PIERBURG Rebuild - pre build advice

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WreckTangle
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Re: PIERBURG Rebuild - pre build advice

Post by WreckTangle » Wed Jun 09, 2021 10:30 pm

I used a little hand held vacuum pump for testing. The USPro thing I mentioned before. They are sold as part of brake bleeding kits and are very cheap. You can just suck, but it’s a bit distracting especially if you want to test whether components will hold a vacuum. I used a length of vacuum hose with a suitable bolt stuffed in the end to block ports for testing. You could just put your thumb over it.

What you need to do is confirm that with a suitable vacuum the plunger on the 3/4 point unit will withdraw fully and stay there. This is the “throttle plate actuator leakage test” in section A.3 of the manual. If it won’t then you have an air leak in your 3/4 point unit and will need to try to source a working secondhand spare or fork out £400 for a new one.

Assuming the 3/4 point unit is good then either you’re not getting a good enough vacuum due to a leak somewhere else or, if your vacuum tubes are definitely connected up correctly, the idle over run valve may not be closing properly when it loses voltage.

The idle at normal operating temperature depends on air at atmospheric pressure being able to get from the red hose connected to the top of the carb, through the blue one, through the overrun valve, and into the yellow vacuum hose. The valve closes when it loses voltage and this enables the manifold vacuum on the pink hose fully to withdraw the throttle actuator; like your test blocking the yellow port while pulling vacuum on the pink one.

Remember I said you’d need to understand the thing before you’d be able to get it working?! 🙂



h11poc
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Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Wed Jun 09, 2021 11:12 pm

I'm pretty much heartbroken.. I'm 200 pounds into this carb and I believe it can be good .. but i really understand why people put a webber on... You and GTii have been so good that I shall carry on... I think it may be the overrrun solenoid and I will investigate but I might have to call it quits... I just dont have the time and money to fix this.. I will of course sell the carb tos omeone on here as I think it really is just a few settings and screws .
My issue is that I have had a hard year. i work for the government and have been part of their covid surge team. i just want a summer drive to make things seem ok... I don;t want a show queen or anything like that , just to enjoy my scirocco.. This carb is killing me and I can't afford to carry on.
Ive seen the webber on ebay and I am confident i can borrow the cash to get this on just so I can drive.,... If anyone wants a pierburg with new wax stat and hoses and gaskets etc then please just ask me...



WreckTangle
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Re: PIERBURG Rebuild - pre build advice

Post by WreckTangle » Thu Jun 10, 2021 3:56 am

Before you throw in the towel and fit a Weber be aware that they aren’t a panacea. My Scirocco came with a Weber fitted by a previous owner and it never ran right. It would conk out due to fuel starvation, especially going uphill. I restricted the fuel return (which seems an awful bodge) and this improved it a lot but it still had flat spots and sometimes seemed like it was thinking about conking out. It was also running a bit lean and tending to overheat. It has run perfectly since I restored the Pierburg and installed it. That said, I think some of my Weber’s problems were due to a leaking carb flange.

I feel your pain! I also work in the public sector and had a busy and anxious year. That said, it was great as a “keyworker” driving to work on deserted roads in the Scirocco.

My advice is to work through the Pierburg testing regime methodically. You don’t actually know what’s wrong with it yet. When I first installed mine I struggled a bit with the idle settings until I realised the throttle cable wasn’t quite right and was holding the throttle slightly open.



GT_II
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Re: PIERBURG Rebuild - pre build advice

Post by GT_II » Thu Jun 10, 2021 11:43 am

h11poc wrote:
Wed Jun 09, 2021 11:12 pm
I think it may be the overrrun solenoid and I will investigate
The manual suggests to test the overrun solenoid, simply unplug while the engine is running and the engine should shut off. It would be interesting to see if unplugging it has any effect at all. To test the electrical part of the solenoid, with the ignition switched off, measure the electrical continuity between the connector and earth. If there is no continuity. the solenoid coil has failed. If you do have continuity (I'm guessing between 10 ohms and 100 ohm), I'm guessing the fault could be mechanical (solenoid stuck) or vacuum related.


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h11poc
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Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Thu Jun 10, 2021 3:27 pm

SO I tested everything as suggested. The current is all present, when removing the plug to the overrun solenoid the car carries on running.
There is 0 volts when ignition off and 12 to it when on. There is no vacuum past it when ignition off but vacuum past it when on so the overrun solenoid is not the issue.
I now have the carb off and checked all lines which are fine and new.

