EOC in a Saturn

[Christ]

Originally Posted by BackroadBomber

Hi, you wouldn't happen do have a subwoofer or any additional electrical devices in the car, would you? My one friend had a saturn with a subwoofer in it and the saturn transmission has some sort of electronic shift assist or something and my buddies car would never shift right and throw a cel (don't remember what code) if his system was on, even when it was on low power.

Nope, and the sub/amp probably wasn't his problem, so much as how/where it was wired.

My best guess for the service wrench is the CC module, since the two lights associated with it work, and the ECT is brand new ( and the coolant temp gauge is correct).

[Frank Lee]

Those coasting distances are way gooder than I've ever done.

Do that route in the other direction and see how it goes.

[Christ]

It shouldn't be too bad, on another part of the same route, going the other direction. Obviously, I won't do so well in the other direction, as it's a downhill preference.

I was just pointing out that the Saturn coasts like a dream.

If I get a chance before winter, I'm going to do a EOC coast down test on the flats, since there's a marked 1/4 mile there.

[dcb]

Originally Posted by Christ

The car doesn't run right, so instead of coasting in neutral (watching the RPMs jump to 2k+)...

The quick fix for a saturn (and maybe others) is to warm it up, turn on some accessories, and while it is idling good, unplug the idle control valve connector (lower plug by the throttle body/firewall). Then use your foot for idle speed control when it is cold

[Christ]

I did that in my Civic for awhile, until I ended up just opening the throttle plate a bit and blocking off the IACV.

Alas, it's the wife's car... she'd never go for that.

[dcb]

Did your civic rev it up to 2k rpm when coasting? I thought it was just some saturn idiocy. Well it is conceivable to take one of those atmega chips (whatever) and make a better idle speed controller, I've just never gotten around to it, want to get my cruise control back first (97 computer with a 92 stick shift), will probably recruit a microcontroller for that, read the resistive buttons plus whatever else, and control the pedal.

[Christ]

My Civic did the IAC dance... it would rev to 1400RPM, then cut fuel and drop back to 775, then rev up, then drop, then rev up, then drop. I could let the clutch out in gear, and it would drive the car up to 1400 RPM, then cut fuel.

It's two things that cause it on the Civic - TPS and IACV. The IACV only works if the TPS is at or below 1%, to keep the engine idling. When the TPS gives the wrong signal, or the IACV isn't adjusted properly, the CAS (crank angle sensor) and TPS start talking to each other, and notice that the engine is getting up to unreasonable idle speeds. Once they get to the DFCO point (1400 RPM), the ECU reads the signal, cuts the fuel, and the engine speed drops.

Lather, rinse, repeat.

I don't think the Saturn has quite the same feedback loop, but the symptoms are close.

Also, the Civic, like most other cars, does increase idle when moving under no load, but not 2k.

I think I'm going to figure out why it's doing it in the first place before I start working magic on it.