VX Ecotec 3.8 L Mods

[grogadile225]

Good evening gentlemen,
Have an interesting issue with an Ecotec in a VX Automatic Station-Sedan.
It currently has 180,000KM on the clock having bought the car at 90K and then fitted it with Pacemaker headers, SS Inductions CAI and Yella Terra 1.8 roller rockers. This has served well with a diversion of a "PowerChip". Vehicle was Dynotuned with factory CPU and above mods and made 118RWKW. After installing the "Powerchip" and running the vehicle for a 4 week period the car was Dynomomer tested again and struggled to make 102 RWKW. A factory stock VT can make 96 RWKW as a baseline. After 3 trys by the "Powerchip" Dealer to make it work, I decided to put back in a genuine factory CPU assy (at their expense) and re Dynotested at 116 RWKW. Some years later with compression down on two cylinders (middle two on both banks from running ultra lean with "PowerChip") a freshen up was called for. Exchange cylinder heads (mildly cleaned up) and a Wade reground camshaft was the solution. Also added was a FIT 25mm plenum to manifold spacer, 12 mm plenum spacer, 69 mm throttle body and their MAF sensor relocation. Now it runs, roller rockers can't be used due to cam base circle being different, will need to measure and use Gen III pushrods. To cut to the chase Idle quality is poor. The engine "hunts" after a throttle "jazz" or when the aircon or engine fans cut in. Start, idle, drive hunt stall. Restart, idle drive, fluctuate idle in drive. Any way to speed up the responsivenes of the idle circuit. Have done curb idle check as per factory manual. Annoying plus. Suggestions please. Perhaps plenum size is too big. Cheers PS at least with an OMC 3.0L 2 stroke V6Boyessen reeds, 2.7 heads you get 260m flywheel HP....

[Michelson4301]

Sounds like you need to cut that ECU out and find yourself a VT V6 ECU then wire in. 2nd step would be finding someone to tune that bad boy with Kalmaker.