Hello everyone, have some issues with a starter relay, here's the story:

I have a 1990 F53 with a 460 7.5l fuel injection. It's a new purchase and has sat for at least 6 years without running, it has ran prior to me buying it and know both pervious owners personally, so I decided to finally get it going. When I first tried to start it, the starter relay was bad, so I replaced it, and it cranked with no start. So I had a buddy help crank her while I shot some starting fluid in the intake, and it did finally catch and the motor ran, which points to a fuel problem. So the next day I went and got a set of noid lights and when I went to test, it cranked and no light, so I wanted to check the other side, but when I did the starter relay clicked and no crank. I have since replaced the relay 6 times as everytime I try to starter her, it just clicks, and also I lose all power. I have check, double and triple checked all battery cables for any issues, cleaned all connections, and made sure I had a nice tight connection, but keep ending with the exact same results, no crank, one click from the relay, and power loss. I have verified all connections to the starter relay and tested for both 12v and ground at every turn. Now I'm totally lost as what to check for now. Any help would be greatly appreciated!

 

NOID light not flashing and "catch" on starting fluid with maybe fuel pump running all the time with the key in the run position says bad PCM Computer.
Open the PCM up and check for bad caps.

 

The fuel pump does not run all the time when in the run position, it runs for a few seconds and then stops. I am getting fuel to the fuel rail. Can you explain 1st, where the PCM is located and 2nd, how to check for bad caps?

 

Basic checks, cleanup needed:

(1) Run a capacitance test on the battery to determine integrity --- CCA reading (load test if you don't have the capacitance tester)
(2) Use a test light to check the Ignition Switch to Solenoid circuit with Key in START (also pull codes ---many use the "morse code" OBD1 reader, but the newer scanners all eliminate that and report the actual codes)
(3) Clean the fuel source (ie tank), replace fuel filter, refill with fresh gas, run a pressure test at the Schrader Valve on the fuel rail (passenger side) --35 psi or so with pumps on, higher when running
(4) Visually check the EEC-IV (PCM / "computer" ---that's a stretch) and get the VM (I've been using my Fluke 88 Automotive for decades) out to check voltages --- I can give you testpoints later
(5) Pull the TFI (either on the firewall or on the distributor) --- OHM it out, clean up the heat sink, use a heat sink compound when reattaching
(6) Ohm out the COIL --- primary and secondary windings -- primary should be around 1.0, secondary in the Ks
(7) Set up basic spark tests at coil, plugs -- key is quality of spark, not just presence -- hot "white" spark, jumps a distance" (the basic physical spark testers allow you to confirm visually)
(8) I normally use a relay checker (Relay Buddy), but you can apply 12v manually with alligator clips to both the EEC and Fuel Pump relays (removed from the driver side fender well) to determine if they're ok.......

My gut feel -- bad fuel, shorted EEC-IV, wiring or other electrical

 

Wow, ok so....I'll have to get a volt meter for most of this and will report back with my findings. I did replace the fuel pump with the newer updated one, got fresh new gas, did a full tune up including a new fuel filter, and have checked for spark, which is present at both the plugs, cap and coil. As for codes, because I have to disconnect the battery everytime I try and start it, it is not listing and codes. It used to crank just fine, with no problems, then all the sudden no crank. I'm also going to run a few tests on the NSS to see if that's working correctly

 

Good luck !! (I still have my 1990, but she's ripped apart getting the frame blasted)..................................

 

PCM Computer Location near left foot while driving.
Bad Caps would be bulging or leaking.

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Question, when replacing the NSS, does the center bolt come off, or does it slide over the attachment? Looks like this:

 

If I recall right it just slips off after the nut ans bracket are removed.
With the gear selector in "N" line up the lines and bolt it in place.
Attachment 282936

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Ok thank you