Intermittent power loss

[newsh]

Also, there's a bundle of earth wires bolted to the rear LH corner of the inlet manifold, near the dizzy, everything to do with the engine management is grounded on the bolt so check for corrosion and breakages there.

[predding]

Great - thanks so much again. Car is 1990 RR UR Quattro 20v. Going to check all the wiring in that area. Is there a diagram or photo anywhere of the coil low voltage connections, I have removed and cleaned the HT side but the opp end looks like a big plug. Apologies for all the basic questions but I am also mech eng not electrical and whilst I can follow logic, electrics are not my forte

[predding]

This is the coil area against the bulk head and this is the WFV incl hoses. All inspected and pressurised, no leaks. Also the Chinese sourced MAF and the Original Bosch unit

[predding]

Hi John, I sent you a couple of messages re the MAF...

[newsh]

Hi John, I sent you a couple of messages re the MAF...

Replied

[predding]

** Update **

Thanks to newsh great kindness, I have fitted another loan MAF and car runs 95% (still some stuttering but maybe needs a good run) so seems there is an issue with my MAF; I cannot believe there are no companies out there that can test these and repair them as I am sure being of that era its a mechanical contact or hot wire failure rather than a pcb fail (see pic) BTW does anyone know what the blue box on the right with the copper conn strip is as the outside port is blocked with a blue plug? and this component doesn't feature on the Chinese MAF or Bosch replacement))

During testing the water temp went to maximum but after lifting off and coasting, immediately went to normal, like the temp sensor was connected to the boost pressure! Then back up to full overtemp on pressing the throttle ie with the turbo coming back in

I am going to drop all the coolant (last filled July 2015) and check the thermostat, radiator fan switch and after run relay as mentioned in post #3 in this thread

https://www.s2forum.com/forum/techni...-connected-now

Its probably fate as I chickened out (lost mojo) removing the Inlet Manifold when I saw I had to remove the vertical radiator cowl and probably radiator to access the 5x lower IM Allen bolts to gain access to the distributor so I can fit the new HT leads and check the cap and rotor arm etc

I also need to check the turbo aux water pump and connections when I can find it...I think the old girl is just giving me grief for being ill and not having driven it in 3 years..

Thanks for the link posted on other threads to the SJM Autotechnik pages as these are a godsend to drilling into stuff

[newsh]

Glad I could help and shame there wasn't time to meet up. Hopefully we can meet when you bring the car to the UK next year.

BTW, saw Pete Berry yesterday and he said the rad probably needs bleeding. He says he usually puts a bit of pipe in the header tank filler to raise the water level. I think he uses plastic plumbing pipe that’s a tight fit. Alternatively you can detach the header tank and lift it a couple of inches. Bleed the screw in the top of the rad (and the heater matrix).

[newsh]

** Update **

Thanks to newsh great kindness, I have fitted another loan MAF and car runs 95% (still some stuttering but maybe needs a good run) so seems there is an issue with my MAF; I cannot believe there are no companies out there that can test these and repair them as I am sure being of that era its a mechanical contact or hot wire failure rather than a pcb fail (see pic) BTW does anyone know what the blue box on the right with the copper conn strip is as the outside port is blocked with a blue plug? and this component doesn't feature on the Chinese MAF or Bosch replacement))

During testing the water temp went to maximum but after lifting off and coasting, immediately went to normal, like the temp sensor was connected to the boost pressure! Then back up to full overtemp on pressing the throttle ie with the turbo coming back in

I am going to drop all the coolant (last filled July 2015) and check the thermostat, radiator fan switch and after run relay as mentioned in post #3 in this thread

https://www.s2forum.com/forum/techni...-connected-now

Its probably fate as I chickened out (lost mojo) removing the Inlet Manifold when I saw I had to remove the vertical radiator cowl and probably radiator to access the 5x lower IM Allen bolts to gain access to the distributor so I can fit the new HT leads and check the cap and rotor arm etc

I also need to check the turbo aux water pump and connections when I can find it...I think the old girl is just giving me grief for being ill and not having driven it in 3 years..

Thanks for the link posted on other threads to the SJM Autotechnik pages as these are a godsend to drilling into stuff

The blue thing is a multi turn variable resistor (potentiometer) I imagine it would be used to calibrate the MAF at the production stage.

[predding]

Glad I could help and shame there wasn't time to meet up. Hopefully we can meet when you bring the car to the UK next year.

BTW, saw Pete Berry yesterday and he said the rad probably needs bleeding. He says he usually puts a bit of pipe in the header tank filler to raise the water level. I think he uses plastic plumbing pipe that’s a tight fit. Alternatively you can detach the header tank and lift it a couple of inches. Bleed the screw in the top of the rad (and the heater matrix).

