Weak Hot Start

A non-functional coolant temp sensor should have other symptoms too... does the engine make good power? Does it get good fuel economy? How is the idle quality, and normal idle speed? Your PM indicated it is idling quiet with the 0w40.

 

The sounds at idle such as top end ticks and some of the rattles the engine has had are now quiet.
Now if it idles for long periods over 5 minutes it begins feeling a bit rough. Nothing crazy but nothing great either.
I'm not thinking the sensor is not functioning as that would cause a MIL but maybe on the outer limit of the specifications. Hot timing not where it should be.

 

http://www.knowyourparts.com/starter-will-not-crank-when-hot-heat-soak/

I still think its something with your starter...but maybe a heat shield will help...

 

Not required. The starter is a Nippondenso gear reduction starter. These starters can crank high compression diesels with ease. They are used in many industrial applications and in many forms of construction equipment and agricultural equipment. Radiated heat is not the problem neither is heat transferred by contact.

 

I got nothing...good luck.

 

Mine does this and has done this since I bought it 7 years ago. It's never died once it cranks but you have to crank on it longer to get it to fire when the engine is warm.

 

fuel injectors are leaking.

When truck sits while hot, the injectors leak fuel into the intake. This is flooding the engine with too much gas. Too much gas and not enough air makes for hard hot starts.

You don't have this problem on cold starts because the gas has dissipated over night.

New or rebuilt injectors will be in your future if you want this problem to go away.

 

Have you checked the lash on the valves, maybe they are tightening up when the engine gets warm and that's why it's cranking over slow.

 

Check your grounds !!!!

 

Hydraulic system. No valve lash adjustment needed. It's not cranking slow. It's normal just weak to no start.

 

Already done lol.

 

I am checking that today along with multiple sensors. I do believe the resistance value on a few may be on the polar opposite of the scale on a few sensors.

Keep everyone in the loop.

 

So far the Camshaft Oil Control Valve has failed the resistance test. Resistance value too low. Next to try and check the coolant temperature sensor.

Coolant drain time!

 

Well then wouldn't you know it. I have to remove the intake manifold to remove the sensor. At the same time it is revealing all of the dealerships fine handy work. Gaskets not seated correctly etc. If I ever got my hands on a Toyota engineer I don't think it would end well. Removing a major engine component to replace a 50 dollars sensor is uncalled for.

 

Sensor out. Checking now.

 

Sensor out of spec. Hot check would not drop below 370 ohms and it should have been lower. What's odd is the resistance began rising after 5 minutes and the water remaining a constant 180 degrees. The cold check at 70 degrees showed the sensor below the cold threshold.

The bad. Toyota had been in the truck some months back after selling me the wrong number 1 coolant bypass pipe. During the removal of the intake manifold I found a bolt on the intake manifold loose and several gaskets damaged possibly during the installation.
When I had picked up the truck from the dealership they had left the Camshaft Oil Control Valve disconnected. It ran but ran rough misfiring etc. Went home that moment (less than 5 minutes) and opened the hood I found the Camshaft Oil Control Valve disconnected and somehow had no CEL and the air filter box was not closed.

The good. I am reassembling everything back to spec.

Making a phone call to Toyota Corporate and filing a formal complaint. Dealership and I will have a phone meeting and I do plan on them compensating me for my time and for hard parts.

If anyone on here is watching from Toyota Corporate you are welcome to PM me.

 

Well installed the new sensor and now bleeding off the bubbles and warming her up. Hopefully it fires a bit smoother now. Still need to install the new cam shaft control valve tomorrow evening and see if things get any better. What sucks is buying all your own gaskets from an aftermarket supplier because Toyota can't get them until early November.
My Tacoma is my over grown golf cart but that doesn't mean drag your feet with getting my parts Toyota.

Toyota Corporate has decided to stonewall me saying "not my problem, service is on the dealer, all we do is support the product". All I have is a claim number for the case and that's it. Bet I get no where with my complaint to corporate.

 

Well after much work and a few choice words my hot start problem still persists. Beginning to think failing coil packs, ECM or internal damage. The good part is the truck is even smoother than before and has a bit more umph.

 

So if I shut it down and wait a minute she starts fine. I will see what a 5 minute soak does.

 

5 minute soak shows a good solid start. Now for the 10 minute soak.