50 PSI at fuel rail?!?
50 PSI at fuel rail?!? I have a 98' z28 M6 that is bone stock as far as i know from the guy i bought it off of 2 weeks ago. When i bought it i did a typical tune up..... all fluids, plugs, wires, fuel filter, seafoamed and cleaned TB. That was last week. About two days ago i noticed what sounded like a misfire at idle so i held it at 1,500 rpm and it was a very distinct misfire or fuel starve BUT no codes every popped on. so i had a buddy plug a scan tool in and he got P0131 ( lean on bank one) so i double checked spark and checked plugs for cracks all was good so he mentioned a bad o2 sensor before the cat....... i changed it out........same issue, Still no codes but that rough sputter so i put a fuel PSI gauge on the rail and with the key on after the pump primes i get 50 PSI +/- 1 or 2 which im told should be more like 55-60 PSI? but what is also weird is that when i crank the motor the PSI doesn't drop down 3 to 10 PSI like im was told it should, it actually shoots up to a solid 60 PSI when running. So now im leaning toward a bad pressure reg. which is now my understanding its in the tank(1998 model). If it were the pump wouldn't i be getting codes for both bank 1 and 2 running lean? not just bank 1?
I'm open to suggestions
and i have checked for kinked lines and all injectors are clicking but thats as far as i could go till the rain came today
I'm open to suggestions
and i have checked for kinked lines and all injectors are clicking but thats as far as i could go till the rain came today
If you cycle the key a few times and the non-running pressure is about 58 psi, that is normal, the 60 psi running is normal as well.
I would unplug the injectors one at a time on the drivers side to see if you can isolate the miss, with new plugs and wires (unless one is damaged) should be fine. Clicking doesn't matter. You can check the resistance of each injector to see if they are all the same. I don't remember what the stock resistance is but if you test them all you should get a good feel for what is average.
I would unplug the injectors one at a time on the drivers side to see if you can isolate the miss, with new plugs and wires (unless one is damaged) should be fine. Clicking doesn't matter. You can check the resistance of each injector to see if they are all the same. I don't remember what the stock resistance is but if you test them all you should get a good feel for what is average.
thanks, that will be my next step to try and figure it out. The reason i lean towards the fuel pump going out is i've noticed everyone with similar issues eventually find out it being the fuel pump
, i got a break from the cheesy "faye" storm down here and will go inspect again would you recommend any area i might be overlooking on the vacuum lines?
this is my first LS-1
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so the update is after double checking and busting out the volt-o-meter i decided that i will clean the MAF sensor, i thought maybe its dirtier than i thought so i rolled to auto zone and when i was getting the cleaner in a can i had them scan the car again and turns out its throwing codes for both bank one and two o2 sensors before the cats, i havent been able to put the much cleaner MAF back on yet due to poor weather to see of the results........i wish the original kid would have told me it was both o2's in the first place, but now im back to troubleshooting any inputs would be great, thank you
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