hello everyone,
I have 2002 ranger3.0, I just did a head gasket repair on the ranger, it's got 228,000 miles on her, she has been a good truck, anyway, since I did the head gasket, I have two codes coming up, PO172, which is bank 1 system to rich, and PO175, which is bank 2 system to rich, I also replaced both upstream O/2 sensors, kind of stuck now, I don't want to start changing all the sensors, anyone have any idea what could be giving these codes? let me know please, thank you for any kind of help

 

Good idea to have replaced the upstream O2 sensors with that many miles on them.
I didn't see that the fuel injectors had been serviced, or replaced, or that the fuel pressure has been checked. So, maybe you have some runny nose injectors from them being dirty & or the fuel pressure being out of spec.

 

hello pawpaw,
I replaced all the injectors, new plugs, wires, I don't have a vacuum leak anywhere, I haven't checked the fuel pressure, would that give me a rich reading? don't have the tester to check the fuel pressure, I have to find out what the tester looks like, and how to work it, I will try to check the fuel pressure and let you know, thanks

 

A number of things could be causing the rich both banks DTC's & fuel pressure is one of them.

Good feedback on having replaced the fuel injectors, were they re-mans, or new & were they the specified injectors for this engine?

With this many miles on this puppy, were you using a oiled foam, or cotton gauze air filter? If so, or you developed a intake air leak, the MAF sensor may be dirty & corrupting it's PID to the computer about true air flow into the engine, causing the computer to have the fuel injectors squirt too much fuel.
If you think it's dirty, remove it for Careful cleaning with a plastic safe, non residual cleaner formulated just to clean the MAF sensor, like CRC MAF Spray cleaner. If just driven, let it cool before spraying with the cleaner, don't touch the sensor & keep it squeaky clean upon re-installation.

Seeing as how this seems to have come about after replacing the heads, when you checked for vacuum leaks, did you also check the PCV system plumbing to make sure it's properly attached & the rubber hoses & connections are tight fitting & did you replace the PCV valve with an OEM product? It's lived two life times with this mileage. Seeing as how the PCV system is a calibrated for vacuum leak & is down stream of & not monitored by the MAF sensor, any air leak in it's plumbing, or sticking of the PCV valve itself, or it letting in too much feedback, can corrupt fuel trim.

Finally, probably not likely, but if you've had the exhaust loose & it's developed a leak ahead of the upstream O2 sensors, it could cause them to corrupt their reading of O2 in the exhaust & cause the computer to corrupt fuel trim.

Were the new O2 sensors the specified design for this engine & was/is the wiring intact, not modified & undamaged, no repairs?

It's all a vicious circle, so don't rule anything out. More thoughts for consideration.

 

Betchu got some 'flex-fuel' injectors or the wrong poundage by mistake. That will allow too much fuel to flow, and cause a rich reading.
If you have the old ones, you might try swapping them in place of the new. Ford injectors don't have a lot of problems. At least from what I've seen/read.
I would double check what you bought and installed to make sure they are correct 'size'.
tom

 

hello pawpaw, and tomw,
the injectors were new, not reman's, and I've been using the stock air filter since I bought the truck, filter is not new, but not very dirty either, was going to change it when I change the oil this week, I cleaned the maf sensor with maf sensor cleaner, but I ordered one anyway, I did check for vacuum leaks, found none, I bought a new pcv valve today, will put it on once the truck cools down some, the O/2 sensors I put in were bosch sensors, and I checked the exhaust, everything there is tight, also, I don't have the old injectors any more, trash man took them away, i'm hoping between the new maf sensor, and the pcv vavle, that will do the trick, I need to check my fuel pressure at the fuel rail, never did that, have to get a fuel pressure tester, does anyone know what the pressure is supposed to be? thanks for all your help