Crank no start

Hey guys I’m new to this forum recently came from a first gen Tacoma but no I have a 03 ac with the 4.7 and I’m having a crank no start issue. What I do know as of right now is that fuel pump is not coming on when I start to crank,and these past 2 days I’ve changed fuel pump and strainer filter attached to fuel pump, fuel filter, air filter, cleaned maf and throttle body, changed efi,c/opn and fuel pump relay, efi 1&2 fuses are good checked that power if going to both points of fuse and also changed crank position sensor. Now my question is, where do I go from here? I’ve been going over and over tests and wiring diagrams and this has got me stumbled so plz any advice would be helpful

 

If fuel pump is not engaging when cranking check your crank position sensor. Sensor could be bad or wiring could be damaged from not being secured correctly after timing belt change. If the sensor doesn't work fuel pump may not run.

 

When checking wiring what am I looking for as in test wise other than messed up wires

 

Easy quick test would be hook up a scan tool and see if any codes pop up. Let me do some looking and see if I can find any pics on here I don't have any personally.

 

Yup that’s the first thing I did with our shops snap on zues scanner and nothing popped up other than my airbag codes

 

https://www.tundras.com/threads/wha...t-gen-tundra-today.2558/page-721#post-1881283

https://www.tundras.com/threads/2000-tundra-fuel-problem.89500/#post-2251059

Here's a couple

You can search using the search button and click more at the bottom and change it to first gen only an search around yourself too.

Here's a link just to my search

https://www.tundras.com/search/5542824/?q=Crank+sensor+wiring&o=relevance&c[node]=2

 

Sounds like you hit all the big stuff, except maybe the fuel pressure regulator, and you should really throw gauges on the fuel line to check for pressure on the lines as you work through this. Oh, and ... It's never the fuel filter. Like, never, ever.

Some debug tips -

You can jumper to bypass the c/opn (resistor) and force the fuel pump into always-high mode.

You can pull out the fuel pump relay and jumper power directly to the correct pin to light up the fuel pump 24/7, then test for voltage at the pump to see if there's a wire break to the pump, since mice love to chew the wires (you'd have seen when you swapped the pump). This will force the pump on, then start, does it run?

But really, I'm leaning on damaged wiring, i.e. a pulley gouge, at the crank pos sensor.

Some people have also hooked a 12v battery pack up to the fuel pump directly, just to have it run all the time.

 

I’ve been going back and forth on checking fuel pressures but the truck has ran before it has just been an intermittent crank no start issue. When I switched the fuel pump it worked drove it home maybe like a 20 minute drive then following morning it started then made it 100ft from my house then it died

 

When you jump the fuel pump is it supposed to come on with engine of key on or is it only supposed to come on when you crank? Cause I also tried that but j couldn’t here the pump coming on in both scenarios cranking and key on

 

Trying to start with starting fluid can be a good way of testing if fuel delivery is the issue. If it turns over and stumbles with ether/starting fluid, that's a pretty good sign you may have a fuel delivery issue, but doesn't always work on computer controlled EFI vehicles.

First things first, standard operation, from my failing memory, based on the fuel pump circuit info in the FSM: Fuel pump won't turn on until you turn the key all the way forward to crank the truck and the starter begins turning. It doesn't start running (pre-prime) just because the key is at ACC or ON position, only crank/START. From that point, the fuel pump doesn't stay on unless the crank position sensor registers that the engine is running. This is really dumbed-down, and is just explaining the electrical side.

As for what happens to the fuel pump when jumpered, you can answer this question yourself by popping out the fuel pump relay, and checking the power line you're jumpering. Is it hot with the key OFF? If so, and you jumper it, the fuel pump will thus be on, and jumpering it should produce an audible sound when the fuel pump pressurizes the line.

But really, if you don't have a fuel pressure gauge on the fuel line to monitor whether you're getting fuel pressure, what's the point? You're punching in the dark. You need to be able to see if you're getting fuel pressure to the rail. The money you've spent throwing parts at the problem is 10x what you'd have paid for Toyota's fuel pressure diagnostic tool.

I'm going to share a video with you to rule out the fuel pump as the culprit and give you some more troubleshooting steps you can do, but again, get a fuel pressure gauge. Make sure you're getting at least 35-40psi up to the regulator, and at least (28? 32? I forget) after the regulator, in case the fuel pressure regulator is your culprit.

DICSLIAMER: This person says "fuel pump should turn on when the key is in ON position", which is WRONG, per Toyota's FSM. The video will help you with testing some scenarios and better explain the fuel system to you. If you jumper the pump and don't hear shit, you need to be checking your power wire between the relay and pump for continuity. I also recommend checking THIS REPLY for the fuel pump circuit and other diagrams.

https://www.youtube.com/watch?v=VoerlgT8pck
​

 

So I wasn’t able to get the pressure tester tool but I for sure know that fuel pump is coming on cause I pulled the feed line and nothing is coming out
And also if I supply 12v via power probe pump comes on and pumps fuel now my question is where is the ground related to the fuel pump cause i know I’m getting 12v to it when cranking but not really sure how to check grounds other then checking for breaks or just cleaning them

 

This should help trace wiring: https://www.tundras.com/threads/ultimate-tundra-wiring-diagrams-collection.81448/

 

Hey guys I just wanted to let you know what the problem ended up being so this will hopefully help someone in the future but it ended up being the ground to the fuel pump,the way I went about it was at first I threw parts at it like a stupid person would I changed fuel filter,fuel pump twice ,ckp sensor and all relays then after those didn’t work I went the smarter route and started to run test and eventually we found out the the fuel pump wasn’t getting ground,the way we did that was we power probed power wire to fuel pump and found out had 12v running all the way through the to the ground wire then we checked for continuity and the ground circuit ended up showing OL so the way we went about it was we ended up cutting ground wire closed to the fuel pump and grounding it to the frame. But I hope this will help someone in the future whenever the time comes and thanks everyone for the help

 

And where is this ground wire to fuel pump at ?

 

It’s a white and black wire that comes out of the harness that grounds to the inside of the cab by the left lower kick panel, so instead of chasing the wire I just cut the wire as close as I can to the tank and grounded it to the frame.

 

Thanks for replying so quickly I swapped the engine off another truck that was running fine and I can’t get it to fire up due to no fuel in the rail . I don’t here the pump running at start up

 

Having this same problem … I appreciate all the information here. Thanks !

 

Let me know if you need any other help cause I had another problem come up and it was completely different problem that didn’t turn the fuel pump on

 

So far we replaced the fuel pump and a couple
relay switches. It’s been 2 weeks with no further issues.