Auto Parts: xtera 2002 starts and stoles, cam shaft position sensor, fuel pump relay

Question
QUESTION: Xtera 2002 Start runs for about 3 or 4 miles and quits.
Sometimes starts over and quits. Other times won't start
at all. You can wait about one hour and it starts. Is there a connection to place a gage and check the fuel pressure? What other problems possible?

ANSWER: Hi Chris,

There IS a Schrader valve on the fuel rail where you would attach a gage to test, but the tool is not cheap and chances are, fuel pressure is not your problem. Sounds electrical to me.

Thanks for the question, I hope this information was helpful to you.
Fred
www.knucklebusters.us
570-453-0910
"Re-use is the best form of recycling" Help us recycle by purchasing used parts from us!
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---------- FOLLOW-UP ----------

QUESTION: Fred
Thanks for pointing out that there is schrader to test the pressure.
Would you also please if you can inform me if XTERRA 2002
has a fuel pump relay that feeds power to the fuel pump;
does it use also an  OIL PRESURE SWITCH or SENSOR that
feeds power to the FUEL pump ether directly or in Series through
a fuel pump relay  to the Fuel pump. I have not been able to obtain
any information on this particular car in the area where I live.
In the past I had problems with fuel pump relays that drove me crazy,
and one of the problems I had discover was that it was not the relay
but the plug where the relay was being plug.
Fred, thanks again for your help.

Answer
Hi Chris,

Sorry about not getting back sooner, sometimes I get busy and forget about things.

I'm pretty sure your system uses a relay that is timer controlled for the fuel pump and probably receives pulse from the crank/cam-shaft position sensor. If the CPS says the engine is spinning and the key is NOT in the crank position, the fuel pump will shift from relay control to timer control. Ok, it's basically the same thing even using the same circuits, the difference is when the key is in the 'crank' position, the ignition and fuel system are in momentary-limp-mode. MLM sends full power to the fuel pump as well as the ignition coils to insure a smooth engine start. During this brief time (about a second) the fuel pump is solely controlled by the relay but as soon as the engine starts, the relay is THEN controlled by the PCM and in the event of a stall, the fuel pump is 'timed' to turn off after a preset period of no CPS signal.

The PCM in your vehicle MAY have a provision for low/no oil pressure fuel shut down too, but it is not as typical as it used to be.

Thanks for the question, I hope this information was helpful to you.
Fred
www.knucklebusters.us
570-453-0910
"Re-use is the best form of recycling" Help us recycle by purchasing used parts from us!
Looking for an ASE Certified shop near you? ASE Certified Technicians are the BEST of the BEST!
Click here: http://www.ase.com/bluesealsearch/locator.php