Thread: Dual Fuel Flapper V8 will not run properly on petrol

My experience was similar after complete engine build.
Yes, I too took my original injectors into a place where they were cleaned and tested.
All working fine and within limits is what is written on the report.

After several very frustrating weeks, running rough and fouling plugs, Did the old Bush Mechanic fuel injector test.
I removed plenum and lifted entire fuel rail, with injectors still fitted to rail, clear of the intake manifold. Doing one bank at a time and wedged fuel rail as high as possible, (about 100 mm or so) easier to do one bank at a time.
I put sheets of paper towels under, and cranked the engine. Coil disconnected of course, No possibility of any spark.

The results surprised me, 2 injectors were dribbling all the time ignition was on. but sprayed a complete large circle.
One none leaking one was spraying a small circle about size of 50 cent piece, all others were complete large circles.
Repeating test with other side, well, similar story. another one size of 50 cent piece.

It's not that difficult to do, a simple test to see what the fuel spray is actually doing.

Conclusion was, never trust shop tests on these old type injectors.
Bought a new set of Bosch 4 hole injectors (from UK) and repeated above tests before fitting.
All good even circles of fuel on paper towels.
and she now runs like a dream.

Edit. I too fitted fuel pressure gauge, pressure dropped from around 36 psi down to almost zero within one minute. I believe it was the leaking injectors.
now holds pressure as it should.

The above is good advice re the injectors, I had a terrible experience on my Jag with having injectors cleaned, it involved engine removal and a new set of injectors due to leaking after getting them cleaned- which I had done when removing the engine for another reason, decided to get the injectors cleaned whilst it was out as they are otherwise inaccessible.... My research suggested that this is fairly common as the built-up deposits can be loosened but not removed during the 'cleaning' process and end up preventing the injector from closing. I suspect that most places with the cleaning & testing bench do not use them much these days- at the joint that did mine, their test bench looked like it hadn't been used in years- and the expertise is just not there.
Another factor with the flapper EFI is the cold-start injector on the plenum, it will never be required in the Australian climate but can cause starting problems if it leaks, best thing is to blank the hose off.
For any Range Rover to top out at 125km/hr is not right; I owned four, from an 84 2-door to a soft-dash classic, and any one of them would do the ton.