So on our 1996 f250 with 5.8 I had the problem of a bad head gasket, that ended up with a bent rod and broken piston. See other thread.


We rebuilt the engine, new rings, rod and main bearings, new to us rebuilt heads from machine shot, ours were cracked. new fuel injectors, new headers. We did reuse cam and roller lifters.



Started getting the 1131, 401, and 1401 after start up and break in.


After reading and testing we ended up replacing the DPFE? module, that failed the test. (believe it was original as it was the pot metal or aluminum one. Then turned to attention to 1131.


Weirdness is that bank 1 sensor one shows pretty flat line, bank 2 sensor 1 shows switching and good sign wave. Since they hadn't been changed since we have had the truck, 2006, we changed both front sensors. Same results. Found some junk in the connector for bank 1 sensor 1, so cleaned that out. Now sensor reading, but a low wave. Swapped front sensors side to side, no change.


Tested sensors for 12v, 12v heater, on all 3. Had voltage. Checking the harness on the driver side, found the clamp that holds the harness to the block smashed. took it apart, and installed new 02 pigtail . Back to bank 1 sensor 1 reading flat.


Side note. Noticed Paint on cyl 1 header still on, tested at 250degrees, while other tubes are all 440-500 degrees and now have lifter noise on bank 1.


Need some help, seems like I may be chasing multiple issues. After doing some reading here, I'll clean the MAF sensor tonight, and also do compression test. This motor has roller lifters and I think I have one or two on cylinder 1 not pumping up.


Any help appreciate.


John.

 

Does the motor run smooth? Rough?

 

at idle it runs a little rough, but smooth off idle, and freeway driving.

 

so after checking fuel pressure 40/33, then compression 150, plugs, we turned to injectors. #1 injector was bad. We replaced all 8 during the rebuild. I believe she got them off ebay.
code has cleared, and now.o2 bank 1 position 1 and 2 both show switching.