VR V6 running lean.

[delcowizzid]

If you have your original tune fit that and see what it does

 

[VPRob]

The VR location is lower down on the pipe. The VP is pretty close to the manifold - a hotter position. Possibly, with headers fitted, which I am told lose more heat into the engine bay, the O2 sensor may struggle to get up to the required temp - even with the heater element in the VR sensor. O2 sensors need to get above 600 degrees F and preferably up to 900 degrees.
Where is your sensor located?

 

[losh1971]

Down near the cat Rob.

 

[VPRob]

so is that different from the normal position with the standard VR exhaust? I believe the heater element in a VR O2 sensor is not a particularly strong heater so moving it further away from the heat source could well adversely affect its performance. Even if it operates satisfactorily it will take longer to get up to temp and that means more time running on the default (rich) setting.

 

[losh1971]

No Rob just before the cat is the stock VR location. Not getting hot enough was my thinking but Delco was saying it needs to be there. I don't mind getting CEL's so much but if it's leaning out I would hate to burn out a valve or damage something else.

 

[VPRob]

Well I certainly can't claim any expertise but I would be amazed if any supplier ever recommended anything apart from the standard use/position for any part they supplied. Probably with good reason, but they won't stick their neck out either.
I fitted the VR heated sensor because I do quite a few very short trips around town and was hoping to get a quicker response from the O2 sensor and so less time running rich. Also a heated sensor is supposed to last longer than a non heated one.
There was no obvious improvement in economy but it doesn't throw codes other than 12 (paper clip method)
My economy is pretty **** these days and would love to get it better. I would like to check fuel pressure and injectors sometime as I have never done anything with those

 

[losh1971]

If you have your original tune fit that and see what it does

Delco i will try the original memcal. What would happen if I leave the Mace memcal in. Will the ECU make adjustments within its parameters? Or will i need to send it back and have it retuned?

 

[delcowizzid]

If you had an aldl cable and laptop you could log the ecu and see what the issue is and see how well the o2 is working and if it is too lean.

 

[losh1971]

Yeah I will get an ALDL soon as i can afford one, im really finding its a necessity.

 

[VS_Pete]

Had a look under the hood for a reminder and I have 2 additional earth wires running to earth points on the front of the block. One goes to the point on the bottom of the alternator bracket and the other to an earth point just below this. I don't believe I cut into the loom anywhere but just made sure the O2 sensor had 2 separate earths. I figure I didn't earth onto the firewall but I couldn't see too well in the gathering gloom and I would have to pull the inlet pipe off to get a good look.

This was done on my VS by aceventura thanks mate
https://forums.justcommodores.com.a...r-earth-problem-–-known-holden-problem.98628/