The most ridiculous wiring issue, Midlife where you at?

[55Mach1 10]

My car is finally running and driving but now its time to work all the stupid kinks out

 

My car is running an FAST Ez EFI system. On this system the main feeds for 12V and Ground must go to the battery no exceptions. We did that perfectly.

 

the 12V Switchable needs to see 12V in the ON/Run Position and On Cranking.

 

Now for some odd reason i have tried 4 different 12V Switchable feeds and when the drivers door closes the drivers door pin courtesy switch trips my fuel pump relay to kick it off. this doesnt happen with the passenger side door courtesy pin switch just the drivers.

 

Now i just checked with a voltmeter. i am getting 11.6 V with the ignition ON all the switchable feeds i tested and the drivers door open. When i close the drivers door the voltage spikes to 12.2

 

Please can someone explain why this is happening and how i can easily correct this issue? I need to stop the voltage from spiking up and causing my EFI to kick my pump off.

 

Should i tear into the steering columns wiring to find another 12V Switchable source? Should i install a Diode on the switchable feed?

 

Need help with this ASAP. Harness is in a 70 Mach 1, if there is a better source that will not spike please tell me which one so i can identify.

 

thanks

[69gmachine 15]

I wouldn't consider 12.2 volts a "spike". That's pretty much your battery voltage. When you close the door and eliminate the lights and fuel pump from the circuit, there is simply less voltage drop than when the courtesy lights and the fuel pump are on.

 

Obviously closing the door shouldn't open the switch to the fuel pump, so you have some other wiring problem. The voltage difference is just a symptom for 2 different states of operation.

 

Where are you taking the measurement?

[55Mach1 10]

well i just checked every single wire under the dash of my car and every single switchable 12v does the exact same thing. the EFI is so basic in its wiring. I almost wonder if the micro relay is bad or something this is nuts. I even went directly to the ignition switch, same thing.

 

the door jamb switches are all good, tested those as well with my meter. the fuel pump isnt connected to anything other than the main EFI harness which houses its own fuel pump relay, the main EFI harness fees the relay off the battery etc however the main EFI harness requires a Switchable feed and every feed causes this issue.

 

spoke to FAST their support is the worst ever they should be ashamed of themselves.

 

the only observation i saw was on my voltmeter the voltage increased with the door shut and under dash lights off. i checked directly from wire to wire under the dash even at the post on the fuse box.

 

no wires are butchered or tampered with. the car didnt have this issue with my old MSD EFi system

[Midlife 814]

I agree that the voltage difference is due to the different loads (lights in particular act as a pretty good load).

 

As to why the door switch affects the fuel pump? Have you tried putting the fuel pump on a separate circuit (i.e. it's own circuit?).

 

I hate modified and aftermarket wiring for exactly the reasons the OP has: all sorts of problems and no tech support.

[55Mach1 10]

Midlife everything that is part of the EFI is not tied into the original harness except the 12V Switchable wire, no matter which wire i connect to under the dash the same crap happens. I spent hours and still no results.

 

i also ran an extra ground from the battery to fender apron just in case, still no change.

 

can it be possible that my door pin switches are defective?

 

 

I also tested tonight a relay coming off the battery + and - to give a switchable trigger and the fuel pump still shuts off after you shut the door, this is beyond bizzare and unexplainable as to why or what is causing this.

 

are the courtesy lights a positive or negative trigger and what about the rest of this cars accessories? this has driven me mad!

 

Could a bad starter solenoid cause this? What about running a mini starter and using the solenoid on the fender and mini starter together?

Edited October 31, 2013 by 55Mach1

[det0326 179]

well i just checked every single wire under the dash of my car and every single switchable 12v does the exact same thing. the EFI is so basic in its wiring. I almost wonder if the micro relay is bad or something this is nuts. I even went directly to the ignition switch, same thing.

 

the door jamb switches are all good, tested those as well with my meter. the fuel pump isnt connected to anything other than the main EFI harness which houses its own fuel pump relay, the main EFI harness fees the relay off the battery etc however the main EFI harness requires a Switchable feed and every feed causes this issue.

