VSS

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   I still cant get the vss signal from sensor to speedo successfully. I have wired 

my own converter circuit and used other peoples, used 2 different ecms, and 

different proms too, and no luck, its driving me crazy, the vss when hooked 

directly to the speedo works perfect but when it goes through the ecm the 

speedo only reads maybe 10% so when going 40mph it says 4mph and so 

on, i cant find any similar stories anywhere, so i dont know what to do.

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orange Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 15 September 2010 Location: United States Status: Offline Points: 106	Post Options Post Reply Quote orange Report Post Quote Reply Topic: VSS Posted: 15 June 2011 at 3:16pm
	I still cant get the vss signal from sensor to speedo successfully. I have wired my own converter circuit and used other peoples, used 2 different ecms, and different proms too, and no luck, its driving me crazy, the vss when hooked directly to the speedo works perfect but when it goes through the ecm the speedo only reads maybe 10% so when going 40mph it says 4mph and so on, i cant find any similar stories anywhere, so i dont know what to do.
	Orange 4.9

Romeo Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Post God Joined: 16 November 2008 Location: Canada Status: Offline Points: 3033	Post Options Post Reply Quote Romeo Report Post Quote Reply Posted: 15 June 2011 at 3:32pm
	Beyond the fact this would be awesome for pleading ignorence when speeding excessively (I thought I was doing 20MPH officer, not 200!), is it not possible to simply modulate the input signal to the ECM up 1000% so that when the ECM pulls it back to 10%, you're back at the original value?
	Never shift into reverse without a back-up plan.

orange Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 15 September 2010 Location: United States Status: Offline Points: 106	Post Options Post Reply Quote orange Report Post Quote Reply Posted: 15 June 2011 at 3:53pm
	Thats what i am ready to try yes, but thats not how it is supposed to be and i dont know why it isnt working.
	Orange 4.9

Romeo Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Post God Joined: 16 November 2008 Location: Canada Status: Offline Points: 3033	Post Options Post Reply Quote Romeo Report Post Quote Reply Posted: 15 June 2011 at 4:38pm
	Could be another sensors signal (Crankshaft Position Sensor/CKP, Camshaft Position Sensor/CMP, Ignition Module Base Timing, etc...) which would all look slower, especially in higher gears. Could also be that the ECU is used to seeing a signal ten times faster, and is thus designed to correct for it. Could be many more things as well. Not entirely sure, to be honest. Easiest solution would be to hook up a GPS, hit the highway and compare speed actual (GPS) to speed output (Speedometer). That will give you as precise a ratio as any, from which you can correct the cheap and easy method - namely, by altering the input signal.
	Never shift into reverse without a back-up plan.

Dawg Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 15 August 2009 Location: Canada Status: Offline Points: 988	Post Options Post Reply Quote Dawg Report Post Quote Reply Posted: 16 June 2011 at 12:13pm
	You need to measure the Vss frequency and strength to see what is going on. Not something you can do with wrenches. There are units you can buy to put the frequency where you want it. But you still need to know how to use test gear. Dawg
	You dream it up....I'll make it