CP3 mod with P0088

Joined
May 21, 2024
Location
California
TDI
2012 A3 TDI
Good evening everyone,

I spent the last few weeks lurking through the forums for a solution but to no avail.

I have a 2012 A3 TDI and within the last year, it has gone through TWO HPFP failures. Both times the mechanic attributed it to fuel contamination. Both times the pump went without warning.

A friend who has a JSW TDI recommended I do the CP3 mod so while I was away in a business trip, I dropped the car off at a shop and they did the mod for me.

I bought the retrofit kit from cascade german which included new injectors, CP3 R70 pump, intermediate pump, filter and new fuel lines. The kit is supposed to be plug

we managed to get the car running but now it has a permanent P0087 and P0088 code. It also keeps flagging a pending P0088.

the car will intermittently start but after some driving, I get the coil indication and the P0088 fail and the car will go into limp mode.

At this point, I’m not sure what to do, maybe it’s the metering valve on the pump?

does anyone have any suggestions?
 
Joined
May 21, 2024
Location
California
TDI
2012 A3 TDI
21:31:59
328.0 bar High Fuel Pressure (specified)
328.0 bar High Fuel Pressure (actual)
37.1 % Quantity Measuring Control Valve


this is what i got from the advanced measuring value. Does this appear to be off?
 
Joined
May 21, 2024
Location
California
TDI
2012 A3 TDI
I replaced the G247-Rail Fuel Pressure Sensor, still the same. I'll replace the N276-Fuel Pressure Regulator Valve tonight.

As far as characterizing the problem more;
I go for a short drive and everything is fine. I let the car sit for maybe a few minutes, then go for another drive. During this drive, within about 5-10 min, the car will then eventually throw the fault. I can feel the power start to decline right before the glow plug light starts flashing. If i cycle the ignition, the fault will go away.

It almost seems like pressure is building up in the rail over time but it cannot bleed off? Any thoughts.
 

McGuirk

Veteran Member
Joined
Aug 30, 2012
Location
Florida
TDI
Audi A3 TDI
So on mine after my cp3 install I had the p0087 when I would launch the car. My fix was to upgrade the rail sensor to a 2200 bar sensor and then had the tuner re code my tune for the increased range of the new sensor. I never had a hpfp failure though. It's possible if you didn't replace the regulator valve on the driver side of the rail that it still has some metal debris in it. If you pull it out you can notice it has a very fine metal screen. If it's clogged or partially blocked it could easily cause your issues.
 
Joined
May 21, 2024
Location
California
TDI
2012 A3 TDI
I fixed the problem and I have some important notes for anyone running into the same issue.

I replaced both the sensor and the solenoid on the fuel rail, both did not fix the problem. I was able to source 928 400 643 FMV from Lithuania and replaced the part and now everything works as advertised. 50 miles today and still no issues. If you happen to run into this problem, here is a sure fire way to isolate a incorrect FMV. If the FMV is wrong, the fuel lines will become boiling hot after just a few minutes of the car being on. Within maybe 5 minutes, the entire fuel system will be too hot to touch. With the correct FMV, you should be able to comfortable touch the fuel lines and they will just be warm. Of course, verify with VCDS but this was the biggest difference i noticed after the fix.

Also, If anyone buys their kits from Cascade German, buy with caution. Apparently they are 3rd party sourcing their pumps and not confirming if the pumps are BMW R70 pumps. I was speaking w/ fisher and he told me that the pump that Cascade sold me came off a Puegot, not a BMW. if you get one without 928 400 643 FMV , it;s not a BMW pump and the FMV will have to be replaced.

Lastly, I'm not sure if Cascades customer service has been hit or miss recently but after I told him there was a problem with the kit, he stopped responding to emails all together. Perhaps this is a one-off or maybe something is going on over there but just keep in mind that this could happen to you.
 

calimustang

Veteran Member
Joined
May 17, 2010
Location
Central FL
TDI
2011 JSW DSG (buyback, RIP), 2014 JSW TDI, 2015 Passat TDI, 2013 Jetta TDI.
Wow, it was extremely hot to touch? Sounds like the fuel flow was too low and starving your engine. I never checked on that part when that happened to me.

I actually experienced the very same thing with the incorrect FMV (pisspoor performance, fuel economy was awful)

Yep! I warned those vendors several times and it fell through the “deaf” ears/eyes. I am very disappointed about that.

so then, 2micron/Andrew helped me with the FMV issue back then

o, I saved it in the notes just in case of future customers’ needing help.

I am truly happy to hear your issues has been solved.
 

McGuirk

Veteran Member
Joined
Aug 30, 2012
Location
Florida
TDI
Audi A3 TDI
I fixed the problem and I have some important notes for anyone running into the same issue.

