Initially the system was constantly logging o2 codes and stallingthen restart when hot was very hard sometimes up to 40 seconds. 1using factory efi intake manifolds the most common error made is using factory intake components on a heavily modified engine.

Tech Installing Fast Ez Efi 2 0 Enginelabs
Fast ez efi problems. I got my ez efi up and running about 3 weeks agoeverything went really well with no problemsits did great until todaywhen i started it up today it fired and idled just as beforebut then it diedhad to cranked the motor over a lot to get it to fire back up and when it. This is too simple but triple check for vacuum leaks. Ive had the fast ez efi 10 on my truck since 2011 and ive always had an issue with the idle dropping way below the set rpms to the point of almost dying sometimes it does die and then the idle recovers. External connections for power coolant temperature the wideband o2 sensor and rpm signal complete the wiring for the ez efi system. Just reading this thread again. This happens when i push in the clutch and let off the gas pedal and let the motor come to an idle.
The ez efi fuel injection system from fast will work with your original carb style throttle linkage oem sensors and all ignition setups. Hard wired the yellow ignition wire for the alarm right to the fuse box. The sensor reads the exhaust gas and the engine control unit the computer ecu uses the information as feedback to the tune. The fast throttle body bolts on just like a carburetor though the wiring harness for the injectors throttle position sensor and intake air temperature sensor has to be plugged in as well. Subliminally most enthusiasts consider the plenum the runners and. I now decline to do fast efi system ignition conversions they are still a full on disaster and total fire drill.
Others i have spoken with have had the same encounters with the fast systems even with the fast recommended distributors. Thankfully bryan pitcher in tech has been working with me to wring out all the bugs. Unfortunately this can cause problems with a self learning efi system. All of the self adapting efi systems use a wide band oxygen sensor placed roughly at the header collector downstream in the exhaust system. The fast ez efi has thrown me for a real loop. Hope this helps future fast ez efi users.
Not real familiar with fast but if its the same as most check the fuel pressure as stated above if its constant then the trouble is with the air maftubing vac leak etc or the control bits maptemp sensor etc. This kit includes an ecu wiring harness fuel injectors fuel pump kit and throttle body. Which after further investigation the alarm tech hooked up the ignition wire to the fuel pump relay so car would not start. Fast ez efi problem. Oct 20 2004 location. All went to the holley systems and the problems stopped.