Aftermarket trip computer for OBD1???

[Vettepilot]

Fixing up/restoring a 1994 GMC K1500.

I absolutely love trip computers for monitoring fuel mileage and averages and other trip info. I know it was done and offered on OBD1 computer systems because my 1987 Vette has it.

I have been searching and searching though, and cannot find a Trip Computer to add to my 1994 OBD1 GMC pickup.

Help anyone???

Thanks,
Vettepilot

 

[Vettepilot]

Still looking/hoping guys.

???

Vettepilot

 

[GoToGuy]

What fuel system did the Corvette use? How did it compute or track fuel used? I have three trip computers with fuel flow meter. The problem is TBI has the regulator and return within the throttle body. Therefore how do you account for fuel returned to tank?
I have thought about ways to engineer around it, but not fabricated anything yet.

 

[Vettepilot]

Well, the Vette (1987) uses a TPI system. I don't know if it uses a flow meter to calculate fuel use, or if it uses injector open times.

I personally don't know if the factories offered trip computers on TBI or not. I don't understand how it could be problematic... Functionally, for what we are talking about there's not much difference between TPI and TBI. Both use a two line, fuel return system, and computer controlled injectors. The only real difference is exactly where the regulator is located, and the working pressure; 9 to 12, versus around 40 or so.

Fuel flow meters are expensive, and I would be quite surprised if that's how they made the system. However, the computer would "know" how often and for how long the injectors were opened, and thus how much fuel flowed. Then, using data from the electric speedo, calculations could be made. A daunting exercise for us, but no sweat for a simple trip computer...

As far as inventing something, there's not enough TBI vehicles now to justify it.

Vettepilot

 

[GoToGuy]

Did the Vette display current MPG or was it miles to empty?
So the volume of fuel used per injector . That combined volume per time period , at what speed would give mpg. Where do find injector specifications?

 

[Vettepilot]

It showed current fuel mpg.

Injectors are rated in lbs. per hour but don't remember what the Vettes are.

Injector Flow Rate	Naturally Aspirated Engine	Engine w/ Power Adder
24 lbs./hr.	280-360 hp	240-300 hp
30 lbs./hr.	350-450 hp	300-375 hp
36 lbs./hr.	425-540 hp	350-450 hp
42 lbs./hr.	500-625 hp	410-525 hp

4 more rows

Gasoline runs 6 lbs. per gallon.

Vettepilot