TOPIC: Nissan Terrano VG3.3

This is my first groove. Car seems to be running great. Not sure if I’ve got mileage gains but exhaust smells clean. Idle is smooth.
I’ve blocked pcv rerouted evap line and reprogrammed cpu. I found it to be a simple process and happy to have my first groove under the belt looking forward to do others.

Congrats, CJ, and welcome to the club!
Please keep us posted on your experience with this vehicle in terms of performance and economy.

No evidence of fuel gains yet. Where 2 from here? Any suggestions welcomed

CJ - It's good you're getting cleaner tailpipe emissions for the time being, but you haven't told us much about this vehicle other than make/model, and for right now, YOU'RE the expert on it.
is 3.3 the displacement of the engine in Litres? does that make it a v6? is it a Port injection or direct injection engine? Is it coil on plug or coil near plug ignition?

Basic recommendations: check/increase your tire pressure, top off your coolant levels/bleed the system, increase the spark plug gap, clean the MAF sensor & put in a new air filter, relocate the MAP sensor...

Thanks for the suggestions, checked tyre pressure. Topped up coolant. Clean maf sensor and got a high flow air filter. Should I relocate the map sensor to before the groove? Still no real evidence of fuel gains. Cars running great the. Yes displacement 3.3 litres v6. Spark plugs quite hard to get to but I will persist. Do you have any experience in removing the egr valve? And do you think it’s worth removing the cats in the long run.

I would leave the cats in place. While Grooved cars are much better at fully burning gasoline, I would tend to err on the side of caution to make sure we’re not going to increase any emissions the Cats are supposed catch that the Groove doesn’t affect.

I have also not removed my egr valve, but I have considered adding manual controls for it in the cabin so i can trigger it. I’ve also considered rerouting it’s flow from into the intake manifold (active vacuum) to pre-TB (passive vacuum) but post MAF/IAT to warm intake air for better fuel vaporization.

MAP sensor needs to be placed where it sees the variances in intake manifold pressure. I relocated mine from 2/3rds of the way down the length and more favouring one bank of my V6 to the PCV orifice, right inside the manifold behind the TB. I figure that’s where the variances are largest, and so far, with a wee and simple modification to the signal the computer sees from it, I’ve had good results.

Will an extension on your ratchet not help reach your plugs?

I can get to most of my plugs but there is one that obstructed by the fire wall.
I’ll try map relocation
I didn’t have any real noticeable power gains when first doing groove. Have you got any good trick for checking vacuum leaks
Cheers cj

Early indications that I have slightly worse mileage
10.5 litres per 100 k before and 12-13 afterwards

On my vehicle with a transverse mounted v6, I discovered that the bank closest to the firewall was most easily accessed from underneath the vehicle. I was surprised to discover more room back under the V of the engine than I had thought. Maybe the same is true on yours.

For vacuum leaks, I’ve seen a neat trick on YouTube: use a fog/smoke machine. On a cold engine that’s not running, feed the output of the machine into the brake booster line. After a few minutes, if there are any major leaks, the fog will start escaping into the engine bay. For minor leaks, if the fog/smoke doesn’t help, warm the engine up and spray carb cleaner at gaskets/mating surfaces and anyplace that a vacuum hose connects to the manifold: any leaks should suck the cleaner into the engine and change the idle.
Last, as far as your decrease in efficiency: if you’ve up-gapped your spark plugs, check the resistance of your spark plug leads: any resistance prevents a strong spark from forming. The lower the resistance in the wires/leads, the bigger the spark and the better the fuel in the cylinder burns. TracyG and I swear by our Ganatelli Mpg+ zero resistance wires. If they’re not easily acquired for you, look for the lowest you can find by taking a multimeter to your parts store and measure the longest wire from each kit/set they have for your engine. There is enough resistance in your spark plugs to keep your ignition coils happy, so get as much of the energy they make to the place it matters most (the spark gap) rather than wasted as heat in the wires.

Another note: you mentioned a high flow air filter. If that means you can clean/re-oil it, consider this: “More” Air makes the computer deliver more fuel. Further, the oil droplets can coat the wires of your MAF sensor, throwing air measurements for fuel delivery off.

Make sure you perform a full re-learn for the computer to figure out that you’ve made these changes.

Thanks heaps for sharing your knowledge and for taking time to help me.

Yes it is a foam oil filter I put this on new only 500ks ago and cleaned maf sensor at same time. Do you think I should reset computer again after doing this mod as I have already reset after the groove 1000ks earlier.
It Hanks again I have lots to try so I will post back once I have explored these things.

CJ - it’s a pleasure. Don’t mention it again.
May I ask where you’re located? I suspect the Southern Hemisphere...Australia, New Zealand, South Africa...???

Anytime you change something in a way you believe will be significant with an engine’s air, fuel or electricity, i’m A believer in a re-learn from cold to a “drive it like it’s stolen” phase, and then letting the numbers as far as mileage goes settle themselves out over a tank or 3. Some computers take time to settle in. That said: if you’ve only driven a few hundred miles (300-600, roughly the 500-1000km you’ve mentioned), be patient for another tank or 2. The fuel savings will come....once we’ve gotten some results (a new benchmark) and can get to fine tuning.

That said, I once did a Groove for a friend while they were on vacation. When they got back, they had a grand time chirping their tires at every stoplight for a while, until they saw that eating through their gas tanks (and tires). I took them for a drive in it with me driving, using the engine’s newfound power to get the car moving before using the gas pedal, and saw a 40% increase in mileage just from my driving style (as the computer re-learned according to my technique). It may be that you’re somewhere between me and my friend. Try a more gentle foot on the gas and see what happens.

Hi again CJ. I see you are well on you way into GadgetmanLand. (what kind of rides would be in THAT Amusement Park?)

I learned to make myself stop and take pics of my Groove jobs as I went. Not only to share here, but as a future reference for myself. Details matter when doing the Groove. Remember to Check your Work after cutting a Groove, CJ. Shine a flashlight inside and out on the Groove, look for any breakthrough holes. Fix any you see! The tiniest hole will reduce results. The Groove increases manifold vacuum- so any vacuum leak is worsened, and you must be more vigilant against them.

Good on You, CJ, for sharing w/ us. Greg K does a Great job of helping other Gadgetmen, do pay close attention to all his input!

And I look forward to more from ya, CJ!

Tracy G