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hi, i have a 1991 toyota hilux single cab ute that i built myself using the holden vn 5 litre v8, marks 4x4 adaptor, solid engine mounts, heavy duty surf 5 speed manual, 4.55 diff centres and 33inch mud tyres. i am after a good tune for it, or the hardware and a bit of a rundown on how to tune it myself. it is running a standard engine loom from vq statesman and the ecu is hsv enhanced from vp calais, it has a knock sensor and the calais was an auto. the problems i am having are the engine stalls really easily when you release the clutch, is quite sluggish and doesn't get real good fuel consumption (around 17-25l/100km) and i believe this to be because the tune is to suit an auto and i used the vss interface from marks 4x4 adaptors so will incorrect vss signal affect driveability and fuel consumption? my problem is the engine is revving at around 2700rpm at 100km/h and i have built another ute for a mate the same but auto and it was revving the same at 100 but constantly returnes figures of 10-15 litres/100km. whats the go here? i want to be able to tune it to make optimal power and efficiency between idle and 4000rpm, also i want to be able to tune it later on to suit the 355 stroker i am building for it now. any help/prices for parts would be appreciated.

i also have a good vr v8 manual ecu here too, and was wondering if its worth using a vr tune, and if so do i have to change the distributer and the plug on the vn loom to suit vr? or is the only difference between the distributers the plug?

thanks heaps, this tuning side is quite new to me and i cant afford to keep running the rig of i get 250-300km to a tank, its crazy

My v6 hilux has 4.875 diffs and at 100kph it is doing 2500. I am going to change the diffs soon. I get 14l/100 on the road. I have 31" tyres. Acording to http://www.osella.com.au/gear-ratios.htm I should use a 3.9 ratio to bring the revs down.
I think you definitely need to fix the manual /auto settings for a start, and there are some adjustments for the speed pulses, but a lot of people use an adaptor box from Jaycar Electronics to sort the speed issues.

I am no expert, there are heaps of people on this site that will help out.

Do your 33's rub at all?

If you are wanting to tune it yourself then the first step would be to check all sensors are reading correctly by logging the the ECU. Might be as simple as a coolant temp or oxy sensor playing up. Are you getting any fault codes?

The VR code has lean cruise which can help along with much better closed loop and idle control. No loom/dizzy mods to run the factory VR V8 manual memcal but will need the anti-theft disabled - can reprogram it with anti-theft turned off.

There are a few ways to go and it really comes down to if you want to sort it out or someone else? Its a big learning experience as a DIY project but rewarding too.