# random or warm engine starting problems...



## jeffk (Dec 14, 2017)

my 2005 nissan xtrail is having problems starting randomly. it seems to almost always start when engine is cold. i have problems when engine is still warm after about 5-10 minutes or more before engine cools enough. i had a scan and it reported codes for a cam position sensor and a crank position sensor. i had a mechanic replace it with a new quality original cam position sensor but the problem persisted. i had the mechanic return part and he tried another to eliminate a faulty sensor but same problem. then i had him return that and put in less quality cam and crank sensors both. the codes went away on the scan but the starting problem persists when engine is warm. Do you think this may be a faullty fuel pressure regulator (22670Z) which fits on top of the strainer that goes over the fuel pump in the gas tank? Difficult to start when hot soaked - Nissan Forum[/url] Or do you think it is most likely something else?


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## tonyvancity (Jan 2, 2017)

hi jeffk.....have you ever replaced your pcv valve and or hoses? i have on my 06 xtrail ...cheap and easy. Sometimes one minor small thing leads to bigger problems....read this article on the pvc valve function and see if any of it relates to your problem. Even if not, good idea to replace with a new pcv valve as it keep the engine running smoothly and better for emissions/fuel economy. A new pcv valve had cost me last year $8 and i replaced it under one minute myself.AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - What are the Symptoms of a Bad PCV Valve


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## tonyvancity (Jan 2, 2017)

or this on fuel pumps......AGCO Automotive Vehicle Questions Page
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After driving and letting my vehicle sit an hour or so, it cranks several times before starting. Other times it starts just fine. We replaced the fuel pump but it is still the same. 

Fuel pumps can cause a similar problem by allowing fuel to drain back to the tank. Normally this will cause a hard start in the morning or after sitting for a period of time. A common cause of the complaint you list is a leaking fuel pressure regulator, on vehicles that use them. Fuel can leak through the regulator diaphragm and lower pressure on the rail. At the same time the fuel enters the intake. This causes an over-rich condition and also makes starting more difficult. Check by removing the vacuum hose from the regulator. Any fuel in the vacuum hose indicates a need for replacement.
For more information, please see our Detailed Topic, What Causes Fuel Pumps To Fail.


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## rogoman (Dec 16, 2004)

jeffk said:


> my 2005 nissan xtrail is having problems starting randomly. it seems to almost always start when engine is cold. i have problems when engine is still warm after about 5-10 minutes or more before engine cools enough. i had a scan and it reported codes for a cam position sensor and a crank position sensor. i had a mechanic replace it with a new quality original cam position sensor but the problem persisted. i had the mechanic return part and he tried another to eliminate a faulty sensor but same problem. then i had him return that and put in less quality cam and crank sensors both. the codes went away on the scan but the starting problem persists when engine is warm. Do you think this may be a faullty fuel pressure regulator (22670Z) which fits on top of the strainer that goes over the fuel pump in the gas tank? Difficult to start when hot soaked - Nissan Forum[/url] Or do you think it is most likely something else?


It looks like you have thoroughly checked out the cam/crank sensors and found the problem to be elsewhere. At this point you'll have to determine if there's an ignition or fuel delivery problem:

* Testing fuel delivery:
- Tee-in a temporary fuel pressure gauge between the fuel block and "adapter"(Fuel Pressure Adapter J-44321-6). If the engine is unable to start, turn the ignition key to the run position but DO NOT TRY TO START THE ENGINE. The fuel pressure reading should be around 51 psi which would be a static reading. Watch the pressure gauge for several minutes, the pressure should hold for some time. If it starts to drop off rapidly, then the regulator may be bad or there may be one or more leaking injectors.

- The fuel injectors may not be firing. This can be tested with a "NOID" light probe for each injector harness connector.

* Testing ignition:
Pull several coil packs to test; use a spare spark plug in the coil pack to test; ground the plug base with a jumper wire to the engine block; see if you're getting a spark while trying to start the engine.

* There may be a major intake system vacuum leak:
Check the intake manifold nuts to make sure they are tight. The gasket may have failed. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.


