Retrofitting an '88 Legend FE display. - Page 2 - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Reply
 
Thread Tools Display Modes
 
Old 07-09-2007, 08:42 PM   #11
Registered Member
 
GasSavers_bobski's Avatar
 
Join Date: May 2007
Posts: 463
Country: United States
Alright, I did another test run around half 55 mph, half at 70 mph and a dash of urban miles for flavor.
I reset the trip and average MPG meters first, and got a much more reasonable number as a result. I noticed that it takes a few hours for the info unit to lose it's settings when completely disconnected from power. I opened up the control unit and confirmed it has a CR-123 size battery soldered to one of the boards. I powered it up with a bench supply for a good hour this morning. If it was recording that time as 100% duty cycle on the injectors, that would explain the first test run's FE results.

Anyway, the test run results:
29.7 miles, averaging 31.2 MPG according to the unit.
I want to just apply +50% to that, but I figure I should actually go through the math to make sure that's a proper shortcut. Someone let me know if I screw up.
29.7 miles / 31.2 MPG reading = 0.952 imaginary gallons burned.
0.952 gallons / 6 imaginary injectors = 0.159 gallons actually metered.
0.159 * 4 actual injectors = 0.636 gallons actually burned.
29.7 miles / 0.636 gallons = 46.7 actual MPG.

And the alternative method...
31.2 measured MPG * 1.5 = 46.8 actual MPG.
Looks like rounding got the better of 0.1 MPG.

That's actually a new record for me, but I haven't done a full tank of highway driving since installing grille blocks. My previous record was about 42 MPG.
__________________

GasSavers_bobski is offline   Reply With Quote
Old 07-10-2007, 08:44 PM   #12
Registered Member
 
GasSavers_TomO's Avatar
 
Join Date: Oct 2006
Posts: 1,108
Country: United States
Send a message via AIM to GasSavers_TomO Send a message via MSN to GasSavers_TomO Send a message via Yahoo to GasSavers_TomO
I found a Legend today that had the FE computer in it. It seems to be part of a Bose Package from the dealer/factory. Hopefully I can start on my How-to this weekend for the OBD1 guys. I'm planning on hooking up the coolant temp and fuel sender as well to utilize those aspects of the FE display. Hopefully it will tell how many gallons and what temp the coolant is in addition to the stock cluster's needles.

Thanks Bobski for sharing the info.
__________________

__________________

Honda Civic VX Info/Links
Remember to use good Webiquette!
Quote:
Originally Posted by ezeedee View Post
controversy is an idea thought up by weak people who are too afraid to hear the truth.
GasSavers_TomO is offline   Reply With Quote
Old 07-10-2007, 09:11 PM   #13
Registered Member
 
skewbe's Avatar
 
Join Date: Jan 2007
Posts: 771
Country: United States
Excellent bobski,

are you thinking about filtering out every third injector pulse? If these came on 4 cylinders, there may be a jumper or resistor inside the unit you could change, or there might possibly a pot to calibrate it.
__________________
Standard Disclaimer
skewbe is offline   Reply With Quote
Old 07-10-2007, 10:08 PM   #14
Registered Member
 
GasSavers_TomO's Avatar
 
Join Date: Oct 2006
Posts: 1,108
Country: United States
Send a message via AIM to GasSavers_TomO Send a message via MSN to GasSavers_TomO Send a message via Yahoo to GasSavers_TomO
I opened up the unit I got today...there is no jumper, per say, that can be set for a four cylinder motor. It looks like they made a component circuit for multiplying the injector pulse reading.

This is one complex unit for being made in the 80's! All that circuitry to decipher the various inputs it looks at takes up quite a bit of space. The unit has two boards. One is a Discrete component board (all resistors and transistors) while the other board is controller ICs and drivers for the display unit.

I would need to see a schematic breakdown of the two boards to change the multiplier for the FE reading.

PS- sorry for answering this for you Bobski, I'm not trying to step on your toes or steal your fire...just helping out.
__________________

Honda Civic VX Info/Links
Remember to use good Webiquette!
Quote:
Originally Posted by ezeedee View Post
controversy is an idea thought up by weak people who are too afraid to hear the truth.
GasSavers_TomO is offline   Reply With Quote
Old 07-10-2007, 11:18 PM   #15
Registered Member
 
GasSavers_bobski's Avatar
 
Join Date: May 2007
Posts: 463
Country: United States
Haha... no problem. I'm honestly more interested in just getting the unit working with my car than figuring out it's innards, but I'll be perfectly happy to read what others have to say about it. I can generally figure out basic circuits, look up component pinouts and such. I've read a textbook on logic gates and microprocessors, but since I've never taken any formal EE courses, I have various holes in my knowledge surrounding some pretty basic stuff, like proper usage of transistors... Switching versus amplification, how to avoid releasing their magic smoke, ect.
I can reliably put things together from diagrams, but designing new devices is generally beyond me.

