Hacking the Saturn Cruise Control ...

[cfg83]

Hello -

I think I have a solution for steady-state cruise control. Here is the wiring diagram :

Attachment 789

Here is how you use it :

1 - Put switch in position that allows for normal cruise control operation. I think this is in the position where "load" and "power" are connected.

2 - Use cruise control as normal to establish desired cruising speed on the flat.

3 - Flip switch.

Once you flip the switch, the cruise control will stay steady on the flat, and will lose speed going uphill, which is what we want.

All of the other CC safety features are present. If I hit the brakes, the CC releases. Once I have released, I need to flip the switch back to set the CC as normal.

Bonus Feature : I used a lighted switch. Since the WOT/IDLE input operates on 12 volt "pulses", I can see the ECU/PCM send signals to the CC Module. On the lighted switch, it looks like morse code. The funny thing is, I can see the ECU/PCM get upset at the CC module. When I am going uphill, it starts flashing signals to the CC module. Eventually, the light on the switch just stays on because the CC module is not responding.

Question : In the above situation, the ScanGauge shows a TPS setting of 0 even though the accelerator pedal is being held in place. Does this make sense? I think this is an symptom of the ECU/PCM being upset with the CC module.

Requirements : lighted switch and gauge of wiring rated at 12 volts / 5 Amps. I chose 5 amps because that is what the fuse for the CC is rated at.

CarloSW2

[cfg83]

Whoops -

Originally Posted by cfg83

...

Bonus Feature : I used a lighted switch. Since the WOT/IDLE input operates on 12 volt "pulses", I can see the ECU/PCM send signals to the CC Module. On the lighted switch, it looks like morse code. The funny thing is, I can see the ECU/PCM get upset at the CC module. When I am going uphill, it starts flashing signals to the CC module. Eventually, the light on the switch just stays on because the CC module is not responding.

...

It isn't as good as I had hoped. When the light "just stays on", that's a sign that the ECU/PCM has given up and let the car decelerate out of CC. I couldn't tell this earlier today because the incline wasn't severe enough to notice the speed drop.

Oh well, I think I'll stop here for now. I like it anyway because now I can "see" what the ECU/PCM is saying to the CC module. Very Star Trekky.

CarloSW2

[cfg83]

Hello -

I recently lost my CC due to my 5th gear swap, so my hacking priorities have changed. I would like to restore my CC funcitonality. Here is something interesting I read over at saturnfans.com :

Start engine w/o clutch
http://www.saturnfans.com/forums/showthread.php?t=65142

The clutch switch does NOT disengage the cruise control. It's at the bottom of the clutch pedal travel. Before it ever closes, the PCM has determined that the revs are skyrocketing upward, but the vehicle speed isn't going up, therefore the clutch is being disengaged, and has thus interrupted the cruise. Obvious test for this: put the clutch down part-way with the cruise engage. You won't open the clutch-starter switch, but the cruise will disengage.

I had a Dodge Omni that had a cruise interrupt switch at the top of the travel, exactly like the brake pedal switch. But the S-cars, at least in '96, have no such switch.

The day I bought my waggin, I unplugged my clutch-starter safety switch, made a jumper out of about six inches of 18-gauge wire with a .250 male blade connector on each end, and jumpered the terminals on the connector. The main reason I did this: imagine your PCM going up the spout. Or your coil packs. Or even something on the fuel side, like the fuel pump. You still have the starter, but the engine obviously won't fire. You're in a bad spot, one that's dangerous in which to get out and push, but 50 feet ahead is a driveway to a parking lot. Well, turn the key, let the clutch up, and for a BRIEF moment, let the starter motor propel the car to a safe spot. I've done this on at least two occasions with previous cars, and would never own a stick-mobile without this capability. Just don't do this for more than a few seconds, as that little electric motor is designed for vehicle propulsion.

Plus, it's nice while working on the car just to reach in thru the window, throw the tranny into neutral and twist the key to start 'er up.

Oh, and I use the cruise almost every time I drive.

If this works, I will get my CC back.

Segway : Notice from the post that *if* you had a super-beefy-macho-tough-guy starter to go with a similar battery configuration, you might have the parts needed to create an "auto-start-and-go" from engine-off at a stop.

CarloSW2

[skewbe]

Dang, you were gonna scope that clutch out signal (lt blue) Does cruise still work in 4th? If so I still hold out hope that you can interrupt/"fake out" the clutch out signal that the pcm sends to the cruise module (because it now thinks the clutch is slipping with the new 5th gear not matching the expected vehicle speed).

If you could, stick a pin in that wire and hook up a volt meter connected to it and ground via some alligator jumpers and note the voltage when cruise is working and again when the clutch is in.

[cfg83]

skewbe -

Originally Posted by skewbe

Dang, you were gonna scope that clutch out signal (lt blue) Does cruise still work in 4th? If so I still hold out hope that you can interrupt/"fake out" the clutch out signal that the pcm sends to the cruise module (because it now thinks the clutch is slipping with the new 5th gear not matching the expected vehicle speed).

I never got to the blue line because it was a PITA to cut the first two lines. I *think* it works in 4th but I have been obsessed with 5th the past few days, so I haven't spent much time in 4th.

CarloSW2

[cfg83]

skewbe -

Originally Posted by cfg83

...

I never got to the blue line because it was a PITA to cut the first two lines. I *think* it works in 4th but I have been obsessed with 5th the past few days, so I haven't spent much time in 4th.

CarloSW2

4th still works. But it looks like the CC hack from saturnfans is for a 1st gen Saturn CC :

http://www.saturnfans.com/forums/sho...4&postcount=23

I may see if I can do it anyway, since it seems like an easy mod.

CarloSW2

[skewbe]

You do not have a switch at the top of the clutch pedal travel though.

The pcm generates that signal in newer saturns AFAICT, that is why I want to know what a valid signal looks like so we can fake it out. Sitck a pin in that lt blu wire for me and measure the voltage to ground with cruise working and again with the clutch in please.

[GasSavers_Dust]

Any update on this one guys?

[cfg83]

Dust -

Originally Posted by Dust

Any update on this one guys?

No, I ran out of steam, . I should have done what skewbe said (access the voltage signal of the blue line), but I inverted myself in the driver's seat to get under the dash for the first two lines, and I didn't have the stomach to do it again.

CarloSW2

[GasSavers_Dust]

I would buy you dinner, and I am sure that alot of other saturn owners would love to know how to get the 5th gear swap to work with cruise.