p0172 too rich bank 1 5vz-fe

Got a 99 4runner ive been slowly fixin for a buddy. Had a leaky injector so i replaced all 6 with new denso injectors. Well get done. drive it for a few days and p0172 pops up.long term Fuel trims are -30% roughly. I have replaced the MAF and A/F to no improvement (use known working parts)

Just looking for ideas.. about to swap the injectors with my trucks old ones next friday and see if the code stays away...

 

The oil is not fuel contaminated is it?

 

No

 

Evap purge valve leaking or FP regulator. Defective injector.

 

I’m leaning towards the injector honestly. Well see Friday when I swap em what happens

 

check the air intake temp senssor as well as the engine coolant temp sensor readings... does your OBDII scanner have live data streaming? The AF sensor can show a false lean and that can force the fuel trims to try to compensate also. Disconnect the AF sensor and see if it normalizes.

 

Everything on my scanner looks normal honestly. I have a snap on modis. Graphiing it everything looks good. A/f is right where it’s suppose to be. Pretty sure it’s fuel system related.

 

Pinch off the purge hose from the canister and monitor fuel trim.

May need to check fuel pressure but its an asshole with those trucks, we usually cut scrap fuel lines to make a pressure tester hose for them.

 

Fuel pressure is my Next test.(I have the factory adapter) I’ll check pinching the hose too. Honestly never had issues like this with a 3.4. And I’ve done plenty of injectors and stuff on these

 

Funny thing is it’s not burning through gas and the light comes on and goes out. Doesn’t feel sluggish or anything

 

We've recently seen regulator failures causing long cranks, but rich is usually MAF or leaking injectors.

Also! I've seen shit Napa injectors leak from new.

 

New Denso injectors. But they can still be bad

 

New, he he ... New = Never ever worked.

 

Ain’t that the truth sometimes.
I had a brand new Toyota torque converter. Put the car together and find out the damn stator pump was machines wrong and didn’t pump...


I was not a happy person. And my field rep was dumbfounded. Lol

 

Any remedy for this. I replaced all 6 injectors with factory injectors and I.a.c valve. cleaned tb and maf still getting a high idle and p0172

 

Resolved the issue with another set of injectors. From Toyota.

 

When I bought new injectors last spring, I sent them to a place in FL for testing. It turned out that two were under performing that would have caused lean conditions.

I got into the practice of sending injectors out for "only testing" for $7 each a few years ago. Once in a while, it can save a headache and rework.

 

i pulled the ones i had in the engine out and compared the spray to my good ones from my tacoma engine... they were DUMPING fuel.

 

Wow.. Uncontrollable flooding.

 

This must be what I'm experiencing. Had a #4 misfire. Replaced all 6 injectors now I'm chasing the p0172 code. Thanks for replying.