Resurrecting the Orange Roughy

Started by typ53, August 19, 2023, 03:51:37 PM

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typ53

A decade ago my Corrado failed a warrant due to a broken front subframe mounting bolt.  Add 1 new child, impending renovations and an interesting new mistress (964) and the Corrado subframe repair dropped well down the list of my priorities so it has sat gathering dust since.

My 964 is now off getting open heart surgery so it is time to rediscover the mk2 itch. 

The subframe bolt was a pain involving drilling out the old shank, a broken tap knocked out from inside and a thread repair but turned out to be the easiest part of the process. 

The Fleet:
Orange Roughy:'90 16v Corrado
'89 Carrera 4. 
'12 330d Touring
Still trying to figure out how to get 'em all to fit in a single garage....

typ53


As a taste of things to come, the clutch pedal went to the floor...it started once, stumbled, died and it didn't start again.

Clutch master, slave and hoses replaced, brake hoses replaced and onto the starting issue:

No fuel.  Power at the pump, relay confirmed working.  The main pressure pump was seized.  New pump and filter fitted and it started, ran very roughly for a bit and then died and refused to start after that.

The lifter pump had voltage but didn't supply fuel so the main was running dry.  The mk2 intank pump assembly has a rubber and metal fitting that changes from 13mm at one end to the 10mm pump outlet diameter at the other end, presumably to absorb vibrations and allow a little flex as the pump starts.  On further investigation that part had turned to chewing gum.  And went NLA a few years ago.

Who knew that rubber parts don't like sitting around unused in fuel? 

I tried replacing it with a brass reducing fitting, some hose clamps and 10 and 13mm ID flexi in-tank rated hose.  2 new pumps fitted.  Successful start, dreadful idle with no acceleration which I put down to poor tune initially.  However it refused to start after that.  Again.

Main fuel pump seized.   Again.  The lifter pump was working but the hoses were all distorted and it looked like the pump was twisting in operation and was closing off fuel flow as it twisted.  The original pump has an oval shaped filter on the bottom with a couple of pins sticking up that attach to the pump assembly via some rubber strips whereas the replacement had a round one with no pins. I just used a nylon cable tie to hold it in place and thought no more of it which looks to have been a mistake.  The oval screen appears to be available on ebayfor about the same price as a new lifter pump.

Fuel was also coming out of the accumulator at the wrong end.  There is a screw at the other end of the accumulator from the hose fittings and it was weeping from there so this time a new accumulator accompanied the replacement main pump.

I happened to be in having a chat with David Gouk about the ongoing 964 engine rebuild and mentioned the lifter pump hose issue.  He suggested some Teflon fuel hose and kindly gave me some short offcuts of AN-6 and AN-8 braided pipe.  Genius! The Teflon core of these is convoluted and semi-rigid and fitted well after some gentle persuasion with a heat gun and secured with jubilee clamps.

So, deep breath and it started repeatedly with a poor idle and no acceleration.  Success of sorts.
The Fleet:
Orange Roughy:'90 16v Corrado
'89 Carrera 4. 
'12 330d Touring
Still trying to figure out how to get 'em all to fit in a single garage....

typ53

#2
It turns out that k-jet fuel metering heads and warmup regulators also don't like sitting for years with fuel slowly turning to varnish in them.  The plunger in the metering head was stuck solidly in place and I had a sneaky suspicion that the wur was also going to need attention so I ordered rebuild kits from k-jet specialties over in Queensland.  https://k-jet.biz   They were really helpful and had all the bits that I needed including a tiny cap from inside the WUR that I misplaced and then found on the same day that the replacement arrived.

The metering head came apart with a little heat and a few gentle taps with a rubber mallet and cleaned up nicely in the ultrasonic cleaner.  The rebuild was fairly straightforward with all the seals replaced.  The WUR has a couple of filter screens, one of which was pretty full of crud on mine.  I took the whole thing apart, ultrasonically cleaned and rebuilt it as per the instructions on k-jet.biz I also drilled out the back cover plug as per the WUR-mod for 16vs thanks to the helpful instructions on www.clubgti.com and replaced the injectors at the same time.

Fuel pressures all set, balancing the injectors using the adjustment screws on the metering head was a bit laborious.  I bought some solvent proof graduated measuring cylinders from a beauty supplies place online for $4 each which made things much easier.   The factory manual calls for 80mls delivered in 40secs at full lift of the airflow plate, tolerance +/- 8 mls across all of the injectors.  I managed to get them +/- 1 ml with 6 or 7 runs.  Getting the fuel flow down took a bit longer and I'm still running a bit rich.

The idle was better and it accelerated at this point but had quite a flat spot.   Ignition timing was way off, so with it adjusted to the factory timing all of a sudden the engine came alive.  Proper tuning to follow, but it is a huge improvement.
The Fleet:
Orange Roughy:'90 16v Corrado
'89 Carrera 4. 
'12 330d Touring
Still trying to figure out how to get 'em all to fit in a single garage....

typ53

#3
Onto the brakes.  15 years ago I bought some (then new) mk4 rear callipers with the intention to fit them at some point. This seemed like the ideal time given that I was going to be bleeding the whole system anyway.  So on went the new braided lines to match the shiny new rear callipers along with new handbrake cables.  What could go wrong?

