Pop/Push starting

One of the big advantages, in my mind, of having a manual transmission is the ability to pop-start the vehicle if the battery dies. I have done this many times, with several vehicles (I was too poor to buy new batteries for a while).

However, perusing the manual for my new-to-me 2002 Tacoma, I run across this passage:

NOTICE
Do not pull- or push-start the vehicle. It may damage the vehicle or cause a collision when the engine starts. Also the three-way catalytic converter may overheat and become a fire hazard.​

Has anyone had difficulties pop-starting their Taco, particularly with overheating the catalytic? Is this a serious threat, or just lawyer-talk?

 

I thought the clutch start was a built-in feature on these trucks, it even comes with a button for it! I've never tried it though.

 

I dont see how push starting it could do anything to the cat. i would love to see the logic on this

 

Yes it can damage the tranny, it's fairly stressful on parts. I can't see anything with the cat being an issue though.

 

Different feature. That's so you can start the truck with the key without pressing the clutch. OP is talking about roll-starting the truck - get it rolling, depress clutch, put it in first, pop clutch to turn engine over and start the truck.

 

First gear is a great way to cause damage 2nd or 3rd is a better way to go.

 

I've done it a few times, haven't noticed anything wrong about doing it. Granted I don't do it everytime I start the truck. But once in a blue moon I will.

 

I say mostly lawyer talk but having said that I have seen people tow with a rope that is 6' long. I could see where the towed vehicle starts and is in such a tall gear that it could run into the back of the towing vehicle. As for the cat convertor I am going to have to think on that.

 

Yeah, I've never done an actual pull start. I just find an incline or even a flat surface, push the thing from outside the driver's door, then hop in and pop the clutch when it gets up some speed. This truck might be too heavy for that; not sure.

 

You are absolutely right about that. Placing the truck in 2nd or 3rd is a MUCH better way to go. And under NO circumstances should one "pop" the clutch when trying to start this way.

 

Right. You don't really pop it when you "pop start." I still wonder how this can affect the cat though.

 

Why is second or third better?

 

If your Ignition is on like it should be the engine is turning but you for what ever reason have no spark and keep messing with this your dumping Raw gas into the cylinders into the exhaust into the Cat also diluting your oil.

Then not knowing when to stop

In most cases your battery is flat enough it won`t crank Starter failure of some sort

Just remember if your battery is below the threshold voltage The ECM goes into Hibernation to protect itself and shuts down

 

Hm. Interesting. It sounds like this is only likely to be a problem if you unsuccessfully try to pop start it several times (which has certainly happened to me before). Is that accurate? How big of a threat is this?

 

Like I said when you don`t know when to quit

If every thing is correct and it does not start the first time you most likely have more wrong

 

Injectors keep firing, truck won't start, so they keep dragging it around hoping it will start and cats get full of fuel. I've seen people smoke starters as a mechanic because some people don't know when to throw in the towel that something is not going to start

 

IDK about diluting the oil but I can see what they are talking about as far as Cat....dumping fuel in the cylinders to roll start then it finally fires..raw fuel in the cat then it has to burn it off. That's why if you have ever had to do it and it took you a couple tries you will usually see a small puff of smoke from the tail pipe or at least a rich exhaust smell.

 

Your always going to get some raw gas leaking down past the rings just depends on how much the rings are worn

 

I can't imagine enough gas would be dumped to cause an issue unless you're doing it for an extended amount of time. Injectors don't spray gallons. I don't think they spray at all when there's no electricity to make them fire in the first place. I can't remember if I've ever actually had to push start anything with FI or my last one was on a carb. It's been a while

I've got a couple jump packs for a reason, no more pushing

 

Damage wise, it's less of a shock load. Push starting isn't a 'gentle' process to start with and most mechanical bits aren't real happy when they are shocked. Push starting in 1st generally resulted in the rear axle locking up (on dirt anyway) and skidding, and maybe some hellacious jerking if they would roll. 2nd or 3rd tended to roll better and be a lot less jarring.

Tranny's and axles are pretty strong but a U joint and gearing is intended for constant and increasing stress. Watch any rock climbing vid that results in a broken Ujoint, usually you'll see a lot of tire spinning and bouncing before the wheel actually catches and then the ujoint lets go. It can handle ALL the load the engine can supply, but it can't handle all that load all at once. It's no different (well it is obviously) between me pushing you down a hallway at full speed and me slamming into you at full speed while you're just standing there.

Process wise:
You're trying to make the engine spin long enough to rotate, get some fuel, have the alternator spin enough to get the plugs to fire and get enough of an ignition that the entire process can happen again, and then become self sustaining. The less start/stop big push to no moving wheels you can make it, the more likely it is to have all that happen. Keeping the wheels spinning steadily is a lot easier to do with 2nd or 3rd.