Another trip computer question

Site Subscriber Joined: 10 Jun 2004 Posts: 2317

How does the trip computer work out milage? I'm assuming its distance travelled devided by fuel used? I'm asking becuase, this morning I reset my trip as I left the house and as i was coming in to town (about 12 miles) it was reading 5.7 miles, so under reading by about 50%. I'd assume this would throw everything else off including reported mpg?

Cheers

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

pin 26 of the ECU is the serial out for the trip iirc.

Basically its inputs come from road speed, engine speed, throttle position and injector pulsewidth.

If its under-reading then yes everything else will be off but I would imagine it would stall a lot to go along with it.

Unless your running large wheels.

edited due to my terrible typing, I barely understood it

Site Subscriber Joined: 10 Jun 2004 Posts: 2317

Nope, standard wheels. What would cause the distance travelled section of the trip to be out by so much? Im guessing its the roadspeed sensor?

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

aye

Level 2 User Joined: 06 Mar 2005 Posts: 44

Chris H wrote:

pin 26 of the ECU is the serial out for the trip iirc.

Basically its inputs come from road speed, engine speed, throttle position and injector pulsewidth.

If its under-reading then yes everything else will be off but I would imagine it would stall a lot to go along with it.

Unless your running large wheels.

edited due to my terrible typing, I barely understood it

Hmmmm, do you know what form of serial it is Chris? (baud rate... ttl serial i presume?) and is it in an easy format to parse out?

Thanks again,

Matt

Forum Moderator Joined: 02 Mar 2004 Posts: 19978

not got a clue and renault don;t do things liek foord or vag which is easy.

Thus I don't have a scooby doo matey