Does bump starting a manual car hurt it?

Posted by RelationNo9374@reddit | askcarguys | View on Reddit | 34 comments

Does starting a manual car by rolling it down a hill and popping the clutch hurt the transmission or anything else?

I did it with my ‘98 Wrangler all the time (owned it for 9 years) without any problems.

But now I have a manual truck with twice the weight and am wondering if it’s asking for trouble down the line.

Thanks!

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Alternative_Candy409@reddit

Common knowledge around here is that it's fine mechanically, but hard on the catalytic converter and could destroy it if done repeatedly. I never understood why. Is this actually true, can someone explain?

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Ghaddaffi@reddit

I damaged my catalytic converter doing this, there was a long downhill road with very slow traffic where I'd just let the car roll down and only start it when going over 20 kph. Check engine light came on after a few months of that and hasn't left. My theory is when cranking with the key the computer knows better what to do with the injectors and if bump starting they might dump more fuel into the engine and some of it makes it to the cat before burning but maybe someone can confirm.

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Butcher_Of_Hope@reddit

It's fine and a great work around in case of a dead battery or starter.

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MEINSHNAKE@reddit

I've had the check engine light come on after doing it with a modern manual but it all cleared itself up within a few minutes... mechanically I can't see it hurting anything.

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SageThunder@reddit

Instantly high rpm with low oil pressure however I don’t think it would be an issue long term with how little you’d realistically need to do it

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MEINSHNAKE@reddit

Exactly, it should be a get out of jail free card not a daily use kind of thing.

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VW-MB-AMC@reddit

Not at all.

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TheFragileRich@reddit

I thought this was only for emergencies, like if your battery died. Or are you just too cheap to replace a battery?

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NinjaBilly55@reddit

In my poor days I had a truck lose a starter and no funds to fix it so I became conscious of always parking on a slight incline.. Also bumping it in 2nd gear seemed to alleviate some of the initial hard bump..

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RadRimmer9000@reddit

I push started my car from California to Oklahoma, just to get to Oklahoma and find it was just a loose wire on the starter. I had a deadline to get there so I didn't have time to fix it the correct way before I got there.

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l008com@reddit

I used to do this all the time with my rx8s and camaros. Every once in a while, the camaro would start wrong and misfire (computer glitch). One time I had to shut it off while cruising down the highway, fully shut the car off. Then put the ignition power back on and drop it in to 6th gear.

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51onions@reddit

fully shut the car off

Would this not cause the steering lock to come on?

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RadRimmer9000@reddit

Steering locks when the key is removed and the locking pin slides into the steering column. The worst thing is no power steering or ABS brakes for a few seconds.

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skankhunt1738@reddit

Yuuup, not my RX-8s, but my 80s Isuzu pickup would just randomly stall before stop signs cold in the morning. Slow down, 2nd gear, slip the clutch a lil get er goin and keep on mini truckin. Did that forever, motor finally gave out at 375k miles.

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PruneIndividual6272@reddit

I don‘t know how modern cars behave- the ECU might not like it.. And many people say the catalytic converter doesn‘t like it.

But mechanically it is not a problem at all

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greenpowerman99@reddit

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Cpolo88@reddit

I’ve had to bump start my pos Mazda 3 quite a few times. It’ll be alright

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mynameishuman42@reddit

No. The clutch is in when you start the engine.

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Liv4thmusic@reddit

Nah. I did it all of the time in the day.

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KiraTheWolfdog@reddit

No it's fine

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NoRegret1893@reddit

No, as long as you aren't going some ridiculous speed and choose the wrong gear for the bump start.

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maine_buzzard@reddit

I'd always used 3rd or 4th, whatever is 1:1 for a rear wheel drive. Reverse in a pinch.

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maxthed0g@reddit

Yeah sure bump it.

But this is your second disabled vehicle? What do ya got against replacing bad starters LOL?

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AutomobileEnjoyer@reddit

I bump start my car and bike down the driveway almost every morning, no issues

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Illustrious-Pin3246@reddit

Your manual might have a recommendation but some later models it may cause a spike in your computer and damage it

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Usual-Ad6290@reddit

I don’t think so, back in the day we called it a hilltop ignition system, didn’t seem to bother the car.

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NightBoater1984@reddit

Used to do it all the time in my truck when I couldn't afford a starter, or battery, or both - never had an issue.

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Artistic_Bit_4665@reddit

It won't hurt the driveline at all. As others have said.... the computer may get a bit confused.

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AbruptMango@reddit

"Popping the clutch" and "bump starting" are very different things. Wait until your left foot can finesse the pedal before you go doing things like that.

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tony22233@reddit

I had an old Chevette, it was so light i could push it myself.

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RelationNo9374@reddit (OP)

The truck has no issues starting it using the starter. I just like to bump start it because it’s a cool trick that catches people by surprise.

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