If codes are reset, they wont pop up again till the next cold start, typically the next morning or when its had enough time to cool down completely.

Temp sensors report accurate values. Nothing strange there.

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Last 6 inches of CKP had cracks in insulation due to heat and age. I removed the heat shield since I have ceramic coated manifolds and that may have had something to do with it. I later added a reflective heat sleeve just in case heat was affecting the sensor or wiring. Anyways I stripped away all the brittle insulation, coated the bare wire (in great condition) in liquid electrical tape, then real electrical tape, then wire loom, and then the aforementioned reflective heat sleeve. None of that made a difference.

I really need to get out there and measure the wire for any resistance to see if there's a small short somewhere in it. I don't have a scope to see the waveform but at least it's something.

I waterproofed the ECU just in case condensation was having something to do with it, and because it's a good idea in general. It looked brand new inside and out so I just sealed it up with silicone upon reassembly.

 

thanks for the clarification.

my moneys on something being wrong with the wiring at your crank sensor

 

Didn't Savannah talk about that being shielded and grounded?

 

My CKP wire consists of two inner plastic insulated wires. Those are wrapped in braided wire strands which I assume is the ground/shield, and then a final layer of insulation. Heat resistant wire loom then goes over the whole wire. HOWEVER, the last 6 inches (approx) does not have any of the outer ground/shield layer, just two wires. Normally wire loom covers those last few inches too so you'd have no idea it was missing. Is this normal? Going to look for photos...

 

I am guessing that may well be the issue. Maybe Paul Grant or Tom or Cosmo or Sava or someonewho has seen one can confirm.

 

Would think that whatever shield is present is OK, or would continue rest of day. Could measure shield to frame, should read dead short.

Another electrical possibility is injectors power. The Multi Function Relay puts 12 volts to both banks thru some splice points, and the ECU supplies a switched ground for each injector, if those splices are loose or heat sensitive, or if the + side cable of any injector is touching ground (they are all one big common splice together) this could cause problems. Exam wiring and shake. Pull fuse 7 of underhood box and meter the harness on the + side of any injector (they are all connected) checking for stray ground, to frame.

See attached.

Also, for the diabolical experimenter, misfire detection is suspended during rough road signal from the ABS. The rough road signal is on pin one of the ECU connector C1017. 0 or 12 volts, could be strapped to 12 or cut, as needed.

 

Maybe try a whole new wiring harness? Sounds crazy but you may have some rotted wires somewhere a long the line.

As you know I have had these codes off and on but honeslty I havent drove my truck in a bit since it's been torn apart. But I think fixing the cracked exhaust manifolds and leaky gaskets may have been the trick.

 

Wow, I need to re-read this whole thread, I've had similar code issues with mine. Great resource.

 

Ooops, attachment had to be added on my previous post. Thought this might make sense because the + volts wire to injectors goes in "banks", would be easy to impact multiple injectors. Guess it could also be bad MFR, perhaps tap on that to see if you can duplicate problem. But that seems like it would happen more often.

ET - also - does engine light flash? notes from GEMS manual:

7. Criteria for Storing Fault Code
If catalyst damage levels of misfire are detected the fault code is stored immediately. If misfire above the emission threshold (only) is detected, then a
set of conditions is stored. A DTC will be stored if misfire is detected on a subsequent driving cycle while the conditions are still stored. The conditions
can be erased on intervening fault free driving cycles as allowed in OBD II regulations.
8. Criteria for Illuminating MIL
If catalyst damage levels of misfire are detected the MIL will be flashed for as long as the catalyst damage misfire level is present. If misfire above the
emission threshold (only) is detected, then a set of conditions is stored. The MIL will be illuminated if misfire is detected on a subsequent driving cycle
while the conditions are still stored. The conditions can be erased on intervening fault free driving cycles as allowed in OBD II regulations.
9. Criteria for Determining Out of Range Input Signals
The crankshaft position sensing system is subject to diagnostics, which detect more or less than the correct number of sensor transitions per engine

revolution.

Perhaps if light is flashing, what ever is causing it is happening at that point. Once it is over, you are left with just more codes.

 

Mine was down to just P1316. I did the following:
1. Seafoam Spray Treatment directly into the Throttle Body 1/4 inch from throttle plate. Very little smoke was produced, unlike most stories I have read.
2. Replaced plugs,
3. Cleaned MAF again,
4. Cleaned Throttle Body thoroughly. (first time I have ever cleaned TB)
5. Cleaned and sprayed the throttle linkages especially the springs on the external portion. I had messed with this before, but this time I thoroughly cleaned to remove all gunk and then sprayed on PB Blaster Spray Lubricant to keep it smooth.

Mine is running better than it ever has, the cold start-up is smoothed out better than it ever has been. If you step on mine starting off and just hold it steady, it winds up quickly to 4000 rpms or so and shifts as you let off.

As winding as the roads are around here and lower speed limits, a few secoinds of pedal will get you in trouble in a hurry. Mine is running very strong and very resposive.


The throttle response is immediate and it is smoother than ever. I had been somewhat reluctant to mess with much on it, but very happy I did. It was really quite simple if any of you are having similar issues..........