2UZ Starting Help - Struggling to Cope (1 Viewer)

[TET1]

Hi All,

I've been having a starting issue on my 2000 Tundra, V8, 4WD, Access Cab. Before this, it was sitting pretty at 300k miles. The issue I am having is starting when hot, or driving for a while and then starting after the truck after it has sat for 1 - 4 hours. Cold starts in the morning are fine - it will crank over 6 or 7 times and fire right up. Hot starts it will crank 1 or 2 times, act like it's gonna stall, and then slowly start up.

This whole saga started when I noticed hesitation when accelerating under load. I ignored that for a time and, since it wasn't throwing any codes, I just let it be. Eventually, it turned into a P0171 (system too lean, Bank 1). It was at that moment that I decided to do some "routine" maintenance. When I say routine, I mean routine for a 300k mile truck. Just thought I'd give it a glow up so it could serve me for another 10 years.

I replaced the fuel pump and fuel sending unit first, which fixed the hesitation when accelerating and the P1071 code.

After that, I replaced the fuel injectors with 12 hole injectors (yeah, I may have been duped, I don't know yet), intake manifold gaskets, and entire throttle body and gasket. I replaced the valve cover gaskets, spark plug tube gaskets, spark plugs, ignition coils, pcv valve and hose. It is at this time that my starting problem began.

I went on a journey to figure out what the hell was going on, and I still have not reached the end. I then subsequently replaced the MAF, crank position sensor, fuel filter, fuel supply lines, engine coolant temperature sensor, cleaned up the battery terminals and grounds around the engine bay, fuel pump resistor, starter relay. And, I even went back in and replaced the starter motor again and all new intake manifold gaskets, again. I even replaced the o-rings, grommets, and insulators on the already new fuel injectors.

Yeah, I have shot the parts cannon at this and am ashamed of doing so, but no level of diagnostics I have done have revealed a problem. When it drives, it drives great and feels amazing. It's just this damn starting issue that has me stumped. I have hooked up a vacuum gauge at operating temp in idle several times and it reads dead steady, at 16, so I don't think it's a problem with vacuum or pistons or anything.

Can anybody PLEASE help or give some advice? I just don't know what to do anymore. Even the dealership and some reputable toyota mechanics say that there is nothing wrong, but I know my truck and how it used to be.

 

[TET1]

Oh, forgot to add, I also replaced the fuel pressure regulator and fuel pulsation damper.

 

[usifnoor]

Oh, forgot to add, I also replaced the fuel pressure regulator and fuel pulsation damper.

I'm experiencing the same issue with my 2004 lx470 Lexus. Despite multiple attempts , I haven't been able to identify the problem.Im frustrated with taking it to mechanics, as they suggesting the same parts need to be replaced, which i have already done..."TET1" Please do let me know if you were able to find out the cause....Thanks.

 

[TET1]

@usifnoor What problem are you having, exactly, and when did it start? Maybe we can help each other figure this out...

 

[TheBussman]

16 is on the low side. connect a fuel pressure gauge, then get it to act up and see what it says. does it start easy on starting fluid?

 

[TET1]

16 is on the low side. connect a fuel pressure gauge, then get it to act up and see what it says. does it start easy on starting fluid?

16 may be on the low side, but I'm more concerned about fluctuations in the vacuum than the overall reading. Right now it's steady as can be.

I have not tried starting it on starting fluid. Do you recommend just spraying some stuff in the intake, or how would you go about testing that?

As for the fuel pressure gauge, there isn't a great place to hook one up on the 2UZFE for my model year. Do you know of kits or solutions to this?

 

[TheBussman]

16 may be on the low side, but I'm more concerned about fluctuations in the vacuum than the overall reading. Right now it's steady as can be.

I have not tried starting it on starting fluid. Do you recommend just spraying some stuff in the intake, or how would you go about testing that?

As for the fuel pressure gauge, there isn't a great place to hook one up on the 2UZFE for my model year. Do you know of kits or solutions to this?

it's still data to consider.

i would just spray a small amount in the intake. best way is to have a friend crank the motor over and then start spraying that way you dont load up just 1 or 2 cyls most fuel pressure gauge kits that comes with fittings should work. you will need to remove the line going to the fuel rail and connect the gauge there.


what brand of parts are you using?

another thing to try: when its not starting. move the key from off to run (position 2) wait about 2 seconds about 10 times and then try to start it. This will run the fuel pump more and if there is a vapor lock issue or fuel pump check valve issue it may move enough fuel around to get it started.

 

[TET1]

@TheBussman

You are right, it is data to consider.

I am using all OEM parts, denso, aisin, etc. Everything has been ordered through Toyota.

