Fuel pressure problem?

2000 Toyota Tacoma 2.4L
Automatic
82000k

After my truck sits overnight the initial start in the morning is rough for a few seconds then fixes itself.. it feels like it’s starving for gas and I’m thinking I’m losing the fuel back pressure overnight. During the day after the initial start it seems to start fine. Some fuel pressure specs i should test for? Also an idea what could be happening? Fuel pressure regulator or is that part of the fuel pump? Or possibly bad fuel injectors…? Two years ago I changed my plugs and then a month or two ago checked and changed them again and they seemed to be worn unevenly. Probably only drove 16-20k miles on them and two were pretty eaten away.

 

-the FPR is on the end of fuel rail......closest to rad here.......


there are vids out there how to test FPR....but part is inexpensive

 

now i had 'hot no start' issue
turned out to be injectors

but tracking down issue and to make sure the original FP was not the cause
i bought a FP gauge from LCE

https://www.lceperformance.com/Prod...MIiLCl14jmhgMVIButBh0svwlqEAQYAiABEgJP1fD_BwE

installed both the gauge and FPR at same time to rule out low FP from gauge
original FP showed 46lbs running but pressure would drop pretty fast after shut down
after RM'ng injectors at MotorWest in CA
im good no issues

46lbs running holds at 46lbs for 45m to 1hr after shut down

(i do have a FP on stand by when it does fail!)

 

First off Thanks for replying!
So my truck starts fine after sitting for a few hours it’s mainly that overnight sit so it gonna take a couple days of testing fuel pressure I think. I’m gonna start by renting a fuel pressure gauge and check the pressure before I start it in the morning. Is there a specific psi it should sit at? Or expect it to be 0?
I do see what your saying tho sometimes the fuel pump isn’t providing the correct fuel pressure to the regulator and if I hook a gauge up to the fuel rail I only get to see pressure after the regulator? So regulator could be holding pressure on rail but fuel pump isn’t holding pressure to regulator possibly?

 

just as long as it holds for a period of time

i searched and searched.....no 'easy' place to hook up FP gauge
toyota's f lines are weird.....rubber and ends are large portion alum(like an AC line)
on my 96 read that the one i needed to disconnect/fashion a fitting for FP gauge/then hopefully test.....was under intake and between left side of engine and firewall.......too many unk factors of stripping banjo bolts/contorting my body to try to reach lines/just general "Hulking It" stress
i just bit bullet and got that $75 FP gauge kit

might want to RR your fuel filter too
hopefully your 00 is not located where my 96 is located!

 

Yea It definitely holds for a few hours or even to let the truck get cold again it’s weird how it’s just the initial start in the morning. There’s no fuel priming either when I turn the key huh? So I cant test if two primes would make it start better I was thinking…
The gauge screws onto the fuel rail? And did you leave it or temporary just to test?
Unfortunately my FF is under my intake I’m pretty sure… read about relocating it… looks like a project lol

 

yeah i found out the same here
only primes when key is turned all the way and engine starts cranking.

i guess you could test FP once the FF removed
(and can find a fitting that works to the hose on FP gauge tool)

dude my hands were not only gashed to crap getting that FF out
hands were actually swollen
glad i did thou

 

oh sorry

yeah both the gauge and FPR install took 10mins total
LCE instructions say 'only meant for diagn purposes'
i have under hood FP gauges on all my 3 old cars 98/96/01
whatever....looks cool....my risk

 

Any ideas where the cold start injector is? After reading this post and the comments. https://www.toyotanation.com/threads/finally-fixed-my-starting-troubles.344719/
I think that’s my problem. Either the cold start injector time switch or the cold start injector itself.

 

Ok I read
But I took off my intake mani and plenum….I didn’t see anything
But
Just to be sure……
Got off with my friend in CA that has 92 22RE taco……he confirmed he has this cold start injector

Thinking that dude changed his truck (screen name) after he found/replaced the injector on a 22RE

maybe someone else can confirm to be sure

 

In fact, the more I’m thinking,
The coolant temperature sensor on back of the head might be your ticket to solving issue

again mine……

 

I think you’re right! I couldn’t find it on my truck either.. and yea I was hoping that ECT sensor was the cause a little while ago when I changed that but unfortunately not.

 

Back to this real quick. So you were actually losing your fuel pressure through your injectors after shut down? What made you think injectors rather than a fuel pump check valve or something? Just curious

 

Does anyone have an fsm on what the fuel pressure should be on the 3.4? im having a similar issue on my 2003 3.4 v6. replaced fuel filter.

 

38-44 psi at idle, with the FPR vacuum reference hose disconnected.
33-38 psi at idle, with the FPR vacuum reference hose connected.

 

DUDE
i was really struggling with the same topic
i was new here to Tworld
i couldnt wrap my head around why leaking injectors would cause 'hot no start'
neither did any of my race car friends
all my other cars/friend's cars/cars that i have wrenched on....injectors NEVER an issue or a cause
i was totally skeptic.

finally(i forgot the seasoned member that explained)....its in one of my threads somewhere.....

nutshell/layman's terms:
engine hot
injectors drip fuel(after shut down)
the fuel drips and vaporizes
this fuel vapor will not combust and takes the place(volume) of the actual fuel that should be combusted
hence, cranking cranking cranking.....no start

again, im repeating(as best i can) what someone with more experience than myself told me


i might be off but a lil but one thread explained it enough to me to get injectors replaced