Have 4L60E, has VSS on tailshaft housing. I found the pigtail I bought for it was wrong, but discovered a CTS pigtail seems to fit perfectly. Now, I need to hook this up to the GPIO and also an aftermarket electronic speedo. I see there's been a lot of issues with the VSS signal over the years. How should I approach this? Before I found out about all the VSS signal issues I was just going to use a drill to make the wires into a twisted pair but then figured I would use some woven metal shield over the twisted wires. But how to hook up the speedo? just splice it in to the wires? at the tranny, at the GPIO, in the middle? Use an output from the GPIO to run the speedo?
What's a poor dumb engine guy to do?
VSS hookup question
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Bernard Fife
- Posts: 1696
- Joined: Fri Apr 04, 2008 1:28 pm
Re: VSS hookup question
tmoble,
Some people have had issues with the VSS input, others have not (but we tend not to hear from the people who haven't had issues, of course).
On my 4L60e, I hooked used a twisted pair to the trans for the GPIO, and then use the GPIO speedo output (PT4, PWM1, Amp31) to signal the electronic speedo. You can certainly put a shield on the twisted pair on the VSS wiring if you like, but if you do be sure to ground it only on one end (ground it to the same spot as the GPIO). Keep the VSS wiring away from the coil(s), etc.. This has the best chance of avoiding noise.
However, you can also splice into the GPIO's VSS wires (best to do it near the GPIO itself to minimize the overall length of the wiring) for the speedo. This has a somewhat higher chance of inducing noise in the circuit, but has worked for many users. I did it this way on my car before the speedo output was available in version 2.1xx.
Lance.
Some people have had issues with the VSS input, others have not (but we tend not to hear from the people who haven't had issues, of course).
On my 4L60e, I hooked used a twisted pair to the trans for the GPIO, and then use the GPIO speedo output (PT4, PWM1, Amp31) to signal the electronic speedo. You can certainly put a shield on the twisted pair on the VSS wiring if you like, but if you do be sure to ground it only on one end (ground it to the same spot as the GPIO). Keep the VSS wiring away from the coil(s), etc.. This has the best chance of avoiding noise.
However, you can also splice into the GPIO's VSS wires (best to do it near the GPIO itself to minimize the overall length of the wiring) for the speedo. This has a somewhat higher chance of inducing noise in the circuit, but has worked for many users. I did it this way on my car before the speedo output was available in version 2.1xx.
Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
Re: VSS hookup question
Wow, time goes by. Sorry I never answered. Thanks for taking time to reply. I'm going to try running the speedo off the GPIO to avoid splicing wires. I'm hoping to avoid having VSS issues since this is a very simple setup in a 57 Chev pickup.
My vague plan is to run a main ground point on the back of the right cylinder head. Stock setup on this truck is the battery grounds with a strap to the hood hinge on the firewall, then a strap grounds the engine to the firewall. Doesn't sound like a low impedance deal to me, so I'm going to run the battery ground cable directly to a bellhousing or starter bolt. Run a strap to the body and the frame. Ground everything electronic to a bolt on the rear of the right cylinder head with a starlock. The WBO2 wants a 2 grounds, one apparently a power ground to the chassis and a signal ground that will go to the head.
I want to avoid ground loops. Alternate plan was going to run a ground post on the firewall connected to the battery via a factory pigtail off the side terminal batt cable and ground everything to that, skipping the the bolt on the back of the head. This post is on an insulated plastic mount block, doesn't ground on it's own. The engine would be grounded through the neg batt cable, with small ground straps to the body and frame.
The back of the cylinder head is inconvenient, very close to the firewall. A real PITA if any work needed there.
There is a mega-squirt in this deal. I was planning to run all the grounds for it to that ground terminal block too.
Any comments, criticism, upgrades?
My vague plan is to run a main ground point on the back of the right cylinder head. Stock setup on this truck is the battery grounds with a strap to the hood hinge on the firewall, then a strap grounds the engine to the firewall. Doesn't sound like a low impedance deal to me, so I'm going to run the battery ground cable directly to a bellhousing or starter bolt. Run a strap to the body and the frame. Ground everything electronic to a bolt on the rear of the right cylinder head with a starlock. The WBO2 wants a 2 grounds, one apparently a power ground to the chassis and a signal ground that will go to the head.
I want to avoid ground loops. Alternate plan was going to run a ground post on the firewall connected to the battery via a factory pigtail off the side terminal batt cable and ground everything to that, skipping the the bolt on the back of the head. This post is on an insulated plastic mount block, doesn't ground on it's own. The engine would be grounded through the neg batt cable, with small ground straps to the body and frame.
The back of the cylinder head is inconvenient, very close to the firewall. A real PITA if any work needed there.
There is a mega-squirt in this deal. I was planning to run all the grounds for it to that ground terminal block too.
Any comments, criticism, upgrades?