Crank no start. Ignition Coil Resistance?

Trying to get my truck to start.

I cannot find the resistance spec for ignition coils on the 2UZ. I have one ignition coil that is non - oem, all the others are original denso. I checked the resistance of them all but I don't know what they are supposed to be.

- 5 of the denso test with 345 ohms at pins 1-2, and 2100 ohms at pins 1-4
- The other 2 denso test 345 ohms at 1-2, but then 4779 ohms at 1-4.
- The non-oem coil tests way off from all the denso- Pins 1-2: 380ohms Pins 1-4: 0L

I know I need to replace the non-oem, but I don't know about the denso ones. Anyone know the proper specs?? None of the coils have cracks.
I'm going to try the starter fluid in the intake tomorrow too

Also is rock auto going out of business?? Haven't been able to access their website for a while, which is unfortunate considering they have coils for $50 and everyone else charges $80.

 

Try clearing all your cookies and see if you can access the RockAuto website. That has worked for me in the past. I can log onto RA - no prob.

 

Unlike the Tundra 5VZ ignition coil that has primary and secondary coils to check for resistance, the 2UZ uses COP(coil on plug) design and the ignition module (transistor) is integrated on top of the coil, so you don't have a coil negative wire to attach to, meaning you can't measure the coil's resistance.

Good decision on replacing the non-OEM one.

 

Can’t help with specs but I can help by saying this.

One bad coil doesn’t prevent a truck from starting or running.

Two coils rarely fail at the same time, suddenly.

Cracks in the coils don’t cause misfires (but cracked or missing boots will).

You need to test for spark before you dig deeper. Starting fluid is your friend, as are spark testers. Both are cheaply purchased at the local auto parts store.

 

Ahhh interesting, good to know.

Thank you guys! At this point I have:
- Brand new camshaft sensor (Wires were fraying on the old one, thought for sure it was my problem)
- Cleaned off crank sensor, 2100 ohms (in spec)
- Clean maf, throttle body, air filter
- I can hear the fuel pump when key is on. I could smell fuel at one point when the engine was stumbling. Now its back to just cranking
- Cleaned battery terminals, battery has 12.4+ volts and 11 volts while cranking.
- Bad gas shouldn't be the problem, I was about 75 miles into a fresh tank.

I'm gonna verify for spark soon, and will update.

I did at one point get a P1126, but I believe that was because I left a sensor disconnected on accident. I will also rescan for that. I cannot find a single mention of it in the FSM.

 

P1126 is the throttle body circuit, if you unplugged the (4-pin?) harness on the (passenger side?) of the throttle body assembly, it would've done that, IIRC.

I'll ask it:

1. Did you pull the negative battery cable for 10mins after all those steps to reset the ECU and force relearn?
2. Did you try slapping the gas tank a few times to cause vibrations before attempting to start, just to ensure it doesn't fire up (failing fuel pump will often give another start or two with some tank slaps)?
3. Any prior work (engine swap or harness swap or similar) we should know about?
4. Any new codes to know about?

​

 

Just reinforcing what shifty' said. Check the basics first before loading up the parts cannon.
And maybe some specifics on the symptoms? Is it just cranking and no ignition at any cylinders at all? Does it start to run but not keep going?

 

Sprayed some starting fluid in there and she fired right up and then promptly died less than a second later!!

I unplugged one on the driver side, anyway the code is gone now.
1. Yes, I have had the battery completely out twice now to recondition and charge it.
2. Yes, no change.
3. None that I know of, but I wouldn't know. Bought the truck last year. Wouldn't be surprised if there was. Cylinder 3 (Non-oem coil one) has been re-tapped and uses a different spark plug.
4. No codes at all today. Did have a P0420 for a week or two before this.

Yeah, so I drove it 20 minutes to cal ranch and then it decided it wanted to stay there, was stumbling and trying to fire at first but eventually just cranking with no firing at all. Replaced my cam pos. sensor since the wiring had been chewed up. Still didn't start, but at first it did stumble, but now it is back to just cranking.
As far as basics go, I think fuses are the only big one left.

What steps now? The starting fluid means the issue is fuel correct, usually wiring related?

 

I'd try starting fluid now. Just to figure out if fuel delivery is your primary issue.

I'd be checking (at minimum) the EFI1 fuse under the hood.

I'd be checking the crankposition harness is correctly routed, behind its bracket, correct routing info here. And I'd be checking its harness (trace up from the sensor at ~4 o'clock from the big crank pulley) to be sure it's not damaged.

Starting fluid should tell you really quickly if this is a fuel delivery issue or not. And if it's a fuel delivery issue, the 2nd and 3rd things I recommended to try could both be reasons why.

