Cadillac mpg gauge transplant?

[jwxr7]

I just got back from the junk yard looking for trip computers. I found at least 8 late 80s early 90s cadillacs with the same mpg readouts.
The guy said $20 for one. They are mounted in the dash to left of the steering column. It shows instant and average mpg + range and gallons i believe. One car already had the dash apart so i could see the 9 wire harness running to the unit. Does anybody here know anything about these displays? I need to know if there is more to it than the box with the display. If anyone has a manual with wiring diagrams that could help, please let me know. This could be a good supply of readouts to retrofit to our pre obd2 cars.

[Flatland2D]

They are probably designed for carbuerated engines.

[jwxr7]

No, these are fuel injected 4.5l v-8s. Looks like a throttle body with two injectors on it. Most were 1988-1990 DeVilles and one was an 89' fleetwood.

[Bill in Houston]

Seems like it should be for TBI or even port fuel injection, by late 80s and early 90s... OOPS I type too slowly

[unstable bob]

Originally Posted by Flatland2D

They are probably designed for carbuerated engines.

I just retired a 90 Caddy Fleetwood that had the trip computer, and the engine was port fuel injected. I don't know if my situation was an isolated case, but I found the trip computer to be pretty inaccurate. For example, it would be giving me a average reading of 23 MPG, but when I did the math and figured it out I was only getting 19 MPG.

[jwxr7]

Originally Posted by unstable bob

I just retired a 90 Caddy Fleetwood that had the trip computer, and the engine was port fuel injected. I don't know if my situation was an isolated case, but I found the trip computer to be pretty inaccurate. For example, it would be giving me a average reading of 23 MPG, but when I did the math and figured it out I was only getting 19 MPG.

That's okay as long as i can get a relative readout to go by. Do you have a repair manual for it still?

[unstable bob]

Originally Posted by jwxr7

That's okay as long as i can get a relative readout to go by. Do you have a repair manual for it still?

Sorry, never got the manual for the car. I prolly should have, though, 'cause it turned out to be a big POS.

[jwxr7]

Oh well, thanks anyway.

[Bill in Houston]

Ebay maybe for the manual?

[minic6]

jwxr7 Check out some of the search engines. Lots of things that I wanted to know were found right on the web. As it was stated they are pretty poor at there results. Problem was it wasn't always constant. They were if memory serves tied into the ecm.