Technical 1242 16V injectors not opening - multimeter test (and ELM327 OBD2 Android app)

[TheRadeon]

Hey you all!

I'm currently swapping a Punto 176 Sporting 1242 16V into my Panda 141A and struggling to start the engine.
I'm very certain that it's the injectors not opening. Also certain the immobilizer is being properly lifted, I got the fuel pump priming, fuel at the fuel rail (and return), and healthy spark at the plugs, however they are absolutely dry. Measured around +/-700 Ohm at the Crankshaft sensor, so that seems to be working as well!

I measured voltage at the 3 pin connector injector wiring loom coming from the engine loom/ECU side:
Between the top (white/blue) and middle (white/yellow) pin I got nothing
Between the top (white/blue) and bottom (white/brown) I got 12,5V while priming the fuel pump and again (around 9,5V) when cranking
Between the middle (white/yellow) and bottom (white/brown) I got 12,5V while priming the fuel pump and again (around 9,5V) when cranking


So I'm assuming that the ECU is doing it's job, but the fault has to lie in either the injector loom, or the injectors themselves!? - did not yet disassemble the intake manifold to get to the fuel rail and individual injectors properly again, that's the next step. I find it rather weird that presumably not a single injector is opening...

How can I properly diagnose the injectors eg with a multimeter?

FYI, the engine ran fine back in the donor car three years ago, got some maintenance like new timing belt and water pump, thermostat, spark plug and leads, crankshaft seals and oil pan and I cleaned the injectors, they had some crud on them, but didn't replace them when I redid some of the engine in January/February.




Furthermore I just received a 3 pin to OBD2 adapter cable and a bluetooth ELM327 OBD2 Dongle, with which I wanted to read error codes off of the ECU. Do you know an Android app that'll work with the old Fiat ECU protocol? I tried Car Scanner and picked "Fiat OBD-II / EOBD", which seemed to be the only reasonable option - I'm getting connection to the ELM dongle, however am not able to connect to the ECU.
Or is the only option with those older ECU a USB connection to a PC? In which case which software would work with the Fiat protocol?

Thanks heaps!
All the best from Germany
Fabian

 

[Frank Folker]

you need a VAG KKL OBD cable (they are usually blue on ebay/aliexpress, one side has an OBD port and the other side is USB), a windows laptop and a free program called iawscan2 to perform diagnostics. Free version of Multiecuscan doesn't allow connection to the ECU but it can connect to airbag and ABS units so it's useful for that.

Bluetooth ELM327 modules are not usable for old fiat diagnostics, and I don't know of any way to perform it using an android phone, but if someone does, please tell me

Measure resistance on the injector pins, they should have a few ohms of resistance but not a complete short

 

[TheRadeon]

Hey Frank!
Thanks for your reply!
The program tip for iawscan2 should be useful! Have to get the OBD to USB cable instead of bluetooth dongle first though. Thanks!

I was able to measure the restistance on the injectors, bang on 15 Ohm on all, so should be fine. Also checked each cable in the injector loom for continuity, again everything checks out fine...
Checked the fuelrail with injectors in whilst being poped out of the intake manifold during cranking - no fuel, no spray pattern, nothing. I don't get it, why aren't they opening...