Changing the fuel pump ?

Desertacoma · 04-06-2008, 06:26 PM

I believe it is the fuel pump, after hard exceleration it acts like the car just completly custs out but all the electrical works. I am pretty sure that it is the pump. Just asking advice on changing the fuel pump on my MK1. is there a way I can get to the top of the fuel tank from the inside of the car so I don't have to drop the tank? It is just a pain to drop the tank is all. any advice would be appreciatied. thanks. fellow MK1 owners.

muffinman · 04-07-2008, 01:09 PM

Unfortunately the only way to change the pump is by dropping the tank. I have read about people cutting some of the metal out from under the center console so that in thee future it's easier to replace but I think that's probably not the smartest thing to do.
Besides my stock one lasted 21 years.

hosh · 04-07-2008, 02:09 PM

Their is a chance you MAF door is closing momentarily.

If it was your pump, it should happen during the hard acceleration, not after. If it has anything at all to do with your pump, its the wiring. Check all your connectors to see that there aren't any loose connections or wires crapping out on you.

When I changed out my fuel pump if was because it set to long and trash locked it up. Mine is an 85. The pump worked after I got it out. But I put another one in anyways.

On the parts car I cut the top out to make it easier to remove the pump. I also had to cut the fuel lines(these are hard lines by the way) in order to remove it from the hole I cut. It really wasn't any easier than dropping the tank. Not to mentions you now have a potential fuel leak in a hard to access part of the car.

I would really recommend looking at other potential problems first.

Desertacoma · 04-08-2008, 01:17 AM

Thank you for the help. I am more of a Toyota 4x4 nerd, not the small fun MR2 one, just starting on these. please expound on the "MAF door"? mass air flow? in the intake I take it. Is this the flaps that are like a dual plane manifold for lack of better words? but I hear these only open at 4200 RPM anyway. I will check wires and make suer sensors are clean with clean air filter.

hosh · 04-08-2008, 02:03 PM

Yes the MAF is mass air flow. The MAF or volume air flow meter as Toyota calls it has a flapper door in it. The more air that flows over it, the more it opens. If this closes it opens a switch that tells the ECU that the car is not running. The ECU then shuts off the fuel pump.

Also if the computer doesn't see this switch close when you start your car it will kill the fuel pump. (This caused me great amounts of grief before i figured it out. In the pic below you can see that my pins are corroded and the computer couldn't get signal and kept killing the fuel pump.)

As a fellow Toyota 4x4 nerd i would also like to point you to yotatech.com if you don't already belong to it. My handle over there is also Hosh.

MAF meter

The two pins of the switch.

Fuel tank

Desertacoma · 04-13-2008, 11:49 PM

Thank you much. I will check this out. I may end up selling the MR2 and getting a newer Toy 4x4. I need a truck for truck use instead of using the Runner. Plus I am getting tired of almost getting ran over and pushed off the road in the MR2. I do go onto Yotatech, but am not signed up. It is a great site with alot of info.

F0Bman · 04-24-2008, 01:17 AM

Wow great writeup.

mr2tim · 04-24-2008, 02:30 AM

Keepn' the car?

Flush the tank when you add the/a pump.(Next owner will love it)
Tie a line to the wires you unhook from the tank at the shifter area for the pump and the float sender as it makes it so much easier to re-assemble thru that tiny hole.
Use a floor jack to push up the tank (it's one tight fit)
Easy with the rubber filler hose, it's brittle-use silicone paste to ease re-assembly.
Be sure to label (or draw) where all those tiny little hoses go to before starting.

I've got an 87 tank w pump in the garage attic if you get overboard.

Happy Motoring?

