rcmf5525

Well, after a long haul, I have a 2001 5.3l in my son's 1978 K10... The engine ran well when it was removed from the Z71 donor. We just tried to start it for the first time in the k10 and no joy... We are getting fuel, but no spark... I'm guessing it is the computer not functioning properly, but I can't say for certain because I am unsure of how to functionally test the ECM... The ECM was reflashed to delete the trans, anti theft, emissions (AIR and EGR), but all other sensors were left alone. At least that is what I was told. The only sensor that is not connected is the VSS. I am waiting on a replacement adapter from Dakota Digital... I don't think that sensor will effect the stationary operation of the engine/ecu because it will just think it is in park. I am reusing the 2001 under hood fuse block. The IGN1 relay feels warm... Is this normal?

The connectors to each coil has 4 wires... One of them is hot 12v, the middle two are hot 8v (I found this to be a strange number), and the fourth wire has a very small amount of current. None of the terminal's voltage seems to change when the engine is being turned over... Would I be able to see the signal being sent from the ECM to the coil with a volt meter or would it happen too fast to register? I have also tested the coil itself while the engine is being turned over and received no signal...

I do have the OBD2 diagnostic port wired. Would that be able to tell me if the ECM is functioning and what, if any, codes are present even if the engine hasn't run since the reflash?

Sorry for the long post. Just thought I could give as much info as possible...

rcmf5525

I have also tested both the batt to ecm and hot/run/start to ecm and they are both supplying power.

wait4me

iTrader: (10)

Ok, Here is what you need to do.

Watch to make sure that the pink wires in your harness HAVE 12V WHILE THE KEY IS ON< BUT BUT BUT ALSO WHILE YOU ARE CRANKING IT NEEDS TO HAVE THAT 12V as well!


On a lot of those old key ignition setups, I have seen people hook up to to the wrong ign output so it has 12v when the key is on, but looses voltage while they are cranking so it never starts..

Also check for your grounds on the back of the block to be good to.

rcmf5525

Thanks! I'm gonna dive into some diagnostics in about an hour... I had another response that was very informative from another website:

The coil plugs have four wires as you know.

Cylinders (2 4 6 8)
A ground
B Ref low volt (Brown to Brn/white C2 pin 61 PCM) (Control Grd)
C Ign control signal (these go to PCM to tell each coil to fire)
D 12v voltage (Pink wires all tired to E6 C2 under hood box)

Cylinders (1 3 5 7)
A ground
B Ref low volt (Brown to Brn C2 pin 60 PCM) (PCM Control Grd)
C Ign control signal ( these go to PCM to tell each coil to fire)
D 12v voltage (Pink wires all tired to E12 C2 under hood box)

Quote:
The connectors to each coil has 4 wires... One of them is hot 12v, the middle two are hot 8v (I found this to be a strange number), and the fourth wire has a very small amount of current.
Check the grounds at pin A or at the coil extension harness plug by the valve cover. Ohm them out with engine off and battery disconnected just in case of a wiring problem. Or you could hook a test light up to pin A and the other end to batt 12v. If it lights then coil ground is good. Made sure they are good or it will not run. It sounds like something wired wrong as pin A should be ground its on the one end of the plug to the right if looking at the retainer clip. It should not have any voltage. Look at the picture below.

To test pin B PCM low ref control ground. Use a meter: place it in DC mode, place the black lead on pin b, and the red to 12v batt. should be proving ground during start so should read a voltage.

If that all checks out it could be the IC control wire, Bad PCM, or VATS not disabled. But usually it will fire for a few seconds if its VATS anti-theft.

rcmf5525

I didn't think about the hot/run/start for the pink wires... I will make sure to look at that.

gagliano7

On my 1992 chevy pickup i hooked the pink wires to my original distributor hot wire.That wire stays hot while cranking.Worked perfect.

wait4me

iTrader: (10)

You have to make sure that the amp load is physically able to handled by the gauge wire you are using.

That distributor wire is not sufficient without the use of Relays being used.

The load on the pink wires needs to be at least a few 30 amp fuses. What I Normally do is, just use the ignition as a trigger to turn on the relays to supply the full amperage needed via larger BATT wires.

An example.

4 bank fuse setup from car stereo company.
Input is 4 - 8 gauge from battery.
Use 3 relays. With pink wires split evenly between them. "depending on how many you have.
pin 30 goes to fuse output
pin 87 goes to pink wires
pin 85 goes to ground
pin 86 goes to IGNition key switch.

That way you are also relieving the load from the key switch itself so it wont burn out.

rcmf5525

Just an update, we got her to start and she runs well!
There were several things going on...
The cam position sensor plug wires were decimated so we had to replace them and splice it into the harness. I have no idea how we missed that...
I purchased a newer, used, intake with injectors and throttle body locally for $50... Killer deal, but the injectors would not work with the stock plugs so I switched back to the stock ones... That was a problem because the injectors that came with the intake were flex fuel and flow at 36lbs compared to the 24lbs stock... The PCM was flashed with the part numbers of the flex fuel injectors so it would not fire the stock ones long enough to supply ample fuel...
Once we sourced new injector plugs, spliced them in, and re-installed the flex fuel injectors, it runs properly...
This was an experience to say the least!
Thanks for the help!!

wait4me

iTrader: (10)

Awsome, glad you figured it all out.