OMVLR90/ECONVERTER
MIXTUREADJUSTMENT
AdjustingtheidleandsensitivitysettingsoftheOMVLR90/Econverterisasimpleprocedure.
Justtakealittletimetostudythisadjustmentsequencebeforecommencing.
IMPORTANT.BeforeadjustingtheLPGmixture,youMUSTmakesurethatallpreliminarytuningchecksand
adjustmentshavebeencompleted,asthefuelmixturereadingscanbedramaticallyaffectedbysomethingassimpleas
valveclearances.Also,besuretodisableanyairpumps,gulpvalvesandanyotheritemwhichmightaddairtothe
exhaustandcorruptyouremissionreadings.Checktheexhaustsystem(includingtheEGRvalve)forleaks,asaircanbe
drawninandindicate(incorrectly)aleanmixture.DeactivateanyairintakeredirectionflapswhilstrunningonLPG.
NOTE:AllstatedCOreadingsarebeforethecatalyticconverter(ifsoequipped).
1.
Warmupenginetooperatingtemperature,theholdengineat50%rpm.Adjustthemaximumflowadjusterfor
approximately0.2%CO(noload,openloop).Ifclosedloop,followprocessorinstructions.
2.
Closethe8mmtop(idle)screwandinitiallysettheconvertertoidleonthebottom(sensitivity)screwforseveral
minutes(onlynecessaryonanewconverter,tobedinseats).
3.
Withtheengineidling,quicklyclosethe10mmbottomscrewuntiltheenginebeginstorunpoorly.Nowundo
thescrewuntilidlejustreturnstooriginalidlespeed.
4.
Openthe8mmtop(idle)screw,(1/4to1/2turnmax.)andadjusttheidlemixtureto1.5%COunlessotherwise
specified.Note:Ifthesystemistobeoperatinginclosedloopatidle,leavethetopscrewshutandsetthe
bottomscrewforoptimumlambdaoscillation.
5.
6.
7.
8.
Resetthevapourlinemaximumflow(power)adjusterto:
(a)1.5%CO@maximumload(Dynoormobileanalyser),or0.2%CO@50%rpm(noloadapplied).
(b)Ifclosedloop,followinstructionssuppliedwithprocessor.
RechecktheidleCO%aftercarryingoutmaximumflowadjustments.
Checkthethrottleresponseforasmoothprogressionfromtheidlecircuittothecruisecircuit.Averysmall
amountofflatspotwillindicateastableidlecircuit.Iftheresanunacceptableflatspot,simplywindoutthe
bottom(sensitivity)screwafewflats.Onautomatics,putthevehicleingearandturnontheairconditionerto
checkidlestabilityandsensitivityadjustment.
Finally,aroadtestshouldbeperformedtotesttheconverterforresistancetostallingduringUturnsandquickly
negotiatingroundabouts.Ifthisisnoticed,thensimplyturnthebottomscrewafewflatsclockwise.
Note
Afteradjustingthesensitivity,boththemaximumflowandidlecircuitsshouldbecheckedforcorrectmixturereadings,asallthree
adjustmentsareinterrelated.Eg:windingoutthebottomscrew(sensitivity)reducesthesecondaryspringtension,allowingthe
secondarydiaphragmtosenseasmallermixerdepression(signal).Thisfeature,alongwiththeinnovative
selfcheckingautomaticpilotcircuitallowsthesameconvertertobeadaptedtovehiclesfrom500ccto5000cc.
Thinkofthesensitivityscrew
Intermsofafloatlevel
IDLEMIXTURE
Tooloosemeansfuelisdrawnfromthemains
circuitatidle,possiblyresultinginunstableidleand
stallingonturns.Tootightmeansan
annoyingflatspot(orprogressionfault)above
idle.Followthecorrectprocedureandyoullbe
rewardedwithasmooth,stableandefficientLPG
system.
SENSITIVITY
(SECONDARYSPRING)
TECH HOTLINE
VIC HEAD OFFICE
QLD
WA
NSW
1800 810 149
(03) 9350 5500
(07) 3262 4822
(08) 9417 7222
(02) 4956 6041
OMVLR90/ECONVERTER
MIXTUREADJUSTMENT
ADJUSTMENTWITHSPRING
IDLEMIXTURE
SENSITIVITY
(SECONDARYSPRING)
ADJUSTMENTWITHSPRING
ANDLOCKNUT
IDLEMIXTURE
SENSITIVITY
(SECONDARYSPRING)
ADJUSTMENTRECESSED
IDLEMIXTURE
SENSITIVITY
(SECONDARYSPRING)
TECH HOTLINE
VIC HEAD OFFICE
QLD
WA
NSW
1800 810 149
(03) 9350 5500
(07) 3262 4822
(08) 9417 7222
(02) 4956 6041
