P0131 and P0305 (Page 1/1)
Odin JUN 19, 01:31 PM
Hey guys, getting these on my 3800 II SC swap. One is O2 low voltage and the other is misfire on cyl5. Getting loss of power big time in high rpm. Checking the ignition system tonight. Could misfire cause a P0131?
Dennis LaGrua JUN 19, 02:32 PM
Based on the code you have it can be a bad O2 sensor or a lean mixture. Its a good idea to check fuel pressure before anything else. Could be a bad FP regulator or fuel pump or a deteriorated hose connection in the fuel tank from using the wrong hose.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Odin JUN 19, 04:39 PM
So the car has a brand new ACDelco EP381 in it. I just had the tank out and replaced all of the hoses/strainer/filter. No kinks, restrictions etc. The pump has submersible fuel hose connecting it to the sending unit. Its holding 55plus PSI through acceleration in the top end. So not sure where to go after this. How do I check the regulator? Would it still hold pressure if the regulator if the regulator was bad? Thanks

[This message has been edited by Odin (edited 06-19-2019).]

Dennis LaGrua JUN 19, 04:57 PM

quote
Originally posted by Odin:

So the car has a brand new ACDelco EP381 in it. I just had the tank out and replaced all of the hoses/strainer/filter. No kinks, restrictions etc. The pump has submersible fuel hose connecting it to the sending unit. Its holding 55plus PSI through acceleration in the top end. So not sure where to go after this. How do I check the regulator? Would it still hold pressure if the regulator if the regulator was bad? Thanks




Sounds like the FP regulator is working. One sensor very critical to fueling is the MAF sensor. If its dirty, the engine will run lean. I had this problem with a new Delphi MAF sensor that picked up an oil film from a new "permanent" K&N filter. I would try cleaning the MAF sensor with special MAF cleaner. A defective IAT, ECT or O2 sensor can also make the engine run lean. The only way to tell is to do a scan and watch all the sensor readings.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "