vase Posted January 25, 2009 Share Posted January 25, 2009 (edited) Hi, I'm currently running 1000cc injectors controlled by autronic sm4 (ecu is quite good, shouldn't be a problem). I can't seem to get a proper afr at idle unless I lower my fuel pressure. Is this normal with supra which is using large injectors? When the idle fuel pressure is set to 40psi the car won't idle properly unless I set se afr to about 13afr. When I lower the fuel pressure to 30psi I'm able to set the afr to 14-15 with a good idle. What kind of afr are you guys getting with a standalone ems and large (about 1000cc) injectors? Thanks Edited February 22, 2009 by vase (see edit history) Quote Link to comment Share on other sites More sharing options...
JamieP Posted January 25, 2009 Share Posted January 25, 2009 (edited) Mine idle's around 14 on stock fuel pressure, Solaris EMS and 800cc injectors. Edited January 25, 2009 by JamieP (see edit history) Quote Link to comment Share on other sites More sharing options...
Steve Posted January 25, 2009 Share Posted January 25, 2009 Mine idles fine (14.7ish), on stock fuel pressure, 850cc injectors and Apexi PowerFC EMS. Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted January 25, 2009 Share Posted January 25, 2009 Hi, I'm currently running 1000cc injectors controlled by autronic sm4 (ecu is quite good, shouldn't be a problem). I can't seem to get a proper afr at idle unless I lower my fuel pressure. Is this normal with supra which is using large injectors? When the idle fuel pressure is set to 40psi the car won't idle properly unless I set se afr to about 13afr. When I lower the fuel pressure to 30psi I'm able to set the afr to 14-15 with a good idle. What kind of afr are you guys getting with a standalone ems and large (about 1000cc) injectors? Thanks Are the injectors low or high impedance? Although with 1000cc i would normally aim for around 13.5:1 - 14:1 to keep the idle smooth espically with the larger cams i expect you have also Ryan Quote Link to comment Share on other sites More sharing options...
vase Posted January 25, 2009 Author Share Posted January 25, 2009 Thanks for the information guys. The stock fuel pressure is around 35psi right? The injectors are low impedance and I'm using stock cams atm. I will change to aftermarket cams as soon as my car passes the yearly emission test we have here in Finland. Well it seems that your cars are running fine on higher fuel pressure with large injectors so something is definitely not right in my setup. I'll have to figure it out. Quote Link to comment Share on other sites More sharing options...
Steve Posted January 25, 2009 Share Posted January 25, 2009 Thanks for the information guys. The stock fuel pressure is around 35psi right? The injectors are low impedance and I'm using stock cams atm. I will change to aftermarket cams as soon as my car passes the yearly emission test we have here in Finland. Well it seems that your cars are running fine on higher fuel pressure with large injectors so something is definitely not right in my setup. I'll have to figure it out. Stock pressure is around 36-38 psi IIRC Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted January 25, 2009 Share Posted January 25, 2009 What battery offset have you got set for those injectors? Quote Link to comment Share on other sites More sharing options...
vase Posted January 25, 2009 Author Share Posted January 25, 2009 What battery offset have you got set for those injectors? I'm not sure what the offset is but there is a list of injectors in autronic to choose from. Of course this is a bit problematic if your injectors are not in the list but mine are so there shouldn't be a problem in that area. Quote Link to comment Share on other sites More sharing options...
TLicense Posted January 26, 2009 Share Posted January 26, 2009 Do you have a ballast pack or can the autronic directly handle low impedance injectors? I had a similar problem with my siemens 870cc injectors with an AEM ecu. I was going to fit a peak and hold injector driver, nut after I bought it I never got the chance to fit it before the engine went. Quote Link to comment Share on other sites More sharing options...
vase Posted January 26, 2009 Author Share Posted January 26, 2009 Do you have a ballast pack or can the autronic directly handle low impedance injectors? I had a similar problem with my siemens 870cc injectors with an AEM ecu. I was going to fit a peak and hold injector driver, nut after I bought it I never got the chance to fit it before the engine went. Autronic can handle them directly. It might be that these 1000cc deplhis are just too slow for 14.7 afr at idle but I'm not sure. I previously had 780cc injectors and they were fine. If someone else has 1000cc or bigger injectors please chime in. Quote Link to comment Share on other sites More sharing options...
