CarForum.net - Car Forums, Automotive News and Community
Home Gallery Register Calendar Members List

Go Back   CarForum.net - Car Forums, Automotive News and Community > General Car Discussion > General Automotive Discussion

Reply
LinkBack Thread Tools
Unread 05-11-2010, 12:28 AM   #1
Retired Staff
 
Retrospekt's Avatar
 
Join Date: Jul 2006
Location: Chicago, IL
Posts: 599
Rep: 67 Retrospekt will become famous soon enough
Default Fluctuating Gas Mileage

My 200sx is acting a little weird. My Dad and I share the car, each of us using it for very short trips (about 2 miles to work or school). When I calculated MPG last time, I got 29.1. When he went to the gas station (we take turns filling her up) he got 22.1. He also said that two times he's gone, it won't pump gas to full. He said it'll pump in 5 or 6 gallons then force stop, as if the tank were full. What could be going on there?

The car seems to be driving fine. The style of driving between the 29 and 22(We both drive very slow/accelerate slow) nor did the type of driving (ie. both was city). The calculations were done correctly.

I do have a CEL on, it's an evaporator system leak, somewhere near the evaporator canister. I haven't had time to look at it yet but I don't think it's that serious. Could it be causing this?
__________________
Family Cars: (Bold is mine).

1998 Nissan 200sx SE | i4 1.6L | 83,000 miles | Green | Running 100% |

1996 Nissan Sentra | i4 1.6L | 122,000 miles |Black |
2001 Nissan Maxima | V6 3.0L | 94,000 miles | Black |
2010 Toyota Camry | i4 2.5L | 5,500 miles | Silver |
1993 Toyota MR2 | 2.0L i4 560HP | 26psi Boost | Unknown Mileage | White| Scary to drive

Retrospekt is offline  
Reply With Quote
Unread 05-11-2010, 06:41 AM   #2
Community Director
 
Mike's Avatar
 
Join Date: Jun 2008
Location: Minneapolis, MN
Posts: 7,602
Rep: 153 Mike has a spectacular aura aboutMike has a spectacular aura about
Default

Could be.

Should also be noted that 2 mile trips are bad for your car - you should let the car warm up to full temp before shutting it off.

Have you done plugs/wires?
__________________
"He shouted: 'You've won! Didn't you know?' I didn't, and it's about the nicest thing I've ever been told" -Bruce McLaren, 1968 Belgian Grand Prix
Read the rules! | DO NOT REPLY TO SPAM
2009 Pontiac G8 GT - 6.0L, 6AT - 95k miles | 1994 Chevy Blazer K5 - 350, 5MT - 140k miles | 2006 Mazda 3 S sedan - 2.3L, 5MT - 130k miles
Wife's Car: 2013 Chevy Volt - 70k miles
Bikes: 1979 Yamaha XS 750 | 1985 Honda Sabre 700


Mike is offline Mike's Gallery  
Reply With Quote
Unread 05-11-2010, 06:55 AM   #3
Spah sappin' mah susp!
 
Kenny McCormick's Avatar
 
Join Date: Jan 2009
Location: Earth...I think
Posts: 3,271
Rep: 96 Kenny McCormick will become famous soon enough
Default

My F150 likes to kick the pump off at times. I usually open it back up and it will take the gas, you just have to force the issue. It's really annoying. It may be something related to the EVAP system or some vents.


As far as the poor mileage...wow, I couldn't get my 200SX to get 22MPG if I drove it like an absolute lunatic. Which I did, most of the time. But again it may be the EVAP system, I'd fix that and see what happens.
__________________
Tired Iron ain't got no time to wear out...

My rigs:

1985 Ford F150 | 4x2 | 300ci OHV inline six | 4-speed OD manual | 310K | No power brakes | Running 100% - It hasn't driven this good in 15 years!

1984 Ford F150 | 4x2 | 300ci six | granny four | 3.55 rear end | 210K | Brakes shot. Rear drums are doing most of the work. Not fit to drive due to that.
1997 Ford Explorer XLT | 4.0L Vulcan V6 | 5-speed automatic | shift-on-the-fly 4WD | 210,000 miles | Running 95% - Needs brakes on all four corners + bald tires
1989 Ford F150 | 300cid six...again | 5-speed | 4x4 | 160K | Needs brakes done as well. Oi!

