Tips on Push Starting a car?

[fleabag]

My friend got a 1985 BMW 5 series for free, problem is the battery was dead and we needed to transport it. We ended up towing the damned thing and I felt really bad because we had tried to push start it like 5 times. I had read prior that you can push start a car but I had never done it before. I read that you shift into second gear, keep the clutch pushed in, get it rolling and then quickly let out the clutch, unfortunately this did not work.

So afterwards, I looked up online and now I'm hearing slightly conflicting information, for one thing I'm now reading that instead of letting it up slowly (like you would when you're normally driving), also got to press the on the gas pedal, both things I did not do. I should mention that the battery was completely dead, and I don't know if this car if this car will prevent starting up unless the clutch is completely depressed. Can anybody confirm this?

The street we were on was inclined on both sides, it was weird because every time we did this, at first it felt like the clutch had not engaged at all and then as the car started to lose speed, it then bucked, finally coming to a stop. The closest we got was when it was shifted into 1st gear and my friend smelled some fuel.


Can anybody describe in great detail EXACTLY what they did in push starting their car?

 

[coldmeat]

Watch this.

 

[jagec]

If the battery is COMPLETELY dead, you can't push start it...it needs power for the ECU, injectors, etc.

So.
Turn the car on.
Put it in second gear, hold the clutch down.
Get friends to push the car. Get a decent rate of speed up, and then let the clutch out, slowly enough to prevent a big jolt but not too slowly. No need to press the gas.
While many cars have a switch that prevent the starter motor from turning unless the clutch is pressed in (crap IMHO), this does not apply to push starting. The starter motor doesn't factor into this.

Time was I had to push-start my old Celica by myself a couple times a month. That car was a real POS. Luckily, it wasn't too heavy, and I parked on a flat section.

 

[Demon-Xanth]

You can still push start a car these days, but it's gotta be a manual and it's gotta have power for the fuel pump and ECU. I used to "push start" my truck occasionally because I parked on a hill. I could get in, (I usually leave it left inf 1st gear) turn the key to the on position and "pump" the clutch to get a little bit of momentum going and the weight of the car moving down the hill would turn the engine over and be enough to start it up.

 

[lurk3r]

Push starting a car depends on the fact the car is capable of starting. If the car does not fire on the first couple cranks normally you'll have huge difficulty getting it to push start. The other consideration with newer cars, and especially BMW is the theft prevention system. It would not surprise me at all if BMW has disabled push starting in the ECU. I did have to push start my 02 suby a few times when my gf left the light on, but like DX said, you have to have fuel pressure to have any hope.

 

[LTC8K6]

The alternator should supply enough power once the engine begins turning, shouldn't it? A completely dead battery shouldn't matter, should it?

That said, I recall a 280Z that would not push start for nothing, but it jump started immediately.

 

[mooseracing]

Originally posted by: LTC8K6
The alternator should supply enough power once the engine begins turning, shouldn't it? A completely dead battery shouldn't matter, should it?

Most alt's don't put out enough juice till at least 800rpm if not higher, usually above 1000rpm. Push starting is also doen better in a higher gear, i use 3 or 4th on a truck, less abuse to the drive train from such sudden shock.

I also can push start my auto, but thats a properly designed car.

 

[JulesMaximus]

Did it start right up after replacing the battery?

 

[JulesMaximus]

Originally posted by: jagec
If the battery is COMPLETELY dead, you can't push start it...it needs power for the ECU, injectors, etc.

So.
Turn the car on.
Put it in second gear, hold the clutch down.
Get friends to push the car. Get a decent rate of speed up, and then let the clutch out, slowly enough to prevent a big jolt but not too slowly. No need to press the gas.
While many cars have a switch that prevent the starter motor from turning unless the clutch is pressed in (crap IMHO), this does not apply to push starting. The starter motor doesn't factor into this.

Time was I had to push-start my old Celica by myself a couple times a month. That car was a real POS. Luckily, it wasn't too heavy, and I parked on a flat section.

It's even easier if you park it on a hill.

My first car was a SAAB 99 and I remember driving it to Jamestown in western NY with a friend of mine while we were in high school to stay at his sister's place for a few days while she was off getting married. My battery was old, it was winter, and the battery wouldn't hold a charge overnight so we just parked it at the top of a nearby hill on the street facing downhill so that it would be easy to roll it and get it started in the mornings.

 

[jagec]

Originally posted by: Demon-Xanth
You can still push start a car these days, but it's gotta be a manual and it's gotta have power for the fuel pump and ECU. I used to "push start" my truck occasionally because I parked on a hill. I could get in, (I usually leave it left inf 1st gear) turn the key to the on position and "pump" the clutch to get a little bit of momentum going and the weight of the car moving down the hill would turn the engine over and be enough to start it up.

Technically you can push-start an automatic, but you either have to push it with another car, or have a LONG downhill, since it has to be moving quite a bit faster before the wheels are able to really spin the engine.

Another reason why slushboxes SUCK.

 

[Vic]

Don't.

