Changing PD injectors

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desertstorm
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Passat model: B5.5 130 TDI AWX
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Changing PD injectors

Post by desertstorm »

Recently changed the injectors on my car to upgrade to slightly bigger ones. Normally not worth it for the difference but I got them really cheap off Fleabay.

This thread refers to some information on part numbers and injector flow numbers.

viewtopic.php?f=33&t=59164

Here is the official replacement procedure off ELSA WIN.
Injector replacement.doc
There appears to be several tools required. I never used a puller I found the injectors not to be that tight and ended up using an Allen key to help them out. I never used a DTI however I did buy a small 1/4 inch torque wrench from Screwfix as I only have a 1/2 inch one good for cylinder head bolts but useless for 20Nm
Here are the injectors I bought after a bit of cleaning.

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I started the change over by taking the car for a bit of a run to warm it up, things usually come out easier when hot. Didn't go too far just got the engine to around 60 degrees.
Took the glow plugs out to allow the engine to be turned over easier, managed to get the number four plug out by just moving the coolant rail out of the way a bit.
Removed the rocker cover, lots of 10mm bolts and the injectors are clear to see.

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Cleaned up some of the oil around the rocker cover sealing face to stop it dribbling down the side of the head.
The injector rocker bolts secure two rockers so turn the engine over with the nut on the camshaft until the injectors on 1 and 2 or 3 and 4 are uncompressed. The bolts can then be undone. They are 12 point spline bolts for both the rocker bolts and the injector clamping bolts.

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I used a drill to dip the holes and remove any oil from the bottom of the holes, just keep dipping and wiping till it comes up dry.
When you remove the first injector the any fuel tthat is in the rail in the head will end up in the cylinder, to reduce that amount of fuel I used a vacuum pump to suck fuel from the head, you don't have to do this but I had the tool and it took a few minutes.

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If you don't remove the fuel make sure you spin the engine over a few times to blow the fuel out of the bores before you put the glow plugs back in after you have put the new injectors in. I did this anyway just to make sure.
Removing an injector is just a matter of removing the pinch bolt and then taking the injector out. Apparently sometimes they can be quite tricky to get out which is why VW have a slide hammer tool.
I just rotated mine side to side a bit after removing the electrical connector on the harness and then used an Allen key to lever them up gently. Obviously don't apply too much pressure but I found this to work quite well.
You don't want to snap the Allen key and have a piece of it rolling around in the engine.

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After the injector is removed you will see fuel coming from the rail in the head and going down the hole in to the cylinder. Make sure the brass heat shield comes out with the injector.

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You may notice in the hole that some fretting has occured between the injector and the side of the bore. This happens on the side away from the securing block. You can see the wear on an injector caused by this rubbing that occurs due to the fact that the injectors are only secured on one side.

I replaced all the O rings and heat shields with new ones as if the top O rings in particular leak you end up with diesel in the oil and this can cause all kinds of issues causing the turbo to fail and potentially wrecking the engine.
I got a set of 5 complete off Flea bay for £30. You don't need any special tools to replace the O rings.

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The small ones fit in the top of the injector.

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Oil the rings thoroughly and I smeared a little oil on the rough area where the fretting occured to make sure the rings got to where they need to be to sit .
I had cleaned the injector solenoid connections with contact cleaner before putting the injector in and also sprayed the harness connections so there would be a good contact on the solenoid.
Put the injector in the head and align it so it's square, I didn't measure it I have a pretty good eye for things like that. I tapped it down gently to make sure it was seated fully in before starting to tighten up the securing bolt.

All the bolts under the rocker cover are torque to yield and as such VW say should not be reused. As I got the injectors cheap I decided to replace them all, got a complete set from Darkside, You can get them from the dealers or TPS either way you are looking at something like £60 for 12 bolts. I measured the lengths of the new bolts all genuine VW parts and the bolts that were removed.

Measuring the 4 injector securing bolts and averaging the result new bolts are 70.13mm long used bolts 70.85mm, about a 1% increase in length however I am sure the bolt was probably stretched longer but relaxed when undone.
The 8 rocker securing bolts were 97.71mm before and 98mm after so only about 0.3% which isn't a lot at all.
So in future I would reuse the rocker bolts but definitely replace the injector securing bolts as when tightening them up there was lots of squeaking going on.
The injector securing bolts are tightened up to 12Nm and then a further 270 degrees or 3/4 of a turn . I definately wouldn't reuse these bolts as this amount of tension on the bolt does seem like a lot.

The rocker securing bolts seem a lot less stressed 20Nm and only 90 degrees.

Whilst you are in the head you can check all the cam lobes for wear.

http://www.myturbodiesel.com/1000q/mult ... vw-tdi.htm

After the injectors have been replaced the adjustment needs to be made on each one so the the piston doesn't bottom out in the injector when the engine is hot.
This involves altering the adjustment screw on the top of the rocker. The process in the VW document using a DTI is OK but complicated.
I checked it with a DTI and this works much better and is a lot quicker.

http://forums.tdiclub.com/showthread.php?t=306911

Basically The injector is pressed to full depth when the top of the INTAKE valve cam lobe is aligned with the center of the injector lobe roller. Note that for each cylinder, the intake lobes are located across the head e-i-e-i-i-e-i-e (i=intake, e=exhaust) .

The VW document states 270 degrees where as it seems that it's 180 degrees now so I used 180 degrees.

Having made sure all the bolts are torqued correctly, the injector connectors are connected and all thew lash adjusters have been adjusted and tightened. I put the rocker cover back on.
I used the vacuum pump to suck fuel through into the head to reduce the amount of cranking the engine needs to do.
I removed the injector plug and cranked the engine for a few seconds to blow out and diesel then installed the glow plugs and put the connector back on.
Cranking the engine for about 30 seconds it burst into life with a lot of smoke for the first 10-15 seconds but soon settled down.


Karl.
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