'00 5.0 cam position sensor voltage questions (p0340)

[Dylan Rodriguez]

Thought so just wanted to double check. And for sure.

I had ordered a MSD DIS4+ for when I turbo and all that...anyway with all correct wiring, the two ignition adapters (PN8912), and all their wiring correct, the dis unit would still give me an "intermittent input signal" error code. With this information, would that lead any of you to check wiring somewhere else that finally let go? The truck would run fine with the MSD's harness connected and the bypass plug in, but as soon as the ignition adapters were plugged in and wired up and the harness plugged in to the MSD, truck wouldn't run. Already sent the unit and the 8912's to msd to have them tested and they checked out. Could it be a bad ecu maybe? This was an ecu I bought off eBay and the guy flashed it with my vin number and stuff.

 

[Dono]

No experience at all with that ignition. I'm just using factory ignition.
I have not seen this upgrade before. Would you need 2 adapters? Do you have any wiring diagrams? How do the plug wires mount?

Sorry to derail your thread.

Edit: Did you wire like this? It looks like it keeps the existing coils. Seems strange. What do I know though?

 

[Dylan Rodriguez]

Yessir, keeps coils, they have adapter harnesses where you plug them in to the factory coil pack connectors and wire it to the DIS's harness, so you don't have to butcher factory wiring any. The 8912's are used to tell the injectors when to fire from what I was told by MSD. I was able to get the truck to run before without them, it just had a misfire or hesistation if you blipped the throttle. No worries about thread jacking as I'm wondering if there's been a connection problem somewhere that the MSD was sensitive enough to have been triggered by, but the stock ecu just looked past it.

 

[Dono]

Can you unplug the MSD box and confirm if the p0340 still shows up? I think your right, the msd box controlling ignition just might be throwing off the ignition timing enough for the ecu to pop the code.
On a side note (Sort of related) I have a J@S knock sensor that retards timing when it hears knock. My ecm was throwing ignition codes because the J&S box was changing the dwell so much on the timing. Once I brought my timing tables closer in line, I quit getting the codes.

 

[Dylan Rodriguez]

It's the other way around, the box is always unplugged since it keeps giving the intermittent input signal code. It's been running recently with everything MSD taken out including the harnesses. Full stock now. Running screaming demon coil packs. Double checked and made sure the ground/black wire on the side of the coil packs was good and making a solid connection also.

 

[Dono]

My money is on the idle needing to be higher.
It just sounds like you have covered all the obvious bases.

There is no way anyone could magically equate a p0340 code with low/eratic alternator output. Its just something we have seen on this board over and over.

 

[Dylan Rodriguez]

I'm wondering if it's something tune related also. Left dyno, we had just allowed closed loop again, and the code has progressively gotten noticeable. Went from a slight dead zone in deceleration where the engine would sound like it would miss/not fire then continue running fine. CEL wouldn't illuminate even though the code would register with the SCT device. Drove for a few days after, very sparingly because torque converter was slipping and going out, but it drove fine. No misfires or anything. Get it home one night, go to start it the next day and won't stay running. Weird.

I'm honestly wondering if its ecu related also. I had a problem last year where when I'd turn the key to ignition, the relays would click, then the fuel pump relay would start clicking rapidly, along with CEL flashing at same rhythm. Theft light flashing also, different rhythm though. Couldn't find anything wrong. Disconnected ecu harness after two or three days of diagnosing, let it sit over night, worked fine the next day. No problems since

 

[Dylan Rodriguez]

Quick update, got the truck back together with new converter, fired it up, ran fine for a bit, shut it off, started it up abain and same thing. Surging then stalling unless throttle is applied. Tried raising the tune through the SCT device when I flash it, same thing. Now, also, STFT Bank 1 is always at .7. Never did that before. Bank 2 reads proper. Unplugged sensors, threw codes for o2 heater circuit error, so they're getting power and signal. Not sure what else to do now. Thinking new ecu, and new tune, but not sure. Tried about everything else out there seems like. All ears though!!

 

[Dono]

Are you sure all cylinders on bank 1 are firing?
Un-burnt gas will not be seen as fuel, and the pcm will try to add fuel to that bank.

 

[Dylan Rodriguez]

Seems fine when some throttle is applied, just won't idle. I did remove coil packs, so maybe I have one wired up incorrectly. But I doubt it based on how it's running. Would assume it'd run a lot worse if I had one misplaced

 

[Dylan Rodriguez]

Tried raising idle to 900 @ park/neutral, still doesn't want to idle

 

[Dylan Rodriguez]

Are you sure all cylinders on bank 1 are firing?
Un-burnt gas will not be seen as fuel, and the pcm will try to add fuel to that bank.

Also, it's still throwing the p0340 code so could that have something to do with the STFT bank1 reading .7?

 

[Turdle]

Is there a possibility you have the bank one o2 sensors wired incorrectly, reversed?

If not, are you certain all the cylinders on bank one are firing, in the correct firing order-
Possible bad spark plug wire? Make sure they are not arcing or touching the manifolds. Spraying them with water in the evening will show arcing real well, if it is occurring that is. Bad spark plug?

 

[Dylan Rodriguez]

O2 plug was bad. Changed it out and both banks reading proper now. Still p0340'ing though. I think I'm gonna have a sticker made up that says that. Lol.

 

[Turdle]

Do you have a timing light available for use?

 

[Mbrooks420]

I’m f you haven’t done it, I’d replace the plugs again. They are easy to crack putting them in.

 

[Dylan Rodriguez]

I do have a light. I'll see if I can get it to idle long enough to get a good reading. That was my next course of action.

Also, plugs have ~1500 miles on them. Haven't touched them since initial startup on this build. Too hard to get to #7 & #8 especially with these OBX headers. Will do that as a last resort

 

[Turdle]

I want you to take the cam sensor cap off, hook the light to the number one cylinder like usual, run the engine and see where the flag is when lit. It should strobe nice for you being dark down there.
does the flag appear toward the firewall or toward the front of the engine. Since you have the p0340 anyway, it should run long enough for this test with the sensor cap off--

 

[Dylan Rodriguez]

I want you to take the cam sensor cap off, hook the light to the number one cylinder like usual, run the engine and see where the flag is when lit. It should strobe nice for you being dark down there.
does the flag appear toward the firewall or toward the front of the engine. Since you have the p0340 anyway, it should run long enough for this test with the sensor cap off--

The sensor drive itself hasn't moved since it was installed in this engine so it's got about 1500 miles on the current setting as well, so physically it should still be set correctly unless something has let go somewhere in the drive. Still going to give it a test regardless of course

 

[Turdle]

The ignition is triggered by the crank sensor, which can shift when the balancer rubber loosens. The Cam sensor signal is "compared" to it. Did you use a new balancer?