HELP - New timing belt, starter won't engage with ignition

Hey everyone. Been struggling with this for a few days. Finished changing my timing belt, can turn the engine over by hand, can bypass the starter relay to engage the starter. However, when I turn the key the starter relay does not engage. I've bench tested the relay, and swapped it with the heated mirror relay to prove the relay is good (mirrors get warm). Also worth noting, pretty sure with the key on and starter relay bypassed, the truck should fire up, but it doesn't.

I get 8.5v to the signal pin on the relay socket when I turn the key on, and the same 8.5v when trying to start it.

The battery is fully charged, and I've tried another known good battery.

I've checked all connectors I unplugged while doing the timing belt and they're all well seated. Tried starting in neutral, park, tried working the column a bunch, no luck. I've tried talking to it, tried rubbing it, no luck. Any thoughts or ideas tundra people?


2005 4.7L 4x4 access cab TRD off road

 

Please tell us more details about your truck. What year, engine, drivetrain, cab type. Yes, all four things, because wiring may be different for others.

Just want to see that up at the front of the thread so people know how the truck will be wired, as differences in those four may result in different wiring.

Also, am I misunderstanding? You can get the starter to turn over by jumping pins at the relay, but turning the key won't start it?

https://www.youtube.com/watch?v=0jWouSQYTnU

 

Sorry, added those details. 05', 4.7L 4x4 access cab, TRD OR.


You are correct, I can jump the pins to engage the starter, but turning the key will not engage it.

 

Trying to think through that, electronically.

While we're talking about it, are you 100% positive you reattached the crank position sensor (not camshaft position sensors) AND you routed the way that the serpentine belt won't nick or gouge it?

EDIT to include more info.

Look from above and below at the front of the block to see if any wire looms are nicked or damaged. (link to sample). But also make sure it's plugged in. Big pulley in the pic is the harmonic balancer, if I'm not mistaken, sometimes angles are weird tho.

 

I had the same thought. It has to be something simple. I would retrace my steps thinking about everything I unplugged along with the way.

 

I've just triple checked the crankshaft position sensor, cleaned it up. Rechecked the wire loom, I was pretty careful about routing when I was re assembling. Nothing is nicked, close to the belt, or left unplugged. It has to be something simple for sure, I'm baffled though. Fuses are all good, but the 8.5v to the starter relay is strange.

 

Well, there's always the FSM, for 05-06 find that here. Probably want to start by searching for page: di-928

Read that paragraph, then review the diagram for access cab, and skip to the pages just below the diagram. For each section of the diagnostic flowchart, you can choose "OK" as in 'it works' or "NG" which I always interpret as 'no good'

If all is as you say, you only did the timing belt, all is attached as expected, all cables and grounds tight, and the engine turns over freely when you manually jump the relay (does it start, though?), then I'm stumped also.

 

Did you reinstall the "star plate" correctly between the harmonic balancer, and the shaft? It needs to be flared outwards.

If it's flared inwards, it'll eat your timing belt, and it wont read on the sensor.

 

It goes here, and reads on the sensor on the bottom right.


You can see the sensor just to the right of the crank. You already know, but that's where it lives for future people looking at this thread. I wish I had pics of that plate.

 

This plate.

 

Could possibly be the starter relay on the starter? , maby an intermittent starter?

 

That would suck to need to tear all that back down again because one thing was installed backwards.

The more I see about doing the TB/WP on the 2UZ, the less interesting it becomes.

 

It's not that bad really. More of a challenge than anything else, but I suppose for you the biggest challenge is having the time to do it...

 

Tiiiiiiiiiime ain't on my siiiiiide, no it aint!

Yep. The last part to finish remodel (last pack of ceiling tiles) just got dropped off on the porch. Getting that done now, and each day this week, shelving, storage, data cabinet, bathroom hangers, will come in day by day. Have a big nuclear-level job to finish (months in the making) Saturday, and if it doesn't explode in my face - i.e. all of my preparation and process planning was well-thought-out and flawless - life should return to semi-normal next week, so I can finish the rest of the house shit, get all my stuff packed back up, and maybe get back to wrenching by the 15th-20th. We'll see...

