Aux Pump ground point

[nmerrill]

Folks,
I'm installing a transaxle lube circulation pump to be controlled by a VEMS box, via a relay.

After digging around on the net a bit, I could not find an answer to this question:

Should, can, or should I not connect the pump ground wire to my common ground point at the ECU?

Nat

[ChrisAudi80]

Folks,
I'm installing a transaxle lube circulation pump to be controlled by a VEMS box, via a relay.

After digging around on the net a bit, I could not find an answer to this question:

Should, can, or should I not connect the pump ground wire to my common ground point at the ECU?

Nat

No! Please put the pump power ground to chassis. The relay switch ground goes to VEMS.
So: relay pin 30 to switched or battery 12v, 87 to pump +, 86 to switched 12v, pin 85 to VEMS pin ECxx-xx

Can you show what this pump is going to do btw?

[nmerrill]

Thanks Chris.
Yes, relay ground to ECU, but I was not sure about power ground.

Well, I don't have any good pics, but the VW syncro vanagon transaxle has some well known limitations under increased stress, like more HP, increased weight, larger tires...
I've plumbed ports to add oil streams to the 4th (top) gear, and mainshaft main bearing to improve cooling, and lube.
A basic system compared to some sophisticated systems being built.
Realized that VEMS should be able to control the circulation pump - I don't want, or need, the circulation all the time - The most important is highway 4th gear, but other times won't hurt.
I have a oil temp sender in the trans, and am installing a wheel speed sender, so I think I can configure VEMS to turn the pump on when the oil has warmed, and speed is above X.

Thanks again!
N

[ChrisAudi80]

Thanks Chris.
Yes, relay ground to ECU, but I was not sure about power ground.

Well, I don't have any good pics, but the VW syncro vanagon transaxle has some well known limitations under increased stress, like more HP, increased weight, larger tires...
I've plumbed ports to add oil streams to the 4th (top) gear, and mainshaft main bearing to improve cooling, and lube.
A basic system compared to some sophisticated systems being built.
Realized that VEMS should be able to control the circulation pump - I don't want, or need, the circulation all the time - The most important is highway 4th gear, but other times won't hurt.
I have a oil temp sender in the trans, and am installing a wheel speed sender, so I think I can configure VEMS to turn the pump on when the oil has warmed, and speed is above X.

Thanks again!
N

Aha, I see. Good idea. It might also be an idea to install a trans oil cooler, too. You could just use a digital thermoswitch to turn on a fan. That way you can monitor oil temps.