PicoScope 7 Automotive
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FORD FIESTA 1.4 DURATORQ INJECTOR CURRENT QUERY
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RechargedAutomotive
- Newbie
- Posts: 1
- Joined: Mon Dec 13, 2021 10:04 am
FORD FIESTA 1.4 DURATORQ INJECTOR CURRENT QUERY
Hi all,
We are really new to PICO scope and desperately trying to learn and improve! We're struggling to understand the waveform on this vehicle, as we can't find a known good and in the books we have the waveform looks completely different to what we're expecting to see.
Not sure if we have the scope setup properly or it's something else? We're assuming the injector is piezo due to the negative current draw on the waveform and the resistance measured in the injectors.
A Ford Fiesta 57 plate with a 1.4 diesel engine came into us today for a running fault. The fault code stored is a P0201:60 - Injector 1 circuit fault.
Car runs and drives fine, momentarily when it's been idling in the workshop it will have a hiccup/misfire for 1 second then recover and continue to run OK. Customer has said it occasionally cuts out and misfires worse than this - intermittently.
Customer has changed Air mass and we have checked the injector resistance all of which are around 193-196k Ohms.
From scoping this morning, we can see a difference in waveforms between cylinder 1 and the other 3 cylinders, there is a no oscillations after and also looks like the "on" time is shorter in comparison. Scope is setup up from a guided test of CRD Bosch Piezo using a 20amp current probe. Our waveform looks nothing like the illustrated waveform however?
I think I've uploaded the waveform with the faint line being cyl 1 and the darker line being cyl 4.
If anyone could advise us on what's going on in the picture, or if we have the scope setup wrong etc it would be very much appreciated.
Thanks all!
We are really new to PICO scope and desperately trying to learn and improve! We're struggling to understand the waveform on this vehicle, as we can't find a known good and in the books we have the waveform looks completely different to what we're expecting to see.
Not sure if we have the scope setup properly or it's something else? We're assuming the injector is piezo due to the negative current draw on the waveform and the resistance measured in the injectors.
A Ford Fiesta 57 plate with a 1.4 diesel engine came into us today for a running fault. The fault code stored is a P0201:60 - Injector 1 circuit fault.
Car runs and drives fine, momentarily when it's been idling in the workshop it will have a hiccup/misfire for 1 second then recover and continue to run OK. Customer has said it occasionally cuts out and misfires worse than this - intermittently.
Customer has changed Air mass and we have checked the injector resistance all of which are around 193-196k Ohms.
From scoping this morning, we can see a difference in waveforms between cylinder 1 and the other 3 cylinders, there is a no oscillations after and also looks like the "on" time is shorter in comparison. Scope is setup up from a guided test of CRD Bosch Piezo using a 20amp current probe. Our waveform looks nothing like the illustrated waveform however?
I think I've uploaded the waveform with the faint line being cyl 1 and the darker line being cyl 4.
If anyone could advise us on what's going on in the picture, or if we have the scope setup wrong etc it would be very much appreciated.
Thanks all!
- Attachments
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- Ford_Fiesta_2007_Diesel_20211213-0001.psdata
- (26.28 MiB) Downloaded 254 times
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- Ford_Fiesta_2007_Diesel_20211213-0001.psdata
- (26.28 MiB) Downloaded 197 times
Re: FORD FIESTA 1.4 DURATORQ INJECTOR CURRENT QUERY
Good information on Piezo injector waveforms here https://markstammersdiagnostics.com/ref ... injectors/
Your amp clamp was the "wrong" way round as the first peak should be +ve to open the injectors.
To me it looks like either a wiring/pin fitment issue with a high resistance somewhere dropping the voltage and so current to the injector.
Possibly an injector issue - you need a Mega tester to test Piezos, there are directions on the web as to how. If the input voltages are the same (ref to gnd) then that would point more at the injector.
I would expect the capacitors in the ECU to drive 2 injectors each - if so that would rule them out as you only have 1 injector problem, see if you can confirm.
Get the cyl 1 waveform on the screen and gently wiggle wires and connectors see if you can induce the fault. Another alternative would be to bypass the wire from ECU to injector.
Just be aware that you must not disconnect them whilst the engine is running - if they are in the "open" phase and you pull the plug they continuously flow fuel and bad things happen - I would have someone on the key whilst wiggling just in case !
Your amp clamp was the "wrong" way round as the first peak should be +ve to open the injectors.
To me it looks like either a wiring/pin fitment issue with a high resistance somewhere dropping the voltage and so current to the injector.
Possibly an injector issue - you need a Mega tester to test Piezos, there are directions on the web as to how. If the input voltages are the same (ref to gnd) then that would point more at the injector.
I would expect the capacitors in the ECU to drive 2 injectors each - if so that would rule them out as you only have 1 injector problem, see if you can confirm.
Get the cyl 1 waveform on the screen and gently wiggle wires and connectors see if you can induce the fault. Another alternative would be to bypass the wire from ECU to injector.
Just be aware that you must not disconnect them whilst the engine is running - if they are in the "open" phase and you pull the plug they continuously flow fuel and bad things happen - I would have someone on the key whilst wiggling just in case !
Re: FORD FIESTA 1.4 DURATORQ INJECTOR CURRENT QUERY
Although I cannot help with your capture I can relate to the symptoms and this engine, on the one I worked on it had been to a few garages but I got lucky with the visual inspection and found the wiring to the Crank sensor had fell out of its clip on the rear o/s of the engine and was rubbing the o/s driveshaft and it would randomly hiccup as it shorted to ground, it had no codes either but once found I could recreate the fault.