What's wrong with my fuel gauge after GT500 pump install?

[US-1]

I use Shell 93 every time. No problems.

 

[06281SC]

The lock ring wasn't fully seated. I fixed it, which is a bitch to do with only two hands....

I don't understand what you mean.. could you explain a little more??

 

[bigray327]

I don't understand what you mean.. could you explain a little more??

If you're asking what I meant by not seated, take a look at the picture I attached on page 1. The tab at the top of the pic is not under the black guide, like the others are in the picture. That was apparently letting some fumes out.

If you meant why was it a bitch, because you have to push the fuel pump basket into the hole a little to compress the o-ring and make the lock ring tabs clear their guides. So it's kinda hard to push down on the top of the basket while turning the lock ring. I can see where the ($93!!!!) wrench from Ford would come in handy, but I just used a flat-head screwdriver and a rubber mallot.

 

[Dex]

Yea, its a pain to line all the tabs up and wack it in.

 

[06281SC]

Understood. I saw a few tools on ebay, but nothing that indicated with was for an '05-'08 car... In the Ford Dual Fuel Pump Install Manual, they call it a "special tool" but give no part number or anything. Anyone have a link to one?? Just curious to see what it looks like and where I could buy one if I wanted to...

 

[Dread53]

I didn't read all the responses, but mine did the same thing. After driving around for a bit it came up, then it would bounce back and forth and it finally started working right. This all took place in the first 100-150 miles. It hasn't messed up since.

 

[Hufen]

If you're asking what I meant by not seated, take a look at the picture I attached on page 1. The tab at the top of the pic is not under the black guide, like the others are in the picture. That was apparently letting some fumes out.

If you meant why was it a bitch, because you have to push the fuel pump basket into the hole a little to compress the o-ring and make the lock ring tabs clear their guides. So it's kinda hard to push down on the top of the basket while turning the lock ring. I can see where the ($93!!!!) wrench from Ford would come in handy, but I just used a flat-head screwdriver and a rubber mallot.

Interesting, i had a shop in houston install mine too and they didnt get the ring on either... had gas start comming through the hole into my backseat and some other huge puddles on the driveway too.

 

[Wyld]

What shop was it?

 

[Hufen]

What shop was it?

psi motorsports, They have always done nice work for me, except for this incedent. I called and told them what was happening, and they sent and paid for a tow truck to come get my car so they could fix it.

 

[bigray327]

psi motorsports, They have always done nice work for me, except for this incedent. I called and told them what was happening, and they sent and paid for a tow truck to come get my car so they could fix it.

Interesting. PSI did mine too... the pumps, -8 lines, and Aeromotive fuel rails. The rails started leaking in my driveway the next day, like a waterfall of fuel, and they basically gave me a screw you attitude. And they're insisting the lock ring was installed properly; it obviously wasn't. I wonder why they'd kiss your butt with a tow truck and not mine... I've spent thousands of dollars there.

 

[Hufen]

Interesting. PSI did mine too... the pumps, -8 lines, and Aeromotive fuel rails. The rails started leaking in my driveway the next day, like a waterfall of fuel, and they basically gave me a screw you attitude. And they're insisting the lock ring was installed properly; it obviously wasn't. I wonder why they'd kiss your butt with a tow truck and not mine... I've spent thousands of dollars there.

Thats weird they gave you that attitude, never really see that from those guys before. Theres no way they could have denied yours or mine sounds like. My gas was spraying up from where the lock ring is, and was going inside of my car. The other half of the gas was draining down and dripping right by my exhaust underneath the car(think this worried him). I Managed to drive 21 miles using half a tank of gas before i realised something was wrong.

 

[bigray327]

Update: the stuff I did the other day seems to have fixed my fuel gauge problem. I'm not sure if it's because all of the tabs are now seated properly, or if I knocked loose some debris when I cycled the arm up and down, but I'm close to empty now and the gauge is hanging in there. If the lack of seal on the ring was the problem, I would gather that the tank needs to be air-tight for the fuel system to work properly. I don't know if that's a valid assumption, though.

Thanks to all for their advice!

Edit: dammit, I spoke too soon... the gas gauge dropped to zero on my way home. Shit!

 

[bigray327]

Additional data points: when the fuel level is less than a quarter of a tank and the gas gauge drops to zero, I can shut the car off overnight and in the morning, it reads fine for about 30 seconds, then goes back to zero.

Also, on the way to work this morning, the car started running out of gas, even though there was at least three gallons in there.

 

[bigray327]

Just to document my own pitiful saga, here's an update: I plan to replace just the sender unit on Thursday. Getting the fuel pump assembly out with the fuel cell still in place is too much for my patience, so I'm gonna drop the tank.

Does anyone have any experience with swapping out just the sender? It looks like one small screw holds it in place, and one wire powers it, so how hard could it be? (famous last words)

 

[one eyed willy]

you need to make sure the pins are correct for the fuel sender,here is my DIY,you will have these problems if the pins on the harness are not done correctly, they could look correct but because you have to disect the harnes there could be something you arnt seeing in there that is not correct, i would really look hard at those 2 wires.its alot of very small parts in that plug that have to be all lined up.

http://www.mustangforums.com/forum/2005-2010-mustangs/504117-gt500-fuel-pumps-diy-w-pictures.html

 

[thump_rrr]

Just to put out in the open the info I PM'd you about the fuel sender.

"On a standard Mustang GT fuel pump you have 4 pins on the connector. When looking directly at the pins you have pin#2 on the lower left and pin #4 on the upper right. They are identified if you look at the back of the connector.

With the fuel level at the lowest point I have 15 ohms resistance and with the fuel at the highest point I have 165 ohms resistance.

Hope this helps."

I'm pretty sure that on the GT500 pumps even though it's a 6 pin connector the pin numbers remain the same.

 

[06BBR]

I fought this same battle last winter. The problem i had was that the fuel cross over from the pass. side was not pumping/sucking the fuel to the drivers side where the pumps are. When you know your getting low on gas pop open the pass access hole and see if the pass side is still full. you have to be very carefull lowering the pumps into the tank because the cross over line will pop off easily. I ended up using zip ties to hold the line inplace so it would not pop off during re-install. Maybe your really getting around 24mpg (whitch sounds about right) and its only using half the tanks compasity???
http://www.modularfords.com/forums/showthread.php?t=107000&page=1

I had this exact problem, and fixed it the same was as Nickoli.

 

[bigray327]

I'm pretty sure that on the GT500 pumps even though it's a 6 pin connector the pin numbers remain the same.

Thanks again for the info.

I waited until the fuel level dropped to zero and tried measuring the resistance on my GT500 connector. I got all zeros no matter which pins I used, so I guess this confirms that the sender is shot.

I'm gonna drop the tank and put in a new sending unit tomorrow. It sucks that they only give you a half-assed access hole to do it from the back seat.

 

[thump_rrr]

Thanks again for the info.

I waited until the fuel level dropped to zero and tried measuring the resistance on my GT500 connector. I got all zeros no matter which pins I used, so I guess this confirms that the sender is shot.

I'm gonna drop the tank and put in a new sending unit tomorrow. It sucks that they only give you a half-assed access hole to do it from the back seat.

I've done 2 of them so far and I never needed to drop the tank.
As a matter of fact it's never taken me more than 15 minutes to get a pump out and another one in.

 

[05stroker]

I've done 2 of them so far and I never needed to drop the tank.
As a matter of fact it's never taken me more than 15 minutes to get a pump out and another one in.

Ive pulled mine more than I want to admit. LOL!