I'll work on getting a fuel pressure adapter set up. It almost seems like it's getting TOO much fuel on start up.

As for the ignition, I don't think turning the key to the ON position runs the fuel pump in this 2000 Toyota Tundra. You can read about that here in post #27:

HELP!!! TRUCK Won't start!!!

My 2000 Tundra usually runs like a top with no issues. Two days ago, as I was pulling out of a parking lot, a guy cut me off requiring me to hit the...

www.tundras.com

 

[smokeysevin]

Have you cleaned the throttle body?

Sean

 

[TET1]

Have you cleaned the throttle body?

Sean

Per the original post, the throttle body is brand new, and it’s still clean.

 

[TheBussman]

@TheBussman

You are right, it is data to consider.

I am using all OEM parts, denso, aisin, etc. Everything has been ordered through Toyota.

I'll work on getting a fuel pressure adapter set up. It almost seems like it's getting TOO much fuel on start up.

As for the ignition, I don't think turning the key to the ON position runs the fuel pump in this 2000 Toyota Tundra. You can read about that here in post #27:

HELP!!! TRUCK Won't start!!!

My 2000 Tundra usually runs like a top with no issues. Two days ago, as I was pulling out of a parking lot, a guy cut me off requiring me to hit the...

www.tundras.com

yea your right it doesn't turn on with the key i just checked.

have you tired holding the pedal all the way down when it won't start?

 

[smokeysevin]

Per the original post, the throttle body is brand new, and it’s still clean.

My bad, I missed it.

I would start by swapping one factory part back at a time and see if it does anything.

I wonder if the AC compressor clutch is sticking, that could be extra drag on the belt on start up.

Sean

 

[usifnoor]

@usifnoor What problem are you having, exactly, and when did it start? Maybe we can help each other figure this out...

My car starts well in the morning without any hesitation but after a drive of 20 minutes if i turn off my car for five minutes than it gives me tough time to start again ,like i have to try literally 5 to 6 times than only gets started.

I have changed the Fuel Pump and fuel filter ,crank sensor ,Map sensor,Vacuum sensor,cleaned injector,spark plugs replaced with new one,ignition coil replaced with used one.

But still i face this issue.

It started after I changed my car engine as the previous engine was having a knocking sound

 

[gnob]

look into the ect sensor

 

[Jetboy]

I would consider swapping a junkyard ECU. Might find one locally for cheap and give it a shot. They do go bad in intermittent ways that are very hard to diagnose.

 

[usifnoor]

look into the ect sensor

I have replaced the ECT sensor but still the same.

 

[gnob]

are the new injectors toyota?
might be worth a revisit since you're this deep.

 

[vipergrhd]

Did you check timing belt? You mentioned a lot of parts being replaced but not the timing belt. It's possible the belt skip or stretched?
It sounds something is out of sync.

 

[usifnoor]

Did you check timing belt? You mentioned a lot of parts being replaced but not the timing belt. It's possible the belt skip or stretched?
It sounds something is out of sync.

Latest Update on my Lx470: A friend recommended an electrician to address my hard starting issue when the engine is hot. After examining the problem, the electrician suggested bypassing the injector connection due to potentially weak signals. He installed a relay switch on the main engine wires. Eager to solve the issue, I agreed to proceed, but unfortunately, the hard starting problem persisted, although there was a slight improvement in the car's performance while driving.

I then consulted another Lexus specialist who conducted a thorough diagnosis by replacing each part with used ones from a similar car in his garage. On the fifth day, he identified the problem as the ECU unit and asked if I could find another one with the same part number. It took me a few days, but I eventually found a matching used ECU.

This morning, after the specialist replaced the ECU, the hard starting issue remained, and I also noticed smoke coming from the exhaust. Now, I'm at a loss for what to do next.

 

[Jetboy]

Latest Update on my Lx470: A friend recommended an electrician to address my hard starting issue when the engine is hot. After examining the problem, the electrician suggested bypassing the injector connection due to potentially weak signals. He installed a relay switch on the main engine wires. Eager to solve the issue, I agreed to proceed, but unfortunately, the hard starting problem persisted, although there was a slight improvement in the car's performance while driving.

I then consulted another Lexus specialist who conducted a thorough diagnosis by replacing each part with used ones from a similar car in his garage. On the fifth day, he identified the problem as the ECU unit and asked if I could find another one with the same part number. It took me a few days, but I eventually found a matching used ECU.

This morning, after the specialist replaced the ECU, the hard starting issue remained, and I also noticed smoke coming from the exhaust. Now, I'm at a loss for what to do next.

Smoke from exhaust only comes from 3 places: oil, excess fuel, or coolant. Can you tell which one it is?