Could my engine or gearbox possibly be braking/holding back my car?

[mart]

This is a strange one, to me anyway.
Corolla 2Lt diesel turbo manual box

I can't remember when I first noticed this happening, but even going down hill when I take my foot off the excellerator the car feels like the brakes are being applied and it is very notable

First I thought it was a caliper siezed on. Then I thought it could be low pressure in tyre (s). However, if I put it in to neutral the 'braking effect' does not happen.
Is it possible that an engine or gearbox can cause this?

 

[daleyd]

All cars have some degree of engine braking, usually (though not always) more noticeable in diesel engines cars, and also more noticeable in lower gears.

 

[brightspark]

modern engines hardly have any braking power .older engines had a larger mass flywheel giving braking .modern smaller ones hardly have any

 

[Ubique]

Engine braking on modern diesels is more pronounced due to higher compression ratios, flywheel mass - especially dual-mass ones are just as heavy as older style solid ones, if not moreso.
What vehicle is it? if it has a freewheeling clutch on the alternator, this can give some braking effect if it has siezed, the same goes for the engine cooling fan if belt driven.
If it's an auto box, then torque converters should disengage on overrun - unless in 'sports' mode, some autos just have a flexplate, some have DMF's which can give the feeling of engine braking if the springs are weak or have excessive backlash.

ETA - inlet port deactivation failing to operate correctly can also lead to excessive engine braking - but would normally set a DTC - not always causing the EML to illuminate.

 

[Memmeddu]

All cars have some degree of engine braking, usually (though not always) more noticeable in diesel engines cars, and also more noticeable in lower gears.

Compression ratio, displacement and flywheel weight affect engine braking too
Obviously gear reduction of the transmission has a key role

 

[mart]

It has the dual Mass flywheel.

 

[daleyd]

Compression ratio, displacement and flywheel weight affect engine braking too
Obviously gear reduction of the transmission has a key role

Yes there’s all sorts that will influence it, you could literally list almost everything in an engine that has some effect - I was trying to keep it simple though.

 

[bricol]

Engine braking can be pretty strong - if I lift off quickly and fully at the wrong moment on a damp road in the Caterham, it will put enough braking through the rear wheels to start a slide.

Flywheel mass will tend to keep things moving - that's why its a "flywheel" . . .

 

[brightspark]

i had a 2ltr pug about 90 hp had good engine braking now have a 16oo pug still 90 hp but engine braking is crap drop a gear and engine will over rev its titts off

 

[Memmeddu]

modern engines hardly have any braking power .older engines had a larger mass flywheel giving braking .modern smaller ones hardly have any

That's not entirely true
In racing application lighter flywheel are often used but I'm many cases the diameter of it is as much important as weight
A lighter flywheel on a relatively high compression ratio will have a quicker brake .
Do to the less inertial energy of the rotary masses
At lower speeds no engine braking if not the one provided by compression.

Heavy flywheel on low speed will detach your neck from the body.
At high speed it will keep going .
Light flywheel will just help brakes at both speeds but you can't rely on it alone for braking .

Tachometer will go up and down slowly with heavy flywheel and quicker with the lighter.

The ideal would be to find a compromise between both to have all the advantages possible .

 

[voipio]

What's the mpg like? Has it recently got worse? A certain amount of engine braking is to be expected; more so in the lower gears. If the brakes are binding then, after a longish steady drive with no braking, the brake discs/hubs will be warm, even hot. Another possibility may be the brake servo or vacuum pump is misbehaving, so the vacuum is putting the brakes on. If it's an engine friction problem, the engine would sound as if it's labouring on tickover. Another possibility is excessive toe out on the front wheels, causing tyre scrubbing. Have you hit any speed humps lately, or landed the front heavily after going off a kerb? Check the insides of the tyre treads for evidence of excessive tyre wear.

 

[Ubique]

It has the dual Mass flywheel.

What vehicle is it? petrol/diesel, auto/manual transmission?

ETA - just seen your addition to your first post, no real experience with Toyota stuff (other than they don't like the number 13 so use 12 or 14mm head sizes on their fasteners), all the above gives you some good pointers to check, especially the binding brakes.

 

[Gareth J]

Blocked catalyst/DPF?

A previous vehicle I had, I drove a relative's one, same model but they'd put a straight through exhaust on it. The engine braking was noticibly missing. Would thing an even more restricted pipe would have the opposite effect.

 

[Morrisman]

My diesel Mondeo has next to no engine braking. If I throw it into neutral at speed it slows down no differently than if I leave it in gear, with no throttle.

My 1100 BMW two cylinder bike has phenomenal engine braking, so much so that brake pads last 20,000+ miles, I use them so little.

 

[PhillipM]

Blocked catalyst/DPF?

A previous vehicle I had, I drove a relative's one, same model but they'd put a straight through exhaust on it. The engine braking was noticibly missing. Would thing an even more restricted pipe would have the opposite effect.

This is a good shout, blocked cats give a huge amount of engine braking (I mean it's basically a truck exhaust brake).

All the flywheel weight stuff is a complete red herring, you're barely slowing fast enough on the overrun for flywheel weight to matter at all.

 

[Migmac]

My diesel Mondeo has next to no engine braking. If I throw it into neutral at speed it slows down no differently than if I leave it in gear, with no throttle.

My 1100 BMW two cylinder bike has phenomenal engine braking, so much so that brake pads last 20,000+ miles, I use them so little.

I wish BMW made quad bikes, my Yamaha quad has no engine braking at all. Makes for a very interesting ride down hills

 

[dobbslc]

i had a 2ltr pug about 90 hp had good engine braking now have a 16oo pug still 90 hp but engine braking is crap drop a gear and engine will over rev its titts off

Modern diesels with no engine breaking are horrible in slow traffic or on a motorway when people in front cant keep a steady speed, its hard to keep a decent gap in front without having to use the brakes

 

[waddycall]

I reckon Mart knows enough about driving to decide if his engine braking is normal or not.

 

[bricol]

The only car I've suffered with a blocked cat was a company Mundano many years ago - it didn't allow the engine to work well enough in the first place to see if it affected engine braking! The engine ran extremely poorly, limited by what exhaust could escape via leaks in the exhaust before the cat.

 

[Robotstar5]

My 1100 BMW two cylinder bike has phenomenal engine braking, so much so that brake pads last 20,000+ miles, I use them so little.

I noticed that with mine (650 V twin) rolling off the throttle is like putting the brakes on.