88 Touchscreen - missing screens?

[KDirk]

Was perusing the owner's manual for my 88 tonight, and in the section on the ECC (CRT) under diagnostics it shows a "coolant level low" warning screen in the manual with an associated animated icon recirculating coolant. Oddly, this screen is apparently never displayed as far as I can tell. In fact, having dumped and examined the program ROM's from the CRTC, the data to create this screen is not in the program at all, so could not be displayed in any case.

This raises the question, does anyone know why this was omitted? I'd guess that there is no coolant level sensor (only a temperature sensor), and thus the functionality of this warning screen was not implemented. Could also have been due to lack of memory, as the program is rather tightly packed into a total of 64K. This one extra screen may have been cut due to space constraints, but that is only speculation.

KDirk

[Guest Mc_Reatta]

Computer memory space may have been a deciding factor over what options were implemented and what wasn't.

The software switch for options content #2 shown in BD91 has values for the washer level and oil level options, but doesn't show one for the coolant level although the BCM inputs have an input reserved for each. (BI09, 88, and 10)

There is a brake fluid level input (BI21) also, but apparently this was not considered optional.

If the 88/89 Riviera and Reatta shared the same CRTC, then maybe it was an option in the 86/87 Riviera that had to be given up to gain space for the washer and or oil level monitoring? The fact that our CRTC has the screens for the compass which was never installed in the Reatta, leads me to the conclusion that there wasn't a different PROM used in the Riviera CRTC vs. the Reatta.

[KDirk]

Mc-

you are correct that the Rivi and Reatta shared the same ROM set in the CRTC, actually they used the same CRTC period. Option configuration determined changes to (or omission of) certain screens. For example, the splash screen seen during the light show. There are bitmaps for both the Reatta and Riviera logos in the ROM. Which one gets displayed is based on option content. You already pointed out the compass, and there are - I think - 4 screens in ROM related to operation of the optional cell phone. These would only display if the factory phone was present and functional.

Something I wonder about is if the car is configured as a Riviera, if the "top down view" car image used on several of the diagnostic message screens gets changed to more closely resemble the Rivi body style. The image I get looks like a Reatta - though simplified somewhat. It should be noted that the compass screen has a view of the rear of a car on a roadway running towards the horizon. This back view of the car is clearly drawn as a Riviera, and this is hard-coded into the screen bitmap. No alternate Reatta image exists for this, as the compass was not offered, even though it will work in a Reatta if configured correctly.

Also, the 86/87 Rivi setup was actually less-advanced, as it lacked several features and screens present on the 88/89 version. I am thinking it had the same amount of ROM (2 32K chips), but the screen set design and program were a bit rough around the edges yet those first two years. I have read an account from someone involved in the program development that the screen designs and executable code were developed on an IBM 3270 mainframe, in Fortran initially. This completed program was somehow compiled into 8088 machine code and burned to PROM's.

Later, IBM offered an actual development platform to do this with a PC and the process was streamlined a lot. This is all covered in 3 separate IBM patents of which I have copies. Interesting stuff, and what I'd give for access to the development system and associated software now.

Lots of potential to improve the CRT system with new or revised screens and functions, if one is able/willing to write it in straight 8088 machine code. Without the original development tools [interpreter, compiler, macro assembler, etc.] that is the only way. I am working on some improvements, but the first few will be small, easily implemented things. Might be more exciting stuff later as I become more familiar with the way 8088 machine code programs are structured in ROM.

KDirk

[Guest Mc_Reatta]

I'm thinking the screen for low coolant level was the figment of some engineers fancy. While there is an input for a signal to the BCM, a review of the parts list for 86-93 E types shows no switch or sender in the cooling system that would provide that signal. So it doesn't look like that function was ever available in a Reatta or Riviera of those years.

Know we have some vintage Cadillac owners out there, was a low coolant warning signal available on any Caddy models.

[zoltanb]

Low coolant level is in my 87 Olds 98

[wws944]

My '90 Regal too.

BTW, the IBM 3270 was a block mode display terminal. I would imagine it was connected to some 370 follow-on (e.g., 3030 or 4300 series) running VM or maybe TSO.

Edited March 7, 2012 by wws944 (see edit history)

[Guest Mc_Reatta]

zoltanb and wss944, is the switch to determine the level built into the coolant overflow reservoir similar to the one that's in the windshield washer reservoir on our Reattas?

And I'm assuming you have a warning light telltale on the instrument panel somewhere that lights up when low.

[zoltanb]

In the Olds it is in the radiator, it flashes ared light and a high pitched warning. Sensor is in the trans cooler side.

[wws944]

zoltanb and wss944, is the switch to determine the level built into the coolant overflow reservoir similar to the one that's in the windshield washer reservoir on our Reattas?

I know it is not in the overflow tank. Good question tho... (thumbing through 90 Regal FSM...) Looks like it is on the right hand rear of the radiator in my car too. Note that the switch unit also doubles as a corrosivity sensor.

And I'm assuming you have a warning light telltale on the instrument panel somewhere that lights up when low.

Both the level switch and corrosivity sensor feed into the ECM. There is no BCM, so outputs from the ECM go straight to the IPC. One of the wires is for a 'coolant' idiot light.

Edited March 8, 2012 by wws944 (see edit history)

[Guest Mc_Reatta]

Thanks for the info guys. More hi-tech than I expected. I will have to look and see if there's a plugged port on my radiator somewhere where a sensor could be installed.

Curious why this function just seems to have faded away. Must have been problematic or not deemed important enough to justify. The function was included in the computers of that era so installing it wouldn't have been very difficult or that expensive especially in higher end models.

Must have come close to making the cut if Kevin found mention of it in the 88 owner's manual. Good question for someone to ask of the early developers of the Reatta at some point before details are lost.

[padgett]

Back in the seventies, a number of engines were lost due to overheating (particularly Vegas). My 78 Sunbird V8 had a low coolant light and a sensor in the radiator. Perhaps by 86-88 it was no longer needed.

After all, the 88 IPC has "diesel fuel only".

BTW I have several versions of MASM modified to write BIOS code.

[wws944]

Thanks for the info guys. More hi-tech than I expected. I will have to look and see if there's a plugged port on my radiator somewhere where a sensor could be installed.

I looked today. On the Regal the switch/sensor is located on the filler neck, just below the radiator cap. Looks like a little black box with a black cable hanging down housing the three wires. (Level switch, corrosivity sensor, ground.) On the Reatta, I'd think the upper tranny cooler line would get in the way. However in the Regal, the tranny cooler lines are on the drivers side of the radiator. So no issues with placement.