I am trying to test this 3PU as it has to be that unit causing the issue which is ironic in that its more expensive as a part then an entire carb
The reason i think it is this is that given the nature of the system it can't be anything else. The ovverun and switchover have current and have passed the tests as per the manual.
I'm hoping someone will have a spare one.



h11poc
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Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Thu Jun 10, 2021 5:26 pm

Attached is a picture of the 3 point unit. Port blocked off for the test. Thanks kindly to Ian who is seeing if he has a spare.

Today while I had the carb off I read that Pierburg manual again. But this time looking at the carb on a table and being able to see everything.
It has started to make a little more sense now.
You do not have the required permissions to view the files attached to this post.



h11poc
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Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Thu Jun 10, 2021 6:52 pm

Ok, no spare found so I will have to find one.



mark1gls
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Re: PIERBURG Rebuild - pre build advice

Post by mark1gls » Thu Jun 10, 2021 10:12 pm

I think after this you are going to be the “go to guy” for anything Pierburg carbs.
Great thread with plenty of info for anyone searching so please keep updating us on your progress.


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h11poc
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Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Thu Jun 10, 2021 11:08 pm

I'ts really odd but it snaps into place all of a sudden. Suddenly today i just got it. I now know I will have to wait for a 3 point unit so I bought a weber anyway as a good deal that got listen on ebay. 150 all in including adaptor flange for base and also for airbox plus a spare.. I'm going to change the jets and at least I can drive while I source the 3 point unit.

That Pierburg manual GTii and Wrecktangle talk about is worth reading a few times as what seems complex actually become a very simple procedure and working mechanism.

The weber is temporary for this summer but this pierburg will be back on the car as soon as the 3 point unit is found.

Now the issue more pressing is servicing the entire car and I guess it's across a few sections of this board but if anyone has recommendations as to what spark plugs, oil , filter, anti freeze or whatever please let me know or point me in the right direction .



WreckTangle
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Re: PIERBURG Rebuild - pre build advice

Post by WreckTangle » Fri Jun 11, 2021 8:54 am

You probably want to start a new thread on servicing. What I used was.

Spark plugs - New old stock Bosch W7DTC
Oil - Quantum Synta 10W 40 Semi-synthetic
Filter - VW 056115561G
Coolant - Comma Xstream G48

The oil and filter change is one of the easiest I’ve ever done. Everything is so accessible. I have at the back of my mind that the spark plugs are fiddly to get in - use an off-cut of garden hose to hold them. If you’re going to do a coolant flush it’s probably worth getting a new thermostat and plastic thermostat housing too.



h11poc
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Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Fri Jun 11, 2021 5:18 pm

I can put this under the Engine category. I will remove the section of my post about servicing as if anyone else searching for Pierburg finds this post I guess they won;t be interested in servicing lol.

Thank you for the advice.

P



RussGLAuto
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Re: PIERBURG Rebuild - pre build advice

Post by RussGLAuto » Sun Jun 13, 2021 12:19 pm

Now this is interesting, it seems the Chinese have copied (but of course!) the 2E2 and offering them for sale on eBay:

Cheep at the price if they are any good...

https://www.ebay.co.uk/itm/324574398084


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GT_II
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Re: PIERBURG Rebuild - pre build advice

Post by GT_II » Sun Jun 13, 2021 2:05 pm

RussGLAuto wrote:
Sun Jun 13, 2021 12:19 pm
Now this is interesting, it seems the Chinese have copied (but of course!) the 2E2 and offering them for sale on eBay:

Cheep at the price if they are any good...

https://www.ebay.co.uk/itm/324574398084
Opinions on this aftermarket version of the 2E2 varied on this earlier thread:

https://forum.sciroccoregister.co.uk/vi ... se#p152246

However, the one person who said they'd tried it seemed reasonably happy, although it seems it needed some mods to work properly:

https://forum.sciroccoregister.co.uk/vi ... 47#p153147


1992 VW Scirocco GT II 1.8 90PS Brilliant Black 30k
2011 VW Caddy Van C20 Startline 1.6 TDI 102PS Beluga Blue 60k
2015 Skoda Yeti SE Outdoor 1.2 TSI DSG 105PS Brunello Red 30k
2013 Fiat 500 Pop 1.2 69PS White 35k
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h11poc
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Re: PIERBURG Rebuild - pre build advice

Post by h11poc » Sun Jun 13, 2021 5:28 pm

I can add my own opinion here to Chinese made copies. The reviews are mixed in most instances but biased towards badly made parts or needing some adjusting. I am a Musician too and the Chinese produce copies of various guitars which when modified can be as good as originals, however please note "when modified". I would be wary of a cheaper Chinese version as you must not expect it to bolt in and be as good as the originally built part.