bad mileage question

Reply Subscribe

Thread Tools

Search this Thread

Nov 24, 2003 | 09:29 AM

FNG

Thread Starter

Instructor

Joined: Mar 2002

Posts: 247

Likes: 0

From: las vegas nv

bad mileage question

hi guys. just got through going through the fuel system on my 85. new from pump to injecters. new filter, fpr, injecters, throttle body. everything. was cruising down the street and mileage went from 16 to 11. from the archives ive read , should be the coolant sensor, or maybe the ecm. 02 senser is new.

so my question i guess, is that the way the coolant senor goes out, just all of a sudden?? would the ecm go out the same way?? the car runs strong, just gets really crappy mileage all of a sudden. thanks guys, ill get this thing right one way or the other with a little help from the forum :D regards, fng

Nov 24, 2003 | 02:14 PM

George Dickel

Pro

Joined: Aug 2001

Posts: 617

Likes: 14

From: Loudon, TN

Re: bad mileage question (FNG)

Figure your mileage the old way before computers. Check actual gas mileage by the odometer and amount of gas to fill the tank. Could be the computer has messed up. Not financially sound to start changing sensors and such if the computer is broke. If the mileage agrees with the computer then start changing sensors.

Nov 24, 2003 | 07:06 PM

greg84

Burning Brakes

Joined: Apr 1999

Posts: 754

Likes: 0

From: Lehighton PA

Re: bad mileage question (FNG)

hi,any engine codes or check engine light on your dash? greg84 :cool:

Nov 24, 2003 | 07:24 PM

Davidsvette85

Advanced

Joined: Sep 2003

Posts: 56

Likes: 0

From: waxahachie texas

Re: bad mileage question (FNG)

I hope what I'm about to tell you is not your problem. My 85 three years ago was getting 18 in the city and as I added new sensors and things on the car and a year or two went by I was getting 14 if I was lucky. Couldn't figure it out at all. Then I started having some more problems so I finially threw my hands up drove it to a shop and told them to pull out the motor and completely overhaul it. And I told them I wanted to know everything they found bad. Well the first thing they called me on was I had 8 teeth missing from my cam timing gear, they were in the pan. The car still felt good and ran good but it had started overheating that was why I took it in. But the timing was off 2 degrees one time out of three times I checked it and the shop told me it could of had the right timing at idle but it may have been changing too much when I was driving it. If you have never changed the timing gears or no one has that you know of the cam gear has aluminum teeth on it. Mine is doing really good now and is getting 18.6 in the city. Check your timing over and over at different times and see if it stays the same.

Nov 24, 2003 | 09:00 PM

FNG

Thread Starter

Instructor

Joined: Mar 2002

Posts: 247

Likes: 0

From: las vegas nv

Re: bad mileage question (Davidsvette85)

greg........no no codes and car runs great

davevette......no overheating, timing is rock solid.

thanks for the input. got a senser today, 12 bux my cost. will try it and see what happens. thanks again, regards, fng

Nov 24, 2003 | 09:12 PM

severe-1

Racer

Joined: Jun 2002

Posts: 411

Likes: 0

From: Palm City FL

Re: bad mileage question (FNG)

If I make alot of stops (bank, store, lunch etc..) my gas mileage falls way off.
Are you making alot of short trips lately?

Nov 25, 2003 | 07:06 PM

greg84

Burning Brakes

Joined: Apr 1999

Posts: 754

Likes: 0

From: Lehighton PA

Re: bad mileage question (FNG)

is your tcc working the way it should?this summer when doing highway driving i was lucky getting 16mpg and it was throwing me a vss code,after troubleshooting the code i found that the feed wire from the computer to the tcc soldnoid was broken.once i repaired the wire the mpg jumped up to 24-26 mpg.good luck greg84 :cool: