Some good advice needed (Radweld question with prob history)

[Ka` 0]

Hi gals and guys,

 

I am sorry for the long thread, but I am really at my wit's end and appreciate your opinions.

 

I try my best to learn about my lovely car as I go, but I am stumped and need some levelheaded (hopefully unbiased) opinions.

It's a late 1993 VR6. 86,000 on the clock.

 

My car's had a problem on and off for two years. I am driving along (no matter what speed, what weather, time of day) and

occasionally the engine just 'dies'. It stops pulling so fast that everyone is thrown against the seatbelts. Then it starts running

again as if nothing's happened. Occasionally, it doesn't recover from the initial hitch and kangaroos down the road. Rarely it just

gives up the ghost and stalls properly.

 

Other thing it does occasionally is going in the 'safe mode' where it limits the revs to just 2000, while feeling like it's running too rich

(engine feels like it's choking). Nothing helps with this situation, I need to coast it to the side of the road with the hazards on,

changing down the gears and trying whether it will start pulling again. If while coasting I turn the engine off and try to start it again,

it usually just idles very roughly and then stalls as if flooded. Once again, it may recover from this fault by itself and happily continues

pootling down the road.

 

Suffice to say, I am now slightly afraid of driving the car as I never know when someone not too alert is going to smack in the

back of me while my car's doing the jiggy of occasional death.

 

Now, the car's been in and out of garages. VAG (I know I know, I'll don the flamesuit), VW & Audi specialists and the fault's

never been fixed. So far, over the two years, I've had the hall sender, MAF, sparks, lambda and ignition leads changed. Still, consistent

errors in the engine speed sensor (yeah, I know it faults if not running), MAF and lambda appear. The errors are 'erratic'.

 

It seems to have a cooling issue as well, as I've had the radiator hoses and the radiator changed. Both just gave up the ghost, bursting leaks.

Still, I fill the coolant system so that the level's between the min and max in the expansion tank. It can be fine for weeks, then drop the level

so that you can barely see it in the tank when cold. Occasionally it drops an inch a day.

 

I've now finally submitted it to another VW & Audi specialist (Follett in St. Albans, please someone tell me if I shouldn't). He's looked at it for a

couple of hours. He says that he thinks there is a pinhole leak somewhere in the nether regions in the cooling system. He suggested Radweld

(dons the flamesuit again) to see whether that would fix it as otherwise he's quoting about £500 to have it fixed properly (I take it that's

labour for dropping the bumper and so on). He says that the cooling system fix should be tried first, as all my other problem could be related

to the erratic drops causing the water temperature sensor sending wrong info back to the ECU and therefore causing it to put too much fuel

into the engine (Temp sensor thinks the engine is cold?). He's noted that the CO2 emissions are also high, which would probably explain the

lambda sensor reported as faulty as it works overtime.

 

Should I really Radweld it? I've looked at the other posts on the forum and most of you hate it. I am mainly asking, because I am worried

that I don't have money to fix the problems. Let's just say that I spend the money on fixing the cooling system properly (I suppose this would

be a perfect time to check and fix engine mounts as well) and that didn't fix the problem. (Mr. Follett has looked at the electrical wiring to see

whether that is causing the problems, but as my luck goes, the car's been behaving like a model citizen, thus the wiring looks in working order.)

 

Let's just say it is the ECU... I dread to think... How much do they cost? If they're anywhere near over £500, I won't be able to afford a £500

cooling system fix and another £500+ for an ECU. If Radweld helps me for those couple of months so that I can fix the other problems and then

start saving for cooling system overhaul, is it really that bad?

 

Any ideas? And thanks for reading...

 

Cheers,

 

Rica

[Ka` 0]

*bump*

Sorry about that.

[stevemac 0]

Hi Rica,

 

I'm not too well versed in VR's but one piece of advice that I can offer is not to use Radweld.

 

Radweld is a "bodger's repair". There are ways & means to find coolant leaks, however small. I can't beleive a qualified mechanic has even suggested it as a permanent repair.

[Ka` 0]

Hi stevemac,

 

Yeah, I cringed myself when he said it, especially knowing the previous posts on the forum. I just so want it fixed as the C is impossible to drive atm.

 

But yeah, am sure I'd just have more problems if I took the cheap route... :cry:

Cheers,

Rica

[stevemac 0]

Only way that I can see of definitely eleminating the ECU is to borrow a "known working" one from somebody & see if that cures your problems.

 

I've seen numerous causes & fixes for symptoms similar to the ones that you are experiencing. Usually caused by a dead or dying sensor - working out which one is the problem.

 

External coolant leaks are usually fairly easy to spot. Checks need to be done when the engine is HOT. The coolant system may only leak when under pressure.

[vr6storm 0]

get it on VAG-COM asap to find out if you have a dodgy sensor(s),also it could be a sign of your fuel pump on its way out(mine used to oncein a blue moon stall suddenly......since having my fuel pump changed in 2003 its not done it since......................

 

and avoid using radweld,might be and idea to buy a samco set of coolant pipes and replace them all,have you checked the little plastic elbow that sits next to your slam panel going into the rad?......mine had a pinhole leak in it,used to lose some coolant every so often,got it replaced and no more leakage

[Ka` 0]

Hi vr6storm,

 

Everytime I have it on VAG-COM, lambda, engine speed sensor and MAF come up as sporadic. VW just erase the faults and return the car to me, but they come back every time. As the lambda and MAF have been changed and proven to be working fine, I am worried that after fixing the coolant leak, it could be either wiring (earths?) or, worst possible case, the ECU.

 

Cheers,

Rica

[Supercharged 2]

Everytime I have it on VAG-COM, lambda, engine speed sensor and MAF come up as sporadic. VW just erase the faults and return the car to me, but they come back every time. As the lambda and MAF have been changed and proven to be working fine, I am worried that after fixing the coolant leak, it could be either wiring (earths?) or, worst possible case, the ECU.

 

Hmmm... I wonder if these all point to a wiring fault or bad relay?

[vr6storm 0]

hi Rica

not sure on the lambda or MAF but pretty sure the engine speed sensor will flag up everytime due to the engine not running while its being VAG-COM'd,best person to ask is RW1.....he's the best one to talk you thru things to eliminate/find common faults etc,if you haven't any history of the fuel pump being replaced chances are after 12years its starting to give up the ghost,mine did after only 8 and as i mentioned it would stall every so often at junctions etc,also be as well checking all the fuses and relays are securely in their positions,ive also had a fuse go stopping the spoiler midway and the engine not running,after replacing the fuse i noticed all the relays and other fuses weren't seated too securley

[dr_mat 0]

Did you actually change the crank sensor then? If it's showing up as "intermittent" then chances are it's marginal. They usually get worse with higher engine temperatures.

I had the exact same driving-along-sudden-loss-of-power that you're talking about above and though it wasn't the engine speed sensor, it WAS the signal from the engine speed sensor (my unichip was faulty, and it remaps the engine speed signal). These two factors tend to suggest a genuine engine speed sensor fault.

As for the fuelling problems, that could really be down to lots of things.. You've already swapped the MAF and lambda - the primary culprits. What about this temp senor - is it genuinely faulty? You can see the values it's returning live on vagcom. These are very cheap and if there's any doubt at all you should definitely start here ..

The coolant loss being pretty major can mean you've got head gasket issues (had a compression check?), but it can also blow out if the coolant is overheating - there's a pressure release valve. I would expect you to see >110 on the dash before you start losing it from the pressure cap though..

You've got some complicated set of problems there ... ! :(

[dinkus 10]

Firstly, I'm no expert :)

 

But from a logic point of view, it sounds like it's something electrical/sensor related and I don't see how the loss of coolant would change the sensor reading so drastically that the car would stall. If VAG-COM was just throwing up a single-sensor error then it could be worth looking at that or the physical area around it. Three separate sensors all coming up with sporadic errors and then working perfectly normally again afterwards it does sound more like it's a wiring and most likely earthing problem.

 

It's worth checking all your earth points to make sure that there aren't any loose connections that could be causing you problems - maybe a connection drifts loose if you accelerate and turn left or somesuch, but then falls back into place when you slow down again?

 

With regards to the coolant system - don't put rad weld in! If, as Steve says, you get the engine nice and hot, then keep it running and take a look under the bonnet - is anything hissing or steaming or wet? Jack the car up and take a look underneath as well. Wiggle the pipes around a bit and see if that makes a difference (be careful tho, they'll be hot and if you do find a leak you'll get a jet of steam!).