I'd love a nice mechanical challenge, but I hate mysteries like what OP is dealing with. Nothing sucks more than bolting it all together again and it doesn't work.

 

God Damn! Ain't that the fucking truth. Hate that shit.

 

i am having the same issue as well but mine is a little different. heres the link to a thread i have going about it
https://www.tundras.com/threads/2000-tundra-no-crank-no-start.116623/#post-2998454

 

It does not start when I jump the relay which is also concerning. The fuel pump relay does not get power with the key on, nor does it while jumpint the starter relay to get the starter to turn.

Crankshaft sensor plate is on right.

 

The fuel pump relay never gets power with key on. It only receives power when turning the key fully forward, and only with certain considerations.

Fuel pump won't engage unless the fuel pump resistor is working, and won't stay running unless the crankshaft position sensor is valid and showing a reading.

The fact you have two things which revolve around the crankshaft position sensor being intact, plugged in fully, and working correctly makes that a big suspect, eh?

Have you popped off its connector, confirmed the pins look OK, nothing jammed in it, no bullshit like that?

 

At least we don't have to talk about Scissor Gears....

 

I have checked the connector a couple times. About to pull that whole loom apart that goes over the front of the engine. It's the only bit of electronics that were touched during this job.

I was not aware that the crank position sensor was a requirement for starting, thought it would just throw a code. I was going over the wiring diagrams for the starting circuit and it's not on there. Was thinking the park/neutral safety switch would be the culprit as looks like power gets to the starter relay from that and the ECU. I do wonder though if the ECU isn't sending the power it should because it's missing a signal from something else. Is this where the crankshaft position sensor comes in you figure?

 

I'm not sure the CPS is required to start. Ultimately why I posted the link to the FSM and section to start debugging. Haven't been on the forum as much as usual the last couple of days. Swamped at work and at home.

 

Thanks, yeah I'm swamped as well. My son has been home with a fever all week. Got other projects piling up, need this beast out of my shop! I'm poking through the FSM tonight, working my way through each step. Thank you for sending that.

 

I only mentioned the bit about the CPS because the fuel pump won't keep pumping unless the CPS is working, so while it may not be crucial to the cranking process, it is crucial to staying running.

Anyway ... Quick tag to @empty_lord -- I know you're hashing through that BS with the truck that's clipping out randomly. You have any thoughts on this? After timing belt, truck won't crank unless you manually jump the starter, key does nothing. I'm assuming OP checked all fuses etc.

 

I had the truck die out today and it’s doing the same thing… no starter now. Not sure why. Still trying to dig into it as I have time. Maybe a similar issue here? I can manually jump it’s starter but nothing fires even with key on in accessory

 

If when you jump the starter with the key ON, and your engine doesn't start as well, we definitely have similar problems.

 

I actively await a fix! Lol. This is a customer truck in the shop… it’s been a cutting out issue… but now it’s just dead

 

OP I am not an ASE but I have an electronics background. You measured 8.5V at the relay...shouldn't that be 12V? As I look at the circuit, the most obvious culprit would be a bad fuse, or a loose ground. Just me, but I would check the fuse in series, placing the black lead on one side of the fuse and the red lead on the other side, it should measure 0V. Then I would take a reading from the frame to the negative lead of the battery. Like I said, just me and just trying to help.

 

UPDATE:

So I started to tear it apart thinking I'd retrace my steps and find what I messed up. Disconnected that whole front wiring harness with crank position sensor, oil pressure, AC, etc. and tried it, it turned over with the key! By process of elimination, found that the having the left camshaft sensor plugged in is what's preventing it from turning over with the key. The truck will now start, but runs rough for a moment then shuts off. It did initally present engine codes due to the MAF sensor being disconnected still, as well as a P2135 which I believe is tied to the throttle/pedal position sensor but that code is not coming back.

I'm going to start pulling it apart enough to get that left side timing cover off and see if one of the wires is pinched or something.

 

Well I found the problem, pinched and gouged a couple wires for the camshaft sensor while installing the new water pump. Red wire and possibly white wire were grounded to the block. Repaired the wires, reinstalled, truck now runs. Got it up to operating temperature and it runs just fine, no codes, all good. Thanks everyone for your help and suggestions!

 

I would've definitely never guessed that one.