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1970-1995 Range Rover Classic
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95 Posts
Discussion Starter #1
Hi all,

Remembering back 30 years ago to when a friend of mine added a trip computer to his new Jeep, I was wondering if anyone with a 1995 RRC has done the same - add a computer with LED or LCD read-out to the dash that could show fuel economy, miles travelled, average speed and the like?

If so, how did you wire in the OBD cable? If anyone knows something about this I would appreciate their reply.

Thanks,

Bob
 

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95s were not OBD compliant because they didn't need to be. Here in the states OBDII was not required until model year 1996 P38s. Without knowing the specs on your buddies Jeep I would have no clue. If he had an OBDII port/96 or newer he could have used an after market kit. If he was 95 or older he most likely used a standard Chrysler trip computer. They came out as optional on higher end models and were the same basic system from83/84 on up across Dodge, Jeep, Chrysler and Plymouth. Only the keyboard and screen layout changed. He only would have needed a local junk yard and a wiring schematic.
 

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1970-1995 Range Rover Classic
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210 Posts
I have found this easy to calculate as you are stopping for fuel, oil, ATF, PSF and water so frequently; it is all hard copy from the receipts...

Seriously, I am not sure an OBD Trip computer could process the consumption rate quickly enough? : )

However, I am averaging 13/17 MPG with my 95' LWB with a 4.6l short block. My 99' P38 averages slightly better.
 

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1970-1995 Range Rover Classic
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95 Posts
Discussion Starter #4
95s were not OBD compliant because they didn't need to be. Here in the states OBDII was not required until model year 1996 P38s.
OK - thanks, since I was unclear about that. So, not knowing if this is possible, I'll ask a follow-on question: Is it possible to use an OBD or other output device to show trip/gas mileage information by integrating it into the ECU? I know the ECU shows fault codes, but I'm unclear if it possesses capabilities beyond that.

Thanks for your time!

Bob
 

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1970-1995 Range Rover Classic
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95 Posts
Discussion Starter #5
Thanks Lockettc - yes, I am using "old school" techniques to record my mileage and fuel consumption, but I'm looking to see if there were ever any after-market units that people have used. My friend used a third party's trip computer on his Jeep and I remember that he needed to wire a lot of things to show mileage traveled and gas usage. I have tried my best to find these systems today, but it seems that after the '80's, with the advent of OBD, everything taps into that system.

Bob
 

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1995-2002 Range Rover Classic
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1,413 Posts
it is such a broad subject, but basically you will have to use the signals form the oxygen sensors for fuel parameters. as far as speed, you have the abs sensors of the transducer.
OBD1 stands for on board diagnosis protocol version 1. virtually you could tap into diagnosis port under the rear of the right front seat or on a 95 right side kick panel, and read codes and engine parameters.
now you need a way to interpret this signals on demand and display the way you want it...there is where it becomes difficult, it may be something of a gadget you will have to create, as I'm sure you don't want to carry a full blow rover diagnosis tool with you. they are expensive, big, cumbersome and values are a bunch of numbers on a small screen only making sense to a mechanic.
is it worth it? only you can be the judge of such.
I have always driven vehicles with big engines, my first car was a 73 impala ss with a 454 4 barrel. fuel economy does not exist on my vocabulary so consumption on a rover is the least on my worries.
good luck on your project and keep in mind, one of the reasons for development and existence of OBD 2 is to have an easier and universal channel of communications. OBD 1 was manufacturer pertinent thus one brand to another would not share the same diag port type, location or parameters that could be read.
not being negative just realistic of your many hurdles to come.
keep us updated.
 
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