injector duty cycle

samh22a · Message par **samh22a** » ven. juin 04, 2004 7:07 am

how's the idle with the UR injectors ?

did you had any problem to get you short / long fuel trim stable ??

Do you know if they have the same dead-time as a stock inj ??

Sorry for all those questions !!

Thanks

Sam

Rick Hunter · Message par **Rick Hunter** » ven. juin 04, 2004 8:47 am

Ha, questions are cool, that's what these boards are all about

Idle hunts for stoich AFR (14.7:1) a bit when the engine is cold. Once it warms up, idle is rock stable. But, on throttle tip in from idle, say when starting in 1st gear from a stop, I sometimes get a brief (1/4 sec) miss. The AFR goes lean during that miss. I haven't worked on the fueling enough, I'm sure that my short/long fuel trims are whacked.

I also don't have a delta-dash to monitor my trims, so it'll be a bit more difficult (trial and error) to smooth out the trims. The nice thing is that with the UTEC, we can run open loop fueling, so we don't have to deal with fuel trims past the TPS crossover (30% for me).
Supposedly the URs have similar dead-time compared to the stockers. I'll try to tune it this weekend and will let you know.

ciao

samh22a · Message par **samh22a** » dim. juin 06, 2004 7:31 pm

excellent...thanks !

Sam

Rick Hunter · Message par **Rick Hunter** » sam. juil. 03, 2004 10:39 pm

Sam: The UR600 do *not* have the exact same characteristics as the stockers. They are a bit slower to respond. This means that if you are using 600cc injectors, set your open loop fueling to ~550cc (not 600) - this will almost completely eliminate the occasional light tps tip-in miss from idle. Remove ~2.5% fuel across your entire fuel map to offset the increase of the maf voltage (the smaller the injector size is set, the more rich the car runs). Might want to add some fuel 0-5% at 500-1500 rpm at 0% load zone as well.

Still tuning the final map - haven't had that much time lately...

How's your car coming?

samh22a · Message par **samh22a** » dim. juil. 04, 2004 7:59 pm

I was not sure about the dead time on the UR's ..thanks for the clarification..

Car is running well.. I still have a small hesitation when going back and forth between stock ECU and UTEC.. sounds like I would need to lean my fuel map a little bit...but I'll wait...I need to buy a tuna first.

PM me next time you're going to napierville !

Sam