 

Edit: Oh and if your guy can't figure out what's wrong, it could be worth taking a trip up to Stealth - if there's something Vince doesn't know about VR6 Corrados, it aint worth knowing :)

[RW1 0]

wonder if these all point to a wiring fault or bad relay?

 

Tend to agree Supercharged/Dinkus. This failure has all the hallmarks of an ECU relay, marked "109" on the fuse/relay panel. A grey plastic cover type for this age of car and it a regular fault due to improper lacquering at the base leading to corrosion and cracking of the conductor strips on the inside of the base. As these grey plastic covered relays have a problem, I suggest that it is changed out for a new one. Part number is the same but it will be a black plastic covered unit – 357 906 381A. It on the second row above the fuses, 4th relay position from the driver’s door side.

 

The MAF, Lambda & Engine Speed Sender all derive power from the Engine ECU or directly from this relay. So the ECU stored fault codes are indirect problems. Also, the injectors derive power via this relay direct and the "It stops pulling so fast that everyone is thrown against the seatbelts" is the fuel being totally cut off to the cylinders.

 

The coolant leak sounds like it only occurs when the engine gets overheated on the radiator fans, so it’s only when the coolant pressure is at maximum. Explained by the times it does it and doesn’t. Top up with pure coolant (G12+) and look for witness marks (pink!) and look for any leaks when it's hot like Steve says and best done when the radiator fan is running on/off when the engine is at it's hottest.

 

Also take a look at the exhaust tailpipe inside. Does it have white deposits at all? If no witness marks around the engine bay, it may be that the head gasket is in the first stages of leaking coolant directly into a cylinder and so the exhaust tailpipe will show deposits mildly.

 

The other is water in the oil. With this there may be a rise in oil level coupled with creamy white “goo” deposits on the inside of the oil filler cap. If this, then again, the head gasket is suspect for leaking coolant into the oil ways. The “goo” is not a conclusive test as a car that does short runs of 5 miles or less fairly often may also have these deposits on the oil filler cap.

 

Radweld – Sack the mechanic and drag him out at dawn to plead for mercy!

 

.

[Ka` 0]

WOW,

 

I remember why I frequent this forum. This is the first time I've really asked a proper question and am very happy with all the suggestions.

 

Did you actually change the crank sensor then?

No, crank sensor hasn't been changed while I've had the car...

 

This failure has all the hallmarks of an ECU relay, marked "109" on the fuse/relay panel.

Thanks for that. I have been reseating the fuses to various components, but have never even taken the relays out. Probably 'cause I would've been mighty upset if I found one of them dead, and could not get a replacement immediately. Stupid, I know.

 

I tend to agree with all of you. It sounds more and more like an electrical problem than a mechanic one (apart from the coolant). As I said, currently the car's purring along as if nothing's happened, so all the wiring testing I've done comes back as OK. I'll do the simple relay check/change and see what happens.

 

Thanks once again! I'll keep you posted. I'll owe quite a lot of people a pint once this is sorted :D

 

Cheers!

Rica

[chrishill 0]

Rica, I've had the exact same problem for a while now, driving along normally and the engine momentarily cuts out, and before I've recovered from nutting the windscreen its back to normal and I'm wondering if it ever really happened! does reseating the relays cure the problem for a bit? it seems to with mine. I thought it was the fuelpump relay to start with but swapping that didnt seem to work. Depending on the outcome of my accident I'll have to try swapping the ecu relay too, but chances are I wont have to worry about it :(

 

just thought i'd add my 2p and let you know you're not alone in your indavertant kangaroo hopping!

[Ka` 0]

Hi Chris,

 

I haven't had the time to check whether relay reseating/checking/replacing works yet. I am at work and the car at the garage. What I tried before, was to pull and reseat fuses, especially no. 15 (engine electronics, continued coolant circulation pump (VR6)) and no. 18 (Electric fuel pump, Lambda probe)

 

Suffice to say, am getting at least relay 109 sorted and keep my fingers crossed!

 

Cheers,

Rica

[Ka` 0]

Hi all,

 

Just an update.

I didn't go for Radweld, I saw the light.

I also picked up the car yesterday as it was doing nothing in the garage's yard.

The relay will be bought and seated today and I'll let you know what the old one looked like, whether it made any difference. Problem is, is that the Rado is purring along as if nothing's ever been wrong.

