SiriusProjects Posted July 23, 2015 Share Posted July 23, 2015 Hi All, A short while ago I posted on here as I was trying to diagnose a problem with my car where it is down on power and is occasionally experiencing hesitation. So far I have changed the MAF, cleaned the air filter, had car serviced today so spark plugs have been changed, etc and the rest of the car has been checked over too. I was hoping that all the above might of sorted the problem, but alas no. I went out for a drive in my zed earlier and the problem still exists. Having read some articles online, the symptoms are in line with what you would expect if the fuel pump was malfunctioning. One article stated that the engine might idle fine when stationary, but will lose power and experience hesitation when under load which is exactly what is happening. I'm becoming more and more convinced that this is where the problem lies. It obviously hasn't failed completely as the car does start, but I get the feeling that it might be on it's way out and if it's not sorted, it will get to the point where it will stop working altogether. I'm not mechanically minded and my knowledge is quite limited, but are there any tests a novice like me can perform to determine if there is indeed a problem with the fuel pump? Thanks. Quote Link to comment Share on other sites More sharing options...
Irn Bru Posted July 23, 2015 Share Posted July 23, 2015 Have you changed the fuel filter and or checked for leaks in the fuel line ?. If not worth doing these first before shelling £'s out on a pump Quote Link to comment Share on other sites More sharing options...
jumping350 Posted July 23, 2015 Share Posted July 23, 2015 maybe the injectors might be causing issues also Quote Link to comment Share on other sites More sharing options...
SiriusProjects Posted July 23, 2015 Author Share Posted July 23, 2015 Where exactly is the fuel filter? I have read that's it's in the same location as the fuel pump. Am I right in saying that the fuel pump is in the fuel tank and can be accessed via the sub woofer compartment? Quote Link to comment Share on other sites More sharing options...
MITZ@CougarStore Posted July 23, 2015 Share Posted July 23, 2015 No external fuel filter on the 350z... Quote Link to comment Share on other sites More sharing options...
SHEZZA Posted July 23, 2015 Share Posted July 23, 2015 Was gonna say didn't think there was a fuel filter, either that or mines never been changed in 10 years ! Haha Quote Link to comment Share on other sites More sharing options...
SiriusProjects Posted July 23, 2015 Author Share Posted July 23, 2015 Am I right about the location of the Fuel Pump and how to access it? Quote Link to comment Share on other sites More sharing options...
GMballistic Posted July 23, 2015 Share Posted July 23, 2015 Am I right about the location of the Fuel Pump and how to access it? Yes it's in the fuel bucket inside the fuel tank (drivers side). Fuel bucket below... Modified example of a fuel bucket below but shows the fuel pump as n#174 Hope that helps. Quote Link to comment Share on other sites More sharing options...
SiriusProjects Posted July 23, 2015 Author Share Posted July 23, 2015 Thanks for the info Gmballistic. Can someone give me an idea on how long a job it is to replace the fuel pump? I wouldn't attempt it myself, but just want to know how difficult a job it is so I can estimate roughly what labour my local garage would charge. Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted July 24, 2015 Share Posted July 24, 2015 Once you get all the plastic trim out the way, it is a 30 minute job to replace the pump unit. They are not prone to failure, so I would get a fuel pressure gauge hooked up before you splash the cash. Is the EML on and are there any codes stored ? Alex. Quote Link to comment Share on other sites More sharing options...
SiriusProjects Posted July 24, 2015 Author Share Posted July 24, 2015 Thanks ZMANALEX, I wish it was reporting an error code. That's what is annoying. There is definitely a problem there, but whatever it is, it's not registering any codes. If it's not the pump, then could it possibly be a blockage in a fuel line or something? I'm running out of ideas. The MAF has been replaced, the air filter has been cleaned, new spark plugs went in on Thursday, Engine flush has been added. I got the garage to give the car a thorough check over as well to see if there were any obvious surface issues, but they said it was all fine. The engine idles well enough when the car is stationary, but the problems with lack of power and hesitation come when the engine is under load and has got to operating temperature. It's certainly noticable when driving up hill, it struggles more and I find myself having to change down to a lower gear then normal. Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted July 24, 2015 Share Posted July 24, 2015 Did you carry out a compression test when the plugs were out ? Could be numerous other things, coil packs or sensors spring to mind. A fuel pressure test will answer your fuel concerns that you mention. Quote Link to comment Share on other sites More sharing options...
SiriusProjects Posted July 24, 2015 Author Share Posted July 24, 2015 Hi ZMANALEX, I have just hooked up my OBD2 adapter and got the following readings with the engine idling. Fuel Trim Bank 1 Sensor 1 reading at around 19/20 % Fuel Trim Bank 1 Sensor 2 reading at around 99% Fuel Trim Bank 2 Sensor 1 reading at around 19/20% Fuel Trim Bank 2 Sensor 2 reading at around 99% As for the O2 sensors, I'm getting the following: Bank 1 Sensor 1 - 0.3 V Bank 1 Sensor 2 - 0.3 V - This remains static when engine is revved Bank 2 Sensor 1 - 0.6 V Bank 2 Sensor 2 - 0.3 V - This remains static when engine is revved I do note that Bank 2 Sensor 1 is reading at 0.6 Volts whereas all the others are reading at 0.3 Volts, which to my untrained eye indicates an issue. What do you think? Quote Link to comment Share on other sites More sharing options...
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