QuestionQUESTION: I have a 1991 Nissan Pathfinder 4x4 3.0 v6. I have replaced the fuel pump, fuel filter, plugs, wires, starter, MAF sensor, oil and filter.
When I got the truck a year ago I drove it very little. It was as if it was starving for fuel. When I would gas it to go it wouldn't do anything, just taking its time, then the acceleration would just kick in and would go. But if you were in a hurry to gas it, it wasn't an option. Then a week ago I was coming out of the gas station and gave it some gas to cross the street. It almost died in the road. So i smashed the gas down the RPMs shot up then down and nothing. Then I held on the gas to the floor and it was barely putting slowly crawling to pick up speed. Then it kicked it and started driving as if nothing happened. When I came to a stop. It started the whole process over again. I made it home. Went through the basic checks and couldn't find anything. I asked around and a few people said it could possibly be the MAF SENSOR or the O2 SENSOR. When I tried to turn it over yesterday it wouldn't. There was spark, it would fire just wouldn't start. I bought a new MAF sensor and replaced it tonight. Checked the fuel lines and pump. It still will not start. I turn the key and it tries, but cant make it all the way over. It sounds like lack of fuel or no air. The injectors have been cleaned. I don't know what else to look for. Any input would be greatly appreciated.
Thanks
Thera
ANSWER: Thera,
Check the fuel pressure to verify it has fuel pressure. Get a Haynes Manual or a factory service manual for the readings and procedures. It could be as simple as the fuel pump relay or as complex as the injectors needing to be homed out. Also, check the throttle position switch and the ignition relay fuse. Email me back with what you find.
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QUESTION: How do i check the fuel pressure if i cant get it running. from my understanding you have to have the vehicle driving or running atleast to check the pressure to see if it drops.???
Thanks
Thera
AnswerThera,
If you just put gas in prior to this happening you might have water in the fuel. Second, to check the fuel pressure get a fuel pressure gauge and screw it on the fuel schrader valve on the fuel injector rail. That is located on the engine, on top, where it looks like a tire air fill valve. There is a fuel pressure regulator on the same rail that has a vacuum diaphram on it. Unplug the vacuum line and cover the end of the vacuum line with your finger and watch to see if the fuel pressure jumps up. You are going to need to turn the key on to get fuel pressure and you should have pressure without the engine being turned on.
