pulling my hair out 1 at a time.

2001 Tundra 4.7L cranks fires but will not run, New Denso starter. 8 new coils denso, injectors test out at 14.5 +- .03 injector, node tests good on all 8. cleaned throttle body. no codes. all fuses good. fuel pressure and pump working. has remote start , cranks but will not run. new toyota map sensor. Battery cables in good condition. will run on spray of starting fluid but then dies. had exhaust disconnected not a clogged cat. scan shows fuel pump working . timing belt was changed but date unknown.

 

While trying to crank, does it turn over smooth, like its supposed to? Too fast? Choppy?

 

Seems like you might have a broken ground somewhere

 

A. will run on spray of starting fluid but then dies.

B. scan shows fuel pump working

My guess would be that B isn't correct or fuel line stoppage. Exact symptoms with my Camry. New fuel pump cured it.

 

Try holding throttle slightly when starting. After cleaning throttle body it may need to relearn for a minute before it will idle on its own.

 

Start with easaiest, move to more invasive things to check.

The ECU requires input from the crankshaft position sensor (which sits at 4 o'clock position behind the crank pulley) in order to keep the fuel pump on. That sensor's harness travels down to that sensor from near the driver timing cover, and IT MUST BE ROUTED BEHIND THE FAN PULLEY BRACKET (like this, notice where it goes behind the metal bracket). If it is not routed correctly behind that bracket, its harness typically starts being rubbed/nicked by belt or pulley, and suddenly the ECU cannot sense anything from the crankshaft position sensor, so it shuts off the fuel pump to prevent fire/disaster. This routing is often something people screw up, they don't route the wire correctly, and suddenly the truck won't run. It's almost always the first thing I ask people to check, after testing with starting fluid of course.

Next I would check: Is the throttle body clean? If you see buildup, get a can of Throttle Body Cleaner and a rag. Disconnect the negative battery cable for 10 minutes, spray the cleaner into a rag (never into the throttle body directly), and wipe all buildup away. Gently lift the throttle plate and clean the edges and around the inside. Don't let the throttle plate slam shut. Reinstall the negative battery cable after - you're removing power so the ECU is forced to re-learn, and it will return to baseline running parameters. If the truck runs after, that's potentially your problem.

Next I would check your fuel lines and vacuum lines. If this problem didn't exist before removing the intake manifold, there's a strong possibility you didn't fully click-together your fuel lines OR you didn't properly reattach some vacuum lines, this may be causing your issue.

Next thing I would check, is to make sure the cam position sensor (which lives under the driver side cam cover) doesn't have exposed/rubbed/shredded wires, and also make sure the wires aren't being pinched under the edge of the water pump.

Let us know what you find.

 

What do you know about the remote start, who installed it and when?

 

https://youtu.be/GCPvmZrOK7I?si=gRHvsz__R-iaVlJw

Im not sure what else you’d expect?

 

Have tried the ECM relearn by jumping 3 and 14 for half hour. vacuum lines are all good. Throttle body has been cleaned. No clue on remote starter. Who installed or when The engine ran ok before the flex plate broke. truck sat for about 6 months. no indication of mice. but will check wiring to crank sensor and cam sensor next. Has a new fuel pump.

 

Broken torque converter? Extra friction? Pretty sure something traumatic cracked that flexplate. ‘99-‘02 were jap drivetrains.

also, i thought touching the positive and negative terminals together to clean out the capacitor or whatever resets the learning? I usually wait a beer or twelve.

 

Test for fuel pressure. Watch to see if it drops suddenly before dying. But yeah ... check that sensor/wiring. And also know, if it's been sitting, these trucks have problems with water intrusion into the in-dash fusebox and ECM which can cause all kinds of weird issues.

 

Remote start is high on my list.

 

Would be helpful to know exact model# of the remote start.

 

checked crank sensor wiring looks to be in good condition no rubs fuel pressure is 38 psi while cranking. still no codes .still not starting cranks over and fires but will not run

 

38psi isn't perfect but should be enough.

More info on the remote start, can you get a picture of the black box under the driver's side of the dash (with its label or part/model number), show a pic of the wiring, see if it'll run when remote start is unplugged?

Any codes logged at this point?

Do you have a cracked windshield, has the windshield been replaced, or do you live in an area with salt, or where the truck stays outdoors parked often? I ask for a reason ... these trucks usually don't have a ton of electrical issues. You checked the crank position sensor wiring (example pic of rub-thru here), and there's also a similar problem with the cam position sensor under the driver side cam cover (example pics here). But I'm asking about windshield stuff because occasionally if water gets into the A-pillar, or around the windshield, water will run down the dash electrical harnesses and either (A) into the ECM behind the glovebox (pics, pics), (B) or the in-dash fusebox (pics & pics & pics). FYI, it happens a LOT. There's a reason we have so many pictures of these examples, we help 1-2 people a year with these exact problems, they're pretty well known to happen.