 

Now, the leak. As the mechanic said, he cannot pinpoint the leak exactly, but he thinks it is the (plastic) coolant tube. If he's going to delve so far, I agreed I may as well change the thermostat housing, thermostat and both sensors/senders while I am at it. This must be a bumper and radiator off job? So, I may as well have him look at the engine mounts? How much should the engine move when throttling?

 

Here's hoping I get my baby back soonish!

 

Cheers,

Rica

[vr6storm 0]

no need for the bumper to come off for any of that.................and any competant mechanic with a ramp shopuld have a new front engine mount off and replaced within 30 mins,in total for the replacing of the thermostat,sensors/senders,front engine mount and associated bits you should be looking at well under 2hours

[dinkus 10]

If you put the car in 1st and bring the clutch up, the engine shouldn't move any more than 2cm at most.

[dr_mat 0]

.. and don't forget to try the same test in reverse. The gearbox mount seems to be the first to go, and you can only tell that that's gone by using the reverse gear test.

[Ka` 0]

Hi,

 

How about gearbox mount then, is it a big job to have replaced? No use replacing front mount if the gearbox is the first to go :D

 

Cheers,

Rica

[dr_mat 0]

No, it's pretty easy to swap from what I hear.

 

I wouldn't swap it unless it's bust though, no point. You'll know - it's full of dirty old oil and will leave sticky black crap all over your subframe below it if it's gone ... :)

 

A lot of people suggest you use solid ones/uprated ones/golf diesel ones (i.e. a bit stiffer); which is fine - if that's what you want. But if you're looking to keep the car standard you'd be better off sticking with VW part, cos otherwise you'll hear a little bit more gearbox whine inside the cabin.

[Ka` 0]

Hi all,

 

Just a quick update. The relay in the car was black already, but I swapped it anyway to be sure. Car's been behaving until last night,

but that is very typical of it , so I don't think the relay changed a thing. Oh well. It's going in for the coolant tube + surrounding parts

change soonish.

 

Cheers,

Rica

[Roger Blassberg 0]

Rica,

 

Back in this thread you mentioned that you have in the past entrusted your VR to Follett in St. Albans. As a (probably cheaper) alternative, I suggest that you give Mike Chapman a call on 01727 844179; he is VW trained, operates from Hatfield Road, St Albans and has always given me very good service on my VWs. Together we have spent ages getting to the bottom of all sorts of issues with my VR6, and he has owned one himself.

 

There are several weak points in the cooling system, one of which you have identified. Another is the hose from the back of the cylinder head to the heater, and furthermore the short hoses to and from the oil cooler/heat exchanger behind the oil filter.

 

For parts I go to Murray McDonald in Hatfield 01707 272686; he is also very knowledgeable.

 

Good to hear of another Dragon Green VR6 in the area, but what is this "Ugly Duckling" business??

 

Best wishes

 

RB

[Ka` 0]

Hi all,

 

Well, the car's coming back tomorrow, with all the parts changed. Fingers crossed this is it. The mechanic's driven it and naturally all's well in the kingdom of Rado.

 

Good to hear of another Dragon Green VR6 in the area, but what is this "Ugly Duckling" business??

 

Roger, I've had the car almost two years now and it still has scratches and dings from the previous owner. As soon as I've managed to save some money, something more important comes up. Hence the ugly duckling.

 

Cheers,

Rica

[Ka` 0]

FFS,

 

Well, the car's as before, being a right biatch. I pootle on the motorway and suddenly the engine just stops pulling. As I haven't put the clutch in, the revs stay

in the normal range, the pistons are definitely going but it is as if the sparks won't fire. I usually just feather the gas pedal, ready for when it kicks in again and starts pulling. If I stepped on the pedal, you can hear the whistling from the K&N as it pulls in more air, but usually (not always!) the car then dies a choked death.

 

I've changed all but the coilpacks.

What does a failed coilpack feel like? Can it fail just partially?

 

I also have another ECU I can try. Will also have a look at the ECU loom when I know I can have the car off the road for a while. It does sound more and more like the is a serious electrical issue going on somewhere. I am going to change the whole ECU unit instead of just lifting the chip. Does anyone know the implications of this? Surely my mileage and so on will be completely screwed and I take it that VW will not certify the mileage, especially if the ECU is not new/installed by VW?

 

AND to top it all off, someone's taken a nice chunk out of the passenger side front wheel arch this weekend! Currently, I just want to sell 'it' and buy something more boring.

 

Please help, I am losing hair fast!

Cheers,

Rica