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Efi wiring issues


stranger_5oh

Member
Joined
Oct 9, 2014
Messages
23
Hey guys I've got a 91 ranger I'm doing a v8 swap in. I'm using a 5.0 out of a mustang and I have a wiring harness and ecu out of a 90 5spd mustang. I'm wondering what wires need to be spliced in order for to start and run. I've looked in a lot of forums and with so many different combos of yr model or what the harness came out that it makes it hard to figure out. Any info would be great and thanks in advance for any given
 
It can be admittedly confusing and you may have already looked at the llinks below, but here is the advice everyone gets. Buy the Harwood conversion manual. $25 well spent and very helpful with the wiring although not perfect. Also buy the EVTM for your Ranger and for the 90 Mustang. You will need both to give you all the answers. It takes time, patience and some organization of your process to get it all done. I am just finishing my 1992 swap, but I used a Marquis harness, so I had some additional challenges. Good luck. Give us some pics.

http://broncoii.org/forum/index.php?topic=511.0
http://www.therangerstation.com/tech_library/EFI_Wiring.htm
 
I've got most of the wiring figured out. I have spark at the plugs, I have power to the injectors but all it will do is turn over.
 
Is the Inertia switch by the passenger feet under the dash wired into the system? You may have to reset it by pushing the button on top. Can you hear the fuel pump run briefly when you turn the key to the "ON" position ? Do you have fuel pressure at the schraeder fitting on the fuel rail? Just some of the stuff I would be looking at.
 
No the inertia switch isn't wired in only because I have the fuel pump on a toggle switch and yes I have plenty of fuel pressure at the Schrader valve
 
Fuel injection works by the ECU Grounding each injector, with key on each injector should have 12v, but no Ground so it remains closed.
ECU needs good ground wiring to operate the engine, '90 Mustang 5.0l should have sequential fuel injection, so the fact there is no firing at all would mean no injectors are opening, but you have spark, you could add some gas to the intake to test if spark is working and firing at the right time.

ECU starts injectors based on PIP signal(Profile Ignition Pick up) from TFI module, assuming you are still using TFI system.
Good read here on testing TFI module(toward bottom): http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

Without PIP signal ECU doesn't even know you are cranking over the engine.

SPOUT(spark out) is the signal From the ECU to the TFI module for advance and retard timing changes
 
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First. Take that toggle switch and throw it in the garbage. If you're gonna do something, do it right! You have 2 fuel pump relays, one in the vehicle harness, one in the mustang harness you are using. Wiring up a toggle switch essentially just added additional wiring that was not needed or necessary. The mustang harness only requires about 5 or 6 wires to be hooked up, its kind of hard to screw that up, unless you start adding unnecessary switches. That being said...
double check you have the EEC relay hooked up correctly, and your injectors, maf, IAC, O2, TPS, ECT, ACT and EGR sensors all have ignition power.

I'm not trying to be an a$$, but there's reasons ford didn't put the fuel pump on a toggle switch, safety...

SVT
 
Its cool man I understand. I'm going to undo what I've done so far. I did find a guy that did almost the exact swap I'm doing and he explained the wiring in his feed from the two plugs needed from the mustang harness.

The only thing I'm leaving on a toggle switch is the electric fan.
 

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