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MG MGB GT V8 Factory Originals Technical - Cleaning Injectors

Before finaly bolting everything down I thought I should give the fuel injectors on my 3.9 Rover motor a clean. There are local guys who specialize in doing this on a changover basis, but charge hundreds. We have pleanty of ultra sonic cleaners where I work and obviously I feel reluctant to part with my hard earned needlessly.
The question is, what solvent is suitable. I was going to use toluene, or possibly gum solvent. Has anyone experience doing this or know how resistant to solvents these injectors are? How long do you usualy give them in the bath?

Somewhere on the web I found plans for a fuel injector cleaner. I think it was for a Vega-Cosworth club of some kind. You might do a web search on or your favorite search engine. I beleive they used solvent and techroline (Chevron's fuel injector cleaner), but it still took hours to get them cleaned. They put them in an ultrasonic cleaner first

The problem is that unless you are going to do a lot of them, it is hard to justify the cost and time to build a test stand.

The cost around here to have fuel injectors cleaned varies wildly, and it pays to shop around and ask questions to determine competence.

The place I had mine done charged $20 per injector. They start by putting them in an untrasonic bath. They then put them on a flow bench where they cycle them by varying the pulse, checking to make sure the spray pattern is acceptable and there is no leakage at shutoff. They also get heated up eneough to see if the injector winding has any internal shorts. They replace any cracked caps.

It's not a very big sample, but both Rover (Bosch) sets I've done have had bad injectors. One set had an injector that was about 20% high in flow and the other had a injector that was about 15%low. The high flow injector had to be replaced and the low flow was run through the ultrasonic and cycled until it flowed correctly.

FWIW - Phil

I have had my injectors tested and cleaned by a Bosch specialist and the cost was about $30 each which I thought was good value.

All were OK but I was told they were the earlier, non rebuildable type and when it was tme to replace them get the later rebuidable type fitted.

As to solvents try Brake Kleen (from Autobahn or Repco)but be careful this is not pleasant stuff although it is effective.

Soak for about ten minutes and inspect frequently with a magnifying glass. The solvent simply softens the resins gums and varnishes on the injectors and then use the bath to remove the rubbish.

Injector pintles are usually hardened steel or stainless steel and it is normally wear on the seat which causes dribble and leakage.

Cheers, Pete.

Peter Thomas

I nailed this one. Cheap and easy. From the junkyard, a fuel rail, complete with regulator, an FI fuel pump, and a relay box, and an injector harness. Ford parts work good, and they have a chassis mounted pump on the dual tank pickups. Figure maybe 30-50 bucks. Spray carb cleaner is a good solvent, for that I cobbled up a fitting to pressurize the injectors directly from the can. Wire the relay as a buzzer and use it to cycle the injector(s). Flow some carb cleaner through them, then plug them into the fuel rail and harness, power everything up and check the spray patterns. They can be run backwards to backflush as well.


One spark and your entire test area can go up in flames!
So get out that fire extinguisher. And don't smoke. Pay particular attention to where the injectors are spraying gasoline.
Works for me,
Jim Blackwood

Thanks all,
good advice ,every bit.

This thread was discussed between 29/11/2002 and 03/12/2002

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