fuel injectors - can they be cleaned?

Ford Falcon, 4L, inline 6cyl. 94' ED model.


can fuel injectors be cleaned or serviced either at home or in a garage?

my car is duel fuel (lpg + petrol) and it used to run on petrol regular but one day started chugging so we left it on lpg for a bit.
now it wont run on fuel at all, you might aswell have turned the ignition off as it just dies if you try it.

had fuel pump replaced, and i seen good strong fuel pressure readings at the fuel rail but the car still wont fire.

i had it checked and was told that the device under the bonnet that changes between fuel/lpg is working and that its an injector prob and i needed new ones. (6 @ $80aus ea... ka-ching!)

are they easy to remove and service at home? i have an intermediate level of car knowledge and do my own brakes, oil changes, wheel bearings etc on all my cars over the years (sometimes with the aid of a workshop manual)

any help would be greatly appreciated.



[edit on 26/12/07 by Obliv_au]

I have no first hand knowledge of this, but I found a website that breaks it down for you.

www.aa1car.com...

I hope it answers your questions.

thank you kindly ma'am. /me tips hat.

it does explain a few of my Q's, but seems to suggest that its not something i can do at home by poking a pin or bit of wire around and blasting it clear with an air compressor or spray can.

It wont even attempt to run on fuel, so an on car clean is out of the Q since theres no flow.

sounds like some coin and a mechanic is involved, and as a guy who usually repairs most things its hard to find a mechanic you can trust NOT to shaft you or your wallet.
($100 to change 6x $5 spark plugs? - i hate them types) :bash:

looks like its time to try find a mechanic i'd trust it with.



[edit on 26/12/07 by Obliv_au]

Google Queen, at your service.

i don't know if you can buy the stuff at the auto parts store but when i was still in the shop wrenching(few years ago), we'd use this 3m # that cleaned the injectors. you tap it right into the fuel rail and it will run the car for like 5 minutes.
then you're done.

probably gonna have to take it in dude.

you want/need to disable the fuel pump to make sure the injector cleaner is running the car. when the can is empty, car stops running and in theory, they are now 'clean'

reply to post by Obliv_au

As with all cars, the level of difficulity depends on the model. You need to get a Haynes manual for your car.


www.oztion.com.au...

I've replaced the injectors in my car, and it wasn't that bad of an ordeal. Once I took off the air intake manifold they were accessable and were easy to change. Again, get a maintenance manual at Autozone, or whatever your favorite parts store is and follow their step by step instructions.


[edit on 27-12-2007 by dbates]

firstly you need some Injector cleaner which you usually add to your petrol tank.

I like redex
but make sure you don't add too much as it does tend to get a bit smokey. It makes your engine look like it's burning oil.

Seems you got a problem starting anyway, so you could try some Easy start Small squirts down the air intake as you turn engine over is sufficient, do not flood engine with this stuff, an engine can become dependent on it.. seriously, it's like the engine gets addicted to this stuff.

This will help you get the old petrol through the lines and burnt off allowing the redex to do its stuff.

If these methods fail, then you will have to consider removing the injectors themselves and cleaning them manually. brake cleaner is a helpful way of cleaning most parts, either that or use some petrol. You might have to invest in some jet cleaning needles.

Removing the jets themselves is not too hard. They should all have some electrical connectors on them too. I'm not sure on your engines design so read up on it.

After re-installing, some injector systems need pressurising . Using the easy start will help here, but normally these days the fuel pump is sufficient. It just might take a few turns to get the petrol drawn up.

thanks for the tips, i guess it wont hurt to give em a go myself. if it doesnt work it'll still cost me the same anyway.

at the moment there is fuel to the fuel rail, but zero out the injectors. at a guess i'd say theyre 100% blocked :shk:

i do have a workshop manual so that'll make it easier.

cheers for the help guys (and gals - mm )

You might know this, you might not, but take your spark plugs out and compare them to this chart
It will give you an idea as to how well/bad your engine is running and which jets may be causing the problem.

It might be all the jets, but if only a few are badly blocked then cleaning them first might allow the redex (or similar) to do its job.

REMEMBER this.... if you disconnect the HT leads from the spark plugs, label and number each one first, or you may end up not having a scooby doo as to which went where.

A bit of masking tape wrapped near the end of the lead and then just use a marker pen to write the number of the cylinder it came from.

Be sure to clean the plugs before putting them back, wire brush usually enough to clean them up. Blow them off to be sure all bits of dirt gone.

Some mechanics say you should put the plugs back into the same cylinders they were in due to threads and seats and firing orders. But not always too important.

Brake cleaner is flammable too, sometimes you can use this instead of the easy start. this just might help you save some time here. Turn engine over, and squirt a few short blasts of break cleaner down air intake. With a bit of luck it will give the jets an immediate wash.

I was just thinking... have you got a spark at the plugs?

It might be electrical rather than fuel.

I don't know the garage you took it too , but sometimes you do get the dodgy mechanic who will rip some off for a "major" job that only really takes 20 minutes.

Spark plugs, HT leads, distributor cap and rotor arm all wear down over time.

HT leads lose their ability to transmit the full current to the plugs.

reply to post by Extralien


it runs perfectly fine on LPG.
about a year ago i went a few weeks without running it on unleaded, and with the tank down it probably circulated some crap from the bottom of the tank - although thats what a fuel filter is for but i guess some finer particles might bypass it.

so yeah, runs fine on LPG.
but no fuel at all out any injector so it wont run on unleaded. (all 6 injectors blocked)



[edit on 10/1/08 by Obliv_au]

Ah, ok...

It might be possible that soot from the gas has caused the blockage.

I presume you've got electronic ignition, I couldn't see any data for that on the link you gave, but it would make sense for this day and age.


If not, and you've got a set of points under the distributor cap, I was wondering if you were getting any 'pinking' (pre-ignition) when engine under load. It sounds like a metallic rattle.

Could be why the jets are blocked now. Pinking would help explain how that's happened, unless you've got a lot of miles there and the valve seats are worn, or maybe even the valve stem seals...

Do you burn engine oil? Have you noticed any difference in the engine oil levels on a regular basis? As long as there are no oil leaks yet you seem to be topping oil up often, you may have badly worn valve stem seals.

Any left over combusted gasses could be pushed back up the inlet stems to dirty the jets rather than be completely pushed out the exhaust ports. Un-expelled gases will definitely be pushed back up under compression.