Get jumper cables.

 

[mrblotto]

Originally posted by: JulesMaximus

Originally posted by: jagec
If the battery is COMPLETELY dead, you can't push start it...it needs power for the ECU, injectors, etc.

So.
Turn the car on.
Put it in second gear, hold the clutch down.
Get friends to push the car. Get a decent rate of speed up, and then let the clutch out, slowly enough to prevent a big jolt but not too slowly. No need to press the gas.
While many cars have a switch that prevent the starter motor from turning unless the clutch is pressed in (crap IMHO), this does not apply to push starting. The starter motor doesn't factor into this.

Time was I had to push-start my old Celica by myself a couple times a month. That car was a real POS. Luckily, it wasn't too heavy, and I parked on a flat section.

It's even easier if you park it on a hill.

My first car was a SAAB 99 and I remember driving it to Jamestown in western NY with a friend of mine while we were in high school to stay at his sister's place for a few days while she was off getting married. My battery was old, it was winter, and the battery wouldn't hold a charge overnight so we just parked it at the top of a nearby hill on the street facing downhill so that it would be easy to roll it and get it started in the mornings.

LOL.........I grew up right around there, about 10 miles away across the border in PA. Jamestown has plenty of hills and bad winter weather, thats for sure!

 

[Arkaign]

I used to push-start an '86 Ranger 5spd V6, as well as some other misc 80s/90s small cars of various types.

NOTE : From your description in the OP, that 5-series may have more serious problems. Push starting it causes the crank to turn, which in turn can get the motor turning over fast enough to get somewhere. 2nd gear is usually optimal, and in my experience, it helps to sort of pop the clutch in and out rapidly at first, trying to get things loose, then fully releasing it and giving it the beans. Every vehicle has a different feel though, and as others have said, not all cars can be push started.

But yeah, sounds like that thing has serious issues.

 

[fleabag]

Originally posted by: Vic
Don't.

Get jumper cables.

You can't boost a car with a completely dead battery.

 

[Arkaign]

Originally posted by: fleabag

Originally posted by: Vic
Don't.

Get jumper cables.

You can't boost a car with a completely dead battery.

Actually, I've jump-started cars with no battery at all. It's probably not recommended, but I've been able to do it. Dodge Cummins Diesel to a Dodge Caravan 4cyl. As long as your alternator is good, you can usually keep on truckin until you shut the vehicle off. Running a/c, radio, lights, etc is a no-no, but you'd be surprised what's possible

 

[Vic]

Originally posted by: Arkaign

Originally posted by: fleabag

Originally posted by: Vic
Don't.

Get jumper cables.

You can't boost a car with a completely dead battery.

Actually, I've jump-started cars with no battery at all. It's probably not recommended, but I've been able to do it. Dodge Cummins Diesel to a Dodge Caravan 4cyl. As long as your alternator is good, you can usually keep on truckin until you shut the vehicle off. Running a/c, radio, lights, etc is a no-no, but you'd be surprised what's possible

Diesels don't have sparkplugs.

However, yes, you can jump-start a car with a completely dead battery. I've done it on several occasions, with a battery so dead the dome light wouldn't even come on. In fact, I used to have this problem with my old 3rd-car Toyota truck. It wasn't a daily driver, every few weeks or so, and sometimes I'd forget and leave the alarm on, which would drain the battery to nothing (yes, I know, this bad for the battery, thanks). You just have to wait a little while and let it get a charge off the jump before trying to start it.
edit: and then don't shut it off too soon either.

 

[crosshairs]

Originally posted by: jagec

Technically you can push-start an automatic, but you either have to push it with another car, or have a LONG downhill, since it has to be moving quite a bit faster before the wheels are able to really spin the engine.

Another reason why slushboxes SUCK.

not anymore you cant....there hasn't been an automatic built in over 30 years that was capable of being push started...

It would require a front and rear pump...and rear driven pumps are no longer used and haven't been since the early 60's

 

[jagec]

Originally posted by: Vic

Originally posted by: Arkaign

Originally posted by: fleabag

Originally posted by: Vic
Don't.

Get jumper cables.

You can't boost a car with a completely dead battery.

Actually, I've jump-started cars with no battery at all. It's probably not recommended, but I've been able to do it. Dodge Cummins Diesel to a Dodge Caravan 4cyl. As long as your alternator is good, you can usually keep on truckin until you shut the vehicle off. Running a/c, radio, lights, etc is a no-no, but you'd be surprised what's possible

Diesels don't have sparkplugs.

Eh? What does it matter if the donor car does or doesn't have spark plugs?

 

[Arkaign]

Originally posted by: Vic

Originally posted by: Arkaign

Originally posted by: fleabag

Originally posted by: Vic
Don't.

Get jumper cables.

You can't boost a car with a completely dead battery.

Actually, I've jump-started cars with no battery at all. It's probably not recommended, but I've been able to do it. Dodge Cummins Diesel to a Dodge Caravan 4cyl. As long as your alternator is good, you can usually keep on truckin until you shut the vehicle off. Running a/c, radio, lights, etc is a no-no, but you'd be surprised what's possible

Diesels don't have sparkplugs.

