I've just finished reading your entire post, I feel for you. I know your getting frustrated so let me added my 4 or 5 cents. I know this is long but I put a lot of info in it.

Three big clues that the computer is not working. Not necessarily broken, just not working. 1. no fuel injection, 2. no fuel pump, 3. no code reader coms

>>> bumped up from end of post
I got all the way to the bottom of this response before I remembered you saying the ignition switch is broken and you have to start the car by moving the rod. The EEC power is switched on from the ignition switch I believe. If the switch is not working it might not be turning on the computer.

Does the radio work when the rod is in the on position?
>>>

It definitely sounds like a computer problem, as opposed to the fuel pump. The fuel pump not running is a big clue though. On EEC/PCM cars the fuel pump is controlled by computer. When you turn on the key, the computer turns the fuel pump on for about 3 seconds, to prime the fuel lines. Then, once the engine is running, the pump stays on continuously. The fuel pump regulator maintains the correct pressure in the fuel rail, and lets any extra fuel/pressure return to the tank via the return (small) line. Generally the FPR is mechanical, but may have a pressure sensor built in as fault sensor to generate a check engine light if fuel pressure is too low. The FPR does not control switching on or off of the fuel pump. It's normal for a lot of fuel to make it back to the tank. When the engine is at idle (or off) most of the fuel will be returned. The supply line comes from the fuel filter and the fuel pump (they are on the same line).

The fuel injectors are another big clue. The computer controls the firing of the fuel injectors. The fuel injection circuit starts at the distributor. On EEC engines the distributor has a position sensor just under the distr. rotor that connects to the computer to tell it when the distributor is sending sparks to the spark plugs. The sensor is basically a magnet with a spinning slotted metal plate attached to the dizzy shaft that creates pulse signal whenever the dizzy spins past a plug wire. This signal gets adjusted by the computer for timing curves and rpm and gets sent to the injectors as firing signals. If you are not getting fuel it is most likely either the PIP or the computer. The distributor PIP (Position Indicating Pickup or hall effect) sensor also is used to control spark once the engine is warm. I have seen a problem where the pip went out, and the engine had spark but no fuel injection and so would not start.

Since the computer controls both, and you are unable to talk to it with a code reader, you should focus there first. If the code reader can not talk to the computer, either the computer doesn’t have power, or it’s dead and you know yours isn’t dead.

So lets start at the beginning, Power.
First check the fuse(s) for the EEC/PCM to make sure 1. they aren’t blown, and 2. they actually have power when the key is on. (you can measure from the metal post on top of the fuse to ground to check)
Next locate the EEC relay and use a voltmeter to check and see if it is getting its signals.
Using your meter you should check, with the key on, and the ECM relay pulled, to see if measuring across the sideways (left right, not twisted plug) you have close to 12 volts. If there is much less than 11V it will not work. If you don’t the computer is not turning on. Also check the top to pin to ground to see if it is hot. The top post should be hot all the time.

Relay testing,
You can also use a test light, but I like meters better. Looking at a relay socket. you should see 4 holes with metal in them in sort of + sign type layout. Usually the top and bottom are switched, and the side to side are control. A relay is just a switch, when power comes on one wire, it closes a switch and lets power through on the other set of wires. to check a relay, you can apply power and listen for the click, if you really want to engineerish you can take an ohm reading across the switched legs while your applying power.
Another way to test is to bypass a relay. Use a 3" long piece of nice thick wire (12gauge) with about 3/8” stripped off each end, and bent into a U shape. connect the ends to the corresponding terminals of the switched legs of the relay (top and bottom usually). **Only put in and remove the wire with the key off, turn the key on once the wire is in, to prevent accidental shorts** This is only a short term test and should only be used to test the rest of the circuit.

You could do this for the fuel pump relay to test if the circuit is good after the relay. If the pump comes on, it's almost definitely the computers fault.

If all that is good try checking the power into to the actual computer. I don’t have a diagram handy right now, but I’m sure someone can tell what pin to check for 12v.

