Where are the main and in tank fuel pump ground connections for a 1988 240GL B230F? I am troubleshooting and need to check. Thanks.

What are you trouble shooting? I had a problem where the whole fuel injection system, including the fuel pumps, was not grounding so the car wouldn't run because of no fuel. I may be able to help if your problem is similar. E-mail direct to Keith_Miller@berlex.com. I dont check this board daily.

The main fuel pump is located about under the left rear passenger seat, and its wires go through a grommet under the rear seat, left side. This is very convenient for diagnostics, particularly in a wagon -- but slightly troublesome in a sedan. You will find the pump power there at a tab connecto. The pump ground is also there, at a screw lug, where it's grounded to the metal floorpan.

The tank pump is grounded to the tank sender assembly. The sender is grounded to the car chassis by a wire attached by a tab connector and to the chassis by a screw lug. Unfortunately, the tab on the sender usually rusts off. You can install a replacement ground by connecting the ground wire securely to one of the metal pipes at the sender.
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Don Foster (near Cape Cod, MA)

Don, Is the main fuel pump ground above the grommet going into the rear seat section, or right at the main fuel pump when the protective cover is dropped down? Regarding the in-tank fuel pump, I think I found the ground attached to the floor of the inside of the trunk next to the cover of the in-tank fuel pump. I don't know where the tank sender assembly is to find the ground you mentioned. Thanks again.

The main pump ground is under the seat, on the inside of the car.

Your said "...inside of the trunk.." so you have a sedan. At the rear of the trunk (toward the front of the car), where the trunk floor is more like a shelf, look for an oval plate that's about 6"x8" under the carpet or covering. It's secured by two phillips screws, and has wires through a grommet in its center.

Remove the plate and look down -- you'll see the top of the tank, and the top of the sender is right under your nose. It's about 4" in diameter and has two pipes sticking out plus a wiring harness. The sender is secured into the tank by a lock ring -- which is no doubt completely rusted.
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Don Foster (near Cape Cod, MA)

Don, Thanks for your help and for bearing with me on this. I found the main pump ground under the rear seat (looked clean and tight, but did it over anyway), however, I'm still a little confused as to the whereabouts of the in-tank ground. I found and opened the plate covering the in-tank pump. On top are two pipes with hoses and the wiring harness coming out of the top. The wiring harness leads into the trunk and to what I believe is a ground tab screwed into the trunk metal a bit to the left of the plate opening (other wires from the harness go to a different section). I believe from your post that there is another ground (wire attached by a tab connector) somewhere inside the in-tank opening. Can this be seen from inside the trunk? Or from underneath the car? I looked and couldn't see anything in the area that looked like a ground wire with a tab connector. Thanks again.

The tank pump itself is grounded to the sender assembly. This assembly holds the pump, and also holds the fuel level sensor.

The sender assembly is grounded to the chassis by the wire you saw. One end is secured to the metal floorpan near the oval plate, as you saw. The other end of this wire connects to the sender body by a push-on tab connector. Unfortunately, this tab often rusts off the sender assembly, so your ground becomes uncertain. The sender might be grounded because of the lockring biting into both the sender AND the gas tank, but if the lockring becomes rusty (and they do), then you may have a poor ground. The tab is right on top of the sender, within an inch of the pipes. You can see it through the oval opening. Follow the wire attached to the floor with a screw and see where it goes.

The harness from the tank has two wires. One is power to the pump, and the other is the signal to (or from) the fuel level sensor. Both are referenced to ground.

chuck is right and the main is under the rear seat on the left...
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www.fidalgo.net/~brook4

don't know the main. The intank is under the carpet by the access panel to the pump in the trunk.
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Chuck B '89 245 DL, '85 244 DL