ECM question

[CTX-SLPR]

Howdy,

This may seem like a highly unusual question but I'm going to ask anyway. Whats the relationship between the stock ECM on a turbo regal and the stock ECM on say an early turbo grand prix? The general direction of this question is can I add a headsup display off of an late 80 turbo grand prix to the stock system?

Thanks,

 

[dennisL]

I don't know which ecm is in the late 80's gran prix but there's a good chance its not the 1227148 which we have. I have to wonder though, is the heads-up display being control by the ecm or the instrument cluster? (My 97 Park Avenue Ultra displays mph and turn signal arrows and I'm pretty sure it is controlled by the instrument cluster.)

Oh, I also owned a 65 Riviera GS, but had to sell her. I miss her (wiping tear from eye).

 

[CTX-SLPR]

Howdy,

Yeah it was tough watching her go onto that trailer, but atleast I know she is going to a good home. I think the HUD has its own onboard translator that takes inputs from various sources, however some of those go through the ECM. Here is a Link to a guy that has done all sorts of stuff to his Impalla , good read for anyone thinking about this.

 

[bruce]

Turbo Grand Prix ran the 8F code, with a P4 ecm. The TRs run a 31 code with a C3 ecm. They are very different animals.

The 8F code is just a bear to work with. It has all the bells and whistles in the code of some of the latest PCMs. Cat converter overheat, abuse mode, yada, yada.

There is code in the 31 for supporting the GM Development HUD, that wasn't displayed on the glass but rather in a supplemential dash.

Normally the HUD windsheilds have some gold flakes impregnated into them for the HUD, on some cars that adds $400 to the price of the glass.

Makes a Scanmaster look real reasonable, IMO.

 

[dennisL]

I checked out the Impala mod and did find it interesting. It turns out the HUD does need the ecm or pcm as its called now-a-days. Powertrain Control Module. It requires the vehicle speed output from the pcm. The remainder of the displayed items are driven by the instrument cluster.

The ecms in our cars are parsimonious and only output scan tool data. I suppose if you had a digital dash, you might be able to tap into the mph ... don't know (?)

 

[CTX-SLPR]

Howdy,

One way around the VSS (Vehicle Speed Sensor) is to use the sending unit for an Autometer electronic Speedometer. I called Summit and confirmed that there is no difference between the sender and a VSS. The nice thing about the Autometer sender is that it not only works as a sensor but it also has a drive outlet so you can continue using the the cable drive section for your speedometer, though it was orginally intended for driving cable driven cruise controll setups. Since I was planning on building an anolog dash out of autometer gages anyway this works out pretty well.

Thanks for the detective work,

 

[S10xGN]

That's all I saw when I looked at the diagram - just a 4k pulse/mile input. Which I'm already getting from my Dakota Digital speed interface (SGI-5). There are prolly cheaper ways to go, but this interface is pretty darn versatile...