Smoke and petrol

[mlow]

While running the engine up to temperature in the garage last night, it started to misfire. I opened the bonnet and was presented with smoke and a hissing noise from n/s rear of the engine under the plenum. I quickly switched off and both smoke and hissing stopped which was a good thing because the next step was to go for the fire extinguisher!

The smoke had an electrical burning smell and the area around No 7 injector and the outside of the injector was wet with petrol. I could not see any obvious location for the fuel leakage other than potentially from the injector itself. I did not perform any further diagnostics since it was late and the prospect of petrol spray and hot engine was not a good one. However, I did notice that on switching on the ignition, the fuel pump does not prime. This would seem to confirm that the cause may have been electrical.

Any ideas appreciated before I get my hands dirty tonight.

[blitzracing]

Scary. Ive seen the injectors drop out of the clip that holds them, and leak around the top o ring and you will phyically see the injector is lower than it should be into the manifold. That however was a fuel pressure issue, nothing electrical. If you have a test meter, unclip the injector and measure the injectors coil resistance, compaired to a good one. If the internal windings have shorted out for some reason it should show up as a lower resistance. Odd combination of faults I must say.

Mark

[mlow]

I agree - strange. As you suggest I will start at the injector and work back from there. I will let you know what I find tomorrow.

[blitzracing]

Another thought. If it is fuel pressure, and the return regultor failed, or return pipe got blocked, then the pump might well stall, so it would not run.

[mlow]

I found injector #7 electrical connections burnt out and shorted, injector resistance 17 ohms and fuse #2 blown. On replacing the fuse, the fuel pump now primes and fuel is leaking out of the electrical connector area of the injector. I am glad that I spotted this while the bonnet was up in the garage rather than it happen while driving. The combination of the electrical short and petrol leak at the same location has worrying consequences.

I have no idea why the connector failed. All of the others are in very good condition.

I would suggest it might be worth you all pulling off the injector electrical connections periodically to check for condition or corrosion.

New injector, o-rings and electrical plug required plus a strip down of the fuel rail required for repair.