P0172 Bank 1 rich and hard starts after stalling in 4 low

I'll have to dig out my multimeter and see where the O2 sensors are resistance wise. It will have to be another week or so though

 

Thems bad fuel trim numbers, running rich like @Reh5108 says. You want your trims between -10 and 10, closer to zero the better.

 

Mine are usually right at +5, sometimes see the LTFT hit 7 but never higher than that

 

P0172? P0171 is usually a vacuum leak giving you lean trims, but p0172 indicates a rich condition I thought

 

Haha, didn’t caught that,

 

Last time I had this code it was the o2 sensor, so I replaced them BOTH with OEM DENSO

 

Yeah hopefully for @Wulf 's sake that's what it is...other possibility is a stuck injector

 

Bad catalytic ?

 

In my experience when my cat was bad it threw the dreaded p0420 code but maybe

 

I Hate this about our older ECU that we get only part of the information, grrr

 

I ohmed out both O2 sensors and both were at about 13.4-13.7 ohms

The rear O2 sensor connectors were full of gear oil so o cleared them out and then cleared the CEL with torque pro.

This is what I'm seeing at idle now. I'm wondering if that fuel trim is acceptable given that I have the later model higher flow injectors... Maybe the computer has to pull more fuel to get it to run like it would with the 96 injectors.

At redline in neutral it will go as high as -5.5

 

Your mention of the higher flow injectors makes me wonder the same thing...but even if that's the case should the trims not still be within -10 - 10 to make the ECU happy? Otherwise it thinks you're running rich and then these rich cond. issues present themselves...just guessing here anyway.
With the larger injectors you ideally want to run a piggyback to control them I thought? Like the FIC6 or whatever is called. Or maybe I'm thinking of boosted applications

 

Oh wait never mind you mean the later model 1st gen injectors, I thought you were referring to aftermarket high flow ones

 

Yea, they are 40 or 50cc larger or something like that, I have the larger size too with the older ECU,

BUT I think the fuel trims would be more positive to compensate for the larger injectors and my trims
are not any ware in the neg like that. Typically mine are at zero for idle to -+5,
I got a new MAF and it’s still settling in after the reset

 

I wish I had known what the values were before this all happened.

I drove it about 2 mi and the CEL did not come back on but it also hasn't finished the relearn or whatever

 

Running too rich – High negative fuel trim corrections can be caused by MAF sensor problems, high fuel pressure, leaking fuel pressure regulator diaphragm, faulty evaporative emissions components, leaking injectors, defective O2 sensors, exhaust leaks/pinholes before the O2 sensor, coolant temp sensor problems, and base engine issues such as low compression and incorrect camshaft timing.

Didn’t you have an exhaust leak if I remember?

I guess check these off one at a time.

 

I had an audible exhaust leak in the past but it doesn't sound like it's started to leak again. I did notice that 1/3 bolts that hold the pass header to the collector has fallen out so it's possible there is still a small leak

 

Doing some lunchtime reading and it sounds like I can easily check if the fuel pressure regulator is bad by pulling the vacuum hose off and checking for the presence of raw fuel.

Apparently the P0171 and P0172 codes are only thrown if the fuel trim goes past 15% plus or minus if this post is correct

 

Maybe but don't think so
Mine was +30 when the lean code was shown because of a vacuum leaking off intake

 

Try blocking off the. PCV valve if there’s a change too.

https://www.yotatech.com/forums/f160/long-term-fuel-trim-around-18-a-268925/index2.html

1) Check scan data for LTFT and Short Term Fuel Trim (STFT) while driving. Look for 0% plus or minus 10% to be normal. See if the fuel trims are far negative (meaning the Engine Control Module(ECM) is trying to take fuel away) at idle only, or while cruising down the road too.

2. If the fuel trims are far negative, check scan data for the Mass Air Flow Sensor grams/second and calculated load. With a warm engine at idle and the A/C off, the Mass Air Flow (MAF) Grams Per Second (GPS) should be 3.3 to 4.7 and the calculated engine load should read 15 to 21.4%.

3. If the GPS and the engine load are high and the idle speed is correct, verify the MAF sensor connection and grounds are good and check the voltages. The White/Blue wire at the Mass Air Flow Sensor should have battery voltage. The Brown/Black wire and the Black/White wire are grounds and should read 0.05 volts or less. The Mass Air Flow Sensor output voltage is on the Red/White wire and should read about 1.1 - 1.5 volts at warm idle.

4. Disable the canister purge solenoid in case of a flooded canister and see if the LTFT and STFT come down into the range of 0% plus or minus 10%.