TTur1996

We have and use, the 6012 box on a LQ4, with 14.5:1 compression. We didn't have to do anything. The biggest thing is the ground. It needs to come straight from the battery to one of the heads with a jumper going to the other head per Msd. Ours did the same thing. Bumped the timing up at zero, to 11 degrees, and now it fires right up, the same, all the time. And when you shut it off. It just goes silent. The 6012's wiring harness is already set up for the cam sensor in the timing cover. Sounds like your timing @ zero, IMO. Since it runs good, other than that. We do not run the map, and just flat line it, from 400 rpm out. Since you cannot shut the Map off. At least I have not actually found anything that's says its off. Zero it all the way across. Hopefully this helps. Oh, and I have personally seen ours start at 10 volts, so I'm sure that's not it. Not sure about your hot going to a relay. Was told to take it to the main disconnect, by battery. I really can't see the relay being the problem, but if all else fails. Best of Luck.

The stunningman

iTrader: (47)

The BOLD is BS.

I've seen to many MSD 6012 guys have the same problem (cam sensor fail displayed), with the same cure (switching the wires as I stated when they didn't have the extension harness) as the information I stated.

Petey-Pop-383

Stunningman is 100% correct.
I have the 6012 and switched the wires in the harness and it works with no issues, and I plugged mine right into the sensor, no Pig tail harness.
If you look at the symbols on the sensor and the wiring diagram from MSD it makes sense.

TTur1996

Are you sure your not talking about going to a timing cover cam sensor from a 6010. Because the only harnesses we had to get were for the coils. Wouldn't it run like crap all the time, if that were the case? I guess there is a chance I didn't read something right. But I would not bullshit anyone.

TTur1996

Is there some harnesses that you have to do this to, and some not? Because I know we didn't have to change any wires. And we do not have an extension harness for the cps.

Petey-Pop-383

From my understanding a typical LS2 sensor in the front timing cover comes with a pig tail harness that is part of the timing cover, for 58tooth reluctor wheels.

I used a comp cams cover and it didn't have this extra harness, it's only 6" long.
http://www.briantooleyracing.com/ls2...-12633906.html

link to cover with harness.

All you need to do if verify the pin outs of the sensor, and the wires in the plug.
I also had to cut the keyway/guide out of the sensor to be able to plug the MSD harness right into it.

TTur1996

Oh. We have the edelbrock two piece cover and just used the stock GM. LS 7 cam sensor. It didn't have any wires on it. Just the housing for the harness to plug into. And it plugged right in.

Pop N Wood

iTrader: (1)

Are you guys sure you are talking about the same "extension harness"? This isn't the one MSD sells, but rather the GM one that comes installed on the motor. It is about 6" long and moves the harness connection from the cam sensor at the top of the water pump to a point near the crank pulley. It is more of a pigtail than an extension harness. Not only does it cross the wires but it has a smaller connector on one end. You can't plug an MSD 6012 harness directly into the LS2 cam sensor without swapping out the end connector

The LS1 and LS2 cam sensors clearly label each pin. If you look at the MSD wiring diagram it clearly shows which wire needs to go to which pin.

I ended up deleting the GM pigtail. I did this by unpinning the MSD connector and swapping it for the one on the cam sensor end of the GM pigtail. This simplified routing the wires.

So my suggestion is LOOK at the cam sensor you have and verify the correct color wires go to each pin.

By the way, the motor does not need the cam sensor once it is running. Symptoms of no cam sensor signal are half the time it starts correctly the other half the time it is 180 out and backfires.

TTur1996

You Guys are absolutely right. Just went and looked. I stand corrected. There is a little 6 inch GM extension on ours. My son just told me that he unplugged it from the cam sensor and plugged it into the harness while I was installing the cam sensor. That's why I didn't see anything plugged into the sensor. I guess I didn't notice the little extension on there, when I install the MSD wiring, cuz it plugged right in. I do know that we didn't change any wires though. Sorry, I didn't mean to mislead anyone. Ours didn't backfire. It was just hard to start after warm up. We corrected it by raising the timing at zero to 11 degrees. Now it fires right up warm or cold the same. Again sorry about that. And Thank You for your explanations. Very good info, as always.