ez efi help

[toomanytoys]

is it possible to run the system with a dead head regulator? i am asking because i want to install the system on a 1984 chev pickup with dual SWITCHABLE tanks so running a return line is going to be a pain in the arse ! I dont want to redesign the fuel system if i dont have to

[bluzman2004]

No. Pretty much all speed density EFI systems have to have a return regulator that is also manifold pressure/vacuum referenced. The fuel pressure can't remain constant like on a carb, it needs to be a differential pressure. Basically, when you tell the computer you have 43 psi of fuel pressure, that means the pressure on the fuel side of the injector minus the pressure/vacuum on the manifold side of the injector has to be 43 psi always. When you idle and vacuum is high the fuel pressure needs to be less to keep the 43 psi differential. On boosted applications, if you have 10 psi of boost your fuel pressure has to increase to 53 now to keep the differential pressure the same.

[Webby]

piece off cake to set up return system with solenoid valve connected to your existing changeover switch you can even buy a valve that switches both feed and return.

[67springhill]

I just installed the EZ-EFI system into my 67 camaro and followed the directions to the letter, the only problem that I'm having is that the ECU power light is not coming on when I have the switch on the on /run crank position, I've gone over the wiring 4 times and everything is perfect and "Comm Error" keeps coming on after I put in the Basic Parameters into the handheld, my question is can my ecu be defective or is there something that I might be overlooking

[Webby]

67springhill
Not clear what you are actually saying in your post.

[bluzman2004]

The light on the ECU isn't a power light. It is a rpm input light. It will light up when it sees an rpm signal. It will also flash really fast if there it an error code. Other thank that, if you turn the key on, it doesn't do anything.
If the system lets you input your info, it is communicating with the ECU. If you try to start your car the the handheld loses communication with the ECU, it could be the switched voltage you used is not there during cranking. This is not what you want. Also, if you crank your car and the handheld goes off, your lighter plug might not have power when cranking either. This makes it difficult to finish the Wizard, but it will still work. Check these and post back.

[67springhill]

I think you have a point with your theory about the switched voltage, but what's the cure for this problem? I installed a 18 circuit Painless Wire System into my car about 2 yrs. ago and everything has been flawless, may be I should install a switch with push button start?

[Webby]

You just need to make sure that the supply to both the ECU and the handheld remain live when you are cranking the engine. Quite often certain sources go off deliberately whilst the starter motor is running. This is to give more battery power whilst starting the engine. Obviously ignition and fuel pumps need to stay live to start engine but stuff like headlights, heater, stereo and sometimes cig lighter will often go off momentarily whilst starter runs.

[67springhill]

Well seeing that my ECU controls the new electric fuel pump now I'll try disconnecting the 12V switched power wire from the ECU which I had connected to the swiched radio wire and connect it to the electric fuel pump wire that I had for my carb, I hope this works guys

[bluzman2004]

You really might want to call Painless and tell them what you are experiencing. They are pretty good people there. Tell them you need a switched power line that stays hot when cranking. This is very common to need this. Can you just go to your fuse panel and check for 12 volts when the key is on, then crank the car and see if it stays hot or not?