3rz lean condition p0171

I think HF has these for about $15......

 

I actually bought one of those but I used a different larger dial one from the parts store. At idle I've got like 20 and when I rev the engine it increases vacuum what I guess would be good. I need to rig up something to get fuel pressure reading. What brake boosters are yall using to replace the oem one? Surely some aftermarket company can build a halfway decent booster.

 

As far as our friend hot no start, probably should pull those injectors or pulse test the decay rate or something.

 

New to the forum. Live in Ventura CA. Have a P0171 and have been testing everything. OBD2 and multi-meter. 1996 3.4l automatic RWD.

Fitted a Schrader valve to the fuel rail. (Get everything you need on Amazon. About $40.)

I have the factory shop manual and working through tests.

One thing is confusing me.

-No fuel pressure until the engine is started,
Nothing in the ON position. Another thing is the pressure is at bottom of the range @ 31 psi when the engine is running. The fuel pressure decay is within range and other test of fuel pressure regulator is ok.
STFT maxes out at 19.5. Smoke test, O2, MAF, vacuum…..can’t find anything. Carb cleaner and also water misting. STFT drops with throttle stab suggesting vacuum leak, low fuel pressure…. Any ideas?

 

Check the brake booster for vacuum leaks like me. Fuel pump doesn't start until truck is turning over I believe is normal

 

Last time I checked couple years ago .....Napa had a selection of them from different suppliers...even oems....

they sell denso, aisin, and a lot of oem,,,,,,,,,usually takes couple three days to get it from the warehouse to your store or home address....

this is where I got all new internals for my rear drums......took a week for em to get my store....

 

If the BB check valve hose ‘passes’ blow test, and no visible cracks……

Any test one can do on BB before throwing parts at the issue?

 

https://archive.org/details/1996-toyota-tacoma-factory-service-manual


go to the BR section it has info on the booster.

 

OMG beezer thanks so much ^^^
Site saved.

so again, just discovered the booster check valve IS NOT inside the BB vacuum hose like many cars I have wrenched on
It’s separate
But I noticed that the rubber check valve grommet is beyond loose/perished
#4 in above

will see if still available

 

Check valve is good
Going to clean/lube grommet

 

Both BB tests under that BR section passed

did find out from same link that my FP gauge is mounted on return line!
Ugh
No wonder it’s reading 20lbs

 

Fellas. That's where my booster is leaking. I sprayed maf cleaner there and it brought the rpms up.... not much but with a scanner on it was obvious. I'm gonna try the grommet for now before I replace the booster entirely. I did replace the maf with a Hitachi unit and it improved drivability at rpms over 2k, when the vacuum leak is overcome. At these rpms while cruising my fuel trims drop the zero.

 

little silicone grease can ease a lot of ills....
especially with new hard rubber parts...

 

There is a seal that seals the brake master cylinder “snout” into the booster… the bitch is that it is unobtainium, at least it was the last time I looked.

 

SOMETHING will work