 

spoke to FAST their support is the worst ever they should be ashamed of themselves.

 

 

the only observation i saw was on my voltmeter the voltage increased with the door shut and under dash lights off. i checked directly from wire to wire under the dash even at the post on the fuse box.

 

no wires are butchered or tampered with. the car didnt have this issue with my old MSD EFi system

 

What I would be concerned about is almost 1 volt difference when opening and closing the door . I would check the voltage at the battery

on the positive and negative terminals. If the voltage stays constant at the battery then start looking for loose connections coming from the battery to the sol. , ignition switch and etc.

Also check to insure good ground connections.

Edited October 31, 2013 by det0326

[55Mach1 10]

Come to the following conclusion after wasting most of today on this

 

Fast efi brain is defective or the fuel pump relay they supplied in the harness is too weak for my aeromotive pumps draw. Everything else checks out perfect.

 

Once again i need to waste more time with getting a fast rep on the phone, their service is the worst ever.

[Midlife 814]

Door jamb is controlled by a fusible line (green/yellow) for courtesy power, and when the door is open, power is routed to courtesy lights (black/blue).

 

For your fuel pump, what line did you tap into? It almost sounds like you tapped into the black/blue line that runs into the trunk area.

[55Mach1 10]

Midlife this is my drivers door pin switch, 3 pin , pass side is 2 pin

 

The black and red wires are both hot with key on, the two greens seem to be the triggers for both the drivers and passenger courtousy lights

 

 

As i stated the fuel pump has its 12v trigger wired to the eFI trigger relay off the efi harness. The fuel pumps ground is to the battery

 

The efi main power and ground is to the battery

 

The only wire that needs to be taped into the original harness is a 12v switchable and this is where my issue is

 

Now if i ground out the fuel pump relay the pump stays on continuously and does not shut off when i open and close both doors. This is how i would assume to be normal but according to fast your not supposed to do this

 

According to the vague instruction from fast efi your not supposed to ground out the fuel pump relay, your only supposed to do this to adjust fuel pressure on your regulator then you suppsed to take the ground off. This makes no sense because relays Are supposed to have a ground for them to trip open or closed.

[55Mach1 10]

after countless hours the problem turned out to be a defective china relay for the fuel pump. I jumped the circuit with a Bosch relay and everything works so i just finish making it permanent

 

such a PITA and just another reason why junk from China sucks

[Chris'69Mach 23]

junk from China sucks

 

:thumbup::punk::rockon::thumbup1: YOU SAID IT BRUDDA !!

[MikeStang 247]

Not trying to get off topic, but What MSD system did you have?

was it their new one?

why did you go FAST route instead of the MSD

[55Mach1 10]

Not trying to get off topic, but What MSD system did you have?

was it their new one?

why did you go FAST route instead of the MSD

 

Mike I have owned the MSD Atomic and the FAST EZ EFI throttle body systems prior, the MSD is superior in every way especially the customer support, they even have an active forum for help MSD RULES man so if your in the market thats the one you want.

 

I also had used the FAST EZ EFI as well and i didnt like all the excess wiring and the car never self tuned properly. the live data and options of the MSD are a home run!

 

I really didnt want to go back to the FAST system again but i redid my entire car and went with an Inglese 8 stack and the only system to run those are the FAST.

 

Word of advice if you or anyone buys a FAST product your on your own for help when you need it.

[Midlife 814]

Great! You can start gluing your hair back on your head.

[Rip Rock 13]

Have you posted up your problem on CPG nation forum? A good guy to email would be Brian Macy. He knows his fast stuff. I have a fast xfi and the xim on the Cleveland currently. Going to pull out the Cleveland and putting in a 5.4 twin turbo with the fast system. I like it. Haven't played with the ez stuff though.

[danno 128]

I understand the bad relay, but what has that got to do with the door open or closed. Nothing about that door should have anything to do with the voltage to the relay. Unless you figure that out, you could still have a problem that will bite you later?