I replaced both the sensor and the solenoid on the fuel rail, both did not fix the problem. I was able to source 928 400 643 FMV from Lithuania and replaced the part and now everything works as advertised. 50 miles today and still no issues. If you happen to run into this problem, here is a sure fire way to isolate a incorrect FMV. If the FMV is wrong, the fuel lines will become boiling hot after just a few minutes of the car being on. Within maybe 5 minutes, the entire fuel system will be too hot to touch. With the correct FMV, you should be able to comfortable touch the fuel lines and they will just be warm. Of course, verify with VCDS but this was the biggest difference i noticed after the fix.

Also, If anyone buys their kits from Cascade German, buy with caution. Apparently they are 3rd party sourcing their pumps and not confirming if the pumps are BMW R70 pumps. I was speaking w/ fisher and he told me that the pump that Cascade sold me came off a Puegot, not a BMW. if you get one without 928 400 643 FMV , it;s not a BMW pump and the FMV will have to be replaced.

Lastly, I'm not sure if Cascades customer service has been hit or miss recently but after I told him there was a problem with the kit, he stopped responding to emails all together. Perhaps this is a one-off or maybe something is going on over there but just keep in mind that this could happen to you.
Fisher is an awesome guy. Very helpful and great customer service. Just put a cp3 kit with pump and a hybrid turbo on a friend's A3. He did the tune on the ECU as well. By the way what was the P/N of the FMV that the original pump came with? I know Malone can tune for specific valves if you have the part number.
 

wondermutt

Member
Joined
May 14, 2024
Location
Lake Havasu City
TDI
2011 VW Jetta TDI
I replaced both the sensor and the solenoid on the fuel rail, both did not fix the problem. I was able to source 928 400 643 FMV from Lithuania and replaced the part and now everything works as advertised. 50 miles today and still no issues. If you happen to run into this problem, here is a sure fire way to isolate a incorrect FMV. If the FMV is wrong, the fuel lines will become boiling hot after just a few minutes of the car being on. Within maybe 5 minutes, the entire fuel system will be too hot to touch. With the correct FMV, you should be able to comfortable touch the fuel lines and they will just be warm. Of course, verify with VCDS but this was the biggest difference i noticed after the fix.

Also, If anyone buys their kits from Cascade German, buy with caution. Apparently they are 3rd party sourcing their pumps and not confirming if the pumps are BMW R70 pumps. I was speaking w/ fisher and he told me that the pump that Cascade sold me came off a Puegot, not a BMW. if you get one without 928 400 643 FMV , it;s not a BMW pump and the FMV will have to be replaced.
Not going to lie but I'm happy that I've come across your post. Everything that you posted is comparable to what I'm experiencing with my 2011 Jetta and I purchased the kit through Cascade. Not sure if this adds to your view of the wrong FMV but one of the things that I'm noticing is the hose that connects to the cp3 from the aux pump will 'torque' quite noticeably and as you've noted I've made to myself how hot the lines are while running.

In addition to that I've even had the return line from the injectors that shouldn't need a clamp push off and spray fuel across the engine bay.

If you wouldn't mind sharing, what is the test/check with VCDS that can verify this even further while I'm waiting for a new metering valve?

The metering valve that came with the kit is 0 928 400 751. Do you know if that was the same as yours?

Hopefully you've helped me sleuth this one out.
 
Last edited:
Joined
May 21, 2024
Location
California
TDI
2012 A3 TDI
Not going to lie but I'm happy that I've come across your post. Everything that you posted is comparable to what I'm experiencing with my 2011 Jetta and I purchased the kit through Cascade. Not sure if this adds to your view of the wrong FMV but one of the things that I'm noticing is the hose that connects to the cp3 from the aux pump will 'torque' quite noticeably and as you've noted I've made to myself how hot the lines are while running.

In addition to that I've even had the return line from the injectors that shouldn't need a clamp push off and spray fuel across the engine bay.

If you wouldn't mind sharing, what is the test/check with VCDS that can verify this even further while I'm waiting for a new metering valve?

The metering valve that came with the kit is 0 928 400 751. Do you know if that was the same as yours?

Hopefully you've helped me sleuth this one out.
You’d have to go into the advanced measuring and you can monitor the specified fuel pressure vs the actual fuel pressure.
 
Joined
May 21, 2024
Location
California
TDI
2012 A3 TDI
One more thing to note. If your original CP4 pump cross the bed, expect to but at least 3-4 new filters and change them about every 200 miles after the change. also check the fuel rail solenoid for little fragments that will inevitably make there way there. I hope this helps someone.
 
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