Skewbe: Yes, I mentioned that in one of my quoted posts. Without knowledge of exactly how the system interprets the injector pulses, it's hard to say how it will react to a galloping signal, but I'm willing to try it.

Here's a pic of the control unit's two boards... If someone wants pics of both sides to trace or whatever, speak up and I'll take em.

The yellow connector goes to the display unit (which actually has some more circuitry in it, but not nearly as much), the white connector goes to the rest of the car.
GasSavers_bobski is offline   Reply With Quote
Old 07-11-2007, 05:58 AM   #16
Registered Member
 
skewbe's Avatar
 
Join Date: Jan 2007
Posts: 771
Country: United States
Yeesh I don't see anything to adjust.

Does the thing display RPM? Just thinking out loud here but you will have to tweak the pulse width if you want to keep that working too.

I dug up a dwell circuit on the diy mpg thread, that can take the injector duty cycle and turn it into a voltage. If there is a PWM circuit that can take a voltage and an rpm trigger signal and turn it into a signal of the same frequency but with a proportional pulse width...
__________________
Standard Disclaimer
skewbe is offline   Reply With Quote
Old 07-11-2007, 06:48 AM   #17
Registered Member
 
GasSavers_bobski's Avatar
 
Join Date: May 2007
Posts: 463
Country: United States
Quote:
Originally Posted by skewbe View Post
Does the thing display RPM?
Not that I'm aware of. I'm not even sure why it watches the coolant gauge sender. An overheat warning maybe?
GasSavers_bobski is offline   Reply With Quote
Old 07-11-2007, 06:46 PM   #18
Registered Member
 
GasSavers_TomO's Avatar
 
Join Date: Oct 2006
Posts: 1,108
Country: United States
Send a message via AIM to GasSavers_TomO Send a message via MSN to GasSavers_TomO Send a message via Yahoo to GasSavers_TomO
I'm guessing that the unit can display the temp as well as a low coolant warning for the coolant. Although I am just guessing here. It will be a week or two before I can start on installing my unit as I'm in the middle of renovating two decks at a friend's house (getting some great numbers for FE since it's all highway). I'll make a how-to and a report on the unit then.
__________________

Honda Civic VX Info/Links
Remember to use good Webiquette!
Quote:
Originally Posted by ezeedee View Post
controversy is an idea thought up by weak people who are too afraid to hear the truth.
GasSavers_TomO is offline   Reply With Quote
Old 07-12-2007, 02:22 PM   #19
Registered Member
 
GasSavers_bobski's Avatar
 
Join Date: May 2007
Posts: 463
Country: United States
While looking for a '94+ Integra gauge cluster (the yard sells whole clusters cheaper than a replacement lens - what I actually need - from Acura), I came across a '90 Legend today that had the owner's manual sitting on the front seat.
It's got 5 pages on the info system... I'll post them shortly. Gotta take pics and clean them up a little.
Taking a hint from the manual pages, I also found the odometer set function. Switch to the next service odometer page, and hold down the hour/-> button for 3 secs. The min/0-9 button changes the number, hour/-> switches to the next digit, and reset/set finishes.

Pages:




GasSavers_bobski is offline   Reply With Quote
Old 07-12-2007, 07:36 PM   #20
Registered Member
 
GasSavers_TomO's Avatar
 
Join Date: Oct 2006
Posts: 1,108
Country: United States
Send a message via AIM to GasSavers_TomO Send a message via MSN to GasSavers_TomO Send a message via Yahoo to GasSavers_TomO
Nice score Bobski!
__________________

__________________

Honda Civic VX Info/Links
Remember to use good Webiquette!
Quote:
Originally Posted by ezeedee View Post
controversy is an idea thought up by weak people who are too afraid to hear the truth.
GasSavers_TomO is offline   Reply With Quote
Reply

Thread Tools
Display Modes

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 Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
google+ integration? xchrislee Fuelly Web Support and Community News 3 07-15-2011 02:55 AM
GasSavers.org Stickers Matt Timion Fuelly Web Support and Community News 7 10-12-2006 04:48 PM
FFI GasSavers_MPGmaker Introduce Yourself - New member Welcome 39 05-30-2006 04:31 PM
State of the Union address touches on "oil addiction." Matt Timion General Discussion (Off-Topic) 31 02-06-2006 04:38 PM
Where to get parts? What parts do we need? Matt Timion Electric and Solar powered 11 09-19-2005 09:37 PM

Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 10:50 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.