[KJF95S-10]

Well heres the deal. My truck is a 95 s10 with a 5.3 and a harness made by cpw. The truck didnt originally come with a tach cluster and i drove it without one for about 2 years but last weekend I found a tach cluster in a 96 blazer and threw it in. It seemed to work fine, the idle looked a little low to me (500rpm) I had no idea of that was normal or not for a v8 because most engines I see idle around 900 to 1k but when I rev mine up to 1k it just sounds like its spinning too fast for not much rpm. Also im pretty sure I had my shift points set to 5400 I mayb be wrong, I know its always shifted earlier than I like but the tach says it shifts at about 3900-4k at wot and for some reason the engine sounds like its working way harder than what the tach says I mean I have a really loud exhaust so that may be throwing me off too. Could this be a problem form having a v6 tach on a v8? Doesnt it usually read higher when you do that? Im not saying the tach is wrong im just wondering if theres a way I can check it to be sure. Thanks alot

 

[kybrad]

The only way I know how to check is a scan tool with live data. Mine was off and I had to add another power with resistors in it to make it accurate. I used a Scan tool with Live data and this diagram to make mine correct.
http://lt1swap.com/lsx_tach.htm worked for me.

 

[s10studduts01s]

the LS based motors put out a 4cyl signal and work perfect with a 2.2 gauge cluster. If you have the 4.3 cluster it will be off and you need to either modify it or get a 2.2 gauge cluster

 

[scriptedmind]

I've noticed the EXACT same thing with my tach.

I didn't have a tach so I swapped to a tach cluster when I did my swap. I didn't know the 2.2 vs v6 was different but I remembered the other day that my cluster came out of a V6. Can the computers be retuned to output a different ppm or whatever it is sending to the tach or is a 2.2 tach cluster the only way to go?

Sorry Kasey, don't mean to highjack.

 

[deathphoenix99]

just recalibrate the cluster, I converted a v6 cluster to work with my 4 cylinder. It takes a simple calculation and the use of capacitors for it to work.

 

[KJF95S-10]

Damn that sucks I wish I knew that before, this cluster is super nice and even has the same mileage as my truck so I would really like to use it, what all is involved in altering the tach out put signal and where to put the resistors...anyone care to share?lol No problem at all brandon

 

[Lowsonoma03]

This link http://lt1swap.com/lsx_tach.htm like posted in post #2 should work for you....

 

[s10studduts01s]

that link is to make an aftermarket tach that is set to 4cyl signal work. NOT the stock tach that is in the gauge cluster...try again lol

 

[Lowsonoma03]

duh, i knew that :haha:

 

[kybrad]

I know it say aftermarket but it also works on factory tachs. This is the way my truck is wired and works perfectly. Maybe off 50rpms at most just cause i didnt want to spend any more time on it. Without the extra power wire with the resistors mine hardley moved. Not say that is the fix to his truck for sure but something to look at. But when i built mine i had it set to work with a v6 tach also but still had to run this extra power wire. Some of the pcm signal are not strong enought to operate the factory (or aftermarket) tachs.

 

[deathphoenix99]

This is what I did. It's not complete...but it may help. And you can easily swap the mileage over from one cluster to another. They use the same module. Or you could reset one like I did on mine. 95-97 use the same cluster for you.


http://www.s10forum.com/forum/f62/need-help-recalibrating-tachometer-409561/

 

[KJF95S-10]

This is what I did. It's not complete...but it may help. And you can easily swap the mileage over from one cluster to another. They use the same module. Or you could reset one like I did on mine. 95-97 use the same cluster for you.


http://www.s10forum.com/forum/f62/need-help-recalibrating-tachometer-409561/

Thanks alot. I read the writeup. Im ready to do that to mine, so are you saying the v8 and 4cyl put out the same exact signal or is there still room for difference? How exactly did you figure out how many more capacitors you need to get it right? I dont have an aftermarket tach to compare it to so it might be kind hard. Also do you have any pics or something showing how you installed the capacitors? Im just so terrible when it comes to circuitry. Thanks again

 

[s10studduts01s]

To calibrate the '95-97 tach to a V8, replace the "C103" capacitor with a .0022 to .0018mf. The stock V6 tach has about a.0030mf capacitor and the 4 cylinder tach has about a .0038mf capacitor.

The bold is what you need to do for the GenIII/GenIV motors to have the right signal from what I understand.

 

[deathphoenix99]

yea, I just looked at what the stock cap was and did the math to keep the correct ratio of cylinders. I don't know what the LS stock output for the tach is though. That's not my area.

 

[scriptedmind]

Unless I'm missing something, I don't see why the PCM can't be told to output the proper pulses to run a V6 tach. Here is a link to what I'm talking about.

http://www.hptuners.com/forum/showthread.php?p=239219

If that's correct, it would be WAY easier and more precise than adding caps to the cluster. I almost guarantee that my PCM is at it's stock settings to drive a 4 banger tach because I didn't have this cluster when Jared tuned it.

 

[97ls1s10]

To calibrate the '95-97 tach to a V8, replace the "C103" capacitor with a .0022 to .0018mf. The stock V6 tach has about a.0030mf capacitor and the 4 cylinder tach has about a .0038mf capacitor.

The bold is what you need to do for the GenIII/GenIV motors to have the right signal from what I understand.

I tried that and now the cluster doent work,im gonna get another one n change the output on hptuners

 

[s10studduts01s]

That thread on hptuners is interesting. I would definitely try that first if you have access or the capabilities to use Hptuners.

97ls1s10 are your solder joints getting a good connection? Ill have to try and take my 97 cluster apart to try and see what the exact capacitor is. You sure that it isn't something else besides the wrong capacitor? Maybe a loose connection somewhere from where you were taking it apart?

 

[deathphoenix99]

I know it works for sure, that's how I did my cluster. But I had to add caps, so I just left the stock one and addeed like 4 more to get the correct number.

 

[CPWire]

I usually just change the output in HPTuners. you can make it 4, 6, or 8

 

[97ls1s10]

Yes connection is good cause the cap. Is one there good and solder it on the top and bottom of the circuit board