So long story short, alloy callipers with steel pistons inside really don't like sitting around dry.  The pistons were badly corroded and one of them was frozen solid.

Thankfully I had a rebuild kit for the old ones so they are rebuilt and back on the car.  The rear shock bump stops are also literally dust at this point so that's the current roadblock.  Bizarrely VW NZ had exactly one set of mounting nuts and bolts on the shelf but the bushes and metal parts are now NLA so I'm now awaiting yet another shipment from Spareto.com via James the DHL guy who I'm now on first name terms with.  Silver linings...
The Fleet:
Orange Roughy:'90 16v Corrado
'89 Carrera 4. 
'12 330d Touring
Still trying to figure out how to get 'em all to fit in a single garage....

dubstar

"I am so clever that sometimes I don't understand a single word of what I am saying."

RS ZWEI

Awesome. Funny how so many old school VASKers have come back to the forum.
1980 VW Golf GTI Track Car
1995 Audi RS2
2003 Mini Cooper S (Written off - rear ended)
2005 Mini Cooper S
2006 Skoda Octavia vRS Combi
2009 Renault Megane 230 R26 (Written off - rear ended)
2013 Renault Megane RS265 Redbull RB8

80 Vert

Good to see you back on the Corrado, old fuel if not replaced will seize new pumps as well in pretty short order.
The old fuel dries the pump out causing it to seize. Soaking the pump in degreaser overnight sometimes gets it working again
2010 T5 Transporter TDI  Tuned by Superior Tuning NZ
2003 Jetta Coupe soon to be R36TT
1991 Golf GTI 2.0 TSI swapped
1963 Type 34 Karmann Ghia, turbo 2.0
1990 Porsche 964 911 Carrera 4
1980 1303 Beetle vert, under restoration

GLIDN

#7
Welcome back,

very informative as always, If you can be bothered really, should post some photos too. But that's really your choice to be fair.
Good to see another Corrado coming back to life.
Audi A4 DTM - K04 NZ New | All bolt-ons | Carbon Clean done
2012 MK6R Golf |Stage 3+ | Stage 4 DSG | Tuned & Built by HSP Tuning

typ53

Hey guys,

Good to see some old familiar names still floating around - are Robh and Jem still out there too?  Dubstar...was that you over in Oz now?

I tried to upload some images but the site wouldn't let me.  Something to do with storage.  I'll try again shortly.

This week's little mission was to replace the bump stops on the rear shocks (pretty much orange dust) and also replace the brake proportioning valve. The old one was seized solid.  I've no idea how to set the valve so I've more or less put it and the adjusting spring back where the old ones were.  Fingers crossed there. 

The rear shock bushes were a bit of a PITA to get back in.  The guys that put my Konis in back in the day left a few small parts out and installed the bushes the wrong way around.  I'd ordered a repair kit that had the metal washers and spacers required but they didn't fit.  The Koni shock shaft seems to be a larger diameter than the factory one so I ended up cleaning up the old metal parts and drilling out some washers to make them fit.  Lots of pfaffing around and swearing but done.

Brake bleeding to come this week and hopefully back on the road.  Fingers crossed!

The Fleet:
Orange Roughy:'90 16v Corrado
'89 Carrera 4. 
'12 330d Touring
Still trying to figure out how to get 'em all to fit in a single garage....

RobClubley

The image upload function broke about 15 years ago :)
I host mine on imgur.com and link them across.
1985 ur quattro
1992 Ford Courier - the sensible daily

Period_Correct_

Ha! Welcome back and nice to see project life is still kicking!
1971 Porsche 911T | 1990 Audi Quattro Turbo | 2003 Audi RS6 Avant | 2009 Renault Megane R26

typ53

BIG moment today: the old girl limped around the block, the first time on the road in 9 years! 

It ran like a bag of poos but I take it as a win.  I think the WUR needs a little adjustment so hopefully I?ll sort that over the next few days and see if it will get a warrant.  (Last one expired in July 2014). 

Now to find someone with an exhaust gas analyser to help me set up the CO%.

The Fleet:
Orange Roughy:'90 16v Corrado
'89 Carrera 4. 
'12 330d Touring
Still trying to figure out how to get 'em all to fit in a single garage....

BB

Hello Craig!
I miss the cool old school vaskers.
 Good work you still have the Corrado.
 I just got Spinners old Coupe Quattro a wof.
The end is nigh, but the end of what is the question?

typ53

Hi Jem,

Good to see that you're still floating around.  Hope all is well with you.
The Fleet:
Orange Roughy:'90 16v Corrado
'89 Carrera 4. 
'12 330d Touring
Still trying to figure out how to get 'em all to fit in a single garage....

Pristle

Quote from: typ53 on December 03, 2023, 03:38:20 PMHi Jem,

Good to see that you're still floating around.  Hope all is well with you.

Ditto