Hello everyone, I have Jetta 1.8t Wolfsburg. I went over the manual and it says not to push start the car in case the battery dies. My mechanic told me that it was BS and they just put it in there so you'd have to tow it. Any opinions?
The usual rationale for 'don't push start' is the worry that the catalytic convertor will get a gut-load of unbunt fuel and this causes the cat to overheat when it does get going.
I have no personal experience of this, because I don't cut corners that risk cats. They are very pricey round here. Also, unless you have several large guys shoving, pushing a car as heavy as yours is not an easy, or particularly safe, task.
Call a neigbor with some jump leads?
Charles
Of course the following comes without warranty, but a simple push to start it won't hurt the catalytic converter. By the time the catalytic converter is hot enough to cause the gasses to burn, they have long gone with the exhaust gases passing through the converter.
If you're pushing it up and down the street a few times to start it, you can end up with a lot of gas in your catalytic converter and this might explode while heating up.
Actually the manual tells you not to jump it either.
bummer, eh?
nate
Come on, it's not that bad, is it?. I weigh 125 lbs and had to push-start a Honda Accord a couple times when the battery was too weak to crank but had enough juice left for ignition. Both times I succeeded. And that was solo, on level ground, with a cold engine.
I put the car in neutral, ignition on, stood beside the driver's seat with door open and pushed against the roof pillar. After getting as much speed as possible, I jumped in, selected one of the upper gears and popped the clutch. One time this worked first attempt, the other time it took me two tries. If I'd had a buddy to keep the momentum up, the operation would have been a cinch.
That was many years ago, with a carbureted engine. I have no idea if this would start a modern electronified engine. All I'm saying is that cranking the engine of a small car by pushing it is not terribly hard, if it has a manual tranny.
not likely. most inyected engines take at least two revolutions of the engine to start and need the fuel pump operating. the fuel pump runs with the starter and shuts itself off it the engine is not running... and it takes a lot of amps...
That's what I've heard too but I think it's more of a product liability thing than anything else...since there's a chance of damage to the cat they therefore pretty much have to recommend against doing it.
I'd say if it's just a dead battery that you're dealing with and there's a very good chance that the car will start otherwise (everything else is in good condition), then it's probably OK to push-start it once in a blue moon. If it's not a dead battery and something is wrong that the car won't easily start, then yes...you'll probably end up dumping excess fuel into the car by repeatedly trying to push-start it.
FWIW, I had to push-start my A2 GTI after leaving the dome light on overnight and it started very easily with hardly any motion and a very brief engagement of the clutch so if yours starts just as easy, you're probably fine.
Same here. It doesn't take much to get the engine going. Like 2mph is enough.
Just to set the record straight - isn't the catalytic converter covered under the emissions warranty which is 100,000 miles?
This aside (I've push started my '78 Scirocco and '86 GTI previously), I thought the A4s and other newer VWs had a interlock switch on the clutch that keep it from starting unless you have the clutch pedal depressed..is this not true (for manual transmission, obviously)? Other than defeating the interlock, how would you push start the car if it has this interlock? (also obvious, I've not yet had to push start my A4).
Most ECMs won't operate under a certain voltage, something like 9 volts. So if you battery is below that, you can push it all over town and it ain't gonna run.
Best investment I ever made (OK, so it was free) was a good battery booster pack. Spend the money and get a good one with an inverter on it. Don't leave town without it. Rex in Fort Worth
for what car/year ?
The manual for my '00 Jetta says you can jump and actually gives explicit directions on how to do it.
dv
I don't doubt what you say, but don't understand why this would happen. The starter engages the flywheel and turns over the engine. When push starting you are using the wheels and transmission to turn the flywheel and the engine. Isn't this about the same thing? Not sure why this would result in excess fuel.
Can anyone explain why this would happen?
I was merely reporting why the books (e.g. Haynes) say it is a bad idea. I'm agnostic as to whether the argument is valid.
Charles.
Fair enough...I was just trying to figure out the mechanics behind it.
Haven't done it but I assume it would be like any car since this process isn't depending on the starter functioning...the whole reason you're push-starting is because the starter isn't working in the first place (dead battery or dead starter). Depress clutch, turn key to "on", put in neutral, release clutch, get out and push, hop back in, stomp on clutch, put in gear, let up clutch, car should start, no?
I'm also curious because other than the initial squirt of fuel that always happens when you turn the key on, I would think that the fuel demand is electronically controlled these days and more fuel wouldn't be injected until the engine needed it right? I can see in the old days of mechanical fuel pumps that maybe the engine would be engaged and turning several revolutions (and pumping fuel) before igniting and maybe that would put unburned fuel into the cat, but I kinda don't see how today it'd happen. I think it's mostly a "cover the manufacturer's ass" thing that it's in the manual.
If the battery is totally dead there won't be the power necessary to run the fuel pump and make the alternator charge. An alternator needs some current to excite the windings to start the charging. And old generator will start charging with out any current. Those old air-cooled generator equipped mechanical fuel pump carburated VW's were much more forgiving. That said I have roll started by myself many times with a wide variety of VW's that just did not have enough power to turn the motor over and create spark.
Chris V
Rex B wrote:
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