However, yes, you can jump-start a car with a completely dead battery. I've done it on several occasions, with a battery so dead the dome light wouldn't even come on. In fact, I used to have this problem with my old 3rd-car Toyota truck. It wasn't a daily driver, every few weeks or so, and sometimes I'd forget and leave the alarm on, which would drain the battery to nothing (yes, I know, this bad for the battery, thanks). You just have to wait a little while and let it get a charge off the jump before trying to start it.
edit: and then don't shut it off too soon either.

Huh? I was using the Cummins to jump a Dodge Caravan with a burst battery (we put it in the bed of the truck). Anyhow, the Cummins has two batteries All the Caravan cared about was getting the juice to crank it over so the alternator could take over from there.

 

[jagec]

Originally posted by: crosshairs

Originally posted by: jagec

Originally posted by: Demon-Xanth
You can still push start a car these days, but it's gotta be a manual and it's gotta have power for the fuel pump and ECU. I used to "push start" my truck occasionally because I parked on a hill. I could get in, (I usually leave it left inf 1st gear) turn the key to the on position and "pump" the clutch to get a little bit of momentum going and the weight of the car moving down the hill would turn the engine over and be enough to start it up.

Technically you can push-start an automatic, but you either have to push it with another car, or have a LONG downhill, since it has to be moving quite a bit faster before the wheels are able to really spin the engine.

Another reason why slushboxes SUCK.

not anymore you cant....there hasn't been an automatic built in over 30 years that was capable of being push started...

it would require a front and rear pump...and rear driven pumps are no longer used and haven't been since the late 50's

Hmm? Explain why the RPMs on a modern automatic don't drop to idle on the freeway the second you take your foot off the gas. There must be SOME coupling there...

 

[Vic]

Originally posted by: jagec
Eh? What does it matter if the donor car does or doesn't have spark plugs?

Oops! I misread it.

 

[crosshairs]

Originally posted by: jagec

Originally posted by: crosshairs

Originally posted by: jagec

Originally posted by: Demon-Xanth
You can still push start a car these days, but it's gotta be a manual and it's gotta have power for the fuel pump and ECU. I used to "push start" my truck occasionally because I parked on a hill. I could get in, (I usually leave it left inf 1st gear) turn the key to the on position and "pump" the clutch to get a little bit of momentum going and the weight of the car moving down the hill would turn the engine over and be enough to start it up.

Technically you can push-start an automatic, but you either have to push it with another car, or have a LONG downhill, since it has to be moving quite a bit faster before the wheels are able to really spin the engine.

Another reason why slushboxes SUCK.

not anymore you cant....there hasn't been an automatic built in over 30 years that was capable of being push started...

it would require a front and rear pump...and rear driven pumps are no longer used and haven't been since the late 50's

Hmm? Explain why the RPMs on a modern automatic don't drop to idle on the freeway the second you take your foot off the gas. There must be SOME coupling there...

There is a coupling, its the torque convertor, which is driven by the engine
the front pump is driven by the convertor. , as long as the engine is running , the torque convertor is turning and thus so is the pump.
this creates a "fluid coupling" ..Once that coupling is lost, there is no longer anything connecting the turbine to the stator inside the convertor, thus there is no more "coupling" between the input shaft and the output shaft of the transmission.


Without pressure, the clutch packs and planetary's cant be "held " together, thats why when an automatic car is shut off, it will roll forward or reverse even while in gear... and no amount of pushing or speed will be able to engage the convertor .
older cars that had a rear driven pump could create this coupling by having the driveshaft turn, since the rear pump was connected to the output shaft,pushing the car would turn the pump..which would couple the input and output, thereby causing the engine to start turning.


It actually much more complicated than this, but I'm tired of typing right now..

 

[mooseracing]

Originally posted by: crosshairs

It would require a front and rear pump...and rear driven pumps are no longer used and haven't been since the early 60's

hahah i was waiting for someone to say that....MY push start auto is a 64 Stude, but the push start speed is somewhere near 25mph.....



BTW you can still buy trannys with rear pumps or buy them seperately. Mainly a dirt track and drag car thing though.

 

[crosshairs]

Originally posted by: mooseracing

Originally posted by: crosshairs

It would require a front and rear pump...and rear driven pumps are no longer used and haven't been since the early 60's

hahah i was waiting for someone to say that....MY push start auto is a 64 Stude, but the push start speed is somewhere near 25mph.....

I guess I'm showing my age..

I haven't rebuilt a rear pump equipped unit in over 15 years....But they are still out there in pretty good numbers..

Originally posted by: mooseracing

BTW you can still buy trannys with rear pumps or buy them seperately. Mainly a dirt track and drag car thing though.

yes you can..

 

[Raduque]

I like this thread. I knew it wasn't possible to push start modern autos, but never really knew why. Also, my truck won't move in gear with the engine off. It might be related to the 4wd driveline.