From Paradise,

mr2tim

nitrate · 04-24-2008, 02:41 AM

Pressure Gauge .see if its holding pressure droping at all wile the car is running. hell i drove for a week with a gage hooked up. i have a 1986 MR with over 280.000 miles on it. thought my pump was going out to. was noting wrong with it. and no do not cut a hole in the car to get to the tank. there is more than one layer of steel to cut through. remeber your siting next to a gass tank you do not want holes in your exploshion/heat shield that is built in to the car

Desertacoma · 04-30-2008, 11:35 PM

Thanks, I'll check that. The fuel cuts right off. Wether I am driving hard around town, putting around, or in the drive up line. If I run it down the highway it seems fine. Strange thing. Just hate to buy a $150. MAF for no reason. I have cleaned that up well, made sure intake tube is connected well without air leaks, cleaned Throttle body. there is just a small amount of fuel on top of the fuel filter but the banjo fitting is tight and does not leak when I watch it. thanks for any help.

Desertacoma · 04-30-2008, 11:37 PM

Oh ya, when it does turn the fuel off, I have to turn the car off completly to "reset" and then start it again to keep going, sometimes three times until it stays running. The MAF coneection is good no corrosion.

1fastmr2 · 05-01-2008, 12:50 PM

The best way to check the fuel pump is to put a gauge on it and drive it. If the car will idle it does not tell you the pump is good. The last Mk1 with the same issue we had to drive it with the fuel gauge hook up.

04-06-2008, 06:26 PM	#1 (permalink)
Desertacoma No Skills Join Date: Feb 2008 Location: Southern Utah Posts: 8 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Changing the fuel pump ? I believe it is the fuel pump, after hard exceleration it acts like the car just completly custs out but all the electrical works. I am pretty sure that it is the pump. Just asking advice on changing the fuel pump on my MK1. is there a way I can get to the top of the fuel tank from the inside of the car so I don't have to drop the tank? It is just a pain to drop the tank is all. any advice would be appreciatied. thanks. fellow MK1 owners.

04-13-2008, 11:49 PM	#6 (permalink)
Desertacoma No Skills Join Date: Feb 2008 Location: Southern Utah Posts: 8 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	this will help Thank you much. I will check this out. I may end up selling the MR2 and getting a newer Toy 4x4. I need a truck for truck use instead of using the Runner. Plus I am getting tired of almost getting ran over and pushed off the road in the MR2. I do go onto Yotatech, but am not signed up. It is a great site with alot of info.

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04-07-2008, 01:09 PM	#2 (permalink)
muffinman U-P-G-R-A-Y-E-D-D Join Date: Jan 2008 Location: Sunny South Florida Posts: 5,881 Thanks: 53 Thanked 283 Times in 272 Posts Blog Entries: 1 My Google Map iTrader Rating: (2/100% )	Unfortunately the only way to change the pump is by dropping the tank. I have read about people cutting some of the metal out from under the center console so that in thee future it's easier to replace but I think that's probably not the smartest thing to do. Besides my stock one lasted 21 years.

04-07-2008, 02:09 PM	#3 (permalink)
hosh to many yotas, never! Join Date: Mar 2007 Location: skiatook, ok Posts: 75 Thanks: 3 Thanked 2 Times in 2 Posts iTrader Rating: (0/0% )	Their is a chance you MAF door is closing momentarily. If it was your pump, it should happen during the hard acceleration, not after. If it has anything at all to do with your pump, its the wiring. Check all your connectors to see that there aren't any loose connections or wires crapping out on you. When I changed out my fuel pump if was because it set to long and trash locked it up. Mine is an 85. The pump worked after I got it out. But I put another one in anyways. On the parts car I cut the top out to make it easier to remove the pump. I also had to cut the fuel lines(these are hard lines by the way) in order to remove it from the hole I cut. It really wasn't any easier than dropping the tank. Not to mentions you now have a potential fuel leak in a hard to access part of the car. I would really recommend looking at other potential problems first.

04-08-2008, 01:17 AM	#4 (permalink)
Desertacoma No Skills Join Date: Feb 2008 Location: Southern Utah Posts: 8 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Thank you for the help. I am more of a Toyota 4x4 nerd, not the small fun MR2 one, just starting on these. please expound on the "MAF door"? mass air flow? in the intake I take it. Is this the flaps that are like a dual plane manifold for lack of better words? but I hear these only open at 4200 RPM anyway. I will check wires and make suer sensors are clean with clean air filter.

