Speed Sensor???

jelliott510 · Post by **jelliott510** » Tue Mar 20, 2007 2:20 pm

What are you guys doing about the speed sensor? Or should I call it a reed switch that is in the speedo. I have an old TMO chipped ecu and it turns the check engine light on as where the stock ecu does not, when the sensor goes bad. I tore apart the stock DSM speedo and removed the sensor. Any ideas.

Post by **DJpowerHaus** » Tue Mar 20, 2007 3:00 pm

I never had any trouble with that sensor in the Starion dash. What's it for anyways. I cant imagine the ECU would need a speed sensor.

jelliott510 · Post by **jelliott510** » Tue Mar 20, 2007 3:43 pm

The ECU uses the signal to know when to car is moving. What does with that signal I have no clue. That was part of the TMO chip upgrade. I don't know why they did it that way. All I know is that the check engine light was not set to come on if the sensor was bad from factory. The TMO chip has it set that way. I can't remember why. I've had the ecu for several (5-6)
years. If the Starion has the same sensor, then you are set.

tumuchNOS · Post by **tumuchNOS** » Tue Mar 20, 2007 8:43 pm

They did that for launch control and no lift to shift functions. DSM link uses the same imputs for both of those functions. I am still trying to figure out what will send a similar pulse width, (Tom at DSMlink sent me the pattern) and matches the D50/mightymax speedo lug, then I can finally leave with boost.

jeffball610 · Post by **jeffball610** » Thu Mar 22, 2007 5:35 pm

If this is a 1G DSM, the speedo is run off of a cable. The no lift to shift and such has more to do with the clutch signal. It's just a little switch that reads if the clutch is engaged or not. Some guys remove this switch on the 2G to keep from pushing the clutch to start causing a dry startup on the crank that some believe leads to crankwalk. I'll check my CEL codes and see if the speedo one comes up with anything that I can track down.

tumuchNOS · Post by **tumuchNOS** » Sat Mar 24, 2007 11:37 am

jeffball610 wrote:If this is a 1G DSM, the speedo is run off of a cable. The no lift to shift and such has more to do with the clutch signal. It's just a little switch that reads if the clutch is engaged or not. Some guys remove this switch on the 2G to keep from pushing the clutch to start causing a dry startup on the crank that some believe leads to crankwalk. I'll check my CEL codes and see if the speedo one comes up with anything that I can track down.

The cable leads to a speed sensor in the instrument cluster(1G or not), its called a VSS. And if the ECM dosent know that the car is moving, how can it tell the difference between launching and NLTS? I have driven several cars with TMO's and the cutout is different when shifting than launching in my experience.

89coltgt · Post by **89coltgt** » Sun May 06, 2007 12:13 am

I take it that not running the vss on an automatic will not have any effect?

jeffball610 · Post by **jeffball610** » Mon May 07, 2007 6:47 pm

The no lift to shift mod works with the clutch pedal sensor, not the speedo. It limits the revs when the clutch is pressed. It's the same rev limit you set when you do your launch rev limit. I know there is a pinout on the ECU for a speed sensor, but I have no idea what it's for. I'm pretty sure it has nothing to do with engine function or tuning.

kezark31 · Post by **kezark31** » Sat May 16, 2009 12:36 pm

the ecu uses the vss to know when you are slowing down so it can help keep the car from dying when coming to a stop. anti-stall

4g63mightymax · Post by **4g63mightymax** » Tue May 19, 2009 4:58 pm

I am running a stock 90 ECU in my truck, and have never hooked up the speed sensor wire. For 3 years, it has been perfectly fine. Sadly, I have zero experience with the chipped ECU's. However, from what I understand, they need the VSS to determine different rev limiters. So if you are launching, the rev limit is X rpm, and if you are doing 60 mph, the rev limiter is higher. Without that sensor hooked up, your ECU probably freaks out and sets the CEL. I bet it would work fine if you had a chip without the rev limiters modified.

-Jeremy

Post by **DJpowerHaus** » Wed May 20, 2009 12:37 am

tumuchNOS wrote:They did that for launch control and no lift to shift functions. DSM link uses the same imputs for both of those functions. I am still trying to figure out what will send a similar pulse width, (Tom at DSMlink sent me the pattern) and matches the D50/mightymax speedo lug, then I can finally leave with boost.

If the dash doesn't put out the right signal, you may want to try the pulse generator from the Starion. It goes on the transmission and generates a pulse signal that was used by the Starions for the Rear ABS.

4g63opelgt · Post by **4g63opelgt** » Tue Jun 30, 2009 10:40 am

Hello,
I have been doing some research on the speed sensor. It seems that most people are taking a second gen speed sensor (which moves it from the gauge cluster to the tranny) and wiring it to provide a signal to the ECU. I tried to cut and paste the article off DSMlink forums, but none of the pics came through. If you want, I can see if I can cut and paste again. Atleast you will have the text. I know you are probably not using a first gen tranny, but if you are using a Mitsubishi tranny, you may be able to use it.

4g63opelgt · Post by **4g63opelgt** » Tue Jun 30, 2009 10:45 am

I've seen a few folks inquire about how to exactly install a 2g VSS (speed sensor) into a 1g for use with DSMLink and an aftermarket speedometer, and I finally got it all figured out on my car (thanks to Paul over at www.symtechlabs.com) over the past weekend.

The first part is pretty straight forward, replace the speed sensor in the transmission with the 2g unit, and run it +12v, gnd, and the signal wire from the ECU.

Install your speedo per the directions, connecting the signal wire to the signal wire going into the ECU.

At this point, you'll have a speedo that works great, but an ECU that sees 0mph at all times.

To fix this you need to add a diode and a 4.7k ohm resistor to the circuit (please see photos).

Please note the RESISTOR is on the *SPEEDO* side of the diode. The resistor runs between the SIGNAL wire on the speedo and the +12v power wire on the speedo. You must get this right or it will NOT work.

In the below photo, the brown material between the two wires is cardboard which has been added to prevent any further movement/bending of the resistor lead. The last thing you want is to have to go back in and redo this because the resistor lead broke from metal fatigue.

Below you can see the wiring all wrapped up and ready to go. We would have (should have) used heat shrink instead of electrical tape, however we didn't plan ahead and put it on the wires before soldering them together, and the wiring had already been assmbled into the harness connectors (I didn't have the proper tool to remove the pins from the molex connector) so we opted to tape it instead.

The above information is taken from DSMlink and is accreditted to William Lowey. Sorry, no pics.