Technical Mk2b misfire confusion...can anyone help?

[J4sona]

I have my OBD2 code reader arrived today. It doesn't list Fiat in the manufacturer list.

Do they still read the codes ok under other vehicles selection or have people on here got code readers that have Fiat in the list of compatible vehicles?

Cheers

 

[KRaikkonenNo1]

I have my OBD2 code reader arrived today. It doesn't list Fiat in the manufacturer list.

Do they still read the codes ok under other vehicles selection or have people on here got code readers that have Fiat in the list of compatible vehicles?

Cheers

I have used basic code readers in the past that have not listed Fiat, same with other car manufacturers,

what I say is -- stick it in the obd2 port near the fuse box and if it comes on and reads codes, voila..if not, it wont have done any harm

I'm pretty sure that it will work tho, have yet to come across a code reader that hasn't been compatible unless its not obd2 of course

 

[J4sona]

Ok car is home so I have plugged in the OBD2 reader.

Detected the car straight away and read brilliantly. Initially it picked up 9 code errors as I have been unplugging and testing various things recently.

I deleted all the DTC's. Turned engine on and read again. Had just one DTC come up which confirms exactly what I suspected:

P0204 / INJECTOR CIRCUIT OPEN - CYLINDER 4

So am I right in thinking this confirms dead Injector ??

 

[fingers99]

Or the circuit. Compare the resistance of the suspect injector with a good one ( disconnect the connector, use simple cheapo multimeter set to ohms).

If they differ markedly, new injector. If not, inspect the wiring to no.4 visually.

 

[J4sona]

Was already in progress of that.

Ok results:

Inj 1: 16.1
Inj 2: 16.1
Inj 3: 16.1
Inj 4: ---

Think I'll be buying a new injector. Worth getting a second hand one if I can find one so gonna look around now.

 

[J4sona]

Sourced a secondhand replacement from a Punto breakers. £9.99 delivered

 

[joncoxon]

Was already in progress of that.

Ok results:

Inj 1: 16.1
Inj 2: 16.1
Inj 3: 16.1
Inj 4: ---

Think I'll be buying a new injector. Worth getting a second hand one if I can find one so gonna look around now.

Haynes says 14.0 to 15.0 ohms for injectors but guess the others are ok, Let us know if it sorts the issue, I'm battling my punto tomorrow

 

[J4sona]

Haynes says 14.0 to 15.0 ohms for injectors but guess the others are ok, Let us know if it sorts the issue, I'm battling my punto tomorrow

Good luck with that. What do you suspect is wrong?

 

[atom0007]

It's open circuit, actuator is dead

 

[J4sona]

It's open circuit, actuator is dead

Was that aimed at me or Joncoxon?

 

[atom0007]

Was that aimed at me or Joncoxon?

I aimed to answer the question you asked

 

[J4sona]

Ah ok, fair enough lol. I've got a replacement injector on the way now so hopefully have it sorted weekend if it arrives in time

 

[joncoxon]

Was that aimed at me or Joncoxon?

just the values you have are different to what my Haynes says, could be aftermarket injectors though

 

[atom0007]

I wouldn't lose sleep over the injector resistance. Haynes isn't the manufacturer's specification after all. Maybe there was a design change, maybe there are variants, who knows.

 

[fingers99]

:yeahthat:

To my mind -- without the factory manual -- you took the best course of action.

Let's hope it works!

If you've a lupe, it's interesting to take a peek at the area where the injector joins the harness. I've seen them with hairline cracks (generally from getting thumped) there, which is probably enough to render them worthless.

 

[J4sona]

Well Injector arrived yesterday and I found time to get out today and fit it. Very quick and straightforward job on this car. All done, fitted and running lovely and smooth in 20 minutes

 

[fingers99]

Great stuff.

 

[joncoxon]

glad its sorted. I just swapped a fuel pump for a second hand 1.2 8v 99 one and they look very different despite same year and model. Haynes buy in 1 car, take apart and put back together. There's bound to be a few difference's here and there.

 

[Ziggy122]

So the basic injector test of resistance won

Score!

It'll be worthwhile making a note of the resistance of the 2nd hand one to see if there is a sudden change 5months down line and you find its misfiring again

Punto's dont usually kill injectors, there pretty good on them
to actually have a dead one - obvious via the open circuit/infinity resistance reading is an easy diagnosis

Remember to ensure all codes are cleared too!

Ziggy