put the key to the "ON" position (and prop the vane open on a N/A).

Have you checked for error codes yet as I've mentioned a dozen times? I'm going to assume not as you didn't see the box.. check them now that you know where it is.

Do you still have power in the car (other than the starter)?

batmmannn · 05-16-2010, 02:35 AM

Thank you for your efforts, but unfortunately I am a graphic artist not a pro mechanic so I have no way of checking for error codes and not much money to get it towed to someone that has the tester or knows how to read the codes. So though you have the expert knowledge to instruct me I don't have the tools nor the experience to try certain things. I can only try what I can and then replace parts from a best guess. Yes I have power everywhere except to the overhead interior lights but that was that way when it was running. When you say the Vane what part are you referring to I am not familiar with that. I don't know what a Vane is or where it is located. Thanks again for putting up with me. Scott

Oh Ok so the Vane is the Butterfly air pass through on the intake throttle body? I am looking things up. Oops the vane seems to be in the Air flow sensor? Oh Boy I am confused.

cre · 05-16-2010, 02:57 AM

I already told you before... the details on checking for error codes is in the MKIII FAQ section. Exit this thread and look UP.

Yes, the vane in the AFM (air flow meter, covered that all too sorry, I guess I wasn't descript enough). Think of a weather vane, metal plate that is moved by the wind.

Only the N/A uses this type of meter. There's a switch in it which is open if the vane is closed and prevents the fuel pump from powering up.

batmmannn · 05-16-2010, 03:01 AM

Going to go look at the error codes/ Thanks

05-16-2010, 12:38 AM	#1
batmmannn 12psi boost Join Date: May 2010 Location: West Virginia Posts: 320	How do you test your fuel pump? Is there an easy way to test the fuel pump? My Red Supra has died. I hear no humming from the tank at all when the ignition is turned on even though I have my ear pressed to the tank. I found the thread on replacing it but I am wondering where is the best place to open up the system to see if it is pumping anything. My plugs are dry after a lot of cranking car suddenly died after sitting 6 years and on it's first test drive after a starter replacement. Is it best to disconnect the fuel line before the filter and see if it can pump through on cranking? Can you open up the fuel regulator and see if it pumps and if so where is the fuel regulator on the car and what does it look like? I hear that is hard to get to. Please chime in and let me know. Thanks so much, Scott __________________ 1987 N/A 7MGE Left Hand Drive MK3 Red 5 Speed and Black Auto Supras My Next project is the Batmobile! Last edited by batmmannn; 05-16-2010 at 12:40 AM.

05-16-2010, 12:49 AM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	I PMed you on how to bypass the ignition circuit to test the fuel pump... jumper the +B and FP connectors in the diagnostic box. If you can't hear it try actually measuring for pressure. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

05-16-2010, 12:59 AM	#3
batmmannn 12psi boost Join Date: May 2010 Location: West Virginia Posts: 320	Hello Cre I see in the manual where they say to do the bypass but how can I tell if I am getting fuel I need to see it coming out like out of a hose or something correct? I would have to get the tool to measure the pressure I was just hoping to find a way to see if it is working at all. Or are you saying do the jump and then go see if I can hear it running back at the tank? Oh and I take it there is no access panel under the seat for the pump like there is on the celica? Could it be a bad fuel relay? Thanks Scott __________________ 1987 N/A 7MGE Left Hand Drive MK3 Red 5 Speed and Black Auto Supras My Next project is the Batmobile! Last edited by batmmannn; 05-16-2010 at 01:13 AM.

05-16-2010, 01:17 AM	#4
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Generally, you'll hear it flowing through the fuel rail. To really test it you should get a fuel compatible pressure gauge, disconnect the fuel pressure damper and connect the gauge to the rail there and see what the pressure is. I can't remember if you said this car was turbo or N/A, if it's N/A you need to have the AFM plugged in and you'll need to prop open the vane, otherwise the emergency fuel cut switch will prevent the fuel pump from getting power. You should also test the fuel pump relay and resistor. Most of the trouble shooting proceedures you need to go though are located here: http://www.cygnusx1.net/Supra/Librar....aspx?S=FI&P=1 Give it a thorough read. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

05-16-2010, 01:22 AM	#5
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	http://www.cygnusx1.net/Supra/Librar...aspx?S=FI&P=72 Here they recommend using the cold start injector's connection. What manual are you using? Haynes? __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

05-16-2010, 01:52 AM	#6
batmmannn 12psi boost Join Date: May 2010 Location: West Virginia Posts: 320	Afm Ok thanks I just read through the instructions. I am looking for the small box with the jumper to made in it. I found the box next to the fuse box. Since I don't have the tools to measure the pressure can I just open up the cold start line and then make the jump to see if it pumps fuel? Or should I disconnect the fuel line from the regulator and see if fuel pumps out of fuel line 2? Or as you said if I don't hear any return fuel passing then something is broke. Thanks for your patience with me. I am not a pro at this by any means. __________________ 1987 N/A 7MGE Left Hand Drive MK3 Red 5 Speed and Black Auto Supras My Next project is the Batmobile! Last edited by batmmannn; 05-16-2010 at 02:06 AM.

05-16-2010, 02:35 AM	#8
batmmannn 12psi boost Join Date: May 2010 Location: West Virginia Posts: 320	Error codes Thank you for your efforts, but unfortunately I am a graphic artist not a pro mechanic so I have no way of checking for error codes and not much money to get it towed to someone that has the tester or knows how to read the codes. So though you have the expert knowledge to instruct me I don't have the tools nor the experience to try certain things. I can only try what I can and then replace parts from a best guess. Yes I have power everywhere except to the overhead interior lights but that was that way when it was running. When you say the Vane what part are you referring to I am not familiar with that. I don't know what a Vane is or where it is located. Thanks again for putting up with me. Scott Oh Ok so the Vane is the Butterfly air pass through on the intake throttle body? I am looking things up. Oops the vane seems to be in the Air flow sensor? Oh Boy I am confused. __________________ 1987 N/A 7MGE Left Hand Drive MK3 Red 5 Speed and Black Auto Supras My Next project is the Batmobile! Last edited by batmmannn; 05-16-2010 at 02:47 AM.

05-16-2010, 02:57 AM	#9
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	I already told you before... the details on checking for error codes is in the MKIII FAQ section. Exit this thread and look UP. Yes, the vane in the AFM (air flow meter, covered that all too sorry, I guess I wasn't descript enough). Think of a weather vane, metal plate that is moved by the wind. Only the N/A uses this type of meter. There's a switch in it which is open if the vane is closed and prevents the fuel pump from powering up. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar ---> Last edited by cre; 05-16-2010 at 03:03 AM.

05-16-2010, 03:01 AM	#10
batmmannn 12psi boost Join Date: May 2010 Location: West Virginia Posts: 320	Ok Thanks Going to go look at the error codes/ Thanks __________________ 1987 N/A 7MGE Left Hand Drive MK3 Red 5 Speed and Black Auto Supras My Next project is the Batmobile!

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