94-95 Grand Prix Trip Computer

[GnatGoSplat]

Did 94-95 Grand Prix's with 3.4 DOHC ever come with the trip computer option?

 

Or has anyone put the factory trip computer in a 94-95 GP w/3.4?

[Guest Anonymous]

i have, it works fine in my GT, which is the 3.4

[Guest Anonymous]

Why do you ask?

[THe_DeTAiL3R]

This 94 GTP looks like it has it, although hard to see in the pic

http://www.cardomain.com/memberpage/646206

 

This one here has it, but looks like he's part of a GP club so possible he added it?

http://www.cardomain.com/memberpage/567098

[Guest Anonymous]

I have seen many 94-5 3.4 cars with the trip computer, original from factory.

[GP1138]

My DIC probably came out of a car with a 3.4 DOHC.

[GnatGoSplat]

Why do you ask?

 

I'm thinking MAYBE the Olds trip computer I put in my 94 Cutlass MIGHT work if I get a MEMCAL out of a GP with trip computer.

 

My reason for thinking this is I was looking at the program code from a 94 3.4 DOHC MEMCAL, and there is NO fuel data at all going to the ALDL. Even a 94-95 GP trip computer has to get its fuel data from somewhere! So that means there must be some additional data on the ALDL of a 94-95 GP 3.4 w/trip computer.

 

Perhaps that MEMCAL has some special code that enables fuel data output!

Would ya loan me the MEMCAL from your 94 for a couple weeks?

[Guest Anonymous]

I dont quite follow what you are saying... you are putting in an olds trip computer. ok. what year is it from? If its the same year, then shouldnt it work? But if its obd 1, it wont worn anyway? I'm confused.

[GnatGoSplat]

I put a trip computer in my 94 Cutlass 3.4 DOHC.

Everything works except the fuel econ stuff. They didn't put trip computers in Cutlasses after 91.

I connected my laptop to the ALDL and I discovered the reason: no fuel data is being sent! 94-95 3.4 DOHC's aren't like 88-93's where the fuel data is being sent on the ALDL. The fuel data is 4-bytes before the coolant temp data. I got a program code listing for a 91-93 DOHC, and I see those 4-bytes contains an injector constant and gallons per hour fuel consumption. On a 94-95 DOHC listing, those bytes only points to "reserved data for testing" (basically nothing).

 

All 94-95 W-bodies with 3.4 DOHC use the same PCM. So if a 94-95 GP w/3.4 DOHC has a functional trip computer, there MUST be fuel data being sent on its ALDL.

 

So I'm hoping that if 94-95 GP's w/3.4 DOHC actually have fuel data on their ALDLs, then if I put a GP MEMCAL in my Cutlass, it might make the trip computer work.

[Psych0matt]

if you figure out how to do this, I would love you eternally (provided you tell me how)

[GnatGoSplat]

I think my theory doesn't hold water.

I just checked my parts catalogs, and don't see any differentiation in MEMCALs between cars with trip computer and cars without. The only fuel related data on the ALDL on 94-95 3.4 DOHC cars is something called ACCUMULATED FUEL. It's possible 94-95 GP trip computers can calculate fuel econ using that parameter alone, but to know for sure I'll need to figure out what that parameter means.