# Won't start after head gasket repair??



## Pooch2 (Dec 24, 2016)

I need some help, car has been at shop since May 15, I had the head gasket repired, drove it one day and all was good. Next day check engine comes on so I took it back to shop the have find out why. Well, according to them, they went through 3 bad camshaft sensors, a bad pigtail for the sensors, and now they say it won't start. They say waiting on Techline to call them back ?? I don't know they mean cranks but no start or just dead won't start period. My questions, Any one else had this problem How could they have had 3 bad sensors in row? I can't post the link about the head gasket repair because not enough posts because I had to re register.


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## quadraria10 (Jul 6, 2010)

Kind of curious why you would leave a car with a garage for 2 months, when they do not seem to know how to fix your vehicle. 3 bad sensors in a row is only possible if they are installing the cheapest aftermarket products available, instead of a proper new one from Nissan. ( there is a kit that also includes a new crankshaft sensor, whose failure can also cause no start and stalling problems. The sensor issue is probably wiring related, but again why 2 months to figure it out?


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## Pooch2 (Dec 24, 2016)

I got the car back, it now shows the following codes p0011. Intake Valve Timing Control Performance, p0420,Catalyst EfficiencyBelow Normal Bank 1, p0340 Camshaft Position Sensor Circuit. Can the catalytic converter be plugged or something with only 64,000 miles on the car? The car starts runs and drives just fine, will it hurt to keep driving it?


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## rogoman (Dec 16, 2004)

Pooch2 said:


> I got the car back, it now shows the following codes p0011. Intake Valve Timing Control Performance, p0420,Catalyst EfficiencyBelow Normal Bank 1, p0340 Camshaft Position Sensor Circuit. Can the catalytic converter be plugged or something with only 64,000 miles on the car? The car starts runs and drives just fine, will it hurt to keep driving it?


The P0011 and P0340 both are related to a possible bad camshaft position sensor. The P0420 could be caused by the following:

● Bad three way catalyst (Manifold) converter.
● Intake system vacuum leaks.
● Dirty fuel injectors.
● Fuel injector leaks.
● Dirty spark plugs.

If you're not comfortable with trying to fix it yourself, take the car to a Nissan dealer instead of that shop that tried to fix the problem. If you plan to try to fix it yourself, first thing to do is replace both the cam and crank sensors with OEM Nissan components, not aftermarket components. Don't buy aftermarket types; they've been known to fail in a short time; some are even DOA. Here are some tips:

To properly diagnose dirty/leaking fuel injectors, they need to be remove and tested on a flow bench tester. You can also do a quick leak test by teeing-in a fuel pressure gauge to the fuel rail input, then turn the ignition switch to the "RUN" position without starting the engine; make sure to pinch off the return hose on the pressure regulator when doing this. If the pressure drops off rapidly, one or more injectors are leaking.

How long have you had the old spark plugs? If they are very old, then it's time for a set of new ones.

Use a vacuum gauge to test for a vacuum leak in the intake system, for good accuracy; most auto parts stores sell vacuum gauges. To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source, usually somewhere on the intake manifold. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be around 21 InHg. If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. The gasket may have failed; spray a water mist at the gasket to see if the gauge reading changes. Also check the intake plenum bellows at the throttle body and at the MAF for cracks or loose clamps.

The easiest test for converter plugging is done with a vacuum gauge. Connect the gauge to a source of intake vacuum on the intake manifold, carburetor or throttle body. Note the reading at idle, then raise and hold engine speed at 2,500. The needle will drop when you first open the throttle, but should then rise and stabilize. If the vacuum reading starts to drop, pressure may be backing up in the exhaust system.


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