11-08-2012, 06:29 AM
|
#1 (permalink)
|
|
Master EcoModder
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,907
Thanks: 3,475
Thanked 2,950 Times in 1,844 Posts
|
"Repaired" ECU drops 8-9 MPG
I had a coolant leak from the water pump and during the repair, the dealer noticed that the ECU was slightly out of spec. I was not clear at the time, but I think they made a "repair" by adding a resistor in parallel in the ECU (rather than replace it - which would have cost me ~$1,000!) - and now my FE has dropped from ~45mpg down to ~38mpg. 
I have not seen mileage that low in 4+ years. I'm going to confirm that they did this, and ask if it can be reversed.
It is basically negating all my ecomods... 
|
|
|
|
 Today
|
|
|
|
Other popular topics in this forum...
|
|
|
|
|
11-08-2012, 08:18 AM
|
#2 (permalink)
|
|
Scandinavian creature
Join Date: Jun 2012
Location: Finland
Posts: 146
Thanks: 4
Thanked 27 Times in 22 Posts
|
What you mean out of spec? Now it's using more gas so it will pass the mot test?
Or they made some other mistake, not related to ECU. Same as when i disassembe/assembe some device, sometimes i have an extra scre lying around 
I first read you got increase in FE I'm going to try that increase by replacing current ECU with Megasquirt in my car in next year  |
|
|
|
|
11-08-2012, 10:05 AM
|
#3 (permalink)
|
|
Master EcoModder
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,907
Thanks: 3,475
Thanked 2,950 Times in 1,844 Posts
|
The spec they wanted to fix had to do with a temperature threshold being a degree or so off. It was fine (other than a leaking water pump).
|
|
|
|
|
11-08-2012, 10:10 AM
|
#4 (permalink)
|
|
Administrator
Join Date: Dec 2007
Location: Germantown, WI
Posts: 11,203
Thanks: 2,501
Thanked 2,586 Times in 1,554 Posts
|
It doesn't appear that you've run through a tank yet. It might just be that your SG calibration is off.
|
|
|
|
|
11-08-2012, 11:09 AM
|
#5 (permalink)
|
|
Master EcoModder
Join Date: May 2012
Location: Tampa, FL
Posts: 1,745
Thanks: 206
Thanked 420 Times in 302 Posts
|
if they did anything to the ecu, it will need to relearn your driving habits before you see optimum FE.
__________________
|
|
|
|
|
11-08-2012, 12:34 PM
|
#6 (permalink)
|
|
Master EcoModder
Join Date: Dec 2008
Location: South Jersey
Posts: 553
Thanks: 5
Thanked 45 Times in 29 Posts
|
Sometimes they will "flash" the ECU to the newest calibrations without telling you. Typically the newest calibrations decrease mpg in an effort to fix all of the "problems".
__________________
|
|
|
|
|
11-08-2012, 01:19 PM
|
#7 (permalink)
|
|
Master EcoModder
Join Date: May 2012
Location: USA
Posts: 2,643
Thanks: 1,502
Thanked 279 Times in 229 Posts
|
Is this a Scion? Its my experience if you change anything to disconnect the battery for 15 minutes, then connect, start it and leave it idling for a half hour so it relearns everything.
Sounds kind of odd a national car dealer would go through the trouble to add a resistor vs just replace the whole ecu.  |
|
|
|
|
11-08-2012, 07:17 PM
|
#8 (permalink)
|
|
Master EcoModder
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,907
Thanks: 3,475
Thanked 2,950 Times in 1,844 Posts
|
The new ECU would have cost me ~$1,000, so no thanks. I'll keep you posted.
|
|
|
|
|
11-08-2012, 07:23 PM
|
#9 (permalink)
|
|
(:
Join Date: Jan 2008
Location: up north
Posts: 12,762
Thanks: 1,585
Thanked 3,555 Times in 2,218 Posts
|
My first thought was, perhaps a sensor didn't get hooked up again and it's never going into closed loop... don't know what they did though.
|
|
|
|
|
11-08-2012, 07:25 PM
|
#10 (permalink)
|
|
Master EcoModder
Join Date: Sep 2009
Posts: 5,927
Thanks: 877
Thanked 2,024 Times in 1,304 Posts
|
What symptoms were present with the "slightly out of spec computer". If there was no check engine light or codes present, I think it is crap, frankly.
What was the justification for the "repair".
Federal emissions law requires them to replace a defective ECU for 8 years and 80k miles.
regards
Mech
|
|
|
|
|
