Autometer speedo question
Thread Starter
Intermediate
Joined: Oct 2009
Posts: 43
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From: St. Augustine Florida
Autometer speedo question
I have a 5 inch ultralite electric speedo I am trying to get working. I have it wired up, but its not working. It won't even let me calibrate. I have the purple signal wire spliced into the vss signal wire (straight to the wire coming out of the vss sensor), the lights and 12v wire wired to the radio accessory wire (I want the lights on when ever the key is on), and the black ground to a good grounded bolt. The white wire that is for the square sine is also grounded (as per the instructions). Have I gone wrong somewhere?
Last edited by little98dime; Dec 11, 2009 at 01:39 PM.
Thread Starter
Intermediate
Joined: Oct 2009
Posts: 43
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From: St. Augustine Florida
here is the wiring diagram for my gauge.
http://www.autometer.com/download_instruction/840a.pdf
http://www.autometer.com/download_instruction/840a.pdf
Last edited by little98dime; Dec 11, 2009 at 05:41 PM.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
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From: Tampa Florida
I guess I should have asked if your old speedometer functions/cluster used to work prior to you begining this new gauge installation....it did work right?
What did you do with the other wire that comes out of the VSS plug on the tranny? This other VSS wire I'm mentioning needs to be terminated to a grounded chassis point.....this is also mentioned in the diagram on you link.....your old instrument cluster used to "complete" the grounding loop for the VSS sensor...if your stock cluster is removed from the car then that wire is not grounded. Other than that ensure that you have +12 volts on the lead that powers your new gauge and/or recheck your terminations.
Thread Starter
Intermediate
Joined: Oct 2009
Posts: 43
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From: St. Augustine Florida
The stock gauge didn't work and I think the wire you mentioned is the problem. I didn't ground that as I didn't realize it wasn't grounded. I will try that when I get back to the house. Aside from that, the white square sine wire I mentioned should indeed be grounded correct?
Edit: I need to correct myself. The gauges didn't work mainly due to the fact that the motor has been swaped for a carbed 350. the display would back light, but nothing was being displayed. Most of the sensors are either disconnected or missing. The tranny however is the original which was rebuilt.
Edit: I need to correct myself. The gauges didn't work mainly due to the fact that the motor has been swaped for a carbed 350. the display would back light, but nothing was being displayed. Most of the sensors are either disconnected or missing. The tranny however is the original which was rebuilt.
Last edited by little98dime; Dec 11, 2009 at 07:14 PM.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
The stock gauge didn't work and I think the wire you mentioned is the problem. I didn't ground that as I didn't realize it wasn't grounded. I will try that when I get back to the house. Aside from that, the white square sine wire I mentioned should indeed be grounded correct?
According to the diagram that you linked...in this application it doesn't matter if your VSS is a sine wave or a square wave they just address it as a 2 wire VSS. So yes - you'll want to ground the WHITE (SQ) wire coming from the speedo gauge. I do not recommend grounding the WHITE (SQ) wire in with other negative wires from the gauge though. You'll want to terminated this WHITE (SQ)wire to a grounded chassis point just like you'll do with the other wire on the VSS itself as we discussed a couple post up. The manufacturer kind of does a CYA here instead of explaining it directly they just show a chassis (earth) ground on the diagram as opposed to grouping it with the other negative (-) wires from the gauge.
Hook those wires up and you should be fine....provided your VSS works.
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Thread Starter
Intermediate
Joined: Oct 2009
Posts: 43
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From: St. Augustine Florida
Well, I just finished trying it. Grounded the white wire to a chassis point by the battery and the second wire (looks pink to me but Haynes manual says black and white) on the vss to a bolt on the tranny. No calibration sequence. How do I test the vss sensor?
Le Mans Master
Joined: Jul 2007
Posts: 5,043
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From: Tampa Florida
I'm guessing the gauge unit powers up then just no speedo signal?
Remove the VSS sensor for the transmission, attach a voltmeter to the output connections on the sensor then spin the VSS drive gear and you should see a voltage output on the meter. Those VSS sensors are not inexpensive so use care when handling it.
Recheck/measure resistances for your negative and grounding connections from their termination points back to the negative battery terminal to ensure "solid" grounding connections have been attained.
Other than these last tips you may want to contact the gauge manufacturer and ask some questions regarding the programming and what it is supposed to do or not do.
Remove the VSS sensor for the transmission, attach a voltmeter to the output connections on the sensor then spin the VSS drive gear and you should see a voltage output on the meter. Those VSS sensors are not inexpensive so use care when handling it.
Recheck/measure resistances for your negative and grounding connections from their termination points back to the negative battery terminal to ensure "solid" grounding connections have been attained.
Other than these last tips you may want to contact the gauge manufacturer and ask some questions regarding the programming and what it is supposed to do or not do.
Thread Starter
Intermediate
Joined: Oct 2009
Posts: 43
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From: St. Augustine Florida
Just to update the thread, I figured out that the lack of power up in the gauge was a result of a bad ground. I have also redone the splice to the vss and am wanting to attach it to the wire that would be used by the factory gauges. Which wire on the pig tail would I need to wire into? I have a pinout diagram and the only wires showing connection with vss are C15, D12, and D11.
