Ok, so here it goes. I put a 4.6 modular v8 together and put it in a 2002 ford mustang GT Jack Roush stage 2 five speed manual. It will not start... I have checked the voltage on the throttle position sensor. .986 when closed then 4.66 at WOT. It has a new fuel pump, a new MAF, it has a new Fuel pressure sensor. I have flow tested the injectors as well as pulse test and everything was fine. The ignition coils are brand new MSD coils, and they are sparking fine. When I turn the key to the on position the fuel pump comes on to build up pressure like it is supposed to, all the relays click. (I've tested ALL of them) all the fuses have power. I'm running out of ideas as to what to check. I know the PCM sends the ground signal to the injectors for it to pulse. I just don't understand why its not happening, any help would be greatly appreciated. Thank you.
There is a lot to check, TPS, Cam sensor on driver side, crank sensor on passenger side, did you hook the ground strap back up? Whats the compression look like? Is it a manual? I cant remember if there is a clutch sensor or not verifying the clutch cable is actually depressed.
It does fire if you wait a while. I am assuming this is because injector leakdown. Even though I tested them on the bench to make sure they didn't drip I guess I did not wait long enough. Yes I did hook the ground strap back up, I wire brushed all the grounds to make the best contact possible and used dielectric grease on top of the ground to help seal it off from oxygen and moisture so oxidation/rust could not form. It is a manual transmission and we did half to remove that sensor. I don't remember it we adjusted it back properly... But my understanding of the clutch switch was it was just a switch that would allow the vehicle to crank upon being depressed. I am not sure if it is more advanced, like it is able to read the actual depth the clutch pedal is being depressed. And I haven't hooked up a compression gauge because I was able to get it to run off brake cleaner momentairly and the motor sounded great. But just to make sure I will test all the cylinders for proper compression. And I have checked the TPS and it works fine. I will check the cam and crank sensor to see what I get. Thank you, ill let you know what happens
I'm going to assume this is a crank with no start.
Turn the key on but do NOT crank. Confirm that the theft light goes out after a 3 second "prove out".
Does the check engine light go out during cranking? If so, then likely the PCM is getting a something from the CKP sensor.
Confirm there is +12 volts with the key on at each injector. Use a KNOWN good ground.
The fact that the motor runs off of brake cleaner almost "proves" there's a fuel related issue. For the 1999-2004 model years the fuel rail pressure sensor (FRPS) is a NO START sensor. That is a missing or bad FRPS will cause a no start condition. If this were my car I would check the electrical connections at the FRPS very closely. Look for bent/pushed pins. Dirty connections and so on.
A "noid" style tester can be used to confirm the firing pulse at each fuel injector.
A MAF sensor problem could also "cause" a no start condition. What happens if the MAF is disconnected?
Do you have an ODB2 scanner? IF we knew what the PCM "thinks" the values for:
system battery voltage
Fuel rail pressure
Knowing these values could make real short work of this problem. Here's some information on an affordable Windows based ODB2 scanner.