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-   -   Car not wanting to crank. Tach not working (https://camaroforums.com/forum/ls-series-tech-15/car-not-wanting-crank-tach-not-working-81563/)

00camaroloyd 08-01-2017 02:13 PM

Car not wanting to crank. Tach not working
 
My tach not working and my security lights on and it's been having hard trouble cranking took it to a shop said the cam sensor is out does this sound right? Why would the security light be on and tach not working then?

Gorn 08-02-2017 11:43 AM

We should talk terms first. Cranking is the act of the engine turning. "So on a model T a human would get in front of the car and crank it by hand until it started". Cranking issues are normally limited to Battery, starter, fly wheel and engine issues.

It sounds like you are saying you have a starting issue not a cranking issue. You could also say you have a firing issue. "So the car will crank but not fire"

Your tach is run by the PCM, if the PCM can not see the engine rotating because of a bad sensor it can also not drive the tack. It makes perfect sense that something that would cause the car to not start would also cause the tach not to work.

Security light should be a separate issue that should be address. I believe the Vats system cuts the fuel supply not the sparks. It would have no effect on your tach.

Your issues do not seem like they could be caused by a signal problem. The big question is "is the car loosing spark or fuel when it wont start." Normally with the security light on I would guess you are losing fuel but with the tach not working it seems like the PCM is not seeing engine rotation. Sorry I have no idea if the Cam sensor is your fix. Without a scan tool or a scope to diagnose the Cam sensor I not sure how you would prove either.

00camaroloyd 08-02-2017 11:53 AM

It will crank it turns over a lot before it cranks. When it running and drives fine. But the tach does work. The shop put it on scanner says cam sensor was bad. Was just wondering if anyone has had this issue.

Gorn 08-02-2017 12:56 PM


Originally Posted by 00camaroloyd (Post 721626)
It will crank it turns over a lot before it cranks.

That statement is very confusing. You mean the engine cranks over for an extend period of time before it will start running on it own?

That is commonly associated with a failing fuel pump or we have seen people with security lights on say the same thing. You are this first person I have heard say their CAM sensor has failed but the car runs fine.

00camaroloyd 08-03-2017 12:56 PM

Fuel pump is fine. The code is bad cam sensor. Was wondering if that would cause tach not to work is what I want to know

Gorn 08-03-2017 02:49 PM

If the CAM sensor was completely dead the car will not start. The fact that the car runs is saying that the CAM sensor is an intermittent error or it works but just out of parameters for a short time. This is mostly likely while you are having trouble starting it. If the car is running the CAM sensor is working, it just has a stored code from when it was not working. I do not see how that CAM sensor that works most of the time would cause the tach to never work.

If I remember right there are 3 different Cam sensor trouble codes. They can indicate anything from a bad sensor/PCM to a lose timing chain.

00camaroloyd 08-03-2017 05:43 PM

Ok hoping it just the cam sensor and not chain

00camaroloyd 08-03-2017 05:44 PM

Read on a bunch of ls forms saying a bad sensor will make tach not work.


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