Fuel Pump Woes

HonestTodd · Post by **HonestTodd** » 01 May 2018, 05:01

I am trying to keep my son's '97 850GLT on the road a bit longer. Our very trustworthy mechanic diagnosed his non-start as a bad fuel pump. Could not justify the costs of having this done by our mechanic so thought I would do it myself. Pretty simple process.

Put in a new fuel pump. Still no start.

Put a jump cable in place of the fuel relay just in case the relay our mechanic used to rule out that as a cause was bad. No start.

Decided to test voltage at fuel pump connector when my son turned on the key for a few seconds. Consistently read 8-8.5 volts. Makes me suspect a wiring issue between relay and connector. Does this seem logical to you?

I have pulled the new pump and connected it directly to the battery. It works. So does the original fuel pump. Although, I did learn the hard way that the old pump still had a little fuel in it?

Any help on what to do next?

I am pretty much a novice at this stuff so any help is appreciated.

Final question. The OE fuel pump had two wires going to the connector. The replacement has a third wire (black) that comes out of the ground side of the connector. This third wire is a couple inches long and ends with a bullet connector. Any idea why it is there?

Thank you,

HT

Post by **tryingbe** » 01 May 2018, 08:43

Forget the fuel pump for a moment.

Is the battery fully charged? How long the car have been sitting? What's the compression numbers? How old are the rotor and caps? Do you have spark? Will the car start on carb cleaner? I'm assuming the engine turns over? Did you check the timing belt to make sure the belt is intact?

HonestTodd · Post by **HonestTodd** » 01 May 2018, 10:09

Mechanic checked air and spark before diagnosing fuel pump.

Turns over well.

Battery charged.

Car runs for a few seconds on carb cleaner.

Was not sitting at all. Is my son’s daily driver. One morning it would not start

Post by **tryingbe** » 01 May 2018, 10:58

If you take the fuel return hose of the fuel regulator, turn the key from off to on, does fuel come out of the fuel regulator? If so, then fuel pump is working. Report back.

HonestTodd · Post by **HonestTodd** » 06 May 2018, 14:05

Fixed!

For some reason I was only getting 8.5 volts at the fuel pump connector. Suspected that I needed a better ground.

Bought a female bullet connector, attached a wire to it and plugged it into the male bullet connector that was part of the new pump assembly. Scratched some paint off the car to get metal on metal, attached my new ground and turned the key. Voila, I could hear the fuel pump working.

Car was turning over sluggishly so I attached the trickle charger for an hour.

Car started on the first crank.

I’ve made my new ground permanent and everything seems to be working well.

Hope we can get another year or or two out of this car.