Generally, when you turn on the key, power is supplied to the EEC, the EEC turns on power to the fuel pump for 3 seconds then turns it off until the engine starts cranking.

This is were I remembered the broken ignition.

 

meter results:
connections to inertia switch at engine are hot on both sides of connector.
wires at inertia switch are hot.
pins on comp connector (not the comp) are NOT hot. I checked all the pins that
could possibly be those numbers and nothings doing. that was checked with
key on and off.

thoughts?

 

meter results:
connections to inertia switch at engine are hot on both sides of connector.
wires at inertia switch are hot.
pins on comp connector (not the comp) are NOT hot. I checked all the pins that
could possibly be those numbers and nothings doing. that was checked with
key on and off.
relay wires are not hot either.

its a new computer so that cant be it.

thoughts?

hukd

 

Relay wires for EEC?

If the relay wires for the EEC are not hot, this is your number one problem.
Try looking in your book, sorry I don't have mine with me, to see where the EEC relay gets its signal from (somewhere on the ignition switch assembly)

When you push the rod from off to run, does the radio work, and do you hear several relays click in the engine compartment?

If none of these happen, it could be the ignition switch assembley, (name?) the electronic switch portion of the ign switch that has all wires.

 

clarification: when the key is turned, it turns the power on but it wont go far enough to actually crank the vehicle.

1) the radio comes on with no problem.
2) is the PIP replacable or is it just better to get a new dist.?
3) eec relay: 3 wires = hot, black wire makes relay click, one isnt hot
the relay has 4 pins shaped like an "L". if you # them with 1 being the leg,
2 being at the angle and 3/4 going up, this is what I get from my meter:
#1 crossed with 3 = 12V
any other combo = ~10-11V
4) FP relay: one wire is hot (key on or off) all others have nada!
5) nothing comes from my comp connection still. either way with test light or
meter. I dont see any need in checking the actual comp since its new.
there is continuity there but that doesnt diagnose my problem.

next?
hukd

 

1. The radio coming on says most of the ign switch is working.

2. The PIP is replacable by itself ($25), but you have to pull the distr. drive gear off to do it. Definately wait till the computer is acting normal though, b/c that is the biggest problem.

3. 3 wires is strange, there should be 4 normally. Check and see if there is one floating around. When the key off there should be one hot, whith the key on there should be two hots. If there's not the problem is between here and the battery.
We need some diagram help here. What are the colors of all the wires there. This is the socket under the dash? near the computer?

4. That is what I would expect to see if the Computer is not coming on. The fuel pump relay is energized from the computer. The hot comes straight from the fuse box.

5. You should have power into the computer (at the 60 pin connector) normally, there has to be a hot pin when the key is on. The computer may be good, but it doesn't matter if it isn't getting power.
I should have said switched power.

Check the fuses, Especially the ones in the engine compartment (if there is one). Check them the inside too. I will look up the diagram for the eec relay, and the 60 pin EEC connector tonight if know else has posted it.

Try following the wires from the EEC relay, one of them has to go to the computer, to supply power. Try using your test light on the back side of the relay socket to find the pin that is hot when the key is on, but not when it's off. If you ohm the relay when its unplugged, two pins will have low resistance, the other two will have high. Thats another way to tell the swithced and and control pins.

You could also try jumping the relay and see if the computer comes on (with the code reader) as I described earlier.

 

there are 4 wires at the EEC relay. i just didnt phrase it correctly. i'll look at the rest of it now. more details on what i find later.

hukd

 

EEC relay (brand new)= yellow, black, blue(fusible linked) & white/blk wires
key off = yellow hot
key on = yellow, white/blk are hot, black "clicks"(calling this hot also), blue stays
dead
**the white/blk wire is the one that connects the relay to the ignition switch according to my diagram.
**ylw connects to FP relay and ends in a link that stays hot at all times according to diagram
**red connects to pin (#37) and then runs to injectors according to diagram
**black grounds according to diagram


pin 41 (if Im counting the right way) is the yellow wire and is hot all the time.
pin 21 is the black wire that makes the EEC relay "click"
the black wire at the relay and thru the comp connection is low V @ ~ 10V (maybe 11)

does this mean anything to anyone? if so, whats the solution?

