Semopar Forum

**Redtruck-VA** · 06-05-2011, 05:28 PM

The Code is P0339, not P0309

I hate failures! My LP external monitor sensor died and it uses 5vdc, grnd and a signal output. I connected this external monitor sensor to the OEM LP sensor wires, because it was there and convenient to get at. The external sensor doesn't read any longer and I really don't know what died internally. But I initially assumed it didn't short the wiring so I temporarily left it connected. And started tuning using the PSC1. Took the adjustments to the extremes to see what i had to play with. Started throwing Crankshaft sensor intermittent signal codes (P309). Went down my list of what have I fooled with recently. Unfortunately the list is long. Rolled the tune in for a very nice idle, Cleared the code and removed the connections for the external sensor, thinking it may be screwing with the 5vdc sensor source. Nope the code came back and there is a slight stumble at 2000 rpm that sets the code. So I am now thinking there may actually be something wrong with the crankshaft sensor. I raced last weekend and didn't have any codes and this only popped up while i was tuning the other day. I'll let the engine cool down over night and remove the sensor tomorrow and inspect it. Of course when you are tuning you want to associate everything with what you are currently doing, but at the moment it really appears I have a faulty sensor. Anyone have any experience with bad crankshaft sensors?

Thanks,

**SmokedRam** · 06-05-2011, 05:38 PM

IN my GM days we would be putting a new cam shaft sensor on the Olds every month...HATE those things.

**txbass06** · 06-05-2011, 06:21 PM

Checking recent sales of them in my region, we've sold one since '07. So apparently they're not in big demand. Around here anyways.

A faulty crank sensor can cause anything from the stumble you've got no a non start in worse cases.
We're selling them for $39.99 with a lifetime warranty.

Here's a shitty cell pic of the component location

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**Redtruck-VA** · 06-05-2011, 07:43 PM

Mark, that is absolutely excellent information, thanks. It's still daylight out side so i went out and pulled both sensors. i have headers so was curious if maybe a wire got burned. I am completely anal about wires and headers and you wouldn't believe how I have everything isolated/insulated. The sensor was clean and had never had the plug removed. I used dielectric grease and put it all back together. Pulled the camshaft position sensor and the plug came off, so I'm hoping that it wasn't completely plugged in from the cam install. Dieelectric greased the plug and reassembled. Fired it up and didn't get any immediate codes. I'll check it out completely tomorrow.

**txbass06** · 06-05-2011, 08:48 PM

No problem Greg. I do what I can to help a buddy out. Sometimes knowing a guy that works at a parts store comes in handy lol.
Another thing I meant to say was I've seen faulty crank sensors throw cam codes and vise versa

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**Redtruck-VA** · 06-05-2011, 10:05 PM

Mark, the little reading I did I can see that they are closely associated and can throw false codes. it seems when I really lean it down the code pops. But still it has the stumble on occassion. I played with the tune a little and I got a bad signal a couple of times. I don't believe anything I do with the tune will damage the sensor as they are just a electrical pickup, but being lean may allow a bad signal to be more noticeable.. Neither show any physical damage so if it continues I'll replace them. Thanks for the input.

**Redtruck-VA** · 06-06-2011, 09:16 AM

Fired Red up and it's throwing codes and stumbling badly. What ever has gone south is continuing to get worst. Will change out the sensor.

Update: sensor on order..

**4XLGator** · 06-06-2011, 06:18 PM

Dang Greg, that sucks. But I know you'll get to the bottom of it and figure it out. Good luck.

**Redtruck-VA** · 06-06-2011, 06:26 PM

Originally Posted by 4XLGATOR

Dang Greg, that sucks. But I know you'll get to the bottom of it and figure it out. Good luck.

Thanks Lee, this is straight forward stuff. I'll have a new sensor in a day or two and have done all the trouble shooting. And it simply looks like a bad crank sensor. This is not a common problem, so I'm interested in how this plays..

**Redtruck-VA** · 06-08-2011, 11:24 AM

I got impatient and besides the odds of it being a sensor wasn't very good so i took my wire bundle apart. The good news is that I do all my splicing close to the PCM and it is easy to get at and open up. Sure enough I had a cold solder joint for my rpm window switch trigger. This apparently making and breaking contact was enough to throw a code and cause an intermitten stumble. That's two cold solder joints I have screwed up in about 6 weeks. It has to do with being a little careless and failing eyesight. Gentlemen, take care of your eyes because you will pay later if you don't. Red is running sweet! Anyone need a NIB crank sensor? lol