Brain's broken

So I have a 2002 tacoma that I've posted questions about and I'm completely lost now. It's a 3.4. So the truck is acting like a leaking injector. Has a hard time starting and just cranks and cranks until it finally starts but it sounds weak, but once its running its great. Ive replaced injectors twice since November just to make 100% sure and have bore scoped through the plugs and I'm not getting any fuel on there after i shut it off. When it finally does start my fuel pressure is at 42 psi. Shut it down it holds at 38-40 for a long time but I went up to the dentist for a hour and when I came back the pressure had dropped to 0. So what the heck would it be that it holds fuel pressure for 30 minutes but then does eventually drop to 0? I'm about ready to take the truck to the crusher

 

Nooooo. Enough were already crushed.
Do you think it may be the pump? They can act like just about anything else is wrong.
So it starts easily after 10-15 minutes but after an hour it takes...how long?

 

Yeah so once I get it running if I try it after 10 minutes starts right up. After an hour or 2 it takes 45 seconds of cranking . I'm timing it right now after 30 minutes it has dropped 10 psi. From 40 psi to 30 psi now.

 

Have you replaced the fuel pump and filter, or just focused on the injectors?

 

I replace the fuel pump in 2020, have replaced the filter in the last 6 months. Fuel regulator I don't think has ever been replaced but im not leaking any fuel from it when I pull the vacuum line. I'm at 35 minutes now and down to 24 psi at the rail.

 

Sounds like a bad fuel line check valve in the pump. The check valve is supposed to hold fuel in the line when off so when you go to start you have fuel at the injectors ready to go. If the valve leaks, it allows the fuel to drain out of the fuel line back to the tank, meaning the pump must now refill the line before it can make it to the injectors. If the truck hasn’t been off long, most the fuel may remain in the line, the longer it is off the more fuel has drained out and the longer the start process. I had this issue with a performance aftermarket pump on my 2nd Gen. I just installed an external fuel line check valve on the rubber fuel line right before the hardline near the tank. Problem solved.

 

This is what I'm leaning towards also it just had me confused that the pressure doesn't move for over 10 minutes then finally starts dropping slow. I figured with a check valve it would drop off as soon as you shut it down

 

Mine didn’t. If you recently replaced the pump, I’d just add an external check valve. Easy and inexpensive.

 

Awesome thanks I'll try that!

 

See post #6070 for what I did on my 2nd Gen. I bought a USA made valve, you can certainly find less expensive ones.
https://www.tacomaworld.com/threads...tricks-and-mods.518932/page-304#post-18416972

 

Basically at an 1 hour and 20 min fuel psi at the rail was at 10 psi. I bumped the key and it shot right up to 42 psi then I cranked and cranked for 30 seconds until I pushed the pedal down a little and fired up.

 

I have a new thing I noticed. So when I get the truck started from cold, if I shut it down fuel pressure then at 42 psi and i try to re start it before the temp gauge is up to temp it hard starts everytime.

Now I get it started up, let it warm up to running temp and shut it off it starts right up every time.

So even when it hard starts it is showing 42 psi at the rail. Truck isn't throwing any codes at all.

 

Sounds like possibly multiple issues then. I’d start by cleaning the MAF as a dirty one can cause hard starts and wouldn’t throw a CEL.

 

Is it firing when its hard to start?

 

It eventually does but it sounds weak as it starts. Once it's warm shut it off, start it right back up it sounds just like a normal start.

 

I have replaced the MAF, injectors, spark plugs, wires, ignition coils, IAC, throttle body, intake manifold gaskets, pcv, all the vacuum lines. I honestly hate this truck at this point me and the local mechanic have been trying to figure it out since November. But without it throwing any codes or anything we are about done and I'm just throwing money away it seems like haha

 

What about the ECT (Engine Coolant Temp) sensor? If failed on a hot reading it would make cold starts hard and hot starts easy. It should throw a CEL though, and might affect the temp gauge, so it isn’t a sure thing.

 

I decided to just order one and try it. $33.00 is a hell of alot cheaper than some of the other stuff I've tried so why not haha

 

Might be lucky! I just came down. Truck cold and hard start shut it off try again hard start, try again hard start. I unplugged the coolant sensor. Starts up great. Fingers crossed when the new one gets here thats the problem

 

90% sure its the problem! I plugged it back in hard start, unplugged it started right up!!!