Inconsistent fuel delivery issue.

Hey all,

Chasing a bit of a white rabbit with this one, but I'll attempt to describe the issue as best I can here.

1998 PreRunner Tacoma, I'd say 70% of the time fires right up after a few cranks. The other 30% of the time it'll either crank a few seconds longer before firing up, or in the worst cases will start right up and then immediately cut out and die.

12v battery is healthy
Replaced fuel filter & fuel pump with a new Denso

Not seeing/smelling any sort of gas leaks. No codes on the truck other than a 0446 Evap every now and again.

Where would you look next?

 

Have you cleaned your throttle body and the IACV? If not might help you out. Careful with how you clean the IACV though. I would look up Timmy the toolman on YouTube and watch his video on how to do it. My 98 with the 3.4 had those same problems you are describing. I also put some Lucas Fuel injector cleaner in the tank. Seemed to help but might just be snake oil. idk. Make sure to disconnect your battery before you do all that to reset everything. It will idle high for some time to relearn what's going on (normal). Good luck!

 

Fix your evap code.

Probably time to change your injectors and or fuel pressure regulator.

 

I actually did clean out the Throttle body and IACV when I first got the truck. Was pretty gunked up with carbon, took it off the engine and got everything I could out.

Injectors we're recently changed to the Fiveo MotorSport ones for the 3RZ. Haven't changed the fuel pressure regulator though, maybe I'll give that a shot next. I also have a new charcoal canister on the way.

 

Sucks throwing parts at it. I wonder if you can get the fuel system pressure tested first? Even a compression check. I would assume the evap canister isn't cheap and if you don't use OEM you know what they say about that It could work and then it could be defective right out the gate. Let us know what you find out as I am really curious on what you find.

 

I have similar situation on a 2rz......
has new injectors from Five-o, new regulator, and the 446 code every other tank.....

My only guess on mine is I didnt get the tank seal back right when I put last fuel pump in...
I dont get that whoosh any more when I pop the gas cap.....


When I stop and get gas with less than 1/8 tank......sometimes wont start until I put some gas in....and /or wait a little......
got in trouble when I had to jump to another pump......the push of shame.....

I bought a new seal.....but its a bit of a job getting to it.......unfortunately.......


curious as to what you find......as I also have and extra used vsv valve and almost new canister I bought off our classifieds last spring.....

 

If anyone was interested in the final outcome here is what I did:

- Replaced the charcoal canister with an OEM Denso off eBay ($180 shipped)
- Replaced the fuel pressure regulator with OEM eBay ($80 shipped)

In replacing them I found the fuel line tubing connecting the regulator to the charcoal canister was a bit moist, and when I pulled the fuel pressure regulator out of the fuel rail I found the small o-ring on the stem to be cracked. This was most likely my biggest issue. The new regulator came with a new oring so I just replaced the whole thing since I had it, as well as putting the new charcoal canister in.

Cleared my 0446, and 48 hours later so far so good. Starts up much faster with minimal cranks and so far the code has not returned.

 

still holding up good?

 

Still holds up - no codes since!

 

That's good info, thanks for posting back what seems to be a win, I hope so for you.