Discovery 1999. Cylinder Roughness Readings; Hawkeye

Hi Guys,

Can anyone tell me what the Cylinder Roughness Readings should be on the Hawkeye ?

And if there is a difference,.. What is the problem ? How do you fix it ?

Cheers,

Dons

Hi Dons, Try emailing BEARMACH they should know as they sell them.
Clive.

BigDons said:

Hi Guys,

Can anyone tell me what the Cylinder Roughness Readings should be on the Hawkeye ?

And if there is a difference,.. What is the problem ? How do you fix it ?

Cheers,

Dons

Click to expand...

At idle they,re around +/- 2 or 3. When driving they may go +/- higher. If you start getting +/- 20 to 30 plus, this means the ECU is having to do a lot of " adapting " to get the injector to " squirt " at the right time.

I,ve found that the " roughness " figures for the injectores are,nt the, " bee all ", and, " end end all ", and if the ECU cant " manage " an injector, it will log a fault code.

Del.

50 pence said:

At idle they,re around +/- 2 or 3. When driving they may go +/- higher. If you start getting +/- 20 to 30 plus, this means the ECU is having to do a lot of " adapting " to get the injector to " squirt " at the right time.

I,ve found that the " roughness " figures for the injectores are,nt the, " bee all ", and, " end end all ", and if the ECU cant " manage " an injector, it will log a fault code.

Del.

Click to expand...

And all that assumes that the injector is what needs trimming.The ecu is just trying to get each cylinder to make the same amount of progress,which is normally possible.On an engine with bent connecting rods,cracked heads,valve problems etc the ecu cannot manage to keep it all within limits.i always do an electronic compression test with a current clamp around one of the battery leads.This is connected to a scope so I can see the peaks of current from each cylinder's compression stroke.
Often they are not a similar shape peak - bent rods are common on Td5's where they have taken in water - or diesel.
There is no point in looking at electronics or injectors if the engine is not a good air pump to start with.