its a punto
from the arc
its got basic engine management
please

s and b said:

its a punto
from the arc
its got basic engine management
please

Click to expand...

It's a Punto with Euro-2 spec engine management, focused on being far more efficient than an old dizzy-based system with a basic vacuum advance set-up.

The Euro-3 stuff is intelligent enough to identify (using only the one knock sensor and the cam sensor data) exactly which cylinder is knocking and only reduce the timing on that specific one, rather than affecting all 4 at once, for example. So yeah, really basic.

s and b said:

its a punto
from the arc
its got basic engine management
please

Click to expand...

I agree. Let's not forget that:

1. Several aftermarket systems run without a knock sensor
2. While the ECUs on several modern cars can take advantage of higher octane fuel, there's no evidence whatsoever that peak power is developed a couple of clicks below detonation. It's way more complicated than that.
3. The ECU fitted to MPI FIRE engines is unable to adjust to higher octane -- the knock sensor is simply a "fuse".
4 Several modern ECUs cannot adjust to lower octane fuel (JDM Scoobies are an obvious case in point)
5 For the most part ECUs rely on "maps" not the frenetic jibberings of one sensor.

fingers99 said:

I agree. Let's not forget that:

1. Several aftermarket systems run without a knock sensor
2. While the ECUs on several modern cars can take advantage of higher octane fuel, there's no evidence whatsoever that peak power is developed a couple of clicks below detonation. It's way more complicated than that.
3. The ECU fitted to MPI FIRE engines is unable to adjust to higher octane -- the knock sensor is simply a "fuse".
4 Several modern ECUs cannot adjust to lower octane fuel (JDM Scoobies are an obvious case in point)
5 For the most part ECUs rely on "maps" not the frenetic jibberings of one sensor.

Click to expand...

Aftermarket ECU's are usually fitted to tuned cars with no respect to the EU legislation, so are not geared towards meeting emissions. The mapper will ask the customer to fill-up with whatever fuel they intend to use and adjust the numbers in the table until close to det, then back off a little to maintain a 'safe' margin. Hopefully said customer will continue to use that fuel, otherwise a lower quality fuel will likely lead to a dead engine very quickly, especially on a turbocharged model. Just because a knock sensor is not a part of an aftermarket ECU set-up, doesn't mean it's not needed in all cases. In fact, many people now insist on having aftermarket ECU's with knock control so they don't have to worry about a dodgy batch of fuel wrecking their engine, or having to return to their tuner for a remap if they have to run the car on poor fuel temporarily.

I'm not talking about purely making more power- the ECU (under EU regs) is geared towards efficiency and emissions, by adjusting fuel timing and amount, ignition timing, evap purging, etc... and the knock sensor plays a role in guiding the ECU towards that.

Of course the ECU will have a base map, but it also has self-adaption (which many aftermarket ECU's do not), mainly for taking-up the natural drift-from-optimum figures that occurs as the engine components suffer wear and tear, but also to ensure the engine is running close to peak efficiency and therefore producing the least emissions.

The base map will have both short and long-term ignition advance, fuel trim, compensation for air/coolant temp/batt voltage/etc, and while the base map Fiat provide is referenced to begin with, the ECU will always be testing the boundaries, finding them, and storing the info ready to be written to memory during power-latch to improve on next time the engine is started. Sometimes it gets it wrong and leads to unstable idle/cutting out, so a reset is needed to go back to the original file and start learning again.

So while sensors like the knock sensor are merely for trimming purposes, and the engine will run on the base map without them plugged in, if it's giving the ECU wrong data (by not being bolted to the block and not hearing the det) the ignition timing will keep advancing.

So , four garages and the AA found repeated open cct and knock sensor errors but nobody thought to look for it until and old fashioned guy with fancy gadgets actually opened the bonnet !

Knock! Knock!
Who's there ?
It isn't !

My punto is cheaper to run (£ per mile) on posh petrol than on plain uneaded, so the knock sensor does work. Don't ignore it.

WhiteSei said:

My punto is cheaper to run (£ per mile) on posh petrol than on plain uneaded, so the knock sensor does work. Don't ignore it.

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you have a multi-valve head and higher compressions (hopefullly ) so your car would indeed be more economical over a given distance if you arent over heavy footed

i only use shell where possible (standard stuff) for my diesels for the very same reason ie better economy than standard wishy washy supermarket fuel

by the way my comments further up are in realization to a cooking 8 valve because that is the car we are discussing here

s and b said:

by the way my comments further up are in realization to a cooking 8 valve because that is the car we are discussing here

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Makes no difference what engine it is in the mk2- the knock sensor, if fitted, is better bolted to the block where it's giving the ECU useful info, than plugged-in and left wrapped up out of the way.

I can notice a difference in the mid-range/part-throttle loads between Tesco's pikey 95 and Shell regular in my little old Punto, so my knock sensor is clearly doing something.

D4nny8oy said:

Makes no difference what engine it is in the mk2- the knock sensor, if fitted, is better bolted to the block where it's giving the ECU useful info, than plugged-in and left wrapped up out of the way.

I can notice a difference in the mid-range/part-throttle loads between Tesco's pikey 95 and Shell regular in my little old Punto, so my knock sensor is clearly doing something.

Click to expand...

yes its slowly going rusty as i type

s and b said:

yes its slowly going rusty as i type

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Could be worse... I could've wasted £55 on a new one because my diagnosis path was rubbish.

s and b said:

do buy s/h last new one i bought for a corsa was £55 which is when i found out it was the wires rather than the sensor

Click to expand...

Mine is the HGT which deffo has s knock sensor. It runs best on Tesco's 99 followed by Shell or BP posh stuff. Its rubbish on Tesco/Asda plain unleaded.

My bike which has no knock sensor is the same on all fuels making about 95bhp at 8,500 revs from 900cc.