envmyz Posted August 12, 2004 Share Posted August 12, 2004 Running a l28et here and I've heard from various people that my injectors run at 90% duty? Does that seem right, anyways what is the duty during a cold start? The reason that I am asking is because I can run 12 psi without pinging with the engine somewhat cold. After it warms all the way up I start to ping slightly. If I can rig up an interupt for the engine block temp sensor, at WOT it would think the engine is cold adding more fuel? Or are the engine spraying the same amount of fuel WOT wether or no it's warm or cold? Thanks Chris Cook Quote Link to comment Share on other sites More sharing options...
Owen Posted August 12, 2004 Share Posted August 12, 2004 Are you talking a stock computer? Your injector COULD be running at 90% DC but I imagine it'd be lower. I don't know how the stock computer works, but at WOT hot and cold you should not have the same fuel (assuming there's a temperature to fuel map). I don't know about cutting out a sensor until you know how the ECU uses that sensor in it's fuel calcs. What about your timing cirve? Fuel pressure vs. boost? Owen Quote Link to comment Share on other sites More sharing options...
envmyz Posted August 13, 2004 Author Share Posted August 13, 2004 Sorry, I thought it was lower than 90, but I didn't know. I'm running stock ECU. Pretty much my question is, is there more fuel at WOT when the engine is cold than warm, or is it the same amount? Quote Link to comment Share on other sites More sharing options...
Owen Posted August 13, 2004 Share Posted August 13, 2004 I really couldn't tell you, maybe ask the question in the Turbo section, or the 6 Cyl. section? Just my guess, but you would have less fuel going in when hot and more when cold. From your sig it sounds like you have a good setup. Maybe it's the just the limits of the stock ECU? Owen Quote Link to comment Share on other sites More sharing options...
Clifton Posted August 13, 2004 Share Posted August 13, 2004 You would be no were near 90% at idle. Maybe 7 psi at redline. Shouldn't be more than 3% at idle even with the small stock injectors. The cooler the air the more resistant to detonation. Timing might also be retarded a little more when cold, no sure though. Are you intercooled? Do you pick up fresh in front of the core support? Quote Link to comment Share on other sites More sharing options...
envmyz Posted August 14, 2004 Author Share Posted August 14, 2004 You would be no were near 90% at idle. Maybe 7 psi at redline. Shouldn't be more than 3% at idle even with the small stock injectors. The cooler the air the more resistant to detonation. Timing might also be retarded a little more when cold, no sure though. Are you intercooled? Do you pick up fresh in front of the core support? I've got a huge IC, that's not the problem. Now that you mentioned it, I'm not sucking air from outside the engine bay, I think that my AFM is sitting right in front of the radiator, suppose that could be causeing leaning out, or I guess maybe I am reaching the limits of the stock ecu. I suppose that I should hook up the Rebic AIC and start dumping some more fuel in there Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted August 31, 2004 Share Posted August 31, 2004 Someone, somewhere in these forums or zcar.com has a good post about adding a variable resistor to the temp sensor circuit to fool the ECU into running richer over the entire stock fuel map. Of course you are eventually limited by the injector size and fuel pressure anyhow. Search for "resistor mod" or something like that. Quote Link to comment Share on other sites More sharing options...
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