VZ SS 5.7 Weird Problem. Always Running Rich. Please Help!!!!

Hello All,

I am having a very frustrating problem with my car and my tuner and I are having major problems trying to figure out what is going on.

Firstly some background on my car.
The car is a Holden SS 5.7 (VZ) Automatic. I recently purchased a CAPA Intercooled Supercharger Kit. All the parts were installed correctly and the car with the CAPA Tune produced 265 RWKW (Mainline Dyno) running extremely rich 10:1 AFR's (Air Fuel Ratio) on the dyno. Car had no problems on the dyno. When I got it back took it for a drive the first night and each time I gave it full throttle it will constantly cut out once it hits 4000rpm. I took it back to my tuner/workshop. He attached a Air/Fuel Reader and jumped in the car and took it out for a drive to see if maybe the fuel pump is dying and leaning out the car. It wasn't the car was still running extremely rich 10:1 AFR's.

My mechanic advised me to buy the VCM Suite so he can custom tune the car as the CAPA tune was just a off the shelf tune and didn't look too good. I bought the VCM Suite and my mechanic started tuning the car. He spent a few days tuning the car and got a major increase in power and got the Air/Fuel Ratio to 12:1 and produce 300RWKW in 2nd Gear.

But, and its a big but the car in 2nd gear (Its an Auto) runs 12:1 AFR ratio tuned perfectly, but once the car hits 3rd gear it instantly drops to under 10:1 Ratio, and whatever my tuner does to lean it out it does not respond. 2nd Gear is 12:1 Ratio and 3rd is 10:1????? He has triple checked the tune and everything is normal. We have even called VCM and talked to the person who built it and he has no answers for us either.

My mechanic is now thinking this problem has been on the car way before the supercharger and tune were put on the car.

Before my mechanic installed the Supercharger and Tune the VCM. He did a base dyno run.

1st Dyno Run: Only Mods were full exhaust (including Extractors). Car produced 180RWKW and the air fuel ratio was 10.0:1 AFR's in 2nd & 3rd Gear (running extremely rich)
2nd Dyno Run: Installed CAPA Supercharger Kit + Intercooler 7psi, with the CAPA Off the Shelf Tune. Car produced 263RWKW and the air fuel ratio in 2nd gear was 10:5:1 AFR's & 10.0:1 AFR's in 3rd. (running Extremely Rich)
3rd Dyno Run: Bought a VCM Suite and custom tuned the car. Car produced 300RWKW and the air fuel ratio in 2nd gear was perfect 12:1 AFR's, but once agin when it hits 3rd the AFR's drop and flatline at 10:1 AFR's (Extremely Rich).

I am not that mechanically minded I know a tiny bit, but it looks to me that something on the car (maybe a sensor, ECU Problem, Fuel Issue) is causing the car to dump a lot of fuel in causing it to run 10:1 AFR's. My mechanic even leaned out a certain section of the map to see if it shows a spike on the dyno line in 3rd gear and there was no response inat all. Still 10:1 AFR's.

If anyone has any ideas or thoughts on this problem, I will appreciate it a lot. Anything you can tell me, I am almost certain now that I have had this problem just after I installed the extractors and exhaust. Because I use to get over 400km per tank and after the exhaust install I will be lucky to get 300km out of a tank. Once again, than you for taking the time to read this and if anyone is able to help it will be much appreciated. Thank You.

Manny Kallianis

 

He is using a 1 Bar MAP Sensor. Not a 2 Bar MAP Sensor.