Thanks - since posting, it has gone way beyond that ;-) I drained down the rad and the stuff that came out wouldn't have gone amiss on our ploughed fields after the rains - disgusting. So rad out and all connecting hoses. I also checked the Aux turbo water pump and seized (motor buzzed but impeller didnt turn), plus the thermoswitch was dead as well so would not even have activated the cooling fan.This is what happens when one gets ill and the car stands for >2 years :-(

At least the cooling fan runs well on test. So have new switch and aux pump and have bought flushing fluid to clean all the waterways best I can and cooling tubes around to the turbo though will try and remove as many as I can and do them physically. I also dropped the thermostat housing; the t/stat worked on test but the gunge again was incredible

I also noted the oil cooler lines had finally given up the ghost and the engine had lost 2.5 litres of oil! After many weeks of persuasion and frustration getting access, the cooler is off but the boss conns suffered as the nuts were corroded so it needs a new cooler; I found one but am thinking I have been scammed on it as getting it shipped is like pulling teeth so if anyone has a spare cooler for the UR 20V VAG code 034117021D please let me know

https://audi.7zap.com/en/rdw/audi+qu...46/1/117-9020/

On the lines, I finally have them out. I had to drop the oil filter housing with them attached as an assembly as again, the nuts were all seized. In doing so I had to disconnect the line conns to the turbo body and noted the amount of carbon build up into the tubes at the joint face of the pipe. So here is the $64k question:

How is it possible to flush / decarbonise ? the turbo as with the aux water pump failed for God knows how long ie running hot and not cooling down after a run, it will have really increased the turbo temperature

Do I buy some proper oil flush and just do the turbo or ???

Thanks as usual for any comments - All in all, after 33 years, the old girl is getting a massive service

PS great you saw Pete - hope he is well

[K Simmonds]

I kinda depends how it was being driven, if you were thrashing the the pants of it and shutting it off straight away then there may be a bit of extra carbon on the exhaust turbine sealing rings which you can't do a thing about and it won't hurt the the turbo.

If you were just driving it normally then I really wouldn't worry about it, the after run pump is simply insurance from Audi that they're car will given a long life from -50 degree to + degrees ambient tempreture.

Those old KKK turbos are as tough as old boots and it really wouldn't have bothered it...

The pump is almost certain to failed whilst the car was stood so it's unlikely to even raised an eye brow so speak.

Giving the cooling system a good flush is a good idea, I leave the stuff in for a week if it's really dirty before dropping it and flushing through all the hoses I can get at with a hose pipe. You could also use a good quailty basic oil flush as well, certainly wouldn't hurt, don't use anything that claims to restore the engine or other such snake oil. I use Wynn's flush for both, two tins in the cooling system isn't a bad idea as it's high cappacity.

[K Simmonds]

Forgot to say a little carbon a build up on the inside of the return pipe is normal after this long as it's where the oil from the turbo does a great deal of it's cooling

If the car is running fine now I really wouldn't be worried by the condition of the inside of the turbo if it's not smoking, not all manufactuers even bothered with water cooling on 80's turbocharged petrols, depending solely on the oil for cooling. I'm pretty sure the first 10V UR quattro's didn't have water cooled turbos, I think that was introduced on the second generation cars.

I use to thash the pants off my RS2+ spec S2, until the the hotside was white hot even under daylight and the turbo in that was still going strong when I crashed it...

As I said those old journal bearing KKK journal bearing turbos are seriously tough, I've done work on cars with badly maintained cooling systems and found the water return pipe blocked solid my including own car when I first got it being included so you might want to check the water return pipe is clear... Those cars were however all still running fine with just oil cooling.

Those oil pipe unions frequently seize, a quick blast with map gas normally frees them off, however you oil cooler could probably do with replacing now anyway, I'm not sure about UR's but I know one type of S2 shares an oil cooler with a T4 van under a slightly different part code so it might be worth Googling that as I know the T4 one is half the price for same part... It would probably fit regardless but I can understand wanting to keep an RR quattro as original as posiable.

[K Simmonds]

Just reread your first post and you metion using a cooling flushing agent which is good, don't be scared to leave it in there a week whilst using the car unlike oil flush which is basically glorified parafifin (you'll notice they smell nearly identical) and thins the oil reducing the film strengh ever so slightly. When I first started in the motor trade that's what a few oil mechanics used as opposed to engine flush and if it was really bad half a pint or so of diesel would get used instead, they'd tip it in and take the car for a quick spin, that brings the engine up like new inside but it's not something I recommend.