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## tonyvancity (Jan 2, 2017)

check also your oxygen sensor....from an article i read it mentions ''hard to start'' as one symptom. I replaced my oxygen sensor...part had cost about $60 (it wasnt too expensive...maybe it was cheaper) and it is easy to change on the xtrail. Did your mechanic test it to see if that is causing issues? ****** Symptoms of a Bad Oxygen Sensor
When you have a bad oxygen sensor, your vehicle will run less efficiently, it can sometimes have a poor idle, erratic jerking at steady throttle, hard starting problems, cause the check engine light to come on, and will cause high fuel consumption.

Thus, when oxygen sensor failure has been determined (When the check engine light comes on and sets an O2 sensor code) the sensor must then be replaced, a costly repair if you rely on a garage to do the work for you.*****


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## quadraria10 (Jul 6, 2010)

Part that troubles me, is that the original problems finally showed up as a code indicating most likely the crankshaft sensor and possibly cam. Mechanic then replaces the cam sensor with a quality one? Then repeat of conditions so removes that one and then uses cheaper sensors for both cam and crank. They are the same by the way. 
From what I have read here in a few forums is that the cheaper ones can prove problematic. I wish your mechanic had just gotten you another quality one (either Nissan or Hitachi) and replaced the old crankshaft sensor , rather than sourcing inexpensive ones and rechanging both.
Also wonder if the connector is good or if a wire got nicked.

Replacing the o2 sensors, if they have never been changed would be good maintenance. Likewise the pcv valve, new plugs, possibly new coils, but all that gets fairly expensive in one shot. Besides you don't seem to have gotten any error codes linked to any of the above.

I am not a mechanic, but I know the crankshaft sensor is potentially problematic part. The old style did fail over time, and that is what would have been in your car. It seems too much of a coincidence that a cheaper part did not resolve the issue.
Good luck. Let us know what you find out.


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## Eric andaya (Jul 19, 2021)

tonyvancity said:


> check also your oxygen sensor....from an article i read it mentions ''hard to start'' as one symptom. I replaced my oxygen sensor...part had cost about $60 (it wasnt too expensive...maybe it was cheaper) and it is easy to change on the xtrail. Did your mechanic test it to see if that is causing issues? **** Symptoms of a Bad Oxygen Sensor
> When you have a bad oxygen sensor, your vehicle will run less efficiently, it can sometimes have a poor idle, erratic jerking at steady throttle, hard starting problems, cause the check engine light to come on, and will cause high fuel consumption.
> 
> Thus, when oxygen sensor failure has been determined (When the check engine light comes on and sets an O2 sensor code) the sensor must then be replaced, a costly repair if you rely on a garage to do the work for you.***





quadraria10 said:


> Part that troubles me, is that the original problems finally showed up as a code indicating most likely the crankshaft sensor and possibly cam. Mechanic then replaces the cam sensor with a quality one? Then repeat of conditions so removes that one and then uses cheaper sensors for both cam and crank. They are the same by the way.
> From what I have read here in a few forums is that the cheaper ones can prove problematic. I wish your mechanic had just gotten you another quality one (either Nissan or Hitachi) and replaced the old crankshaft sensor , rather than sourcing inexpensive ones and rechanging both.
> Also wonder if the connector is good or if a wire got nicked.
> 
> ...





quadraria10 said:


> Part that troubles me, is that the original problems finally showed up as a code indicating most likely the crankshaft sensor and possibly cam. Mechanic then replaces the cam sensor with a quality one? Then repeat of conditions so removes that one and then uses cheaper sensors for both cam and crank. They are the same by the way.
> From what I have read here in a few forums is that the cheaper ones can prove problematic. I wish your mechanic had just gotten you another quality one (either Nissan or Hitachi) and replaced the old crankshaft sensor , rather than sourcing inexpensive ones and rechanging both.
> Also wonder if the connector is good or if a wire got nicked.
> 
> ...


Hi sir, may i know if this is already resolved after replacing o2 sensor?.

I have now issue with hard starting of my unit, run scanner but no fault code error found. Except the O2 sensor output is lean and rich then value is .35 lower than normal 1.44

Note: newly fuel filter and change oil also new plugs, fuel pump is normal.

May i know how to resolved my issue?


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