1st gen mucho problemo (Solved)

Hello any help would be much appreciated.
2006 tundra 4.7l double cab 2wd. Problem started while driving as it stalled, a couple of times. Happened about 4 times that week. Then it stalled otw to work and wouldn't start up again. Next day and ever since (almost three weeks) I been tinkering in my off time and it starts up every time but immediately stalls.

Check engine light is on. Code c1241. Low voltage (abs systems).
Replaced battery. Still on but shouldnt keep from running, so I moved on.
Further inspection I have spark when I turn the key and it starts right up but then stops sending spark. At all plugs on driver side. I checked 1 by 1, all the same. Didn't see a need to check other side as this seems to be my problem.
Checked all fuses (ALL) multiple times as well as relays. So I pulled out the volt meter.
Key on 12v at everything as it should be.
Cranking over right around 8v to the few relays I tested. (Cp/open, efi, fuel pump) I forgot to test main will do tomorrow, and 8v at starter relay while key turned not cranking over. This is too low I believe but I am by no means electrically inclined.

If anyone has any insight to this pls share.

 

Did you reset the code? did it come back?

i think these trucks prefer to have over 12v while running. Is the alt pitting out 14+v?

 

I erased it before battery swap. Came back on right after. I would have to pull the alternator to test because the truck won't run for longer than half a second or so. But it should run off the battery as most other vehicles would. Or is toyota different in that aspect?

I would kick myself in the ass but would love for just the alt. To be the problem

 

Any corrosion on the battery cables?

 

None. And I checked the grounds (ones I could find) seems like a bad electrical draw to me. Bad ground or short in wiring maybe. But to everything? Enough to stall the truck everytime. Doesn't seem right but I'm not totally sure.

 

Sounds like a classic case of the crank position sensor wiring getting clipped by the serpentine belt. You have your timing belt changed in recent history?

Have you checked the crank position wiring from underneath the truck, around the middle of the block, to make sure it's not nicked thru?

 

No probably about time for new timing belt. Previous owner did it when he got the truck at 125,000 or so.

I have not went into any sensors or thier wiring specifically. Wouldn't it throw a code for crank sensor?

 

Potentially, yes. But not until it wasn't actually responding. Others here who had it happen gradually didn't throw codes either.

 

10-4 will give the wires a rundown in the morning. Any other sensors potentially cut spark if shorted? Also is the voltage drop normal normal in this case?

 

Yes, this guy is having similar issue it sounds like, and I posted a lot of V8-specific info in my reply to him here: https://www.tundras.com/threads/good-afternoon-i-am-1984-toyota-master-tech-i-have-my-youngest-son’s-2001-v6-2wd-toyota-tundra.127848/#post-3263534

Unfortunately, he has the older version of V6 and my knowledge is pretty limited to the 2UZ because it's what I have and therefore what I dig on.

 

Yeah I've went back to other threads I've previously been skipping. Due to most of them turned out to be crank sensor and I assumed there would be a code. And I've found a lot of info that should help me.

 

The crank wiring goes behind the water pump and into the timing cover? Is that correct there's no way for serp. belt to make contact but maybe timing belt. Imma pull apart and look just need to know where to put it when I throw it back together.


Not water pump runs behind bracket on a/c compressor

 

Next update.
Wires to the crank, cam, temp, sensors all intact.

 

It's been a minute as I've been busy. But ive since been through the whole truck top to bottom, front to back. Finally broke down and had someone else look at it. Local mechanic fellow I used to work for. And he tells me he is 100% sure the key is chipped and it's not reading. Reason for it starting and immediately cutting off. Must it be takin to dealership or should they be able to just cut me a new one and program it off the vin??

Also I've found mixed answers on here as to weather or not any of the 1st gens actually have chipped keys or not. Some say no way. Some say only 2006 DC. Which is what I have.

 

Only double cabs have chipped keys - and not always. I believe all Sequoia in the later years have chipped keys, the DC and Sequoia are practically siblings, while the access (AC) and reg. cab (RC) are pretty markedly different (though siblings to each other). I have an AC, so I often just gloss over no-start situations where someone says it runs for a sec and dies. That's classic immobi behavior, and/or classic faulty aftermarket alarm behavior. Hindsight is 20/20.

What the mechanic says is valid. Dealership will normally cut replacement keys if you have proof of ownership and the VIN handy. I don't know how it works with immobi'd keys, so I'll be interested to hear what they say. Parts dept may be able to tell you. Curious if they can program the immobilizer info into the key at creation, or if it's unique to the key and they'll need to use TechStream to write the key ID into the truck.

 

Thats handy info bout the DC and sequoia. I'll call the local Toyota dealer on Monday I'll update later for the future problem solvers. Because this has surely been a headache. Shoulda kept my old c1500s lol.

 

^ this.

 

My 2006 DC Limited key does not have a transponder or chip. Just a plain key you can get cut at lowes or walmart.

Sequoia started having transponder keys in 2001.

Look at this website showing key and type for the Tundra by year or post a pic of your key

https://lost-car-keys-replacement.com/toyota/tundra/

 

We've had quite a few DC owners confirm having immobi keys. It's not universal, though, and they seem to be in the minority. I haven't been able to find enough of them to figure out what the common option/trim level is that defines whether a DC would have it or not.

Definitely haven't seen any AC or RC owners with immobi.

 

Transponder was not the problem. Did some research and the chip reader would have been on the backside of the light ring on the lock cylinder. Pulled it off. No reader means no transponder chip. Back to square one.

 

Are you 100% positive there isn't and wasn't ever an aftermarket alarm installed?

Have you verified fuel pressure?

 

I haven't found any thing that looks like such. And good fuel pressure round 43 psi while cranking over.

Maybe ecu. I've checked everything else. Literally everything.

 

Maybe if I beat it with a stick.

 

If we are to believe the 2006 "New Features" section of the FSM and the "Engine immobilizer system" section of the Owners manual, immobilizer was available in Canada models only.

 

Idk man I'm out of ideas. I've never tinkered with ecm and I don't know how to troubleshoot it. But that's my last stop with this thing.

 

So, you cleaned out the grounds & made sure your cables dont have too much resistance? Ya'll been getting rain recently?

 

I went as far as to pull the intake manifold to check wires and grounds underneath it. All good and clean. Also testers injectors while torn apart. All working. Replaced gaskets and o ring put back together. No change.
I've put my hands on everything in this truck damn near.

 

And you're positive there's no issue with the crank position sensor? That would stop the fuel pump from running.
Check the fuel relay? Bypass the fuel resistor?
Did you test the coolant sensor the ECU uses? (Two next to intake, passenger side, I think it's the green-topped one)

Have you seen the documentation on how the fuel/spark system works, so you understand what would allow the truck to (or stop it from) running?

 

Checked all of above.
Bottom line is after it starts. (Tries) it loses all spark. Not fuel. At every cylinder. Definitely not cam or crank sensor related. As I've switched them all out with new ones (all 4) for a hefty sum. I've since put old back on and returned new ones tho.

 

Well, ECU could be the issue. But there are other things that'll cause loss of spark. Have you been through the FSM yet to diagnose that?

If you look at your ECU behind the glovebox, get the part number off it - it'll be in format XXXXX-XXXXX for the part number, all alpha-numeric. First 5 digits are usually numbers, last 5 a mix of letter/number. Check in with www.fs1inc.com if you want to buy a replacement, they'll have one, refurb'd, tested, and usually at a fair price. Worst case scenario you could re-sell yours, but ... I think it qualifies as 'throwing parts at the problem'.