3rz lean condition p0171

P0171 yesterday morning. Fuel trims were as close to zero as anyone could want with very small adjustments until this. Lift is 25 percent and stft is holding zero. Vacuum guaged and sprayed maf all over no leaks in intake. It didn't like the brake booster being unplugged and when I pump the brakes it stumbles. MAF seems to read a little lower than I remember when the trims were right. It runs and drives strong with seemingly good throttle response. Ordered a new maf. What's the fuel pressure supposed to be at the rail and what's a good way to check it?

 

2001 3rz BTW 300k miles

 

2.4L 1996
Gauge tested….accurate.(60yrs old)

I’m wondering the same
Every other car I have wrenched on, FP usually 35-42lbs
Read/searched and 20-22lbs is typical
I’m still not positive about this

this gauge is before FP regulator, only way to mount as FPR bolts on to fuel rail.
Have my suspicions as I’m suffering from ‘hot no start condition’

 

Hot no start usually ends up one of two ways....

If your lucky....its just leaking injectors....
......that in itself will eventually pit the top of the piston....


Usually its the head gasket....or worst a crack between the valves in the head....
both of these are very common in taco 4-banger world....

 

Have you tried reading pressure after warmed up? Maybe something expanded with heat and draws too much or too little vacuum.

 

As far as pressure....there was a thread a while back that listed all the bango and gauge stuff needed to tap into the rail....

or shell out $70 for this....

Fuel Pressure Gauge Kit 2RZ/3RZ (lceperformance.com)

pressure should be 42 to 47psi....

 

https://www.amazon.com/gp/product/B000CPJI8I?smid=A2L97JA8DAGJXC

https://www.amazon.com/gp/product/B084YYKC9Q?smid=A1U0GG705VIV5P

https://www.amazon.com/gp/product/B0081TJO72?smid=ATVPDKIKX0DER

https://www.amazon.com/gp/product/B003U94022?smid=ATVPDKIKX0DER

 

I'd buy that honestly. I've got 2 3rz powered trucks and am totally dedicated to keeping them on the road...as far even as waiting for a yota1 3rz at the moment for backup. In my case that would be 70 bucks probably well spent. Altho tools that I can use for other vehicles to offset the cost is a plus

 

My brake pedal feel is inconsistent and the stumbling while I pump it makes me think it's pulling my lean condition. The plan so far is new maf and booster

 

They used to be $50....thats what chapes my ass

wish I had one......if anyone wants to sell theirs.....


however you can pull off that fuel reg return hose,

put an extension hose off the reg......and crank....

gas should come pouring out on the ground......
if that pump is weak or filter clogged, it'll probably show.....

 

YEah there is a check valve where that vac hose feeds into the booster....

thread few weeks ago someone replacing just that....

 

I knew 20lbs ain’t going to cut it


Are y’all saying that brake booster could be cause of low FP??

I’m popping hood now

 

Just drove to town, watched live data. As I pulled out I heard the brake booster hiss while I mashed the brakes to shift out of 4wheel. My road to the main road is rough enough. Anyway watched live data cruising in 4th at 50mph at 2000rpm. Fuel trims dropped like a rock back to long term zero. Pulled into gas station at idle straight back to 25 ltft. Driving home same thing. Truck runs fine down the road and then gives a lean indication and a rich command. That brake booster tho.....

 

O’silver….
Turns out new FPR arrived today
(I tested old one…passed)
Test was running for 15m and seeing if fuel would flow through diaphragm thru vacuum outlet

when I installed new $16 FPR
There was FP….dripping/spraying down side of block

 

Just RR’d FF too

was nasty

 

Levis…….
Same 20lbs
Hot/cold
Revving/idle

 

Your really taking a chance with an aftermarket FPR....
if that diaphragm leaks/fails and sends fuel straight into the intake...
that could cause a slew of problems.....worst being an engine fire...


And yeah ....if you dont know the age of your fuel filter....its time to replace it....

that can leave you stranded....


Be super careful with those hoses on each side of the filter......they run about $200 ea.....

 

These trucks are so weird.....even the evap system can be causing problems....

I'm starting to get that evap code......and most likely my charcoal canister or something around it is starting to leak/fail....

 

I've replaced the fuel filter less than a year ago. I'm pretty sure mines the stupid brake booster

 

I've said this before....those little mini smoke machines can sure come in handy...

they use a tiny 20ml of baby oil.....

https://www.ebay.com/itm/125965095295




I bought a 'D' cell bait fish pump to push the air......