Help please!

[seanco]

What I've done:
replaced the fuel pump. After which i get no crank when turning the key. the lights all come on but do not dim when turned to start. I read this usually means the ignition switch is bad.
I've replaced the ignition switch, starter relay and starter motor. I've checked, i believe, all the fuses and relays. Power is getting to the starter.

I dont know what else could be causing this.
Any help or suggestions would be greatly appreciated

thank Sean

 

[seanco]

ok my anti-theft light is blinking and researching says that means my car is in anti-theft mode.
Trying leaving the key in the on position for 10 minutes to see if that clears it.
If that fails I'll try the manual lock and unlocking the doors method

 

[seanco]

nope that did nothing. the anti-theft light goes out but still nothing when i crank it.

 

[Iceman62]

Ok...throw us a bone here. You're working on a YYYY(??) Mustang with ???mods, and did a simple fuel pump change, but now it doesn't crank??? Something isn't adding up b/c the fuel pump shouldn't kill power...did you re-connect everything back properly? Did you disconnect battery when working on pump (before hand)?

 

[seanco]

Sorry i should have said. 2008 v6.
I put an eaton supercharger on using the modbox kit.
replaced the starter motor, ignition switch and fuel pump.

When i did the fuel pump the first time the float got hung up in the tank so the car thought it was out of gas but it would crank but not run.
I pull the fuel pump to fix the problem. and now i get no crank.
Lights all come on, i can hear the fuel pump prime.
When i turn the key to start nothing happens. the lights dont dim.

this is why i thought i'd shorted out the ingition switch but that didn't fix it.

Any clues? or suggestions? could i have installed the fuel pump wrong? it primes and theres no error codes appearing.

 

[seanco]

I disconnected the battery prior to doing anything, i leave it disconnected so it doesn't get drained.

 

[DieHarder]

My thoughts are it's likely something you disconnected/didn't reconnect/misconnected or replaced....

I guess I would start with why it doesn't crank. I would suggest getting your hands on an electrical wiring diagram for a 2008 and start tracing the starter system for the 4.0 to troubleshoot where the fault is... (I've attached one for a 2006 but not sure if cabling/connector assignments have changed). This will give you an idea how the system is wired and what points/components to check. Do you have a multi-meter (best) or test light? Check the test points on fuse F4 (30A) in the main fuse box; power should be there. The starter relay needs power/ground to actuate which is dependent on the Passive Anti-Theft TX/RX inputs; the PCM (Starter Motor Request & Start Enable) and the clutch pedal position switch. To test the starter relay itself you can swap it with a similar relay to ensure it's working (or not). If you want to test it in the car you can purchase a relay tester that plugs in where the relay sits and plug in the relay on the top of it; these devices have test points on them that can be checked for power and ground while you cycle the key on and off.

You indicated you replaced the starter motor, ignition switch and fuel pump. Have you checked your work for the Mod Box install? I did one for a DOB setup on my car and there were a heck of a lot of cables that I moved and/or extended ... During the install did you by chance remove any major grounds? Not sure of exact locations on a V6... On a V8 there is the negative ground on the passenger strut tower; another for the starter and one on the firewall that connects at the rear of the engine. Additionally, I would check the fuse-able link. Then I would check for proper operation and continuity of all switches/cables/wires (including ignition switch start circuit) to be sure the physical connections are working in the starter system.

Good Luck.

Best,
JM

 

[Buzz]

First thing I'd check is the neutral safety switch if your Mustang is automatic or the clutch safety switch if it is manual.

As DieHarder mentioned, this could be a grounding issue. I have seen this type of non-start behavior when a starter was not getting a good ground. A quick thing you can check is to measure the resistance from the negative battery terminal (or a good ground somewhere) to the engine block. I recommend physically checking the grounding connection to the block as well.

 

[seanco]

Guys thanks for the responses, i really appreciate it. DieHarder, thanks for the diagram.
The car ran after the modbox install but i still needed to install the fuel pump.
Ill look at the diagram and see what i can find. Somehow its switching the fuel pump thats caused this. I replaced the ignition switch and starter motor after the fuel pump because of the no crank issue. Even though i disconnected the battery i thought maybe somehow I'd caused a short. I had to install the fuel pump twice because the first time the float got hung up and the car thought it had no fuel.

Sean

 

[seanco]

well i resolved it. i dislogged the smart system when i was checking the fuses in the side panel inside the passenger door. Derp. It looked and felt connected but it wasn't quit in. You'd think there'd be a code for something that critical.