Usually with the fusebox corrosion, it'll impact multiple circuits. With the ECM rot, well, see the pics, and I think both of those threads will show similar symptoms.

 

still no clue as to what is wrong with not starting fuel pressure is 45 psi when cranking . give it a shot of starting fluid and it starts right up but dies as soon as the shot is used up. have clamped the fuel regulator return line no change. could the crank sensor be bad and not throw a code ? seams to be just not getting any fuel. maybe I should load up my shot gun and put it out of my misery. from what i know the remote was installed at American of Madison long ago.

 

Where are you measuring fuel pressure?

Pull one of the fuel rails, and see if the injectors click with a 9v battery.

 

Before going that far ... sanity check is possible here.

If fuel pressure is up 38-45psi, and not dropping, then it sounds like means the pump is pumping and holding pressure. i.e. the pressure is there, but if the injectors aren't firing, or aren't being told to fire.

That lends to two things:

• The inline fuse that protects the injectors has popped, and you think it's not blown for some reason; I'd need to dig into the wiring diagrams, but I thought that was the EFI-1 fuse under the hood, and I thought it fed power to the MAF and injectors but I can't remember.
• The ECU isn't sending pulses to the injectors to have them fire, either because the ECU is faulty, or some other reason.

If I were you, I'd get a fuel injector pulse test kit / NOID kit. They sell them pretty cheap @ various big box stores and probably loan them out too. Here's one example.

A kit like that will at least allow you to confirm if the injectors are getting power pulses to fire off. Basically, fuel pump pushes fuel to the rail/injectors, and ECU is responsible to light up the injector with power for a sec and spray, then the ECU is responsible to time the spark. You make it sound like you're getting fuel, high enough PSI, but for some reason, the injectors aren't opening to spray fuel into the cylinder.

Even if you know the injectors aren't firing, it doesn't fully answer the question, "WHY?!", but it at least gets you one step closer to understanding the problem at hand.

I echo a lot of what folks said above about alarms/Remote Start. I know from professional experience, a lot of aftermarket alarms aren't designed to last, and we'd expect a lifespan of 10-15 years at the shop I used to work at.

In your shoes, I'd have this nagging feeling it could potentially be responsible, and there will be a brain box for that thing, somewhere, likely up under the box. They're typically black in color, and usually not bigger than 3" x 3" square and an inch or so thick. Almost all of them have writing embossed on them or otherwise. If you can get us a part number, a model number, anything that would help us search the interwebs to figure out which unit it is, we can at least figure out if the alarm/remote start unit is intercepting the fuel pump wire as it passes thru the cab (it does pass thru the cab, btw, so this is a reasonable thought).

But the one thing that doesn't make sense is: Sounds like you're saying fuel pressure is staying up, which would suggest what I said before and @Sirfive is also saying, fuel isn't getting into the cylinders. If the pressure on the fuel rail is up, and doesn't go down, but the engine only runs when you add a combustible into the engine manually, then the injectors must not be spraying?

 

Is it possible that the fuel pressure damper may have failed in such way that no fuel can pass by it?

 

Are we doing a poll yet? I've tried reading as much of this as possible (my eyes kept getting crossed) but it sounds like the injectors are firing up

 

I doubt the injectors are firing. Something is not telling them to fire. The short list is:
Remote start system
Temperature sensor 1 or 2
Cam position sensor
Fuel rail dampner
Fuel resistor
Injector system fuse??

 

A simple circuit tester, verify if there's current at the injectors. If you get nothing then I would be looking for the fuse or relay.

 

Have you tried using a jumper cable to be sure you have a good ground from chassis to block? Haven't looked at diagrams, but it's easy, free, and quick to test.

 

"What do you know about the remote start, who installed it and when"

"Remote start is high on my list."

"Would be helpful to know exact model# of the remote start."

"More info on the remote start, can you get a picture of the black box under the driver's side of the dash (with its label or part/model number), show a pic of the wiring, see if it'll run when remote start is unplugged?

"I doubt the injectors are firing. Something is not telling them to fire. The short list is:
Remote start system"

Before going that route @racer27 , how about doing yourself and those wishing to help you, find that damn remote start and provide info requested.
There's a good chance those asking about this are on to something.