Can someone educate me on injectors...

[nhudson1]

Hello good people.

So the car has been running okay since I broke down with an Injector P1262 cylinder 2, high to low short and P2291 code. Which for about 400 miles have not come back.

I tried to use ForScan to check the Injector values, but... yeah I haven't got a clue. I'm not a mechanic or even slightly capable in that area.

I seem to have some very different numbers - Both images taken just after a 170 mile motorway drive.

One image at idle the other held at 2k RPM - stationary.

Any thoughts or suggestions?

I'm guessing Cylinder 2 Injector is partially blocked? I'm running injector cleaner in the tank at the moment, to see if that helps any.

Car is a Ford Focus Mk3 2011.25MY 1.6 tdci with 130k miles.

[GreenV8S]

nhudson1 said:

I broke down with an Injector P1262 cylinder 2, high to low short and P2291 code. Which for about 400 miles have not come back.

I'm not a mechanic or even slightly capable in that area.

I seem to have ...

It isn't clear whether the original problem has been fixed or has just 'gone away'. If it hasn't been fixed yet, I suggest you get it fixed. And then stop worrying about it.

[NMNeil]

An understanding on how a PCM detects this issue will help.
I have limited experience with diesels but I'm sure the same principle applies as with a petrol engine.
When the PCM gets the pulse from the crank, or whichever sensor it uses for ignition timing, it stores the time interval between the pulses and compares them to each other, if there's a discrepancy between the acceptable intervals, it sets an error code.
Say your engine is at 1000 rpm, there will be a gap of 120 milliseconds between ignition pulses, (1000/60/2; reciprocal of the result gives the time in seconds = 0.12, or 120 milliseconds) if everything is working OK. But if the time interval between 2 of the cylinders changes to, say 130 milliseconds, it means that cylinder is slowing down for some reason, and a code is set.
If the numbers shown on the second screen refers to the time interval between each cylinder firing, it seems to be just fine.

[nhudson1]

GreenV8S said:

It isn't clear whether the original problem has been fixed or has just 'gone away'. If it hasn't been fixed yet, I suggest you get it fixed. And then stop worrying about it.

The fault has gone away... I think. Although on the motorway, it might be just paranoia, I'm sure I kept feeling it jolt/misfire but it is windy and the roads aren't exactly smooth. The garage had it for a few days, drove it, couldn't get the fault to pop up again so said to not waste money on fixing something that might not actually be broken.

This wasn't a ford garage, but the nearest one I was towed to.

[GreenV8S]

nhudson1 said:

The fault has gone away... I think.

Faults like this don't "go away", they just wait until the worst time to strike again. I suggest you get it fixed, and stop worrying about other things you see when you're looking at the ECU.