Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Help on Tuning 3uz in 80's corolla with Link g4x ExtremeX ECU with DBW. Significant power drop above 4000rpm.

General Tuning Discussion

Forum Posts



Tech Articles

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads


Hello everyone, looking for some help on a clients 3uz-fe vvti swap in his 80's corolla. Car currently makes 320tq and only 230hp. I will upload the dyno graph but the power drops off severely after 4000rpm due to fueling issues. According to his innovate dual wideband gauge and our external dyno wideband gauge, the driver side bank is operating roughly 30% richer during WOT than the passenger side banks. During IDLE and cruising before WOT, both widebands read close together to each other but after 4k they diverge greatly. The passenger side is seeing 12.5AFR at WOT while the driver side is seeing 9.5-10.0 AFR's. I confirmed this with our dyno wideband that goes on the tailpipe of each side as well, there was the same difference. Playing with it I removed 10% fuel after 4k rpm to see what would happen and the car picked up almost 40hp throughout the curve after 4k rpm. I have never seen such a gain from that little fueling and this great of a difference between banks.

We had previously seen this issue before we had tuned it last. I had him replace the spark plugs, get the injectors cleaned and tested, and had him calibrate the innovate widebands right before the dyno session. Still the same results. I was hoping some experts here can chime in. This car is now running a return style fuel system at 3 bar regulator pressure. We observed 0 fuel pressure loss over a WOT ramp run.

Is there a way to upload my link tune file and log? The file types are not supported here

edit: I created a google drive folder below


That sounds like the cams aren't the same (thinking timing, but maybe the wrong cam was fitted to one bank).

Hello looking at the map now and you will need to set up the vvt correctly for a good place to start,

go to the vt vt settings open this go too bank one set up and change the tooth count to 3 teeth,

do the same on bank two, then go back to vvti set up and click on the cam angle test,

click on calibrate and then raise the rpm to approx 2000 rpm you can press f12 or R and right arrow across to the vvti run time and watch the calibration taking place, once complete it will turn itself off test mode and you need to store the tune file then,

it will say if it has been successful in doing it, you can also check in the inlet bank one and two tooth counts in the vvti setup menu,

I would also recommend a few other things to turn on in the tune file but let us work on this first, also check for air leaks around the manifold to the head area this can also be a cause of issues like this.

Regards Ross

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?