Speed Issue in Toyota Vitz

[Ahkhan89]

Hello Fyq:

i have Vitz 2001, A/T, CNG
i have two major issues,

1: on motorway i can only get speed of 110 while using O/D and 125 without O/D (But it reduce the Fuel average) so i did't use it for prolong. i oftenly have to drive on M/W and this really frustrate me so please let me know what to do about this. i showed it some mechanic in Pindi he scanned on Computer and told every thing is Ok, he also Cleared the Cylensor, but still same situation.
2: i have 55 kg cylender installed and getting 100-110 in local and 130-140 on long. how could increase the Average and what maximum it could be.

i hope you will reply my questions.

bro it may b due to ur spark plugs...................!

[Electrical_Engineer]

your probelm could be insufficnet valve clearnace (or commonly called tight Tappet, if car has driven more than 20-30 k kms )which prevent full compression and forbade engine to develop full power at normal RPM.
very dirty plugs and clogged air filter can also be problem
CNG adjustment can also be a problem

[salman2k960]

@mafzaltareen

Thanks for your info. I got plugs replaced, oil & air filters changed, throttle body cleaning. Still car maximum goes to 110. And its on petrol, still this low performance what else do i need to do or tune?

is ur problem resolved?
if yes, kindly post the solution.

[pwuser156913218229]

You have to install 1300 cc 2sz engine just change the assembly. It will travel very smoothly and your milage will improve.previously it had 1sz engine and it could not travel more than 110 on o/d on. Today i touched 165 km/ h on motorway sometimes the high speed is fun but it should not be done more often because it is very risky the car is light weighted and could be fatal in high speed. 105 is very good speed on motorway.