Instant MPG Stuck at 0
Thread Starter
Instructor
Joined: Mar 2007
Posts: 174
Likes: 0
From: Lithia FL
Instant MPG Stuck at 0
On my '88 I have lost the Miles per gallon quit calculating on the Atari dash display. The LED lights but for instant mileage all I see is 0 (yes when I'm driving also) and the average mileage says 99.
Any thoughts or ideas?
Thanks
Any thoughts or ideas?
Thanks
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
Atari
I once had a bad ecm that made the fuel calculations go nuts. In my case, the car would start normal, I would back it out of the garage, press the garage clicker, and when I looked back at the dash, the mileage was 0, the instant was 0 also, and the MPG went to 0 also.
when the ECM warmed up a little, it was just like I pulled the battery cable, and reconnected it, and everything started from ground zero.
The mileage was counting like I had hit the reset button, and the car had to read the gas gauge to determine miles left in the gas tank, and the average and instant were starting from scratch.
my vote is a cold solder joint on the ECM main computer board.
Oh, and the speedomete went a little nuts, and on occasion, the RPM of the engine wouldn't go below 1700 RPM. Then suddenly, the engine went to 500 RPM idle, and the fuel calculations came back.
Changing the ECM fixed it.
when the ECM warmed up a little, it was just like I pulled the battery cable, and reconnected it, and everything started from ground zero.
The mileage was counting like I had hit the reset button, and the car had to read the gas gauge to determine miles left in the gas tank, and the average and instant were starting from scratch.
my vote is a cold solder joint on the ECM main computer board.
Oh, and the speedomete went a little nuts, and on occasion, the RPM of the engine wouldn't go below 1700 RPM. Then suddenly, the engine went to 500 RPM idle, and the fuel calculations came back.
Changing the ECM fixed it.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
If your speedo still works, it has to be ECM related, or the connections to it.