Kenny McCormick is offline  
Reply With Quote
Unread 05-11-2010, 08:25 AM   #4
Hammond Hand Luggage
 
cluffenstein's Avatar
 
Join Date: Jan 2007
Location: Chicago IL
Posts: 2,704
Rep: 61 cluffenstein will become famous soon enough
Default

I can get 35 if I drive like an old lady, 25 if I drive like a lunatic like I have been recently!
__________________
Quote:
Originally Posted by TestEcull
He may have ruined his cylinder walls and compression wings.
Quote:
Originally Posted by wierdo124
Yeah. Should hold up fine, long as you don't drive like a primate.

cluffenstein is offline cluffenstein's Gallery  
Reply With Quote
Unread 05-11-2010, 10:17 AM   #5
Retired Staff
 
Retrospekt's Avatar
 
Join Date: Jul 2006
Location: Chicago, IL
Posts: 599
Rep: 67 Retrospekt will become famous soon enough
Default

I think it may have Bosch plugs in there right now. I'm pretty sure this engine would run best on NGK or Denso plugs. Correct me if I'm wrong though. I know my 5SFE got terrible mileage on any other plug.

I'll fiddle with the evap system this weekend. It's a cracked hose somewhere as I've already replaced the purge valve itself.
__________________
Family Cars: (Bold is mine).

1998 Nissan 200sx SE | i4 1.6L | 83,000 miles | Green | Running 100% |

1996 Nissan Sentra | i4 1.6L | 122,000 miles |Black |
2001 Nissan Maxima | V6 3.0L | 94,000 miles | Black |
2010 Toyota Camry | i4 2.5L | 5,500 miles | Silver |
1993 Toyota MR2 | 2.0L i4 560HP | 26psi Boost | Unknown Mileage | White| Scary to drive

Retrospekt is offline  
Reply With Quote
Unread 05-11-2010, 05:23 PM   #6
Community Director
 
Mike's Avatar
 
Join Date: Jun 2008
Location: Minneapolis, MN
Posts: 7,602
Rep: 153 Mike has a spectacular aura aboutMike has a spectacular aura about
Default

Plugs wouldn't cause it to fluctuate.
__________________
"He shouted: 'You've won! Didn't you know?' I didn't, and it's about the nicest thing I've ever been told" -Bruce McLaren, 1968 Belgian Grand Prix
Read the rules! | DO NOT REPLY TO SPAM
2009 Pontiac G8 GT - 6.0L, 6AT - 95k miles | 1994 Chevy Blazer K5 - 350, 5MT - 140k miles | 2006 Mazda 3 S sedan - 2.3L, 5MT - 130k miles
Wife's Car: 2013 Chevy Volt - 70k miles
Bikes: 1979 Yamaha XS 750 | 1985 Honda Sabre 700


Mike is offline Mike's Gallery  
Reply With Quote
Unread 05-11-2010, 08:22 PM   #7
Retired Staff
 
Retrospekt's Avatar
 
Join Date: Jul 2006
Location: Chicago, IL
Posts: 599
Rep: 67 Retrospekt will become famous soon enough
Default

Yeah, I know that. The more I think about it though, maybe my calculations are wrong because of the pump issue. What if I'm only putting in 8 gallons when it wants 11, but I can't even know it?
__________________
Family Cars: (Bold is mine).

1998 Nissan 200sx SE | i4 1.6L | 83,000 miles | Green | Running 100% |

1996 Nissan Sentra | i4 1.6L | 122,000 miles |Black |
2001 Nissan Maxima | V6 3.0L | 94,000 miles | Black |
2010 Toyota Camry | i4 2.5L | 5,500 miles | Silver |
1993 Toyota MR2 | 2.0L i4 560HP | 26psi Boost | Unknown Mileage | White| Scary to drive

Retrospekt is offline  
Reply With Quote
Unread 05-12-2010, 05:30 AM   #8
Spah sappin' mah susp!
 
Kenny McCormick's Avatar
 
Join Date: Jan 2009
Location: Earth...I think
Posts: 3,271
Rep: 96 Kenny McCormick will become famous soon enough
Default

Maybe. But that would include someone writing down more gas than actually went into the car. So maybe the other driver is writing down 11 but only putting 8 in?
__________________
Tired Iron ain't got no time to wear out...

My rigs:

1985 Ford F150 | 4x2 | 300ci OHV inline six | 4-speed OD manual | 310K | No power brakes | Running 100% - It hasn't driven this good in 15 years!

1984 Ford F150 | 4x2 | 300ci six | granny four | 3.55 rear end | 210K | Brakes shot. Rear drums are doing most of the work. Not fit to drive due to that.
1997 Ford Explorer XLT | 4.0L Vulcan V6 | 5-speed automatic | shift-on-the-fly 4WD | 210,000 miles | Running 95% - Needs brakes on all four corners + bald tires
1989 Ford F150 | 300cid six...again | 5-speed | 4x4 | 160K | Needs brakes done as well. Oi!

Kenny McCormick is offline  
Reply With Quote
Reply

Thread Tools

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



All times are GMT -5. The time now is 10:19 PM.

Shogun Interactive Development Copyright 2015 Shogun Interactive Development. All rights reserved.