Fuel Computer/Gas indicator Help Needed

[jgscott]

Hi,

New to the Forum. Been reading for a while but, just joined.

I have a problem that I have researched here but did not see my exact one or what the cause was. Anyway here's my problem :

My Car is a 2002 LS Sport V8, I have about 78k miles on it. In the last 3 months it has run out of gas on me about 5 times.

The Gas Computer will show anywhere from 48 miles to 75 miles left to empty, and Needle will be a little above or below 1/4 Tank. It will cut off and skip on me and will not fire back up until I put more Gas in it. I read here about the Fuel Computer error message but I never got that. Any help as to the cause or part to replace would be greatfull. Thanks

 

[Quik LS]

the LS uses two 'saddle' type fule tanks - each with it's own fuel level sender.

it's possible that one of the senders is messed up - or that your car is not able to get all the gas out of the car (for example - there really is a 1/4 tank let but the fuel transfer/balancing system is messed up).

First try to reset the FEM/PCM to start the counters at zero - by disconnecting the battery for 10mins. It will take a few drives for the fuel calculations to begin working again - but it will reset the mileage/distance calculations.

If the problem still exists - then the next step would be to replace one of the senders - both the fuel pump and the 'jet pump' (fancy second pickup - not an actual pump) are $200+ but easy to change.

 

[jgscott]

the LS uses two 'saddle' type fule tanks - each with it's own fuel level sender.

it's possible that one of the senders is messed up - or that your car is not able to get all the gas out of the car (for example - there really is a 1/4 tank let but the fuel transfer/balancing system is messed up).

First try to reset the FEM/PCM to start the counters at zero - by disconnecting the battery for 10mins. It will take a few drives for the fuel calculations to begin working again - but it will reset the mileage/distance calculations.

If the problem still exists - then the next step would be to replace one of the senders - both the fuel pump and the 'jet pump' (fancy second pickup - not an actual pump) are $200+ but easy to change.

Thanks, I don't think resetting will help, I 've done that a few times already. Also the fact the the Gas Needle shows + or - a quarter of a tank indicates about the same as the computer miles.

Trying to understand what you said about the fuel delivery, sending system. Couple of questions;

1. So you are saying there are kinda 2 tanks connected together right? Each has a sender, jet pump and fuel pump. Are those units combined together 1 set for each tank ?

2. Are they located in each tank ? And are the complete units ( if combined for each Tank ) $ 200 + for the whole jet pump, fuel pump and sender ? Or $ 200 for each ( 200 = jet pump, 200 = Fuel pump, 200 = sender ?

Thanks

 

[Quik LS]

1. So you are saying there are kinda 2 tanks connected together right? Each has a sender, jet pump and fuel pump. Are those units combined together 1 set for each tank ?

two tanks - the fuel is balanced between them using the fuel and jet pump to pick up out of each. the fuel pump is on the passenger side, jet (transfer) pump on the driver's side. each unit has a sending (gas level) float.

2. Are they located in each tank ? And are the complete units ( if combined for each Tank ) $ 200 + for the whole jet pump, fuel pump and sender ? Or $ 200 for each ( 200 = jet pump, 200 = Fuel pump, 200 = sender ?

the fuel pump is in the passenger side tank, jet (transfer) pump in the driver side tank. I believe the fuel pump is ~$280 and the jet pump is ~$218... it's been a few years since I swapped mine. The senders are integrated with each unit - so you get a new sender as part of the package.

here's a pic of the fuel pump - so you get the idea.

 

[Freezer41]

I have this issue now. Twice I have run out of fuel. Once was just a second after I got the low fuel warning and 50 miles to go. Just yesterday I ran out above 1/4 tank it said I had 118 miles to go. I filled up only 12.85 gallons. Does this sound like my problem? I hate having to fill up every 100 miles

 

[02LincLS]

Freezer, sounds like your driver's side isnt flowing gas over to the passenger side properly. The fuel calculation is taken from the driver's side, but the motor gets gas from the passenger side. the fact you don't fill up near 18 gallons means theres still gas in there and its just not getting to the passenger side.

 

[yeefknhaw]

yea, I know it's an old thread

The problem I am having is that my tank is Empty although the guage is showing I still have half a tank left and around 160 miles to empty, but when I fill up, I put in about 17 gallons of gas.

So I know the gas is transfered over but how can I tell which float is bad?
Also, does the whole pump assembly have to be changed out just for the float?

Luckily, I haven't run out of gas, because I keep a close eye on the trip meter

2003 V8

 

[Quik LS]

first try the reset suggested in post #2.

in post #4 you can see the float is part of the canister assembly - you have to buy the entire piece (including pump) - $200+

you first need to figure out which side is bad - since there is a float in each tank.

 

[yeefknhaw]

Thanks for the quick reply, Quik LS

resetting the computer doesn't work.

I figured I would need to buy the whole assy., just wanted to double check.

and now my delima, how would one check to see which float is bad, without having to pull both of them out?

 

[joegr]

Thanks for the quick reply, Quik LS

resetting the computer doesn't work.

I figured I would need to buy the whole assy., just wanted to double check.

and now my delima, how would one check to see which float is bad, without having to pull both of them out?

With a Ford specific scan tool, you can get the readings for each of the two fuel floats. That way you would be able to tell which one is stuck. If you don't have one of those, then there is still a way to do it without pulling them out first. Measure the resistance of each float sensor while it is still in the tank. You shouldn't have to do much more than pull the rear seat bottom out to do that. Unfortunately, I don't have my wiring diagrams with me to tell you which pins to check.

 

[yeefknhaw]

Thanks joegr

A friend of mine has the Ford scan tool at his shop,( had no idea that it could tell which one), guess I'll have to stop in and bug him sometime next week. Or see if he'll let me borrow it over the weekend.