V6 to v8 swap no crank, no fuel issue.

DABURNNOTICE98

New Member
Sep 20, 2020
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I have a 1996 mustang v6 that I swapped a 1998 mustang v8 engine and trans into. I bought a 98 donor car that ran and drove and did the drop the cradle method. After the swap was done, I couldn’t get the car to start, but it would indeed crank. (There was no theft light) after some more research I swapped more things from the 98, and the car still did not start. (No fuel). Randomly after trying it one day the car would no longer even crank, so I replaced the battery and nothing, so I removed the starter and it came back bad. Put a new starter (and tested it) and it still won’t crank. So now I have no crank and no fuel. I’ve tested voltage at the relay and the CCRM and the fuel pump, and I have power to all but not 12v at any. So now all it does with a key turn is click from the CCRM. And all the interior lights and noises come on. (There is no theft light on)

Things I’ve swapped from the donor that deal with pats: CCRM, ECU, Cluster, Theft Module, Steering column (original key to donor).

Some help would be amazing, other then generic answer “sounds like a ground” Thank you in advance.
 
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tsemmett

Active Member
Jul 2, 2019
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How much of the wiring harnesses have you swapped? There's a fair difference between 96 and 98, and V6 to V8; it's not impossible that something's missing.

Some stupid questions first: Do the Theft and Check Engine lights come on when you first turn the key to Run (before you try to start it)? That should confirm the PCM (and PATS system) are working. Is your battery well charged and are the connections clean? Just because the lights come on, doesn't mean the starter is getting enough current. Have you put a fuel pressure gauge on it, or are you just going by the sounds? Not all fuel pumps are loud (mine isn't).

For the starter: The starter doesn't run through anything complex, and PATS doesn't disable it (at least not on a 96-98). Is there power from the large cable at the starter? If you apply power to the smaller cable (the solenoid), does the starter engage? If not, you've got a ground or power cable issue, or your battery is discharged. If it does, you have a short in the ignition circuit.

For fuel: the fuel pump gets power from the fuel pump fuse in the engine bay, to the CCRM (power in on pin 11, Yellow wire, power out on pin 5, Dark Green/Yellow wire), then to the Inertia switch in the trunk and finally to the fuel pump (Brown/Pink wire coming out of the Inertia switch). You also need to be sure the PCM is getting power (pins 12 and 24 on the CCRM, both Red), as that provides power to one end of the fuel pump relay coil, and without the PCM powered on, the fuel pump is never triggered. I'd test down the line for shorts, or at least continuity (in case there's some mismatched wiring that isn't lining up).

Let me know what you find and I can dig a little further. I've got shop manuals for my 98, but nothing on the 96 portion.
 

DABURNNOTICE98

New Member
Sep 20, 2020
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i appreciate the response, I’ve replaced the entire engine harness (including the fuse box) mind you it was at least cranking with the v6 fuse box. The starter cranks with a screw driver in the solenoid. One thing I didn’t replace is the body harness and dash harness. After some research I believe the dash harness is different. So I’m in the process of swapping that. The theft light comes on with the key on position for a brief second and goes off, the check engine comes on as well but dosnt go away. So that mean the ecu is working? The battery could be bad, but I’ve tried with 2 batteries and I’ve tried it while connected to my 14 mustang gt. Starter has power at the starter and the starter relay we tested dosnt click while in the car. Fuel pump relay in the CCRM clicks at crank, and when tested has has voltage at the CCRM. I haven’t tested the ecu wiring but if the CCRM fuel pump relay clicks does that mean it’s workin? I will update after I swap the dash over.
 

tsemmett

Active Member
Jul 2, 2019
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If the starter works with the screw driver, your issue is in the Ignition circuit. Power to the solenoid runs from one of the Ign Switch fuses under the hood (they're terrible at marking which of these 3 fuses is which; I believe it's the 3rd one) to the Starter Relay (also under in that fuse box) and to the starter solenoid. The trigger for the starter relay is off the ignition switch (when in the start position). If it's a manual, the clutch switch has to be engaged, if auto, the transmission range needs to be Park or Neutral. You could verify this stuff at the starter relay; it seems to be a standard relay. Pin 30 is power from the Ign Switch fuse, Pin 87 goes to the solenoid, Pin 86 is ground, and Pin 85 is power from the ignition switch. If all those are good, that relay may be bad.

As for the fuel pump, if you have power from the CCRM on pin 5, the fuel pump relay is working. Check the inertia switch in the trunk next. Test across the 2 pins and see if you see power. If not, test between the Dark Green/Yellow wire and a ground. If you don't have power on the Dark Green/Yellow wire, there's an issue between the CCRM and Inertia switch. If you do, but not between the pins on the inertia switch, your issue is further down (towards the fuel pump).