'01 GM Gas Gauge - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
Ford Crown Victoria | Mercury Marauder | Grand Marquis | P71 Forum for discussion of the Ford Crown Victoria, Mercury Marauder, Mercury Grand Marquis and P71.

 
LinkBack Thread Tools Display Modes
post #1 of 9 (permalink) Old 08-19-09, 02:17 PM Thread Starter
Registered User
 
Join Date: Aug 2009
Posts: 7
'01 GM Gas Gauge

I'm taking my grandfather's Grand Marquis on a cross country road trip. I had a quick question about the gas gauge. Is it top heavy or bottom heavy? The computer says I'm getting 20.9 MPG after going ~250mi with only a quarter tank left. 90 miles or so to empty. If the tank is a 19 gallon tank, that's only 17.8mpg, it seems off.

On a side note, the car has 70k miles on it. I think I'm going to change the fuel filter, Air Filter, PCV and Clean the MAF. Is it worth it to change the plugs? Will it help the MPG?

abefroman is offline  
Sponsored Links
Advertisement
 
post #2 of 9 (permalink) Old 08-19-09, 03:13 PM
Bronco Guru
 
Steve83's Avatar
 
Join Date: Sep 2008
Location: Memphis, TN, USA 38135
Posts: 330
Re: '01 GM Gas Gauge

So you're the sausage KING of Chicago? :D

The gauge is just a gauge - not a meter. It's not calibrated at either end or in the middle. The way to check MPG is 1) fill up, 2) reset the trip odo, 3) drive, 4) fill up, 5) divide miles on the trip odo by gallons to refill. You don't have to drive to EMPTY, or even close - just enough to get a good average reading. But the closer you get to E, the more accurate your calculation will be.

Don't mess with the MAF unless you know there's a problem with it. It's a delicate device, easily damaged by improper cleaning.

If the plugs aren't due for changing, leave them alone. If you EVER install a plug in that engine, be sure to use a torque wrench or a torque-limiting device. It's easy to strip the threads, and expensive to fix them right.

Steve83 is offline  
post #3 of 9 (permalink) Old 08-19-09, 03:17 PM
2002 F150 XLT
 
Bert's Avatar
 
Join Date: Nov 2008
Location: Oregon
Posts: 10,341
Re: '01 GM Gas Gauge

The readings are averaged out on all the different drives. Idling at lights and such throw a curve in the figures. It's just a guess as to what you are doing. It does help if you're on a long trip and wonder aprox. how far you might be able to go. I get 23-25 on the raod with a P71 which is geared for take-off and gets less mileage on trips.

Sounds like a good idea to replace all you mentioned. The spark plugs should be replaced. They can cause poor mileage more than most everything else. Just make sure you use the proper torque on the plugs. If they're to tight the aluminum head stretches and can pull the threads out. To loose is bad too.
Bert is offline  
post #4 of 9 (permalink) Old 08-20-09, 12:21 PM Thread Starter
Registered User
 
Join Date: Aug 2009
Posts: 7
Re: '01 GM Gas Gauge

Plugs should be 15 ft-lbs, correct? Also, is there a tric to getting the coils out? I gave it a quick glance this morning and it looked like there might be some stuff in the way

Thanks
abefroman is offline  
post #5 of 9 (permalink) Old 08-20-09, 01:53 PM
2002 F150 XLT
 
Bert's Avatar
 
Join Date: Nov 2008
Location: Oregon
Posts: 10,341
Re: '01 GM Gas Gauge

The coils come out easily. Just remove the bolt and they pull right out.
Bert is offline  
post #6 of 9 (permalink) Old 08-21-09, 09:43 AM Thread Starter
Registered User
 
Join Date: Aug 2009
Posts: 7
Re: '01 GM Gas Gauge

I think something's wrong with the float or something. The car had 301 miles on it and claimed there were only 20 left. When I filled it up, it only took 14.7 gallons. THat measures out to about 20.5 MPG. However, I thought it was a 19 gallon tank?
abefroman is offline  
post #7 of 9 (permalink) Old 08-21-09, 10:27 AM
2002 F150 XLT
 
Bert's Avatar
 
Join Date: Nov 2008
Location: Oregon
Posts: 10,341
Re: '01 GM Gas Gauge

Run it a few times and see how it does. Mine usually does about that much in bout 300 miles. I don't have the miles to go feature.

It is a 19 gal tank but it's best to quit filling it as soon as the nozzle stops. The vapor tank can get contaminated and not be able to do it's job. That's true with any newer car. As far as the miles to go, they would rather err on the safe side. Imagine someone running out of gas and wanting to sue because of it.
Bert is offline  
post #8 of 9 (permalink) Old 08-21-09, 11:56 AM Thread Starter
Registered User
 
Join Date: Aug 2009
Posts: 7
Re: '01 GM Gas Gauge

SOunds good, just wanted to make sure it's somewhat normal. THanks for all the help rtg143
abefroman is offline  
post #9 of 9 (permalink) Old 08-26-09, 10:58 AM Thread Starter
Registered User
 
Join Date: Aug 2009
Posts: 7
Re: '01 GM Gas Gauge

Well, I completed all of the above maintenance and calculated 28.5 MPG from the pump on a 100 mile trip at about 70mph. Thanks again for the help
abefroman is offline  
Sponsored Links
Advertisement
 
Reply

  Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Cars and PAG Vehicles > Ford Crown Victoria | Mercury Marauder | Grand Marquis | P71


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome