The 510 Realm

Your laugh is well chuckled good sir. Take a wild guess what I'm going to talk about again.

Got the VSS & the Electric Speedometer hooked up and went out to calibrate it. Fired up the car, got to third gear and it started behaving very odd.

my foot on the gas at a steady constant, it started jumping up and down like the fuel or air mix was dropping. It was almost like an oscillation. rev, cut, rev, cut, rev, cut.

So i unhooked the wire from the speedometer and it started running fine (albeit the code 14 issue eventually arose again after a while and some high revs). So I calibrated the Speedometer. And the speedometer started fluctuating jumping up and down in speed.

I'm not sure what is happening, but perhaps the VSS and the Speedo aren't talking properly yet? I called autometer, they said try jumping the VSS wires with a 1.5K resistor. I haven't tried it, but I wanted to ask here what the F could be going on. I even called the big guns (Ermish, Rebello Racing) and they had no idea, save for re-flashing the ECU and getting rid of the problems.

pulling hairs...handfuls.

Some days I just have NO comprehension as to how this swap actually gets done...

Your VSS could be bad. If, for example, it is providing a faulty signal (say, intermittently it peaks extremely high) the ECU would freak and cut fuel, thinking you've either exceeded the engine redline or Vmax.

Since this only occurs with the VSS hooked to the ECU, it's as good a place to start as any. To really narrow it down, I'd try connecting the VSS to the ECU as the factory has it outlined, bypassing the speedo. If you still have the same problem, try a new VSS. If not, rehook the speedo into the mix and then see what happens. If something's up then, your speedo is sending out a faulty signal. I suppose another check could be to switch the VSS wires (signal to ground, vice versa). Or hooking the outputs to a scope and checking out the signal it is sending, though next to no one has a scope any more.

I've not heard of the need to jump the VSS wires with a resistor. My KA VSS and Autometer electronic speedo had no issues.

I've read surprisingly little about hooking autometer electronic gauges iinto a 240 system. I imagine as its so simple no one thinks to cover these little bits of insanity. And when I call in my reserves and they have no clue whats up... boy... I wonder how this craziness befalls me!

I'll give those tests a try. I've got back up VSS units. I was just hoping it wasn't something else.

one last thought... are the S13 VSS for Automatics and Standards different??

RockAuto lists that there are two, looks like the bolt holes are on different sides...Could that be an issue to pay attention to? I know the current VSS is manual, but was going to dig through the junkyards for a back up. wanted to avoid Autos if they wont work..

I don't know for sure. I can't see how it would matter, but again cannot say definitively.

yeah... i wouldn't think there'd be one... who knows. maybe the gears are different? we can change those tho right??

i'll bug the auto parts store.

Things crossing my mind while trying to solve the chaos that is the code 14 VSS BS.

1 - Does the tach signal to the ECU have any connection to the Rev Limiter or Speed Cut? If the signal to the ECU from the tach is bad, will that cause issues?

2 - MAF... Its a stretch, but was suggested by McKinney. I'm not getting a MAF code, but if it was starting to act up, would it somehow interact with the speed signal via the throttle?

I might just try to get the ECU re-flashed so this just goes away. But if either one of those above thoughts are an issue, well, i'll still be digging for fire.

-R

oaklandsyd wrote:1 - Does the tach signal to the ECU have any connection to the Rev Limiter or Speed Cut? If the signal to the ECU from the tach is bad, will that cause issues?

My S14 setup did not have the tach wire to the ECU connected to anything. No issues.

oaklandsyd wrote:2 - MAF... Its a stretch, but was suggested by McKinney. I'm not getting a MAF code, but if it was starting to act up, would it somehow interact with the speed signal via the throttle?

There are extensive MAF diagnosis steps in the FSM.

oaklandsyd wrote:I might just try to get the ECU re-flashed so this just goes away. But if either one of those above thoughts are an issue, well, i'll still be digging for fire.

-R

Would seem to be easier to determine if the VSS is bad or swap it than deal with any of the above, which may create other issues.

First step, VSS stuff. Second, MAF. Third, suicide.

Just trying to plan out my weekend accordingly! I've got the FSM by my side.

thanks, as usual.

Nothing worked.

fuck.

It would be more helpful to fully document in your post what you did and what the affect was. Makes it much harder to help you when we don't know what or how you did...whatever it is that you did.

don't worry about it. taking it elsewhere. I cant do it anymore.

i ran through the tests on everything, all within limits and continuous, no pin damage. I switched the VSS wires, it ran worse. still flashing code 14.

makes no sense at all. Either the speedometer is bad, or there is some strange issue in the wiring somewhere down the line that is messed up, but is somehow impacting an unrelated system. though with ECUs everything is sort of connected...

I did find out that Auto VSS units are different. Much bigger than the manual VSS.

fuck it. thanks for the help though.

oaklandsyd wrote:Either the speedometer is bad,

Which is quite possible. Autometer has great customer service, but their gauge quality requires that great customer service

A quick test would be to bypass the speedo. VSS straight to ECU.

oaklandsyd wrote:I did find out that Auto VSS units are different. Much bigger than the manual VSS.

Bigger in the part that fits in the trans, or the part that sticks out of the trans?

Oh, I forgot to update this. I took the car to DGR in Redwood City.

They poked around found out that there was a little metal cap in the air filter that was loose, and every time the throttle was opened it sucked the metal cap against the MAF. They only heard it rattle around by chance when they shut the engine off.

Ridiculous. Don't by cheap cone filters.

Anyways, we also learned that CODE 14 is NOT the VSS code. Not exclusively. Its the code that signals the car is running in LIMP MODE.

My Non-Cali, Automatic ECUs work fine, and I went back to the mechanical speedometer.

okayfine wrote:Bigger in the part that fits in the trans, or the part that sticks out of the trans?

bigger part that goes into the trans. meaning it will not go into the trans. This is for the s13 versions, i believe.