Ask the Toyota mechanic!

Highly doubt it's O2 sensors. The Toyota O2s are very reliable plus you say it's at a specific rpm. You also mentioned it happens at a certain speed? If the surge happens at a certain speed them it's drivetrain related such as transmission, driveshaft, diff or wheels and tires. The motor doesn't care how fast it's going. If it's rpm specific then it's motor related. Your going to have to narrow down which. What is the specific rpm it starts surging? When it starts does different throttle input change the surge? What speed does it happen and does manually shifting the trans change anything?

 

its a slight hesitation and recovery that repeats itself from about 2100 rpms to 3k rpms.
i had a 2jz engine that acted in a similar manner that was fixed by using a new MAF.... but didnt help this one.

 

How do I add this thread to my watch list without posting? I know this post will add it but I have other threads I want to watch but don't really have anything to add to the conversation.

 

CLICK WATCH TREAD TOP RIGHT OF POST

 

Hi all, this is great.. @LOTSOFTOYS I bought my dcsr brand new in 2017, is a daily driver, during this quarantine I have gone two weeks without driving it and the battery keeps dying. I unplugged the + and plugged back in and I'm getting a spark, even if I unplug it and touch it + remove it, touch it as fast as I can do it, I get a spark everytime. This is normal or is that a bit excessive drainage, I replaced the radio, three years ago, I did it myself, I been working in cardio and in electronics for over 25 years. Do you know what the voltage drainage should be when everything is off? or what the load is when everything is off?

 

I would think the only thing pulling amperage would be the alarm, but I could be wrong.

 

This has happened to me as well. I suspect that the biggest draw is the evaporative system that deals with gasoline vapor. The fix is a trickle charger.

 

Supposely my truck does not have an alarm, I do have keyfob and the security light on the dash. however when I lowered my windows, lock the truck, stick my hands in and open the door from the inside, hothing happens.

 

A slight spark is normal when contacting the battery back up. Do you have a way to measure the current flow from the battery. You will need a multimeter that can read up to 15A. You need to hook it in series with the ground terminal on the battery and the ground wire. You have to use a jumper wire in series along side the multimeter. Everything in the truck has to be off and the key has to be out of the vehicle. If you have smart key the fob has to be away from the truck so the key is not detected. Once your all set up you have to wait for the truck to become "quiet", when the ecu's are sleeping. Could take up to 30 min. Remove only the jumper you have installed and read the amps on the multi meter. The reading should be under .05A. If its higher you can start pulling fuses from the under hood fuse box to determain the circuit causing the problem.

I'm assuming your battery is still in good condition? If you are storing your vehicle for a long period of time you can pull the "short pin" fuse. This forces modules off

 

Quite a few Tundra never came with an alarm. My 2020 SR5 doesn't. An easy way to tell is to look for a hood switch at the latch. No switch, no alarm. To add an alarm you have to buy the module and Toyota does sell a kit.

 

My 13 said no alarm, but when I got techstream it had an option to activate alarm. I said yes and I had an alarm. Might be different now.

 

Do you have a hood switch?

Check out this link for the module kit that's required for the alarm. Notice is says 2014-2020.

https://parts.toyota.com/p/Toyota_2018_Tundra/Security-System/69524457/PT39834142.html

 

IDK about the hood switch. I changed the settings and opened the door from the outside with the window open. The alarm didn't go off before I changed it, but it did after.

 

I have a 2020 Tundra that has several codes that I personally caused. I caused the codes by performing function checks with my scanner. All of the codes were listed as "History" and "Current" on my Autel MS906 scanner. The current codes have been corrected and erased but the history codes still remain. Is there a way to delete the history codes? I attached an image which lists the codes in question. Thank you!

 

2020 Tundra SR5 4x4. 2k miles

When I turn on the car from cold start, like been sitting over night cold, and the AC is turned on there is a crunching sound for a short amount of time. When the AC is not turned on there is no crunch sound. I took it to the dealership, they let it sit over night and could not reproduce the sound. Should I be worried? I tried to get it caught on video but you can't hear it.

