Saturday, May 23, 2009

efi tune up 1.4...

this time we attack the intake side... throttle body...



the original throttle body that came with the injection package had just 46mm in bore diameter... fairly suitable for standard 1.3L engine... but with the current displacement i'm having, i needed something bigger...

i was planning on getting a 50mm throttle body from 4g92p (1.6 wira) but the prices are kinda steep... halfcut shops are selling at approx Rm350 each...

fortunately i found someone selling this particularly rare throttle body from perdana sei which uses 4G63 SOHC engine... it measures 54mm in bore size diameter... price kinda cheap, Rm220 to be exact...



FYI, the ISC for 4G13, 4G15, 4G92p and 4G63 sohc is the same... hence, its plug and play...

installation was done at home by myself... bought new 0.8mm paper gasket to prevent air leak in between throttle body and intake manifold...



installation was abit tough because the coolant inlet and outlet piping is at the wrong position, blocked by the water temperature sensor... the usage of coolant flowing into the throttle body is to actuate the so-called "autochoke" function to ease cold start in the morning... in the end, i forced and twisted the metal piping away and bypass the coolant so that it does not flow into the throttle body...

i also made a crude heat shield protecting the plastic ISC unit from direct contact with the intense heat from the coolant hose running below the throttle body...



fired up the engine... soon after i found my idling rpm is vr high, approx 1.8k rpm... managed to turn down my idle rpm till the minimum by closing tight the idle air bypass hole and throttle spindle hold back screw... yet, my idle still maintain approx 1.2k and fluctuates 1.2k-1.5k when engine warmed up... my mechanic said too much air leaking through, hence causing the idle fluctuation... he suggested me to remove the ISC completely so not much air will leak through...

another problem i'm facing after swapping to larger throttle body is partial throttle response... the TPS that came with the perdana sei throttle body has 3 pinouts while original 1.3 throttle body has 4 pinouts... the previous seller recommend me to use back my original TPS...

the problem is... maintaining the TPS at stock setting, partial throttle has very bad response... as if throttle body isnt communicating with the ecu... this can be solved by advancing the TPS setting, but creates another problem... advance TPS setting will cause high AF mixture, hence deteriorating the fuel economy...

in the midst of giving up, i swapped the 4 pinout TPS with my 3 pinout TPS and see whats what...



to my surprise, the engine runs smoother than before... latest calculation gives me slightly better fuel economy compare to previous original 4 pinout TPS...

due to slightly larger intake, the engine AF mixture would had messed up... and yes it is... oversize throttle body is certainly letting too much air into the engine..



damn, i'm in desperate need of adjustable fuel pressure regulator to bump up the fuel pressure...

Saturday, May 09, 2009

other updates...

bought myself a lightweight, space saving spare tyre... because my current front and rear brake setup requires minimum of 14" rim to clear the calipers, i opt for this lightweight 15" spare rim...



measures 125/70/r15...




lately i also notice my front windscreen has a 4cm long crack... i've enquired from workshop for the fixing cost... they quoted me Rm1xx... they also advice me it is not worth repairing as a brand new windscreen only cost Rm3xx... so, i'll leave it there as it is... unless insurance company willing to cover the damage... hehe...

efi tune up 1.3...

210cc injectors i previously using causes rich AF ratio... this kills my fuel economy and sparkplugs... hence, got my hands on 4g92p injectors... they measures 182cc each... hopefully can achieve close to stoich AF ratio...



changing the injectors are fairly easy... here is step by step on how to change injectors of ur engine...

- unbolt 2 bolts which holds down the fuel rail... becareful not to lose the rubber spacer under the fuel rail...
- disconnect the injectors signal cable... remove the safety pin first...
- pull the injectors out together with the fuel rail...
- unplug each injectors and swap them with ur desired injector... make sure the top o-ring is in good condition... replace it if worn out... worn out o-ring can cause fuel to leak due to high pressure in fuel rail...
- put everything back together in reverse method...