Getting the chimp out of the petrol lines

Driving on regular gasoline ain’t that much fun. Cars passing by, trying to keep up with the traffic and one thing is certain; at some point the engine will just give up. After a minimum of 30 minutes of calm, peace, tranquility, jing-jang and a lot of zen the Black Beauty might spray some fuel around the sparks again. So switching from LPG (autogas) to petrol ain’t my favourite push on the button.

This needs to be fixed, no sweat on my back, while cruizin’ the A4 with an empty LPG tank and a few kilometres to go for the next LPG gas station, anymore.

So I had a plan mind -> work my way from the rear of the car to the front, starting on the easy do change/diagnose parts.

1. Visually check fuel filter
2. Visually check the injectors
3. Visually check the fuel rail
4. Check the fuel pressure on the fuel pump side.
5. Check the fuel pressure on the cold start injector side
6. Check the fuel pressure regulator

Let’s start with the fuel filter. From the looks of it, it hasn’t been changed after the body tectyl spray job which could have been ages ago.

This job is fairly easy to so, giving it 1 chimpy on the technical skill matrix but you need to take precautions! So I disconnected the battery so no electrical sparks can fly, after all we will be handling gasoline/vapour. Then I wrapped a cloth around the starter fuel injector. Gently loosening the bolt and let the squishing gasoline release it’s 3 bar pressure. This indicates that the fuel pressure is there but it is still uncertain what actual pressure is put on the gold.

As the pressure is off I worked my way to the fuel filter, which is fitted underneath the trunk and next to the fuel tank.


It takes one torx screw driver, a couple of spanners and some well dosed applied force to get the ol’ dirty bastard off. Yeah baby I like it rawww…

Changing this bugger is easy-peasy, connecting it all back again is reverse therapy.


The feeling I got while starting the car is overwhelming, undeniable and mind blowing. My generally uplifting spirit went through the ceiling, from the floor below me actually. WTF! Still no power, not even when throttling to 100%, pedal to the metal and still no flames! 🙁

Second action on the list: the injectoraderie! After taking the same precautions as before I removed the fuel rails for the cylinder head, again chimpy-try-chimpy-do-chimpy-succeed easy.

Even a blind monkey can see and explain you that those injectors should look a little different:






After cleaning:


After refitting the injectors, fuel line and the little bops and bits the engine runs on petrol again. Not for the 100% yet, but that may take some time. At least I can drive on gasoline again when the LPG is on a down low.

Update 2013-08-10: after slurping down full tank of 95 on the Autobahn the last stuttering has left the engine. Now I can relax when the LPG tank is empty 🙂

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