johnse2082 Posted January 5, 2015 Share Posted January 5, 2015 I have a 93 2wd pathy .. first twenty min or so it runs great, until however this buzzing noise comes from behind the dash on the passenger side, and usually means that my truck wont accelerate over 2200 rpm, i floor the pedal, and it jus acts like its not getting any fuel .. ive replaced the pump bout 5 months ago, had tank cleaned , lines also .. could it be a weak pump ? Link to comment Share on other sites More sharing options...
djeffrey Posted January 5, 2015 Share Posted January 5, 2015 Did you replace the fuel filter also? On the right front wheel well next to the exhaust manifold and relays. About the size of half a coke can. Link to comment Share on other sites More sharing options...
johnse2082 Posted January 6, 2015 Author Share Posted January 6, 2015 Yessir i did .. twice .. and im almost at my wits end with this truck .. i did trace that buzzing sound under the hood to the line thats coming from the tank up to the filter ,and you can definately feel the fuel line like its surging .. Link to comment Share on other sites More sharing options...
johnse2082 Posted January 6, 2015 Author Share Posted January 6, 2015 I even loosened the gas cap thinking it may have been vapor locking .. Link to comment Share on other sites More sharing options...
Kingman Posted January 6, 2015 Share Posted January 6, 2015 Pull the filter off and see if it's clogged again. Link to comment Share on other sites More sharing options...
johnse2082 Posted January 6, 2015 Author Share Posted January 6, 2015 Ok .. i will do .. if anything happens, i will let you know kingman and djeffery, thanks .. Link to comment Share on other sites More sharing options...
Nefarious Posted January 6, 2015 Share Posted January 6, 2015 Does the truck surge or buck around 2200 ? The ecu had a safety feature that if the maf sensor is bad, the ecu will Rev limit at 2200-2500 rpm. It's pretty much applicable to any 90s or early 80s nissan. Worth a check? You can test it with a voltmeter per the factory service manual in the garage section. Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 6, 2015 Share Posted January 6, 2015 The buzzing and surging fuel line sounds like some air is getting forced through the fuel system. That would suggest issues with the fuel pump. Did you replace the pump chasing this issue, or before it started? I can't think of where else air would be getting in. I can't think of why it would take twenty minutes to become a problem, either, unless it happens at a specific fuel level and just took that long for the fuel level to drop to where the leak in the pickup tube was. You might also take a look at the vacuum line going from the back of the intake to the fuel pressure regulator. It can't hurt to run the codes and see what the computer thinks is wrong too. Link to comment Share on other sites More sharing options...
johnse2082 Posted January 7, 2015 Author Share Posted January 7, 2015 It completely bogs down nefarious.. and to slartibart no i didnt change out the pump yet .. and no engine light is on or running codes through the computer .. its saying all is fine .. Link to comment Share on other sites More sharing options...
johnse2082 Posted January 7, 2015 Author Share Posted January 7, 2015 It does it whether empty of full .. Link to comment Share on other sites More sharing options...
Kingman Posted January 8, 2015 Share Posted January 8, 2015 Hose from the pump to the hard lines would be a good thing to check. They can deteriorate in the tank and you lose fuel pressure at the rail. It's very common if hose not rated for high pressure fuel injection is used, or fuel rated hose in general for that matter (low pressure EFI or carb). Link to comment Share on other sites More sharing options...
Junglebob95WD21 Posted January 8, 2015 Share Posted January 8, 2015 Yeah it would be a good idea to replace all of the hoses with new fuel injection rated hose. It'll run on average $2 a foot but is tough and wont deteriorate. Link to comment Share on other sites More sharing options...
Kingman Posted January 8, 2015 Share Posted January 8, 2015 Is that your cost on bulk hose?? It's way spendier where I've seen it. Pray be just getting hosed. Link to comment Share on other sites More sharing options...
johnse2082 Posted January 9, 2015 Author Share Posted January 9, 2015 Thanks all, imma see what happens .. Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 9, 2015 Share Posted January 9, 2015 Hoses wouldn't be a bad thing to check, but any hoses between the pump and the motor are under pressure, not suction, so any leakage would mean escaping fuel, which I think you would've noticed by the smell. I would also be surprised if a fuel leak like that made the fuel filter buzz. My bet is still that there's a bad seal somewhere in the tank between the fuel pickup and the pump which allows it to suck air from the tank, which then makes noise as it goes through the filter. My only reservation with this theory is that it doesn't really explain the time delay where it runs fine. Maybe there's a very fine crack that fills with fuel when the pump is off, more or less sealing, but dries out and lets air in after a while? Or the pump only starts leaking once it's warmed up? You might also have a look at the fuel pressure regulator and the vacuum line that goes to it. They're behind the intake towards the passenger's side. I don't think air would get into the fuel line there, but if the regulator part is, I don't know, leaking vacuum and fluttering somehow, it might be causing enough variation in fuel pressure to make the buzz, and enough pressure drop to make it run funny. That's a complete shot in the dark, and it still doesn't explain the time delay. Link to comment Share on other sites More sharing options...
johnse2082 Posted January 14, 2015 Author Share Posted January 14, 2015 Ok .. as i sit in the paffy now,its buzzing like crazy .. i did pull up the carpet back there in the cargo area, undid the four screws holding down the access cover, and indeed the fuel pump is the buzzing, and it also seems to be making the relay for the pump buzz too .. Link to comment Share on other sites More sharing options...
johnse2082 Posted January 14, 2015 Author Share Posted January 14, 2015 And i just tried to rev the engine, and it just almost died out , now loping ruffly like its gonna die any second .. Link to comment Share on other sites More sharing options...
Kingman Posted January 14, 2015 Share Posted January 14, 2015 The pump relay should not be buzzing. That's a problem with the relay it's self or power/ground. Link to comment Share on other sites More sharing options...
johnse2082 Posted January 14, 2015 Author Share Posted January 14, 2015 As far as the ground for the relay or the pump assembly itself ? Link to comment Share on other sites More sharing options...
johnse2082 Posted January 14, 2015 Author Share Posted January 14, 2015 I like this truck, and ive never seen and or heard of a 3.0 having this issue .. i ve owned a few 86 and 87 maximas and never had issues like this .. Link to comment Share on other sites More sharing options...
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