A friend called to have a look at this car, Opel Zafira A, 1.6 petrol, X16XEL built in 2000. Beaten car, believe me. Complain, lack of power. 264811 Km.
Hooked up my diagnostic tool, I got one faultcode:
P0443(2) fuel tank ventilation valve voltage low
I could not believe this causes a lack of power so I just ignored, not part of the initial complain. I had a look at the engine bay and indeed, someone else measured something at the valve connector and damaged the wire insulation, and left it like that.
I started the engine and boy, that thing started so bad. Something from 4 to 7 seconds cranking before firing up. Measuring blocks showed Closed lambda loop and sometimes Open. Lambda slowly going from top to bottom and to top again. Unfortunate I am not so familiar with old lambda integrator values so could not gain anything there.
Wide open throttle showed indeed some hesitation at low rpm, but slowly ramping up did not show a problem. Neither with ignition. Because outside was raining cats and dogs, we kept the car in the garage, so no test drive.
Ah, forgot, what I got as an information before hand, car was at another garage, where the fuel pump got replaced and didn't fix the issue (so pump must be good right?) .
So I took the spark coil out, took one spark plug out and had a look to a nice white color. This already smells like lack of fuel. Did a compression test and confirmed that exhaust was not blocked. Was this necessary, probably not, but I just wanted to know.
I managed to trace the cable to the fuel pump and measure the pump current, this is what I got.
Some comments on the waveform. It does not look perfect, however, this pump may still run for some good kilometers. But the speed draw my attention. 7184 rpm is way faster than what I've seen on my car (same pump around 6400 rpm). And 2 amps less current than it normally should. This looks like no load.
After some struggle to connect to the fuel rail service port, I got a picture of the fuel pressure. It was not promising.
Only 1.17 bar of pressure and that was raising so slow at start and decaying so fast at stop. No wonder this engine had no power. But what can be the problem, we can now focus on 3 directions:
- fuel pressure regulator, on this engine is mounted on the rail itself;
- fuel pump not holding pressure
- fuel hose broken
He had the idea to remove the return line pipe from the regulator, and with the pump activated, there was no leak of fuel on the return line. So regulator is fine. I couldn't actually hear any fuel return beforehand.
- fuel hose broken
- fuel pump not holding pressure.
And I said, based on the evidence so far and based on the pulses at the rising edges of the waveform, I put my money on a broken hose. And it remained for him to open the tank to have a look.
Next day I got this picture on the whatsapp, I was thrilled and happy:
Everyone loves a happy ending.
Everyone loves a happy ending. Share your diagnostic success stories here.
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