MPG Computer for 94 GM ALDL

**americasfuture2** · 07-08-2008, 05:35 PM

my 95 C4 corvette had the display. as did my brother and his wifes C4's. i believe it was a late 80's early 90's cutlass with the FE3 computer system that would also tell you this info. i am looking heavily into this as i want a mpg display for my 87 fiero gt.

ha!, a two year bump :P

**malcom2073** · 07-08-2008, 08:56 PM

This has seemed to be fairly accuarate:

MPH / (RPM * Inj Pulse Width * Inj Constant * 0.000212)

Inj Constant is the rating of your injectors in lbs/hr
The pulse width can be retrieved via most GM ALDL interfaces, same with mph and rpm.

You HAVE to average this over say, 2-3 minutes because it jumps around alot depending on if you have the car floored or no throttle at all.

This is only valid for a car with 8 injectors, and I believe only for batch fire cars as that would change the 0.0000212 constant otherwise.

**americasfuture2** · 07-08-2008, 10:35 PM

hmm, sounds hard to figure out for a v6. especially in my case. i have a 87 fiero gt with the 06 malibu 3500 and the 122730 ecm conversion from a 88 beretta. so digging up all the correct info will be very tough.

**Wagonmaster** · 04-30-2010, 04:38 PM

Old thread but I was searching around...........
EBL Flash from DYNAMICEFI.COM will do this for you. I use it for my TBI Caprice and I highly recommend it.

I also have a GranPrix center console and DIC I could sell. I pulled it out a while back to install a Riviera console. I think the DIC calculates MPG based on the VSS signal and the float level in the tank but don't quote me

At the very least it has a cool rotating compass!