Throttle body controller a remedy for lack of engine braking

Can anyone point me as to how to get back engine braking into my life?

BHPian Sandman689 recently shared this with other enthusiasts.

Up until recently this year, I was used to driving a diesel engine powered car (Tavera's 4JA1-L to be precise) and hence enjoyed engine braking. When I had to go down a ramp, I would simply slot in 1st or 2nd depending on the ramp length, with the only input being the steering. The car would glide down in a controlled speed on it's own.

But now that I own a diesel car with a throttle by wire system, things aren't as sweet. The engine in question is the from the same manufacturer - Isuzu 4JK1-TCX. Even in 1st gear, the tachometer doesn't seem to stop rising and eventually having to use the brakes.

Question: Is anyone aware if a plug n play throttle body controller can help here? Or are the gear ratios to blame (the D'Max seems to have a poorly positioned 1st gear)?

Can anyone point me as to how to get back engine braking into my life?

Here's what BHPian audioholic had to say on the matter:

For braking you need some sort of resistance. The engine might have reciprocating parts but it is designed to operate with as less friction as possible. So when the engine is being rotated by the drive train when decelerating, the mass itself would offer little resistance. It is the vacuum created in the intake manifold that provides some sort of resistance since the engine would be somewhat choking due to lack of air. That is why petrol engines offer very good engine braking and diesels with a throttle also provide the same. Throttle body in diesel engines have been introduced due to emission regulations lately and this is closed during deceleration and when the engine is shut off to prevent runaway.

Here's what BHPian Kosfactor had to say on the matter:

If this is a relatively new car then nothing to fault the engine for.

Engine will have engine braking - Inlet air throttle or VGT will be present, along with ECU stopping fuel when there is no load means vehicle will have good engine braking - BUT - the gear ratios have to be proper.

Imagine two vehicles with CR diesel engines with VGT, one goes down a trail with no feet on the pedals (1st gear foot off) and another needs constant application of the brake pedal - the answer is gearing usually.

Here's what BHPian dhanushs had to say on the matter:

The latter engine seems to have a lower compression ratio, which is the main deciding factor (apart from gearing) in engine braking. Hence the lower engine braking.

I dont think a Throttle Body Controller will help, as without any Throttle input, the ECU sees it at 0 degrees anyway. Someone who reads maps inside the ECU will be able to tell you weather fueling has a role to play when coasting. If not, there's nothing much you can do.

The old 540's with Peugeot engines used to have excellent engine braking, not so with the newer Thar. CR played a major role there.

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