vase Posted May 30, 2009 Author Share Posted May 30, 2009 This is an old topic but I thought it would be nice to explain what the problem was. I couldn't get the racetronix injectors to work so I switched to bosch 1000cc saturated injectors which worked fine. However, the idle wasn't as steady as it should be but it was good enough. So I was quite happy with my setup and moved on to other things. Today I was a bit bored and started thinking about that problem I had. For some reason I decided to check the "firing order" of my injectors. As you might have guessed the firing order was completely off which means the injectors were connected wrong. I suppose this was the reason the racetronix 1000cc injectors didn't work properly. I will fix the firing order today and maybe my idle gets a bit better. We'll see. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 30, 2009 Share Posted May 30, 2009 Surely if the firing order is wrong it would run like crap for the whole rev range not just idle Quote Link to comment Share on other sites More sharing options...
vase Posted May 30, 2009 Author Share Posted May 30, 2009 the firing order for the spark is correct but it's wrong for the fuel injectors. It seems to work fairly good even though the injector firing order is wrong but when the spark firing order is off it will run like crap. Quote Link to comment Share on other sites More sharing options...
tDR Posted May 30, 2009 Share Posted May 30, 2009 the firing order for the spark is correct but it's wrong for the fuel injectors. It seems to work fairly good even though the injector firing order is wrong but when the spark firing order is off it will run like crap. That doesn't sound right given that fuel has to be injected at the right time during the intake stroke for the right cylinder? See here: http://auto.howstuffworks.com/engine1.htmengine.swf Quote Link to comment Share on other sites More sharing options...
vase Posted May 30, 2009 Author Share Posted May 30, 2009 That doesn't sound right given that fuel has to be injected at the right time during the intake stroke for the right cylinder? See here: http://auto.howstuffworks.com/engine1.htm Well it even works if all the injectors fire at the same time. I could explain why but my english is not that good. The one thing I don't know is why the bosch injectors work better than the racetronix injectors even though both were connected wrong. Quote Link to comment Share on other sites More sharing options...
Guest Supra2 Posted May 30, 2009 Share Posted May 30, 2009 Well it even works if all the injectors fire at the same time. I could explain why but my english is not that good. The one thing I don't know is why the bosch injectors work better than the racetronix injectors even though both were connected wrong. its because different injectors have different spray patterns and different ohm levels will effect injector performance too. Quote Link to comment Share on other sites More sharing options...
Ian C Posted May 31, 2009 Share Posted May 31, 2009 It'll still work, just the atomisation will be awful - after all, thats how carburettors worked for years -Ian Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted June 1, 2009 Share Posted June 1, 2009 I have often been surprised by how LITTLE difference to power and general running out of phase sequential injectors are, especially on engines with more than 4 cylinders. It does effect idle emissions and stability, but full power and torque figures often show minimal change. Some ecus just don't like huge injectors and don't control them very well at idle, especially el cheapo bored out ones. Quote Link to comment Share on other sites More sharing options...
MartinBattye Posted June 5, 2009 Share Posted June 5, 2009 I have often been surprised by how LITTLE difference to power and general running out of phase sequential injectors are, especially on engines with more than 4 cylinders. It does effect idle emissions and stability, but full power and torque figures often show minimal change. Some ecus just don't like huge injectors and don't control them very well at idle, especially el cheapo bored out ones. id agree, was the ecu actually running in sequential mode? if cam phase problem?? running in grouped would give poor idle on 1000's Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 5, 2009 Share Posted June 5, 2009 I have often been surprised by how LITTLE difference to power and general running out of phase sequential injectors are, especially on engines with more than 4 cylinders. It does effect idle emissions and stability, but full power and torque figures often show minimal change. Some ecus just don't like huge injectors and don't control them very well at idle, especially el cheapo bored out ones. Don't most engines go batch fire at a certain RPM anyway or was that early versions of sequential multipoint? -Ian Quote Link to comment Share on other sites More sharing options...
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