boomer3 Posted April 6, 2012 Share Posted April 6, 2012 Hey Guys, So my recently purchased 280z is running rich. I gave him a call and he said that the injectors are larger than stock but doesn't know the size. It has the factory FPR in it now. I haven't done a lot of EFI tuning so i'm not exactly sure what to do. I'm assuming that with a constant pressure, and larger injectors it will automatically get more fuel every pulse. Can I get an adjustable FPR and crank down the pressure a little? The problem is that I don't have an AF meter, and i'm sure it's dangerous to mess with fuel pressure without one. Any suggestions would be appreciated! I would definitely like to get an adjustable FPR if people think that is an option. Quote Link to comment Share on other sites More sharing options...
kaito Posted April 6, 2012 Share Posted April 6, 2012 Ok, where do I start... first thing you need to do is find out what sieze the injectors actually are. What this means is how many cc's/lbs per hour AT THIER RATED PRESSURE. Many different types of injectors have different operating pressures and changing the rated pressure up or down changes their flow rate. You need to see what the injectors are doing and that rquires wideband oxygen sensor. If I were you I would purchase one of those and then see if I needed an AFPR. Also you can rig the stock regulator to increase its pressure by taking a socket and tappi ng on the top of the regulator. You say you are running rich. What makes you think that? Is your exhaust popping or your intake? fuel smell? Also worth mentioning is if your injectors are barbed style then they are either stock, turbo, or mercedes. If they are o-ring style then they could be anything. You might find part numbers on the injectors. Just some food for thought. Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted April 6, 2012 Share Posted April 6, 2012 No first step is having him tell us if the cars stock. Dont assume because he didn't say. If it is stock just buy some stock injectors on this forum and swap them out. Pics of the injectors might help us better id them. Quote Link to comment Share on other sites More sharing options...
boomer3 Posted April 7, 2012 Author Share Posted April 7, 2012 Thanks for the reply guys. First of all, it's 95% stock. Just has a 2.5" exhaust. I think it's running rich first because of the smell, second some black smoke, 3rd a little bit of popping in the exhaust and idle isn't quite perfect. I pulled the injectors yesterday as i'm in the process of changing the manifold gasket/ replacing fuel lines. The only thing I could find on the injectors was the name Python, and a number 15 somewhere else on the injector assembly. So i'm not sure how i'm going to find out the flow rate of these injectors. I'm going to see about posting a pic of them for you guys to have a look at, as i'm guessing this isn't enough info to go on. Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 7, 2012 Share Posted April 7, 2012 (edited) Python is an aftermarket supplier and rebuilder. They might be able to tell you if the 15 means anything - http://www.python-injection.com/index.php Edited April 7, 2012 by NewZed Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted April 7, 2012 Share Posted April 7, 2012 Getting them flow checked requires you sending them to get cleaned. You know they aren't stock injectors, so just find some stock injectors since that will probably be the cheapest route. Quote Link to comment Share on other sites More sharing options...
LowCarbZ Posted April 7, 2012 Share Posted April 7, 2012 a little bit of popping in the exhaust That's worth the rich mixture in my opinion hahaha. Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 8, 2012 Share Posted April 8, 2012 "some black smoke" on an UNCATALYZED z means low 10:1 or even high 9:1 AFR --- seriously off. But generally this is a sensor or electronic issue. You're way jumping the gun heading to fuel pressure off the bat IMO!!! Quote Link to comment Share on other sites More sharing options...
boomer3 Posted April 8, 2012 Author Share Posted April 8, 2012 "some black smoke" on an UNCATALYZED z means low 10:1 or even high 9:1 AFR --- seriously off. But generally this is a sensor or electronic issue. You're way jumping the gun heading to fuel pressure off the bat IMO!!! I'm not quite sure that i'm jumping the gun. If they are higher flow rate injectors then that must be a major contributor wouldn't you think? But you could be right, I am a novice at troubleshooting EFI still. I'm calling Python tomorrow to see if I can find the flow rate. If it's high, then I'll probably replace the injectors with stock like others have suggested. Save the AFPR and AFR for a future project that actually needs it. Quote Link to comment Share on other sites More sharing options...
boomer3 Posted April 9, 2012 Author Share Posted April 9, 2012 The best Python could do was give me an estimate on what the injector might be. He thought they were 20lb/hr, for 40-50psi. Not very precise info unfortunately. The guy thought they were probably originally sold for a 300zx. Quote Link to comment Share on other sites More sharing options...
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