New 402 install my tach doesnt work help !!!

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Nov 12, 2006 | 11:31 PM

Mrbowtie26

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From: West Haven, CT

New 402 install my tach doesnt work help !!!

Just installed my 402 i put together, rescaled the injectors and raised the idle slightly with ls1 edit. Got the motor started and it has oil pressure... Thats the good news

the bad is that it is running ungodly rich and barely idleing. Problem is that my tach is staying at 0 . I used the racetronix i believe plug and play cam wires for the ls2 block so idk if that could be the problem ? i heard that sometimes wires are on backwards ? is this true ? Any idea's would be appreciated. p.s. car is a 2000 T/A,

Last edited by Mrbowtie26; Nov 13, 2006 at 12:08 AM.

Nov 12, 2006 | 11:44 PM

gman

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From: ct.

If this is a ls2 402 there is a good chance you have the cam sensor wired backwards.

Nov 12, 2006 | 11:53 PM

Mrbowtie26

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Quote:

Originally Posted by gman

If this is a ls2 402 there is a good chance you have the cam sensor wired backwards.

As I said I used the plug and play wire from i believe racetronix. Though i seem to remember reading a while back that having them wired backwards will cause this problem, maybe I should swap wires at the plug ? any other ideas ? and would that cause the motor to run REALLY rich ? i mean I can smell unburnt gas really bad lol.
Thanks ahead of time for the help

Nov 13, 2006 | 12:04 AM

gman

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From: ct.

With the wires backwards not only would the tach not work but the car would be idoling very poorly like it wanted to stall.

You may get more help by posting this in the ls2 specific section also.

Nov 13, 2006 | 06:52 AM

Mrbowtie26

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any other ideas ? ttt for the morning

Nov 13, 2006 | 06:54 AM

orangeapeel

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From: Justin, TX

Moving to the correct section.

Nov 13, 2006 | 06:32 PM

Mrbowtie26

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Quote:

Originally Posted by orangeapeel

Moving to the correct section.

And what section would that be ? It is an Ls-2 motor so i figured it would be ok to ask here also.

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Nov 13, 2006 | 06:39 PM

Mrbowtie26

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From: West Haven, CT

Quote:

Originally Posted by KRAZY K 2000 TA

dude check your private messages

I replied, thanks for the input

Nov 13, 2006 | 09:44 PM

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Rick@Synergy

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Did you try the wires?

Rick

Nov 13, 2006 | 10:02 PM

#11

Mrbowtie26

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Quote:

Originally Posted by Rick@Synergy

Did you try the wires?

Rick

Yes, at this point I have tried swapping the outside wires and got the same results. also I checked voltage to the cam pos. sensor terminal C with ignition on and got 12v once i moved wires back to original location, so being that I got 12v at that pin that is correct according to the manual. Another question I have is when I checked for 12v at pin C I used the chassis ground for negative, also I can use both the other pins A and B for negative and I still get a 12v reading is this normal being that A is cam pos. sensor signal input and B is Refrence low according to the schematic. Also I bought the block from SLP in mid 2005 just havent had the chance to finish it till now so I dont think I got the wrong 2006 can sprocket but wouldnt know for sure unless i pulled front of motor back off

Any help would be appreciated. b.t.w. I live in CT
Thanks
Ron H.

Nov 14, 2006 | 07:07 AM

#12

Mrbowtie26

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ttt for the morning...

Nov 14, 2006 | 09:11 AM

#13

DrkPhx

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Quote:

Originally Posted by Mrbowtie26

ttt for the morning...

You have 2 threads in different sections on the same subject. It would be much easier to to have 1 in the correct section to consolidate the information.

It's not unusual for the original 2005 cam sensor to go bad. GM no longer makes that version and retrofits the 2006 version as a replacement. It will work with the 2005 sprocket. That's what I have and the car is fine. If all tests indicate the wiring is getting the correct voltage and any of the three CMP codes are set (you need to verify) it's probably the cam sensor.

Edit: 3 threads on the same subject.

Last edited by DrkPhx; Nov 14, 2006 at 09:31 AM.

Nov 14, 2006 | 10:57 AM

#14

Mrbowtie26

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Quote:

Originally Posted by DrkPhx

Other thread I switched to here. Here is the latest. All 3 wires going to the cam pos. sensor are correct at the end of the racetronix harness where it plugs into the short 6" harness that plugs into cam sensor. I checked all 3 from pcm plugs and they do not have any opens or shorts in either 3. The outside wires actually swap at the short 6" connector. I pulled the cam sensor and the short connector to check that. At this point I can kind of see into the hole where the cam sensor was. I am going to crank the motor and check with a mirror which sprocket is there. If it has only one raised spot etc... Is there any way to check the sensor itself while I have it out as far as an ohm reading it should have between certain terminals ?
Thanks
Ron H.

Nov 14, 2006 | 11:46 AM

#15

Mrbowtie26

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ttt... I took the day off and am trying to fix my car lol. It's killing me

Nov 14, 2006 | 01:20 PM

#16

Mrbowtie26

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Ok, I checked the sprocket and it's the one with one raised spot on it so I believe it's the right one. I think im gonna go get a new cam sensor and change that. At this point it can't hurt. Any other suggestions ?
Thanks
Ron H

Nov 14, 2006 | 02:23 PM

#17

Mrbowtie26

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Sensor is 66.00 and they would have to order it. Is there any way I can check the sensor to see if it's bad ?

Nov 14, 2006 | 02:47 PM

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Orange Peel

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Quote:

Originally Posted by Mrbowtie26

Sensor is 66.00 and they would have to order it. Is there any way I can check the sensor to see if it's bad ?

Sucks it wasn't the sprocket, I replaced the sensor too before that, still didn't work. So now I have an extra sensor, I would be willing to sell it to you cheaper than that, say $30 shipped if you really want to go that route.

Nov 14, 2006 | 03:00 PM

#19

Mrbowtie26

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Quote:

Originally Posted by Orange Peel

Yeah it sucks it wasnt the sprocket, at least then I would know what it was. The dealer said they could get it next day for no extra charge so I may do that . Not sure though. I think theres a way to check a cam sensor to see if it's good or not with an ohm meter but Im not sure what connections or what values would be correct. Anyone else know ?

Nov 14, 2006 | 05:17 PM

#20

Y2WS6KAH

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I also recently installed a 402 and I too had the same problem with the tach and dummy me - had two plugs reversed. The cam sensor plugged into the MAP- Manifold Absolute Pressure Sensor and the MAP plugged into the new cam sensor extension harness. So then I switched them and it works ok now.