Bad plug/poorly seated plug/bad coil on cylinder 3 won't cause no-run. Chances are this engine will continue running (albeit poorly) with 2, maybe even 3 cylinders having issues. You shouldn't run it in that shape, but ...

You need three things for a combustion engine to run: Air delivery, fuel delivery, spark delivery. If any of the three are missing, no fire for you. With EFI/Electronic Fuel Injected combustion engines, that upgrades to:

• Properly metered air (i.e. MAF and throttle body position, sometimes IAT and MAP sensor)
• Properly timed spark (i.e. plugs, coils are good and ECU is signaling fire in sequence, timing belt OK, timing is good)
• At least 35-40psi fuel delivery will get you firing consistently (i.e. fuel pump is working, fuel pump relay is firing and fuses good, all fuel lines are tightly together, each bank's fuel pressure regulators are working, fuel damper and vacuum to fuel damper are good, and in our case, the crank position sensor is good and its wire harness isn't nicked/damaged by a pulley/belt)
• ECU isn't totally fucked.

We've seen a wild variation in what's caused no start situations. Like, in older trucks, if the green-top coolant temp sensor (passenger side of throttle body) is shorted and reporting the engine is overheating, engine won't fire off. I originally thought this was because the sensor was broken or disco'd, but it's still really not clear to me.

tl;dr - anything you can due to rule out those four items is in your best interest. Clearly, if you spray a 2-3 second shot of starting fluid back behind the throttle plate, and it fires up, you know exactly which of those four bullets is [likely] the problem, and you know where to focus your attention.

All diagnostics, ultimately, is just as much trying to figure out which one it could be, just as much as whittling away what it couldn't be. In other words, if there are 4 branches of things it could be, and you can immediately remove 3 branches with one test, DO IT, and you've just made your major pool of suspects by 75%, and know where to be focusing your attention. Although it's worth noting ... ECU is the overlord of signaling the fuel pump relay, so absence of fuel delivery doesn't rule it out as a potential culprit.

 

Yes, I did the starting fluid and it fired right up and then died. Which means my issue is the fuel delivery. I did try banging on the gas tank to no avail. Is the next step to get a fuel pressure tester?

I did check the EF1 fuse and it looked good.
I tried starting it with my foot on the gas and that didn't do anything.
I will check that coolant sensor too next time.

 

If you are meaning key is in the IGN ON position, whatever you're hearing isn't the fuel pump.

Adding to what @Shifty said, we have to be cranking for fuel pump relay to energize. The smelling of fuel would be something to look further into also. I would consider checking fuel pressure if you're equipped to do that.

from Toyota Techinical Training....

• Engine start: During cranking, current from the ignition switch to the starter relay (ST) coil turns the relay ON. Current also flows from the ignition switch to the STA terminal of the ECM. When the STA signal and the crankshaft position signal (NE) are input to the ECM, Tr is turned ON, current travels through the coil of the circuit opening relay (C/OPN), the relay switches ON, power is supplied to the fuel pump and the pump operates.

Definitely re-check for that code and accuracy of your scanner because the 2UZ(V8) does not utilize a magnetic clutch but you would find that code in a 5VZ(V6)

 

Yes I saw that in the FSM and was puzzled. I did rescan for it and it was gone.
What do I do from here? Fuel pressure tester kit?

If the timing (crank position sensor) were bad, it would then not be operating the fuel pump so there would be no pressure?
And if I were to get pressure then something is causing the injectors not to fire right?
Sorry guys, just haven't dealt with this stuff before.

 

Perhaps I am doing it wrong but I am getting no fuel pressure at all.
i may have broken the fuel pump relay trying to check on it so will be replacing that.

I am now worried that the wiring fix I did on the harness that connects to the cam position sensor is still bad.

truck is trying a little harder to fire, not much but it’s intermittently trying stumbling not just cranking.

 

What method and at what location are you checking pressure ?

As for the relay, it's somewhat of a multi-purpose relay. If you have an Advanced Auto close by, they have the same type 12vdc 20A 5 prong relay type relay you could use in a pinch until you can order a Denso OE or get from Dealer after Holiday.

 

I ended up doing it the way he does it in this video, at the fuel line dampener https://www.youtube.com/watch?v=QEsuSWjMW88
When I took the dampener out there was a decent amount of fuel that wanted to come out. but when I took the tester out, it was dry.

I find it interesting that I could smell gas one time when the engine was stumbling.

 

I'm gonna grab this one from napa https://www.napaonline.com/en/p/ECHAR485
What things can cause the no fuel pressure?

 

Before purchasing try jumping that circuit