Rover 3.9 fuel injectors

Rover 3.9 fuel injectors



Original Poster:

2 posts

25 months

Tuesday 4th August 2020
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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.


6,263 posts

191 months

Monday 17th August 2020
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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


8 posts

144 months

Friday 8th January
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Sorry for this late reaction! I haven't been on PistonHeads for a long time, and after changing my password I hit upon this thread.

I attach a few pictures of the injector cleaning process I had done in 2013, which is now already a long time ago. By now these injectors are almost 30 years old, and I intend to replace my injectors as mentioned in the link that blitzracing referred to in the previous reply.

I asked advice of the guys that remapped my new Emerald system which was installed last year in my Ginetta G33.
They confirmed that the Bosch injectors (0 280 156 045) would be a benefit for my V8 engine and can be managed by the Emerald K6 ECU. The present injectors supply 200cc at 3 bar, while the Bosch injectors supply 208cc at 3 bar, a 4% increase (which seems very limited) but for which a remap and additional rolling road session is necessary. It is not a complete remap, but in certain areas adjustment needs to be made.

Attention should be paid to the pricing of the injectors as mentioned in the thread. The prices mentioned on internet are probably based upon Chinese (?) made products. Investigation by me in the pricing of original Bosch injectors result in prices which are much more then published in various websites.
Via AutoDoc € 33,56 each incl. VAT, versus € 68,16 excl. VAT = € 82,47 incl. VAT!. The difference in price is huge and justifies suspicion.
So beware if you are looking for the original Bosch injectors and, if so, be prepared to spend a lot of money!