Welcome Guest [Log In] [Register]
Posted ImageWelcome to the all new Geo Metro Forum. We hope you enjoy your visit.

You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are features you can't use and images you can't see. Registration is simple, fast, and completely free. If you're already a member please log in to your account to access all of our features:

Join our community!




Username:   Password:
Add Reply
fuel pump not engaging; 93 Geo Metro automatic
Topic Started: Jul 11 2012, 10:44 AM (1,151 Views)
GeoStalker
Member Avatar
"Chicks dig me and guys think I'm cool."

A few weeks ago, after getting a brand new engine from Geo Glenn, my daughter's 93 hatchback wouldn't start. The fuel pump was not engaging, so after some other diagnostic tests I determined it was a faulty fuel pump, and after 100k miles on the body of the car that logic seemed to make sense. I installed a new one, tested the pump before inserting it into the gas tank, replaced the fuel lines, and away she purred.

Today her car wouldn't start again. Again the fuel pump is not engaging. :banghead But yet the fuel pump relay is clicking as normal. Odds are highly unlikely that it is a bad fuel pump since it's only 2 weeks old. I begin my diagnostics. At the time we tried to start the car it was sitting in our driveway on a slight incline. I turned the car around and backed it to the front of the garage and where the driveway is flatter so I could work on it in the shade.

I jacked up the rear of the car, put jack stands under the frame rails, and removed the rear tires. I put the jack underneath the tank and applied a bit of pressure, and then thought to myself "Attempt to fire up the car one more time." just for shits and giggles.

Wouldn't you know it, the car fired right up!!!

Okay my fellow Geobrainiacs, what am I missing here? Could it be a chaffed wire, bad ground, etc.? What do I need to be chasing??? Could the angle of the car determine if the fuel pump engages or not?? Seems weird to believe so, but I tried firing it up 20 times before getting it to flatter ground, and the incline wasn't that bad anyway.

Thoughts???
Online Profile Quote Post Goto Top
 
bansheetaz


check the sending unit on top of the tank for rusty and corroded passthroughs into the tank.
Offline Profile Quote Post Goto Top
 
GeoStalker
Member Avatar
"Chicks dig me and guys think I'm cool."

bansheetaz
Jul 11 2012, 11:58 AM
check the sending unit on top of the tank for rusty and corroded passthroughs into the tank.
Sending unit is clean as a whistle....no rust or corrosion anywhere on the bottom of this car.
Online Profile Quote Post Goto Top
 
96Geoman


There's a ground wire that connects to the back of the intake manifold that turns on the fuel pump.

If the ground wire is not connected, the fuel pump won't work.

Maybe the ground wire connection needs cleaning.
Edited by 96Geoman, Jul 11 2012, 12:48 PM.
Offline Profile Quote Post Goto Top
 
Memphis metro


Just because a relay clicks does not mean it is working. I have seen many that will click but is not providing current to the device. Not that this is your problem but just so you know relays can click and still be bad. Fuel pumps sometimes are hard to hear. Disconnect the fuel line at the tbi and see if any pumps out when it will not start. Maybe you have another issue besides fuel problems.
Offline Profile Quote Post Goto Top
 
GeoStalker
Member Avatar
"Chicks dig me and guys think I'm cool."

Well I took 96Geoman's advice and disconnect the ground wire behind the intake, throughly cleaned the connecting wire, nut and back of the intake, and retightened it all down. The car started fine and drove fine for the one mile test drive. Are there any other grounds which could impact the fuel pump in this way?
Online Profile Quote Post Goto Top
 
GeoStalker
Member Avatar
"Chicks dig me and guys think I'm cool."

Well, the fuel pump wasn't engaging once again, right before my daughter had to take off to meet some friends at the movies. I knew the ground wire behind the intake was fine, so I immediately pulled up the back seat to take a look at the connectors that are located where the wires goes through the body to the fuel tank.

I should have probably done this BEFORE replacing the fuel pump in the first place!!

There are two connectors at this point....the first looks like the power and ground in one connector and the second is yellow and looks like a sensor wire of some sort. The first connector, covered in a white plastic sheath, had some brown burn marks within it. Hmmmm.....

The 2nd connector to the sensor or whatever it's for was sort of pulled apart within a clear rubber sheath, and it ALSO had some browning discoloration within it.

After talking it over with Johnny Mullet, he suggested just splicing and retying everything together. I did just that, car started up just fine, and I had my daughter drive it around the block to see if there was sputtering from the fuel pump. She said the car ran fine.

So I just have to remember that if I ever drop the tank I can't simply disconnect the connecting lines.....but actually untwist or cut and redo.

If it doesn't engage in the future, there has to be a chaffe or something somewhere else in the line.
Online Profile Quote Post Goto Top
 
Memphis metro


Pink and black wires are fuel pump. Yellow/red wire is the fuel gauge sender wire.
Offline Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
« Previous Topic · Engine Tech & Diagnostics · Next Topic »
Add Reply