A few guage questions

[afcamaro]

I have my 5.3 in my truck and the gauges are all autometers in the stock housing.

I have a couple of dumb questions...Does the computer need the stock 5.3 sensors to read its information?

And on my autometers can I tap into the stock sensors or just go with the ones that autometer suggest, as in their electric oil pressure sending unit etc.


Thank you

[BR3W CITY]

We need to establish a rule in this section; tell us what truck this is going into.
we have trucks from 40-something to 90-something getting LS swaps, and the answers aren't the same for everyone.

That being said; The computer needs SOME sensors, things like IAT, MAF (this can be changed actually), 02, knock, cam and crank position etc.

As for things like the oil pressure and temp, then NO, the engine does not require an input. If you are asking if you can put a DIFFERENT sending unit and still have the computer read the info; thats a touch more complicated. It depends on WHICH sensor you are referring to.

As for your autometer gauges; the answer again depends on which gauges. Things like temp sensors can hookup just fine but might read off if the electrical signal output is different than the gauge expects. You have to find out the desired range that the gauge expects, vs the range of outputs from the sensor. i.e. a sensor with an expected input of 0-90ohm won't function the same on a sending unit giving it a 20-70ohm sweep, it will read incorrectly. (these are made up values but the point is the same)

[Matt Cramer]

Originally Posted by afcamaro

I have my 5.3 in my truck and the gauges are all autometers in the stock housing.

I have a couple of dumb questions...Does the computer need the stock 5.3 sensors to read its information?

Yes. Most factory LS applications had the computer control the gauges over a network, unlike older GM EFI systems where the gauges had their own, separate sensors.

And on my autometers can I tap into the stock sensors or just go with the ones that autometer suggest, as in their electric oil pressure sending unit etc.

Depends on the gauge.

Temperature? No. You'll need to add a second sending unit.

Oil pressure? Maybe, if Auto Meter's sending unit has the same output curve as the factory sensor. You'll have to ask them.

Speed sensor? Probably OK to split it.

RPM? There's a signal from the computer that you can use, although I believe for some reason you need to set the tach to four cylinder mode to read correctly.

[afcamaro]

Ok thanks thats really all I needed. I shouldve been more specific since all I need were the oil and temp and I knew most if not all ls would require the same on them too. And since the computer does not need the oil and temp input, Do you guy just get rid of the sensor or just keep it hooked up? Thanks

[BR3W CITY]

I left mine hooked up to plug the hole. Its not in the way of anything.

[Matt Cramer]

Originally Posted by afcamaro

Ok thanks thats really all I needed. I shouldve been more specific since all I need were the oil and temp and I knew most if not all ls would require the same on them too. And since the computer does not need the oil and temp input, Do you guy just get rid of the sensor or just keep it hooked up? Thanks

The ECU will need a coolant temperature sensor for cold starts (like a choke on a carbed engine) and managing warmup.

Oil temperature, not so much.

[Billett]

If you have an autometer tach as well you may have to put a resistor in there to get it to display anything.

[BR3W CITY]

^True, I believe TR65 had a thread about "conventional tach on LS2". It requires a resistor and you need to make sure the tach and output signal are set to the correct output. I have a few extra resistors if you don't want to buy the 10 pack.

[Billett]

pssh 10 pack... My local radio shack didn't have anything but a 500 pack of assorted ones, with the ONE I needed in it... Thankfully resistors aren't terribly expensive, but another $15 wasn't pleasant. If I wasn't in such a hurry I'd have shopped around a bit more.

My tach isn't showing anything at all right now, but I haven't had the time to put the resistor in. From what I've seen online it appears to be random whether you'll need one or not. Some people had theirs work no problem. Mine didn't, but with the torque app I could tell my PCM was reading the correct signal, just not sending it to my tach correctly. Seems like the resistor mod is exactly what I need. Also, keep in mind what Matt said. My tach has 4 settings, but I believe 4 cyl. 2 pulse is the correct one you need.

[ls1nova71]

Generally its the 2003 and newerPCMs are the ones that need the "pull up" resistor to amplify the weaker tach signal they produce. Also if you don't have an aftermarket tach that can be set to 4 cylinder mode, changing the tach resolution in the tune from 6 to 3 will double the signal to 8 cylinder.
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[Billett]

Mine is a 2003 and the two other people I talked to in person had PCMs after '03 as well so that goes with what you said. Didn't know about changing it in the tune though, pretty nifty.

[BR3W CITY]

Even with it changed in the tune, and on the aftermarket tach, the resistor can still be needed (mine did, 2003/4 lq4 with dbw)