 

I actually have the same truck and mine's quiet. If you start the truck first with the ac off then immediately push the AC on does it make the noise? Will it do it every time after it first starts?

 

Is the crunching sound coming from under the dash, or under the hood?

 

Disregard my question about the History codes. I figured it out!

 

SR's from South East Toyota don't even have the wires where the module plugs in, if someone could post a pic of the alarm module, I would be more than happy to take my dash apart and look.

 

Sorry for the delay, I had to test it. It definitely sounds like it's coming from under the steering wheel and I can turn the truck on and not hear anything but when I later go to turn on the fan/ac I hear the crunch sound.

 

Hey Ruggybuggy, I can turn the truck on and not hear anything but when I later go to turn on the fan/ac I hear the crunch sound. It only happens when the truck has been sitting for awhile and happens Everytime it's started cold.

 

I not following. You first start the truck and its quiet but later on it makes a noise?

When you first start the truck (cold) with the ac in the off position and the "floor" setting selected does it make a noise. While it's running does it make a noise if you turn the AC on?

 

Have you started the truck from COLD, raise the hood, have someone else in the cab while you are looking at he engine with the hood up, then have the person INSIDE the cab, HIT the AC button?...All this to try and determine where the sound is coming from?

 

There's a bunch of threads about this, and so far the consensus is that its the AC/Compressor and there's probably nothing to worry about. My 19 does it occasionally too. Definitely annoying though.

https://www.tundras.com/threads/a-c-clunk.28798/#post-1710144

 

2007 Tundra dc sr5 4x4
I removed the rear, and passenger seats to lay down sound deadner, but still have to drive it like this for a few weeks. I notice with the passenger seat out the airbag dash light is on, and the passenger seat light under the radio flashes now. Will this affect the other airbags, because I m thinking about leaving it like this?

 

2007 Tundra DC SR5 4x4 - fuel pump or ECM issue...

Had a lose of power on acceleration, truck would start, but idle rough and die, now no start. Figured it was the fuel pump since I was getting voltage to the connector, however it's only 10.5v; also getting 10.5v from the fuel pump side of the fuel pump ECM. Fuel pump doesn't come on with key on, however if I jump the ground wire on the pump to ground, it kicks on. Also, i get a 12v reading from the hot side of the pump connector to ground. Is this a bad fuel pump ECM or something else perhaps. Any help is appreciated.

 

It's not the fuel pump. They are very reliable. The older Tundra had a problem with the wiring harness that ran from the fuel pump driver module to the fuel pump. The module is located on the driver's side frame above the rear axle. Your going to have to remove the harness from the pump to the module and inspect. You will find some corroded wires that will need repair. I didn't see your location but the areas that use road salt causes the problem.

 

I know the harness you are referring to, between the ECM and the pump. Forgot to mention I replaced that pump about 18 months ago with an aftermarket one... not OEM. So 10.5v should be enough to run the pump; that isn't an issue? Is that the correct voltage coming out of the FP ECM? If so, I'm getting that reading at the ECM and also at the connector for the pump, so not sure what the corrosion would be affecting. The truck is from Philadelphia, but I'm in Georgia, so yea, there is a lot of salt corrosion under there. I'll inspect the wires and see. Thanks for the advice.

 

The voltage is pulse width modulation so the voltage on your meter will vary depending on the fuel demands. Voltage really isn't the best way to diagnose. You could have only a couple of strands of wire still connected and read 10-12v but insufficient amperage to run the pump properly. Do you still have the stock pump? It will be a better pump then the aftermarket pump. The only pumps that I've see changed are usually a result of misdiagnosis or from the vehicle sitting for a long time with a nearly empty tank (go green). I'd pull the harness out and check it. The harness only has two wires.

 

Sorry yes that is correct if the AC and fan are off there is no concerning sound upon cold start. However then when you turn on the fan/ac after waiting a few minutes you can hear the sound. I will try with the floor setting selected tomorrow. Thank you for the help!