LS2 6.0L vss output testing
04-27-2012, 09:15 AM
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LS2 6.0L vss output testing just finished doing a LS2 6.0L swap from an 05 Chevy ssr into a 1968 firebird. Everything is working good but I do not have any signal coming from what is supposed to be the speed signal output to the guages. I am running a wiring harness from SSP and coming from the blue connector on the ECU is the grey wire connected to pin #21 how can I check to see if this is Puting out a signal. I am running Dacota digital vhx Guages and according to Dacota digital there should be no compatibility problems with the signal. When I try to program the spedometer it doesn't pick up any pulse signals. I tested ohms from ECU connector pin# 21 to the input to the Dacota digital box and it was 0.00 any help would be greatly appreciated. I talked to the guys at Dacota digital and he tolde me that with a dvom in AC voltage it should be reading at least 3v and I would assume vary up from there depending on the speed of the relucter ring but I'm getting nothing. Does this seem right? I'm wondering if it might be a bad ECU not outing out the signal or if ssp might have turned this function off then the tuned the Ecu (if thats even possible) I know the ECU is getting a good signal because I can get a live data reading from my scan tool on mph jus nothing from pin 21 as far as I can tell.
04-27-2012, 03:27 PM
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Its a 4l60E and OEM vss the engine and trans both came out of the same 05 Chevy ssr. I am getting an output signal from the ECU bit it is varying between .099 and .200 depending on speed it goes up and down like it should coming from a reluctor ring creating its own voltage its just not the 3 volts that I was told it needed. I'm starting to think the problem is with Dacota digital Guages. I just wish I could get a straight answer from someone how to test the output from the ECU to be 100% sure before I make them send me another Guage set. The guy at ssp said something about the signal needing to be converted for the Dacota digital Guages but when I called Dacota digital yesterday they tolde that there was no problem with there system reading the OEM speed output signal. Maybe I was just talking to someone who didn't know what they were talking about. I'm loosing my mind and this firebird is going to drive me insane.
04-27-2012, 08:12 PM
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I believe I have found the problem. I am getting a reading but it is to low. I am going off of pin #21 that is the ground side of the vss i am going to try to tie into the unused pin #45 that is the vss high and see if it works. luckaly I had a spare harness to use to steel an ECU pin out of. I will post my results eather this weekend or monday when I test it out im not sure yet if im going to work threw this weekend or not. Here is what I found as far as pinouts go for the VSS on the ECU
Pin #21 in Blue C1 (out to BCM)
Pin #48 in Blue C1 (out to BCM)
and
C3 Pin #45 in Grey C3 (automatic trans vss high)
Pin #21 in Blue C1 (out to BCM)
Pin #48 in Blue C1 (out to BCM)
and
C3 Pin #45 in Grey C3 (automatic trans vss high)
