Cel 17 - Vss - Fuel Economy, Hypermiling, EcoModding News and Forum

SVOboy · 06-21-2008, 11:09 PM

Only comes on during engine braking, anyone know what might be up with that?

<3

Red · 06-21-2008, 11:29 PM

Wire grounding out?

SVOboy · 06-21-2008, 11:29 PM

Why would it do that while I was engine braking though?

dremd · 06-22-2008, 12:05 AM

engine shifting over in one direction could short/ break a wire.

not saying that iss your issue. . .

SVOboy · 06-22-2008, 12:15 AM

Nah, that's not it. I did all the wiring myself on it...might just rip it out and redo.

Red · 06-22-2008, 01:06 AM

Yeah the engine moving around in its mounts could do it.

reformed · 06-22-2008, 03:23 AM

Put a test light on your VSS and see if you see any changes during normal driving and engine braking. I believe the computer uses the fuel cut-off during engine braking because it combines the TPS readings with the VSS readings so that may have something to do with it, maybe the readings are off from normal and it only can see a descrepency (sp?) during engine braking.

fritz · 06-22-2008, 03:17 PM

Why would it do that while I was engine braking though?

The way you test to see if the vss is working is to see if the CEL light comes on during engine breaking. In my crx the screw connection on the back of the cluster came loose and I got a CEL. Maybe that's the only way it can tell that you are not sitting still revving the engine

According to the manual you need to jack up the front wheels and rotate the front left tire to see if the voltage pulses between 0 and 5 Volts with the meter
on b10 yellow/blue and ground at the ecu. If your speedo is working then the vss is working and you must have a bad wire. Run an new wire from the supermid to the ecu?

The attachment is from the crx mpfi manual so it uses a different connection at the ecu for obd0

reformed · 06-22-2008, 06:22 PM

Are you using the VX trans? This may not be the issue but I'm just brainstorming a little here... If you aren't using the VX trans then maybe the VSS in your transmission is operating in a different voltage range than in a VX trans and the VX computer sees this as a malfunction. If you are using a VX/CX trans then forget everything you just read here.

SVOboy · 06-22-2008, 06:42 PM

I'm using an HF trans with a random vss not original to the car or transmission. It did this before the vx swap...just did it again so I did a little eoc and then the car wouldn't bump start back to life...I think the main relay must be dying.