3rz random no start need help

So my truck randomly will fire up and immediately stall, it will then turn over and kind of act like a no fuel or like a flooded engine. If I go wot and turn it'll start rough around 250-500rpm then in a couple second rev high normally when I let off the throttle it returns to a normal idle and all is well again.

After some searching I decided to try replacing my fpr with an oem toyota.
I have an lce fuel gauge and static and running fuel pressure are both good. Additionally the front afrsensor, iac, maf, coils and plugs are all newer oldest being maf at about a year and all are oem/denso.

Any ideas what this could be cuz when it starts it runs fine.

 

I had this issue a few years back and ended up being a tear in the breather tube causing the IAC to believe it was receiving too much air and choking of the air flow. If you held the accelorator for about a minute the truck would run normal.

 

Are you referring to the main intake pipe? The two going from valve cover to intake are a year old and oem toyota

 

I think he means this one, well, not this one exactly but you get the idea.

https://parts.toyotaoflakecity.com/...63051350/178820P010.html?partner=BingShopping

 

Ok yea so the flexible part of the intake duct... I'll pull it off and check it out. I was actually working on adapting a v6 airbox with those spectre pipe sections so maybe it's time lol

 

Get a good scan tool with live data/recording capability (not expensive), and attach it to your truck each time you start. Check check PiDs for fuel pressure, injector pulse, spark, fuel trims, IAC, etc... should be able to narrow it down the source system fairly quickly.

 

I've been looking at live data on an otc genesis. Fuel pressure cannot be read on trucks this old, maf readings are good, along with iac %. The truck does have 7.2% long-term ft. And injectors at idle are 3.2ms which I think is within spec

 

Does that engine have a Schrader valve on the fuel rail? What about spark? Any random misfire history codes?

 

No codes at all and coils/plugs are new oem no it does not but I have the lce fuel pressure gauge installed under the fpr stable around 45psi at idle.

 

I think the next step will have to be to labscope each critical component (ie, one that can cause a shutdown) and look for any hiccups in those signals. I'm also wondering about your coolant temp sensor.

 

Oh thanks for the reminder the temp sensors are both less than a year old and also oem. I'm thinking I need scope data of crank and cam position sensors to see if ones failing

 

Yes that is the one, I had no codes with the issue either but would stall out unless I held accelerator for about 20 seconds to a minute

 

Hey so I've been testing theories to no avail with this issue. I replaced the fpr just in case but that didn't help also thought maybe an evap issue but it all tests good. Today I woke up and the fuel pressure was 10psi I didn't start the truck cus I was finishing an hid retro. As I'm getting the second headlight installed I noticed the pressure went up all on its own to 40psi what could cause this? It never had the key and wasn't started so I'm confused and wondering if this is part of my "flooding" no start issue

 

Fuel pressure regulator?

 

Apparently my phone autocorrected, the fpr has been replaced it just seems weird to have the fuel pressure increase over the course of an hour when the truck has been off for 10 hours

 

Just because it was replaced doesn't mean a lot. New parts faulty out of the box is definitely a thing!

You're going to need to approach this systematically and confirm one component at a time. I would definitely start with the fuel side. Watch the fuel pressure at the rail, and see if changes.

 

Haven't had that issue with oem toyota parts as of yet. I do have an lce pressure gauge and all the standard test seem good fuel filter is new and I'm trying to figure out if there is a good way to test for a leaking injector other than pulling the rail. The reason I was leaning towards evap is it is worse right after I fill up

 

Valve clearances? Fuel filter? Faulty fuel pump? Oxygen sensors?

Could be so many different things. Sounds like it'll be tough to narrow this one down..

 

Totally glossed over the part where you were fitting new headlights. I'm putting this down to 'red herring' now. I'm guessing that you did something which woke up the ECU, and it 'topped up' fuel pressure as part of waking up.

 

Ok cool that makes since because when I saw it go up on its own I was thinking I needed to retest all the fuel parts I had already tested I was confused I didn't know the ecu could prime the fuel with no key in