HDD

Hoping someone here can point me to a link on LS3 sensor pinouts. I have looked everywhere and can barely find anything on the LS3 sensors. Everything stops at the LS2, so I don't know if the LS3 sensors are the same or not.
I have a GM LS3 crate motor and am custom making a harness, so I'm needing pinouts for everything. I can only 100% confirm my cam sensor, as it is marked +, -, O. My MAP identifies which pin is number 1, but that is it. All other sensors are void of identifying marks.

Any help would be greatly appreciated.

daveS

https://www.keepandshare.com/doc19/1...f-1-7-meg?da=y

http://www.crateenginedepot.com/pdfs...rol_System.pdf

Is there a reason not to just buy the GM crate engine computer and harness? That what I put in my '37 hot rod build. Real easy to hook up and get running.

HDD

This is going in a boat and it's Procharged, so it's not straight plug-n-play. I could have bought the factor computer, but I'd still need a tuning program. For the cost I'm far better off with MegaSquirt (which is what I'm using).

I'm surprised I can't find any info on the LS3 sensors. I seem to be able to find LS1,2 and pretty much every other engine type, but LS3's are elusive.

Not sure if you were posting sensor info with the keepandshare link, as I can't access it.

daveS

Try the keep and share link again. I pasted it again and it work on my wife's computer. The link is to a PDF of the LS3 crate engine harness, wiring diagram. You have to zoom in and wait a little while for the print to be legible.

Hope it helps.

HDD

Thanks Dave. It worked this time. Schematic is a big help. Still need to determine the function of a couple sensor pins, but at least I now know the correct sensor pin labeling.

Thanks.

stevieturbo

Exactly which sensors ?

And are there not pre-made looms available already ?

HDD

Yes there are, but that doesn't tell me what the sensor pinout is. I'm not using the factory ECU, so I'm custom making my harness.

I now have them figured out except the MAP and Oil pressure sensor.
I can't get a definitive answer on the LS3 GM crate motor MAP, whether the pins are A,B,C or C,B,A. I've seen both. I can't even find out if it's 1,1.5, or a 2 bar sensor. I've seen all three quoted, (on this site and others)

The only thing I can find out about the crate motor oil pressure sensor is that other people can't find a pin out either. The answer is always to change out the sensor.

stevieturbo

Well there would be absolutely no reason for the factory engine to have anything other than a 1 bar map sensor. And the simple answer for a pinout is test it.
Or you could help by at least giving a part number of what sensor you actually have.

And likewise, test the oil pressure sensor. It should barely take 5 mins to do each.

Or this makes some reference to numbers and letters, a few seconds with google

http://lt1swap.com/2010camaro_ecm_pinouts.htm

http://lateral-g.net/forums/showthread.php4?t=20899

https://www.efihardware.com/products...bar-map-sensor

http://www.lsenginediy.com/sensors-inputs-guide/#

HDD

I'm getting the feeling you figure I'm just a lazy *** and am wasting people's time with this question. Sorry if that's the way you perceive me. When I started this thread, I didn't know the pinout for any of my sensors. I figured that there would be numerous people that had the pinouts and wouldn't mind sharing, so I wouldn't have to test each and every sensor. I don't see the harm in asking.

Thank you for pointing out that I can test the sensors. Despite testing, I still wouldn't know for sure which ones use a 12v reference and which use a 5v reference, or if any of them are polarity sensitive. I have now concluded that none will have 12v reference. I am also somewhat confident none are polarity sensitive.

In regards to the MAP sensor rating, I have a GM Crate LS3, and I have found people that swear the crate motor MAP is not 1 bar. In numerous searches, I have not found a part number that matches what is on my MAP.
No other sensors have part numbers.

Thank you for taking the few seconds to google LS3 sensors. Unfortunately, not a lot of new info for me
Link 1 is for the ECU plug pinout.
Link 2 is for a different MAP sensor than I have, although it is the only info I ever saw that specifically refers to a LS3 MAP, that came on the engine from GM, so it does help to confirm the pinout.
Link 3 does show the MAP sensor pinout, but it is not the same sensor, so I can't simply assume mine will be the same.
Link 4 is not even about LS3's. It appears the article was written before the LS3 was even introduced.

I do need to correct my previous response, and I do know which pin on my MAP is #1. I was thinking of my Cam sensor, which isn't an issue anymore

stevieturbo

Link 1 clearly states in the MAP Sensor 5v pin 1 in the listing, MAP Sensor pin2 Ground so it shouldnt be hard to figure out the 3rd pin.

Lazy....I dunno.

You are aware a that each sensor connects to the ecu and do you know how to trace wires ? Well in this case you dont even need to do that when the listing is doing it for you.

And again, there might be various sensors in use, so give proper details of exactly what you have, ie part numbers.

Link 2 may be different...but you havent specified exactly what you have.

Link 3 again may be different...but you havent specified and it shows you a pinout for that sensor.

Have you even looked ?

and almost NO sensor giving feedback to the engine will have a 12v supply. They all take a regulated 5v from the ecu. Some might "also" have 12v but that will not be used for feedback to the ecu. eg lambda sensor heater etc

Some hall effect crank/cam sensors may be supplied with unregulated 12v, but most dont care either way. Some might be 5, 8, 12v.

And it would be very very rare to do damage to these types of sensors from incorrect connections.

But of course all 3 wire sensors are polarity sensitive, there is only right and wrong.

HDD

I stand corrected on link 1. I had seen that posting much earlier in my search, but dismissed it, because I didn't look at it hard enough to notice it was giving actual sensor pin numbers. So that is a help.

I didn't realize the sensors connected to the ECU. Thank you for pointing that out.

You said no sensor giving a feedback to the ECU will use 12v, but then you said some crank/cam sensors may take 12v. That was one of my concerns. I wasn't sure if the cam or crank needed 12 or 5v. I did find out that the LS3 takes 5v (although some people have used 12v with no issues)...so I guess I did at least a bit of looking.

Earlier I was concerned that connecting 5v ref and low ref incorrectly could damage a sensor. I came to the conclusion that it is unlikely, but it could result in incorrect readings. Therefore, meter testing the sensor won't conclusively tell me which is positive or negative, only that they are one or the other. I still needed to know which is pin ABC or 123. There is an incredible amount of conflicting info out there on the pinouts.

Of course, I only found that out by looking......

stevieturbo

Meter testing the sensor will work 100%.

There is only right or wrong. Right will yield sensible readings, wrong will not, it really is simple.

stevieturbo

If you are not sure how to test....there are many videos on youtube.

Here is a pretty well explained example. He knows the pinouts to start with, but that doesnt really matter as with only 3 pins there are a very low number of possible configurations to play with if you didnt know.


But yes you will need some form of 5v power supply. At a push you could probably use 3 small 1.5v batteries to create a 4.5v supply though.

If it's on the car and the ecu/wiring is live, it is even easier as you have your regulated 5v and ground to work with. Just dont ever short the 5v to ground...but that kinda goes without saying

For analogue feedback type sensors I probably wouldnt try say a 9v battery. For hall effect sensors like crank/cam, a 9v battery would be fine, hall sensor just gives a switched output anyway.

So there is a difference between the two types of sensor hence I did mention it above.