04-08-2008, 02:03 PM	#5 (permalink)
hosh to many yotas, never! Join Date: Mar 2007 Location: skiatook, ok Posts: 75 Thanks: 3 Thanked 2 Times in 2 Posts iTrader Rating: (0/0% )	Yes the MAF is mass air flow. The MAF or volume air flow meter as Toyota calls it has a flapper door in it. The more air that flows over it, the more it opens. If this closes it opens a switch that tells the ECU that the car is not running. The ECU then shuts off the fuel pump. Also if the computer doesn't see this switch close when you start your car it will kill the fuel pump. (This caused me great amounts of grief before i figured it out. In the pic below you can see that my pins are corroded and the computer couldn't get signal and kept killing the fuel pump.) As a fellow Toyota 4x4 nerd i would also like to point you to yotatech.com if you don't already belong to it. My handle over there is also Hosh. MAF meter The two pins of the switch. Fuel tank

04-24-2008, 01:17 AM	#7 (permalink)
F0Bman Cage Fighter Join Date: Mar 2008 Posts: 252 Thanks: 0 Thanked 3 Times in 3 Posts iTrader Rating: (0/0% )	Wow great writeup.

04-24-2008, 02:30 AM	#8 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 1,789 Thanks: 8 Thanked 118 Times in 111 Posts My Google Map iTrader Rating: (6/100% )	Keepn' the car? Flush the tank when you add the/a pump.(Next owner will love it) Tie a line to the wires you unhook from the tank at the shifter area for the pump and the float sender as it makes it so much easier to re-assemble thru that tiny hole. Use a floor jack to push up the tank (it's one tight fit) Easy with the rubber filler hose, it's brittle-use silicone paste to ease re-assembly. Be sure to label (or draw) where all those tiny little hoses go to before starting. I've got an 87 tank w pump in the garage attic if you get overboard. Happy Motoring? From Paradise, mr2tim

04-24-2008, 02:41 AM	#9 (permalink)
nitrate All the skills Join Date: Nov 2007 Posts: 439 Thanks: 0 Thanked 6 Times in 4 Posts iTrader Rating: (0/0% )	Pressure Gauge .see if its holding pressure droping at all wile the car is running. hell i drove for a week with a gage hooked up. i have a 1986 MR with over 280.000 miles on it. thought my pump was going out to. was noting wrong with it. and no do not cut a hole in the car to get to the tank. there is more than one layer of steel to cut through. remeber your siting next to a gass tank you do not want holes in your exploshion/heat shield that is built in to the car

04-30-2008, 11:35 PM	#10 (permalink)
Desertacoma No Skills Join Date: Feb 2008 Location: Southern Utah Posts: 8 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Thanks, I'll check that. The fuel cuts right off. Wether I am driving hard around town, putting around, or in the drive up line. If I run it down the highway it seems fine. Strange thing. Just hate to buy a $150. MAF for no reason. I have cleaned that up well, made sure intake tube is connected well without air leaks, cleaned Throttle body. there is just a small amount of fuel on top of the fuel filter but the banjo fitting is tight and does not leak when I watch it. thanks for any help.

04-30-2008, 11:37 PM	#11 (permalink)
Desertacoma No Skills Join Date: Feb 2008 Location: Southern Utah Posts: 8 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Oh ya, when it does turn the fuel off, I have to turn the car off completly to "reset" and then start it again to keep going, sometimes three times until it stays running. The MAF coneection is good no corrosion.

05-01-2008, 12:50 PM	#12 (permalink)
1fastmr2 SPIN Join Date: Apr 2008 Location: Burlington, N.C. Posts: 108 Thanks: 2 Thanked 2 Times in 2 Posts iTrader Rating: (0/0% )	The best way to check the fuel pump is to put a gauge on it and drive it. If the car will idle it does not tell you the pump is good. The last Mk1 with the same issue we had to drive it with the fuel gauge hook up.