VW TDI forum, Audi, Porsche, and Chevy Cruze Diesel forum banner

1 - 6 of 6 Posts

·
Premium Member
Joined
·
124 Posts
--------------------------------------------------------------------------------

I think I have come up with a way to inspect the hpfp cam/roller,piston cup and piston bore with the hpfp still on the engine. This is a work in progress and I'll post pics when I get time and update the info. For now I'd like anyones ideas or thoughts on this as of yet untried procedure.

Thanks,
dweisel

special thanks to member umrpunter for putting this idea into my head.

WARNING! All the details of this procedure have not been worked out yet. This procedure is yet unproven and the final details need to be worked out so the procedure can be done in a safe manner.

DO NOT ATTEMPT THIS PROCEDURE WITHOUT EXTENSIVE KNOWLEDGE OF THE CR HPFP FUEL SYSTEM.

(1) Bleed the fuel line and rail pressure from the fuel system by slowly loosening the a fuel injector line. Place shop towels or rags to prevent fuel spillage onto the engine.

2) Carefully remove the black plastic cover that is on the high pressure pump part of the hpfp.

3) Loosen the metal supply fuel line (17mm line wrench) at the rail and at the hpfp high pressure fitting. Once loose remove the two scews and clamps that secure this metal line in place. Now remove the fuel line by completely loosening the fuel line fitting nuts. Set aside in a clean place or bag it in a clean plastic food storage bag.

4) Now start to loosen the 4 torx screws that hold the high pressure pump part to the hpfp case. Loosen in an alternating manner to let tension off the piston cup spring in an even manner. You want the high pressure pump part to come up out of the piston cup bore evenly. Go slowly as there is a lot of tension on this spring.

5) Once these 4 torx screws are loose you can now remove the high pressure part of the pump from the piston bore.If the piston cup comes out with the hp part of the pump. Note: its position in relation to the hp part of the pump. The piston cup w/roller may come off the spring and remain in the bore. You can remove it by sticking your finger into the bore and simply pulling it out,but first note the position of cup and roller while its in the bore. Once removed set aside in a clean plastic bag. Later while reintalling this is a critical step as the piston cup will have to go back in place in this exact position to ensure that the roller is in the correct alignment with the pump cam.

6) Once removed you can inspect the piston cup and roller for wear. The cam can be viewed by looking into the bore of the hpfp and should be smooth and not have any scratches or heat discoloration. The piston cup should have a dark metal color from a coating and not show any wear on the sides or edges.

7) The pump cam can also be inspected at this time. Shine a light into the piston bore. Look for wear or scratches. Inspect the cam for wear or scratches. It should appear smooth and shiney if its in good condition. The cam should also be uniform across its entire width.

8) Now you are ready to reinstall the piston cup w/roller and the high pressure part of the pump. Place the piston cup back into the bore and in the correct orientation. TIP Use your finger when placing the piston cup back in the bore to orientate it correctly. With the piston cup in the bore rotate the piston cup with your finger and you will feel a slight resistance when it is in the correct position. Place the high pressure part of the pump into the piston bore making sure the high pressure part of the pump is facing the correct direction to line up with the fuel line. Now use the 4-M6X30 100 pitch mm allen head bolts to help pull the high pressure part of the pump back into the correct position. Slowly tighten the 4 allen head bolts to pull the part back evenly. Go slowly and do not over tighten the longer screws. Now you need to replace the 4 oringinal 4- mm torx screws. To do this remove 2 of the longer allen head screws and replace with original torx bolts. Once the original bolts are in place you can remove the last 2 remaining long allen head bolts and replace them with the 2 remaining origninal torx bolts. Tighten in an alternating pattern to ensure that the high pressure part of the pump is pulled down evenly into the hpfp case.

to be continued..........................
 

·
Registered
Joined
·
31 Posts
OK so far. How, exactly, do you refill/reprime/purge the pump so as to avoid possible damage from dry running during startup? Or will the transfer pump take care of that by simply turning the key to the "on" position if the fitting from the pump to the CR is left a bit loose?
 

·
Premium Member
Joined
·
124 Posts
Discussion Starter #3
OK so far. How, exactly, do you refill/reprime/purge the pump so as to avoid possible damage from dry running during startup? Or will the transfer pump take care of that by simply turning the key to the "on" position if the fitting from the pump to the CR is left a bit loose?
The CR fuel system will not prime by keying the ignition on and off. You need to use VCDS or make up jumper cables to run both the sending unit pump in the fuel tank and the elec. boost pump. Running the VCDS priming program as per the Bentley Manual will flow fuel to the hpfp. Once the fuel pressure in the low pressure part of the hpfp reaches 62 psi the pressure relief valve will open and allow fuel to flow through the return line and finally back to the fuel tank. The priming percedure is outlined in section 20 page 20.

dweisel
 

·
Premium Member
Joined
·
23,902 Posts
The CR fuel system will not prime by keying the ignition on and off. You need to use VCDS or make up jumper cables to run both the sending unit pump in the fuel tank and the elec. boost pump. Running the VCDS priming program as per the Bentley Manual will flow fuel to the hpfp. Once the fuel pressure in the low pressure part of the hpfp reaches 62 psi the pressure relief valve will open and allow fuel to flow through the return line and finally back to the fuel tank. The priming percedure is outlined in section 20 page 20.

dweisel
Also outlined at the bottom of the fuel filter change for 09-10 (and newer models) http://www.myturbodiesel.com/1000q/a5/2009-2010-VW-TDI-fuel-filter.htm
 

·
Registered
Joined
·
31 Posts
Ah so, thanks guys.

Sudden thought. Wonder how many HPFP failures might be due to the skipping of priming the system? Obviously, the guys with failures in 7K miles or so may be OK. A heavy concentration of failures in April had me thinking condensation overload of the water separator.

Still leaning the VW way, but..............
 

·
Registered
Joined
·
15 Posts
There might be one time that this thread becomes super important. If an upgrade pump re-call / replacement was ever done by VW. I tend to think there will never be a re-call but let us just say that it does happen.

Right now an operationally failing car will not run correctly and has the whole fuel system replaced. This is based on the fact that wear materials are everywhere in the system. I think wear materials are generally accepted to come from the HPFP roller, and cam slider (steel); and the bore of the roller slider assembly (aluminum); and the roller holder (hard carbon ?). So we have three things circulating in the system: steel, aluminum, and hard carbon. In one sense the very small amount of hard carbon (?) would be a source of all sorts of problems.

At the time of HPFP replacement, a decision would have to be made as to what was replaced by VW. If the decision was based on no codes set and performance normal, you might only get a revised pump; but the system might have a huge amount of wear materials everywhere. So if you inspected the roller assembly, cam and found wear, I would think a whole system replacement would be needed. Not a partial system replacement, but a whole system replacement. Some might want to say: "forget all this and go for a whole system replacement".

I notice this thread is not getting the attention it needs. dweisel has hit on something that needs to be requested by members from VW. I personally think the bare minimum of evidence would be photos of your pump serial # and an internal high resolution photo inspection of the HPFP with the owner present. The day of HPFP removal and inspection the owner / representative should be present (if just a pump replacement was going to be done).

If this is thought through ahead of time, then when and if it comes up everyone will be prepared.

Great thread dweisel.

eddif
 
1 - 6 of 6 Posts
Top