Strange issue

[Z3r0x01]

The reason i suspect broken or chafed wires, when you're testing sensors that require power to function, and keep in mind that I'm only new to obd2 systems, i ground to the battery, i take the positive lead and put it to the +12v wire in the harness socket and when the key is turned to on, +12v reads 2.53, the center pin of that socket should be the signal to the ecu, it reads 2.53 same as the +12v, and ground is ground. I have been told that the +12v should be the only wire reading when the key is on, and the signal wire should only read when the engine is cranking or running.

[Z3r0x01]

If you unplug you ckp sensor and look at the plug on the sensor end and just imagine for a minute that you are looking at mine, and in the plug it appears to be burnt white almost like its corroded but white like it got hot, thats why I'm saying its wiring.

[avguy]

If you unplug you ckp sensor and look at the plug on the sensor end and just imagine for a minute that you are looking at mine, and in the plug it appears to be burnt white almost like its corroded but white like it got hot, thats why I'm saying its wiring.

I obviously can't know exactly what you're seeing that looks burnt, but you need to consider this logically. It takes lots of juice to burn wiring or plastic, and it's hard to imagine that level of amperage not blowing a fuse. So, although not impossible, burned crank sensor connector/wiring would be WAY down on my list of suspects.

And, AFA the crank sensor voltage goes, I think if you check the reference pin again with the engine cranking, it should show 5V. And if you back probe the signal wire (or use a wire-piercing probe) with the spark plugs out and the engine cranking, that voltage should bounce between 0 and 5V (or a test light would go bright/dim). But only a scope can do a valid waveform signal test.

I'm not trying to tell you the crank sensor can't be having a problem, only that I'd want to do the test with a scope before doing anything with the associated wiring bundle. If you can't go the scope route, then at least check the resistance of the 3 crank sensor wires at the connector, back to the ECU connector pins.

[Z3r0x01]

I was told there should be no power at ckp harness side for the signal wire and should be 12v on the live wire, what I'm trying to say is i have 2.53v on both live and signal no matter what and i was also told by a dealer technician that there is more than likely a short and that i can bypass it by running a wire to the live wire directly from battery to see if that will solve the problem.

[Z3r0x01]

But i would need to tap into ecu plug to find the initial wire that goes to the ckp plug for live

[avguy]

I was told there should be no power at ckp harness side for the signal wire and should be 12v on the live wire, what I'm trying to say is i have 2.53v on both live and signal no matter what and i was also told by a dealer technician that there is more than likely a short and that i can bypass it by running a wire to the live wire directly from battery to see if that will solve the problem.

Was that the same guy who told you 165 compression is good? You've been getting some SERIOUSLY bad advice from these people. The voltage that you're seeing on those 2 crank pins with the key at 'on' does not indicate any problem at all. It's simply the low (2.5V) reference being sent along the signal wire, and means nothing when the engine is not cranking/running. The signal voltage will become variable (square wave) once the engine begins turning over.

AFA jumpering a short like this guy is suggesting? Anyone who says to run a B+ wire directly into this sensor is an idiot. Sending 12V into a lower voltage circuit is likely to cause serious damage, not the least of which could be backfeeding and frying the ECU. I suggest you find another shop that knows what they're doing.

[Z3r0x01]

Ok finally a last thought before it goes to the dealer to get checked, wiring i wasn't planning on meddling with, i rereplaced all vacuum lines, and come to find pcv valve is cracked, so i am swapping that out, and possibly looking at a new valve cover that has the screw nuts intact

[petrified.rabbit]

did you ever fix the broken wire on your knock sensor that you said you had? How do you think the engine "sees" a misfire?

[Z3r0x01]

When i run my obd2 reader it shows under pending codes unless being driven a p0300 code, when driven the cel flashes and it goes in ol_fault because of the p0300 code, now i believe it has something to do with the pcv valve being cracked, yes i fixed the wire on the knock sensor, turned out to be a ground wire.

[avguy]

I'd be really surprised if replacing the PCV resolves the misfire. The P0300 can be caused by many things, but you've already eliminated quite a few of the usual suspects. Your description of 'black' plugs sounds like incomplete combustion, so you might want to consider things such as not enough air, blocked cat, or contaminated gas.