Taking oil the turbo feed and and return pipes off at this sort of age is a good idea, compressed air and a bit of welding wire is the way to go on them all apart from the oil return which is large enough diameter to pull a rag through and this is the only one that should by right have any sort of deposit. Though as I've said I've sorted out cars with blocked water return pipes, I drove my S2 on Nothelle K26 hybrid for about a year before I took it off the road to upgrade it and only then discovered the blocked feed pipe...

How long it had been blocked I don't know, considering I gave up trying to clear it out and bought a replacement my guess is quite a while and I wasn't shy with the loud pedal once I'd gotten use to the car and it running properly. Not saying that was good for a moment but it didn't cause any problems with the turbo, I did get it rebuilt whilst it was all appart as it done 100K at 300BHP so seemed prudent... AET did the rebuild and they're really fussy they didn't remark on anything other than a cracked hot-side housing which is very normal even on a low milage car and even reused the turbine wheel/shaft, it's one peice just in case you didn't know. Well over 50% of the turbo's I've stipped have a hairline crack somewhere in the turbine housing, it's quite normal and as long as it's not interfearing with the wheel or leaking it's not really a problem.

After running the car with just water and engine flush for a good while blast all the hoses you can get at through with a hose pipe until the water runs clear out of the bottom of the radiator, paying most attention to the two pipe's going to the heater matrix. You may even want to take your radiator off and back flush it, turn it upside down and leave the hose it the bottom union for a good ten mins, this is best done after a run with a flushing agent. If your cooling system has been negleted for a long time then the matrix may be getting clogged, I'd certainlty be way more concerned about this than the turbo. I've never taken a UR dash out but my guess is that it's not any fun at all with lot's of old brittle plastic bits that can break and not be replaced. If you want to be super vigalant then do it twice, you've nothing to loose other than some coolant flush and time, you never know you may dislodge something extra the second time around. Don't waste coolant when doing an engine flush even a prolonged one, though you do want to get some back in there sooner rather than later with the onset of winter, though it has to be bloody cold to damage an Audi engine of this era..

I hope this more prolonged exlaination put's your mind at rest regarding the turbo. It really impossible to tell what's going on inside but one can at least get a good idea of condition by removing the intake boot and checking the end of the shaft for play, a little side to side/up& down play is perfectly normal, though not too much, the compressor wheel shouldn't touch the housing put it that way. However there must be zero end float, in and out play for want of a better explaination. I did go through a brief phase of building turbo's so had the the KKK rebuild manual on my previous lap-top, I've not bothered downloading it again as I don't rebuild turbo's for customers any longer as it's too much hassle getting them ballanced properly. I use AET or Turbo Dynamics for my rebuilds now if you want two decent companys to keep in mind, there's pleanty of others but those are two I trust, AET are the more expensive but they do a bloody good job and are who I'd use on my own cars...

Oh yeah, sorry to hear you've been ill, I've been ill for a long time myself though more mentally than physically. I hope your getting/are better.

[predding]

Thanks for all the comments, appreciated as it really keeps me going. I have now applied a coat of gloss black to the oil cooler and fitted it; I also had new Aeroquip type lines made up by local workshop who really helped me out in lending their couplings so I could mark and get the exact alongitudinal angle on the runbber hoses (once crimped, that's it!) It all fits well now and with a bit of fine tuning on the final fit will be all good.

I have also just come out of the garage after 3 days of summoning up the strength to literally rip the old HT leads out. I am convinced these were all fitted on the engine prior to its installation into the bay in the factory as the leads pass through 3x sets plastic lead guides and 1x at the back of the head buried deep which is bolted to the block FFS. I have broken 3 of the distributor lead connections but there was no way this was coming out without a fight. I have new distributor, leads and rotor arm and it will be a slow and steady job to thread all the new ones through the space. What a pig of a job. And sure enough, looks like the rotor arm is glued on so now need to re-read the forum and find out how best to remove it.

Then that's it. Apart from finding a new MAF aka The Holy Grail), I have then plateau'd and can start rebuilding everything. What started out as a simple radiator flush has turned into a full on engine bay refurb but as I never did it when I did all the running gear 10 years ago, its time has come.

[predding]

Update. These are the pics of the rotor arm, using a mirror to see the brass strip face. I think its fair to say 33 years of passing high voltage across the gap to the lead contact posts has taken its toll compared to the new one...

BTW - what do you all use now as a replacement for the braided vacuum tubing you can see in the background; I have come this far and there are alot to refit so makes sense to replace them as I am sure the rubber must becoming porous?

[K Simmonds]

I think it's safe to say that rotor arm needs replacing, looks knackered!

I use good quality Diesel leak off pipe to replace the small bore stuff as it has to petrochemical proof an looks OE, whereas a lot of vacuum pipe on the market is rubbish.