 

Unplug the 60 pin connector at the computer again. With the relays plugged in, turn the key on. You should have 12V on pin 37 and 57 - VPWR. You can also test for this power at the idle air control valve, at the ignition coil, and at all the injectors. If you do not have power, the fusible link is blown or the relay is blown. You are back probing the harness to check for power with the relay plugged in, correct? The EEC relay should have a wire that is hot at all times, another wire that is hot when the ignition key is turned on, and a ground. The fourth wire goes to pins 37 and 57 to power the computer, and is hot when the ignition wire is hot and energizes the relay. I'm sure you know all this already though, it sounds like you have already done a lot of electrical tests.

The FP relay is energized by the computer, so if the computer is not turning on, then it will not turn on the fpr either. Even when the computer energizes it, if the truck is not running, it'll only be on for about 2 seconds.

The big yellow wire on the computer is pin 1, all the grounds are on the other end of the connector, and are pins 20, 40, and 60. Check for continuity to ground on these wires too while you are checking. Here's a diagram, hopefully it'll work

 

Thanks for the diagram! I will check these pins again. Your assessment of the wire reactions at the EEC relay are correct and functioning properly. I will test the voltage at the points specified but feel that they will be less than 12V... not sure what "VPWR" is?

Noticed a pigtail connection with 3 slots near PCM connection. One wire is traceable back to injector wire bundle and, when test light is applied, bulb glows brightly and EEC clicks. However, I see no female connection for this piece. Is there one? The other 2 slots do not seem to be hot when the key is on or off. Is this indicative of anything?

hukd

 

When does it click?
When you put the test light on the black wire, the relay clicks?
Or when the you put the black wire on the relay? It makes a big differance.

If the ground isn't very good, then when you probe the black wire, it would ground it, light the test light, and energize the relay, clicking. It should click as soon as the key is switched on when its all connected up.

The Vpwr just means power into the computer.

If power in is good, but the voltage is low, the next check is grounding.

 

VPWR is just what the function of pins 37 and 57 is called. If you don't have full battery voltage at these pins, but the relay functions normally, there is a short of some kind between the relay and the computer. There could also be a short to ground on this circuit which would have caused the fusible link to burn out. Check continuity to ground on the VPWR wire at varous locations to see if there is a short to ground before replacing the fusible link.

 

When the test light is connected to the black wire prong, the relay clicks. Pins # 37 and # 57 are dead. The wires from those pins connect to the bundle of wires that correlate with the injectors. There is also the blue wire from the EEC relay in the same bundle. That wire remains dead.... is it bad? Is the link at the injector bundle bad?

Thanks,
hukd

 

the relay "clicks" when i apply the test light to the black wire prong on the relay or that other 3-slot connection. all when the key is on (for sure...cant remember what happens when the key is off)
I tried sticking the test light into the wires coming out of the injector bundle at the firewall and didnt get any light-up. and still, the blue wire(fusible link) is dead. it attaches to the same bundle.
#1 lights up with power like a tree @ Christmas!! all others discussed are dead. I'll go look for power with a test light on all the wires as far as possible and see if I can find a short.

**a short has been a major consideration from the start. a blown FL or a major short is probably the cause at this point but lets look at all options before jumping the gun**

my gf wants to know how much you guys charge to come fix my truck... im about to lose my roof and food over this deal....u think Im kidding?!?!?!?!

 

pin 41 (if Im counting the right way) is the yellow wire and is hot all the time.
pin 21 is the black wire that makes the EEC relay "click"
the black wire at the relay and thru the comp connection is low V @ ~ 10V (maybe 11)

Do you mean pin 22 here? The black wire here to me sounds like a bad ground. If you are measuring from the relay connection to ground...which in reality, is the same point/ different location....you should read 0v.