djc2004 Posted January 6, 2006 Share Posted January 6, 2006 Hi Guys just a little problem you might be able to help me with, My Holly projection4 fuel injection system is causing me and my tech some problems, After having got it to start and idle nicely, I can't get it past about 1500rpm cleanly, it stutters and farts around. I 've adjusted the 2 power (1 & 2) pots with no luck and have taken the car to a FI technician but he has no experience with this system - it's the 1st one he's seen. I'd like to get your opinion and experience before going back to him with my wallet open... Any clues? thanks, David Quote Link to comment Share on other sites More sharing options...
pparaska Posted January 7, 2006 Share Posted January 7, 2006 Some troubleshooting ideas: Which ECU? Is this the old analog one, or the 4D or 4Di? Are your sure you have good power to the unit and harness? Enough wire gage to handle the current? What about fuel pressure and enough return line diameter so that the return line pressure is low enough (I think Holley recommends no more than 1.5 psi in the return). Are the injectors clogged? Spray pattern look even? What about vacuum leaks? Quote Link to comment Share on other sites More sharing options...
djc2004 Posted January 7, 2006 Author Share Posted January 7, 2006 Hi Pete I've followed your history with both the projection 4 and megasquirt so I'm pleased to get your response. It is an analog one with fuel pressure to the unit at about 1 bar (14.5 psi) which seems about right. the wiring is all ok and we've got good power to the ecu. everything was running fine when I roadtested the car before buying it, so I assume the return line is ok - I will check this and the clog/spray pattern tho - thanks. Quote Link to comment Share on other sites More sharing options...
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