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Discussion Starter #1
My First start is so close I can taste it but the engine won’t fire. I’m using a dieted EFI harness on my 347. I have fuel cycling and returning to the tank each time I turn the key. I tested the coil and have spark. I pulled the distributor turned it by hand with spark plug off the coil and I have spark there completing circuit. What I don’t hear is the injectors firing. I’m going to get a code reader tomorrow any ideas ?
 

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Questions: your using dieted harness, purchased or self dieted? are you using a stock distributor with TFI module? Stock computer?
 

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Discussion Starter #3
The harness dieted by Chucks roadsters. Using stock computer and tfi module. When I turn the dist in either direction the fuel pump cycles which means I have PIP. I have power at the injectors. I guess my next step is to ohm them out or test for pulse ?
 

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FFCobra Craftsman
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The harness dieted by Chucks roadsters. Using stock computer and tfi module. When I turn the dist in either direction the fuel pump cycles which means I have PIP. I have power at the injectors. I guess my next step is to ohm them out or test for pulse ?
If you have power then it's the - side which I believe is what the ecu controls. Obviously it could be an ecu problem but I'd look at the wiring first. A wiring diagram will show which wire goes to which pin on the ecu so you can check w/ an ohm meter. Be sure to disconnect the harness from the ecu.
 

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Double check your computer grounds.
 

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You can rent/ borrow or purchase a Noid light from Autozone, Advance, O'Reilly, etc. Pull the plug off of an injector, put it on the light and crank to see if it pulses indicating that the injector is getting a signal. Craig is correct; the Ford EEC-IV system makes and breaks the ground through the ECU to fire the injectors.

Jeff
 

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Make sure that pins 20, 40 and 60 have no resistance to ground. I'm using a Ford Racing harness and I tied them all together and ran a 10 gauge wire directly to the negative battery cable. Then make sure that your negative battery cable runs to the engine block or cylinder head.
 

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I spent a few months chasing a similar problem with my Holley Terminator system. As CraigS says, check your coil negative wiring. Assuming your ECU operates like the Terminator, the ECU is looking for an RPM signal from the coil negative; no signal = no injector fire. Specifically, pull the connector off the TFI module & look for signs of arcing.

On my car, I found this:

IMG_6122 by jhsitton, on Flickr

You can see the burned plastic on the second pin from the top.

IMG_6123 by jhsitton, on Flickr

This is the plastic spacer removed from the connector above; you flip it out of the connector using a jeweler's screwdriver at the top or bottom edge. Again, you can clearly see where the pin was arcing.

IMG_6126 by jhsitton, on Flickr

And this is the pin itself removed from the back side of the connector. To get this loose, you have to wiggle out the foam insulation at the back of the connector (I used the jeweler's screwdriver to get it started, then needle nose pliers for the rest). Then look in the front of the connector & you'll see a tab that you have to depress (jeweler's screwdriver again) so that you can pull the wire from the back.

Since replacing the harness with that connector on it, my car has run just fine.


John
 

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Discussion Starter #9
I’ll have to buy a noid tester apparently the local zone does not have them. I triple checked my grounds even ran a ground from the harnesses directly to the battery as well as a dedicated ground from the coil. Still no luck. I’ll inspect the tfi connector more closely later. I’ll keep at it.
 

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New injectors or old? If they are used and have sat around a long time they may be gummed up.

As mentioned above confirm all grounds are good.
 

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Discussion Starter #11
They are old injectors that have been sitting around for quite a long time unused. Would 1or 2 bad injectors prevent the system from firing at all?
 

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IF NONE of your injectors are firing, it's a ground issue at the EEC - as stated above, the EEC grounds each injector individually, so if ALL are not firing, it's a ground issue for sure. Pull each injector lead and Ohm each ground leg to verify ground path back to the EEC. Internally, the triacs that control the injectors have a ground path on the EEC circuit board. If your leads show continuity from injector to EEC connector, you'll need to open the EEC and look for ground path circuit traces that are burned thru . . .

Also, did you keep the "Salt-n-Pepper" connectors at the back of the block? These are a known issue if not "serviced" during install. The pins get smaller and the sockets get larger making for loose connections - bad continuity.

Doc
 

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Discussion Starter #13
I’m still using the old salt and pepper shakers which are clean I’ll recheck the pin sockets. I removed the harness from the ECU and rang out each injector ground which all tested good. Guess it’s time to open the ECU.
 

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FFCobra Craftsman
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Unfortunately there are a lot of these ecus dying. The good news is that many can be fixed. They are old school enough that the burn is usually obvious. There are also some tiny XYZs that I forget the name of that are a common failure but relatively easily replaced. Google something like 'Fox Mustang ecu problems' to get more detailed info.
 

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Try the noid lights.

Back when donors were more common there were instances of every injector being hung up.
 

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I do not recall which models, but a lot of the 302 engines were batch fired injection. All the injectors triggered at once. Sequential injection was a later improvement. I do not know if that bit of info will help with diagnosis.
 
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