Ford 2010 1.4TDCI code P1202

[wagggy]

Hi, I have a problem with my sons 2010 Fiesta 1.4 TCDI Edge. thought this is the best place to ask.

2 months ago the car developed a random misfire, whilst driving you feel the engine missing now and again. there was no engine light on dash.

He took it to a garage and they said No1 injector was faulty. so they replaced that injector. after a few days the problem returned so he took it back and they then said No4 injector was now faulty ( did they number them wrong as i know its reversed to normal engines ). He had that replaced.

He drove back home last week and the problem has reappeared. I used Forscan and it says P1202 Injector circuit open/shorted.

It seems weird all the injectors are failing within weeks of each other.  could this be a wiring fault or something else.

Is there a way of testing the injectors with a multimeter. 

thanks
alex

[remmington]

We would swap NO1/4 - with NO2/3 - and road test for a week.


Testing them in situ - is OK but your fault is so random - it may not show up while testing.

[wagggy]

Arnt these coded for each cylinder. thought you cannot swap them.

or are these different to earlier ones

[rhyds]

May 19, 2021 7:37:24 GMT 1 wagggy said:

Arnt these coded for each cylinder. thought you cannot swap them.

or are these different to earlier ones

Its flagging a circuit fault, so I'd imagine the idea behind swapping the injectors is to see if the fault follows the injector (injector fault) or doesn't (wiring fault).

I'd give the injector wiring harneses a close visual inspection if you're not comfortable swapping the injectors themselves.

[wagggy]

Thanks, I understand that it will prove whether its a Inj or wiring fault.  I will clean the connections with contact cleaner first, road test it and see if the fault code clears.

If its still faulty will try swapping injectors round to prove it.   Im not a mechanic but have done plenty of engine work over the years, and I was a electronics maintenance engineer before retirement.  

regards

alex

[rhyds]

I'd suggest checking the wiring itself as well as the plugs. As you know from your electronics experience wiring doesn't like hot/cold cycles and vibrations, which is what an engine bay is full of.

[valhalla]

These are piezo injectors, so the crucial thing is not to disconnect them whilst they are running, or preferably even when the ECU is live (switched-on).

The best way to determine whether the circuit is good or not, other than as Remmington says above, is to monitor the current flow on and off the individual injectors. This requires a current clamp around either of each of the twisted-pair injector harnesses, and then to use an oscilloscope to monitor that clamp whilst the engine is running.

The fault code when read-out with Forscan (or equivalent general-purpose toolset) should pin-down exactly which injector it is that is causing the issue, but do not rely on OBD-level tools to do this, as (as you infer above) there is the possibility that the injector numbering is incorrect on the OBD read-out; you need to use the internal Ford fault codes and diagnostic live-data. This is a problem with other engines in the Ford range, and stems from multiple sharing of engine designs across different manufacturers (primarily PSA, where engines are often labelled from flywheel end) - so confusion reigns at the calibration stage!

Not sure about the controller on this one - I would need to double-check - but some designs in the Ford / PSA car-park are subsceptible to end-stage driver issues on individual cylinders, and that means that the ECU will need to be heated / cooled to find the problem whilst the engine runs.

Sounds more like a injector circuit problem than anything else, so close examination of the harness all the way back to the controller for injectors #1 and #4 ought to find any issues there. Look for chafing and/or burning at the point where the harness departs the engine for the main vehicle structure.

[valhalla]

May 19, 2021 7:37:24 GMT 1 wagggy said:

Arnt these coded for each cylinder. thought you cannot swap them.

or are these different to earlier ones

Technically, that is true. In reality, the coding will likely be close enough between them to permit a temporary swap - you would not normally recode the injectors during a test like this. The engine might not be 100% smooth, and you would certainly be test-driving with caution and keeping the speeds/loads down, but it would prove the point.

[jmac200t]

there are a lot of problems reported with the wiring harness on the 1.4tdci a lot of them
for sale on ebay .harness that is.

[valhalla]

May 19, 2021 6:37:36 GMT 1 wagggy said:

Is there a way of testing the injectors with a multimeter. 

In a nutshell, no. This applies also to solenoid injectors (for different reasons), but with piezo units, it is electrical charge that is the determining factor, not voltage or impedance.

[remmington]

May 19, 2021 11:25:43 GMT 1 valhalla said:

May 19, 2021 6:37:36 GMT 1 wagggy said:

Is there a way of testing the injectors with a multimeter. 

In a nutshell, no. This applies also to solenoid injectors (for different reasons), but with piezo units, it is electrical charge that is the determining factor, not voltage or impedance.

Correct Valhalla - these stacked injectors - you need to test current pull.


I suggested "swapping them" - based on two things.

1. I doubt if the OP is geared up with inductive amp clamps and a scope.

2. Plus this is an intermittant fault. It might not drop at the point of testing.


Recons/exchange injectors on the these "stacked" injectors are not that good - I hate fitting them. VAG 1.6 ones I will only fit new units ex TPS.

[wagggy]

thanks for the responses, its definitely a learning curve on injectors.

I removed air filter and diconnected each inj in turn spraying them with contact cleaner.  cleared the DTC using forscan and went for a drive.

It still misses sometimes when you accelerate. driving at a constant speed is ok.  when I got home i reconnected Forscan and there were no DTC codes.

left engine idling for some time and still no codes showing.   Theres def a problem when you pull away it sometimes misses a beat. but no codes showing.

will keep monitoring it till code appears.

[remmington]

May 19, 2021 14:08:35 GMT 1 wagggy said:

thanks for the responses, its definitely a learning curve on injectors.

I removed air filter and diconnected each inj in turn spraying them with contact cleaner.  cleared the DTC using forscan and went for a drive.

It still misses sometimes when you accelerate. driving at a constant speed is ok.  when I got home i reconnected Forscan and there were no DTC codes.

left engine idling for some time and still no codes showing.   Theres def a problem when you pull away it sometimes misses a beat. but no codes showing.

will keep monitoring it till code appears.

Could be a compression misfire - not an injection misfire? (sorry!)

[wagggy]

Do you mean low compression on a cylinder.  I've had this on a jag where the exhaust valve was burnt out. this caused a permanent judder unlike the fiesta which is intermittant.

[jmac200t]

This was just something i stumbled on while i had a code for misfire on injector 4
the fault would not erase.car was in limphome mode so i brought revs up to the max i
i could 3,000 approx eraced the fault car ran fine and has been since that was 1 year
ago on a ford focus 1.6tdci. since then i have done the same on 2 1.4tdci fiestas
2008 and 2010.I cant explain it it just works for me.