Tacoma 4.0L hard to start when warm

Sub'd

 

Let us know.

 

Boogie, have you done anything on your truck recently to try to fix the starting issue with your truck? Havent heard from you in a while. Just trying to get an idea on where we stand

 

Everything I've done is minor so far and has been covered by you or others on this thread. I will say that mine seems to be doing it less now ... so if before if I would get a long warm start 100% of the time, now it seems like 75-80%. Hey it's progress.

 

So I ran another experiment to just gain some more information. After letting my truck sit all day at work, I went out alittle early and cranked it. Let it run for about 30 seconds to build up fuel pressure, and then shut it off. I went back in and waited alittle over an hour, went back out and it cranked up perfect.

This tells me that whatever the issue is, the truck has to get up to operating temp for it to be effected.

 

And you have changed the ECT sensor right?

 

I changed it out for a day, and when it didn't fix the problem I returned it. I've got a buddy that can get me some parts through his work and return them if they look unused.

 

This really sounds like the ECT. Wherever the issue is stemming from it sounds like it is based on a vital sensor which affects start ability. The vital sensors are Cams/ Crank, coolant temperature and air flow at start up.

You already did your fuel pressure testing right? The one which you told me about to isolate it to the injectors and FPR?

 

No, I ordered the fuel test port from urd, it should come in the mail tomorrow

 

This still sounds like leaking injectors to me. I know you said you changed them, but it sounds like a classic "flooded" intake condition.

Have you considered running a bore scope down the intake and watching the injectors for leakage during the "heat soak"?

 

Funny you mention that, I got a buddies bore scope and was planning on doing that today or tomorrow.

And I haven't changed injectors, that must've been someone else.

 

You literally own the car from hell @Fike. Your truck is cursed or something Lol. Run your fuel test tomorrow if you get the time and get back to us on what you found.

 

My truck was also assembled in Hell.

 

Side note: The flaming banana is my favorite emoji on this site.

 

Flaming banana or TACO?

 

At this point I'm hoping it's injectors. At least I will have an answer and can fix it. It just baffles me how it cranks fine when cold

 

Fuse pump Relay? my integra used have that issue during warner weather.
Turn out to be solder connection is crack .

 

So I got the urd fitting and a 1/8 Schrader valve in today. Going to install tomorrow and test fuel pressure.

Also booked my odb gauges back up. I'm keeping a log of every startup, how it performs, and what exact temperature the engine is when starting. Hopefully it will give us an idea of what's going on.

 

I swapped out all of the relays associated with the efi system and fuel pump with other relays in the box. Also resistance tested them. So either all of my relays are bad or that isn't it.

 

So I got the urd fitting on, and have run multiple pressure tests.

First two tests the engine was cold when started, got fuel pressure around 41 psi. Shut off, had a quick drop to around 35 psi, then over 30 minutes slowly dropped to around 22 psi.

Then I ran the truck up to operating temp and shut it off.
Fuel pressure running was 41, dropped to 39 on shutoff, then a slow drop to 22 psi after 30 minutes. I'm currently letting it drop further, going to wait til an hour and recheck pressure.

The Haynes manual states that as long as the pressure is above 21 psi 5 minutes after shutoff, the system is good. Does this sound correct to everyone?

Or possibly I am reading it wrong, and it is saying that the system should always maintain above 21 psi even after 5 minutes?