Guide: How to Perform a Diesel Purge

[WaldoMcBaldo]

DISCLAIMER: I AM NOT A MECHANIC, I AM AN IDIOT ON AN INTERNET FORUM. IF DO THIS THEN USE COMMON SENSE. IF YOU BREAK SOMETHING THEN TOUGH, THAT'S HOW IT GOES. NOT MY FAULT. IT WORKED FOR ME, IT MIGHT NOT WORK FOR YOU.

I asked a few days ago, in another thread, whether anyone knew the correct hoses to remove to perform a diesel purge. I never got any replies so I figured I'd work it out and put a guide up for anyone else who wanted to know.

You will need:

• Liqui-Moly Diesel Purge - Other purges are available
• 1/4 inch fuel tubing - I had this lying around from my old bike, it fits the connectors nicely
• A clear pop bottle
• Scissors
• An in-line fuel filter - 7 or 8mm connection turned out to be nice and snug
• A hose connector - Again, 7 to 8mm worked fine
• Gloves (Because reasons) - loldiesel etc

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You don't really need 2 500ml cans, I was going to run 1 litre through it but didn't bother. I'll put the other can through our 164,000 mile 206 2.0 HDi instead.

First of all remove your engine cover. You know how to do this I'm sure.

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Okay, so there are two hoses you need to disconnect. One by the fuel rail to the left of the oil dipstick...

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...and one by the metal silvery thing on the left (Low pressue fuel pump? I don't really know)

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You'll lose a bit of diesel but don't worry too much about it. Mop it up if you can be bothered, I couldn't. Next you want to connect the two original lines with your connector. I don't know whether this actually makes a difference or not but I did so as a precaution.

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Next it's time to cut your hose into two fairly equal lengths, put one length on one connector and one on the other.

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Now here's where you have to start paying attention. The hose connected to the silver metal part is where the fuel will be drawn up to, the other line is the fuel return. Cut your fuel feed line in half and add the in-line filter to catch all the crap. Pay attention to the flow direction of the filter, don't plumb it in backwards. There will (or should!) be a small arrow on the filter that indicates the direction of flow.

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Next add your Liqui-Moly to the bottle and put the lines in. I was a numpty and the two lines wouldn't fit in the cap hole so I had to cut another one at the top to get it in.

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This is where it gets messy. You need to disconnect the feed line and prime it with the diesel purge. Do this how you will, I sucked until it came to the top. It doesn't taste good and I wouldn't recommend this method. It worked in a pinch though. Once you've got it to the top, cap it with your finger and get the line back on there ASAP. Now you're all set. Here's my 'before' shot

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Fire the old girl up and watch it flow!

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You can see the colour change from the original shot. Not much stuff came out of my injectors so they're probably good. I've seen videos where some right garbage comes out of them so there you go. Run the engine through the rev range until you're nearly used the stuff up. I found by the battery was a good place to locate my bottle

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Before it all runs out, turn off the car. Now re-assemble everything you took apart and pour any of the remaining purge in the fuel tank. You're done! Enjoy your (hopefully) clean injectors.

[gatos]

Did it make a difference after the purge?

I am planning to do the same on mine sometime soon

[baldmosher]

I had my mechanic do an engine flush, oil rather than injectors (I assume?), I didn't notice much difference afterwards to be honest.

I then chucked a full bottle of Redex in the tank (the low-concentration one that you're supposed to throw half a bottle in every tank) and I've already noticed an improvement in low end torque, but not much else happening, and that's probably as much down to the Redex in the fuel being burned, as any cleaning that it's potentially done.

The big test will be in the next tank, which will be almost pure diesel again, as to whether it's made any lasting difference to the low end.

[WaldoMcBaldo]

Originally Posted by gatos

Did it make a difference after the purge?

I am planning to do the same on mine sometime soon

I did this last thing last night, so I've not had chance to really find out until today. I just got back from a good 50 odd mile run and it's definitely made a difference. I originally did it to sort out this rough loping idle that I had, it sounded like it was slightly cammed! This lope has now gone and it purrs along very smoothly at idle with none of the excessive vibration that it had before. It seems to pull more smoothly under acceleration now as well but that might be due to bum-dyno dynamics.

All in all, it's worth doing for the cost of the stuff I'd say.

[kieran40]

Good guide I need to do mine aswell I'm still having rough idle and funny power loss behaviour.

The mods should make it a sticky see if you can pm des

[cheshired5]

I'm glad my suggestion looks like it's worked WMcB.
You should also notice the effect improving over the next days and weeks too.
If done right like you have, it's awesome stuff....... and cheaper than injector replacement.

[baldmosher]

If you send a message to admins they will make post 1 "sticky" in the Articles section and link back to this thread.

I think Cumbrian_Male is the active admin? Not 100% sure.