Rover 3.9 fuel injectors

Rover 3.9 fuel injectors



Original Poster:

1 posts

14 months

Tuesday 4th August
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Has anyone cleaned up their fuel injectors or had the job done by a specialist? My G33 is now 28 years old and has never had a thorough check-up and clean-through of the whole fuel system. This I will do but, from my amateur research, everything before the injectors is fairly easy, its the injector end that's the problem. Judging by the many Youtube clips of Heath Robinson DIY methods, cleaning them seems a very awkward job and replacing them costs many hundreds of £. Is there a professional, guaranteed, value for money cleaning service? Any advice would be appreciated.


6,107 posts

180 months

Monday 17th August
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Take the plugs out and have a look at the insulator. Dirty injectors produce white on one side and brown on the other, as the poorly atomised fuel droplets wash the brown carbon off one side. If you have this, then try a couple of tanks of fuel with some injector cleaner added, and check again. If that fails Id look at updating the injectors as per this PH post, as it not much more than getting them cleaned. I know the guy who did this post knows his stuff:

The new injectors have a fractionally higher flow rate, that will make the engine run a bit richer, but you can dial this back with the hex screw on the side of the AFM as this control the mixture up to 2400 rpm (assuming you don't have catalysts). Above that the original ECU mapping any horribly lean on the Range Rover Map anyway so extra fuel is welcome. Quite a few G33's have been remapped now, but you wont know unless you open the ECU and have a look at the Eprom. On mapped cars its plugged into a socket, on unmapped cars they where soldered.

I do have a Heath Robinson set up that worked comprising of an ultrasonic bath, cans of carb cleaner and a transformer to pulse the injectors open and closed, that cleaned them OK. A full rebuild should get them re calibrated in addition to a clean.

Edited by blitzracing on Monday 17th August 17:08

Edited by blitzracing on Monday 17th August 18:00