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Discussion Starter · #1 ·
Well, that escalated quickly! lol I set out to look into our no AC issue and also some "woolly" throttle response on our latest toy (abused and thrashed VR6 6-speed highline 4Motion) and also to trace out some sketchy DIY wiring work behind the battery tray (see below for the 10A fused wire direct from batt + to a sensor at the back of the engine/box)

Motor vehicle Automotive tire Hood Light Vehicle


Automotive fuel system Motor vehicle Automotive tire Gas Auto part


However, on closer inspection there was a lot more than initially met the eye...

Hand Automotive tire Motor vehicle Gas Auto part


That's the melted/hacked/spliced remains of the reverse lamp switch and starter trigger wires. And this...

Plant Terrestrial plant Electrical wiring Wire Carmine


Is what greeted me inside the loom trunking. There's obviously been a small electrical fire in this area under the battery at some point, although not into the loom above & not sure what the splices there are about yet...

Following my nose (or more accurately, the gooey mess of insulating tape) led me to the larger ECU plug & this...

Electrical wiring Cable Electrical supply Technology Wire


There was a bit of insulation damage to the green & black twisted pair from the MAF plug so I'm hopeful that was at least part of the running issue. More worried about the "repairs" from this plug going towards the interior though, not sure why the orange twisted pair has been spliced/taped & then there's the grey/white wire that originally went to the orange plug on the bulkhead connectors...

Hand Food Recipe Finger Ingredient


As can be seen, this has some evidence of overheating although NOT on the grey/white wire (which had been overlaid and run direct to a bundle under the dash, more on that later though.) but on the red.green wire that runs to the ECU plug

Hand Finger Circuit component Thumb Electrical wiring


That's not good! Looks like it might have been a bad connection although the heat has travelled a fair way up the wire, it hasn't got crispy all the way along... The red/green and grey/white go to these pins on the large ECU plug...

Automotive tire Bumper Automotive exterior Electrical wiring Gadget


And no sign of distress at that end of the run. So, that's all so far on the engine bay side of things. Not nice, but not horrific either and certainly can be fixed without too much faff. However...

Automotive tire Motor vehicle Hood Finger Automotive design


There's the small matter of this little grey/white wire that was cut and overlaid (admirably in the correct colour and gauge of wire, although that's where the good-ness ends!). It was twisted and taped onto the corresponding tail left on the ECU plug & run through the bulkhead connector block...

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Hand Automotive tire Gesture Finger Motor vehicle


Coming out behind the dash & running NOT to the other side of the orange connector block as common sense would seem to dictate, but to this...

(see next post)
 

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Discussion Starter · #2 · (Edited)
Motor vehicle Electrical wiring Automotive tire Fender Gas


Not sure why my hand and the grey/white exiting above the crash bar is "sensitive content", although it could be electrical snuff-pron i guess lol. Anyhow, said grey/white does not go to the other side of the melted orange plug, but to the above (what can only be described as a confuckulation) of twisted together grey/white wires under the dash to the left of the steering column.. As well as this mess, I also uncovered a lonely black/blue going nowhere (although it's stripped I can't find the "other end" thus far)

Motor vehicle Automotive tire Vehicle Electrical wiring Gas


As well as a few other "bundles" of like-coloured wires seemingly crimped together by sheer force of hopes & dreams, such as these presumed lives...

Hand Gesture Thumb Finger Automotive tire


These earths...

Hand Finger Wrist Wood Thumb


And this bundle of grey/blues...

Finger Thumb Creative arts Woolen Rope


So, as you may have gathered I have a few questions. First one being, what drugs? lol

But in seriousness, if anyone can point me to a decent wiring diagram that'd be amazing. Also, are the above "bundles" factory? They are obviously different to the hackery perpetrated by the last guy, but don't seem a very reliable means of keeping wires together permanently.

Next one, what would the black/blue have been for please?

Next, what are the grey/whites and what are they grey/blues please?

Final one for now, what would the melty red/green relate to? Heavier gauge wire runs back to the ECU connector and splices (factory stylee) into a smaller gauge before terminating at the pin marked on the photo. No melting that end.

I don't know what surprises me more, that the car ran & drove or that the damn thing isn't a melted mess burned to a crisp down some lonely B road at this point!

Brain is frazzled for now but will be back on the hunt to put right the wrongs soon, any guidance from those with more VW experience MUCH appreciated cheers, Dan.
 

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Discussion Starter · #4 · (Edited)
I was half tempted myself to be honest. Spent a few hours tracing wires & cutting out shitty splices/soldering in better ones & threw the dash/column etc back in. Still got strange readings on the lambda heaters but it's behaving a little bit better now & runs better/disconnecting the MAF now has an effect, plus I've got rid of the permanent +12v to the VSS & it's got it's own ign+ back so made some progress. Also cleaned up the gear linkage while the battery tray was out so hopefully resolved a stiff lever when hot problem, and opened the instrument cluster to realign the temperature gauge needle which was inexplicably about 1/8th turn anticlockwise of where it should have been.
 

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Discussion Starter · #5 ·
OK been a while since updating here, not had much playtime on the rats nest...

So it's been running better but not great & still no cooling fan action, so I've pulled the front of the car off to go through the vacuum hoses and electrical bits inaccessible with the nose on. First port of call was an obvious leak through the manifold flap diaphragm, sorted for now with a gob of silicone (don't suppose anyone sells the rubber seperately, guess it's a case of buying the whole actuator?)

Couple of other rotted bits of rubber replaced & deleted/capped off the SAI to gain a bit more space if nothing else & on to looking at the leaky AC compressor... Or it would've been if I didn't see more electrical gimpery, this time in the form of a replacement electric water pump with the wrong connector (so... After spending the time, money and effort to replace the pump & G12 we see the plug is wrong. What shall we do, adapt it to work? Ummm, nah just leave it unplugged it'll be fine.) If I rolled my eyes any harder I'd be looking at my frontal lobe. Hopefully this hasn't been too long like this & caused too much heat issues, how important is the electric pump on the 2.8?

So, pick a connector to fit off a Peugeot parts loom (Brake fluid level sensor to be exact) & splice that in and the pump works. I'm guessing from it's behaviour it's more to keep temps from spiking on shutdown but running without can't be good at all.

Anyhow, with that one sorted I've gone to the fans next as I'm back in electrics mode. Fan switch in the rad is duff & the main fan had no low speed, simple enough fixes just requires a new switch & a rework of the motor with an external resistor off a Pug 206 cooling package (did I mention I'm an automotive hoarder lol).

Back to the AC leak, removed the compressor and am waiting on either a replacement unit or a reseal kit (used replacement £20 or seal kit + shaft seal will work out about £35... Swap bad for "good", or "better the devil you know"? Internally the compressor looks decent, certainly nothing burnt up, then again the replacement has no evidence of UV dye escaping in the first place. Decisions decisions... That's about all to report on the thing for now.

Oh, apart from the MoT expires next month & it still needs at the very least front wishbone bushes, 4 tyres, a back box/repair the original and, umm, a pair of cats... Meow.
 

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I've been though some of these ( silencer back box had a hole) ended up finding a second hand Milltek cat-back exhaust that had been fitted to an S3 or something , found an eBay supplier that made the connector pipe up for the ( I thought it was 65mm but it is apparently 64.8mm) connection to the 2.75" tube. everyexhaustpart on eBay . The vacuum leaks were a nightmare and turned out to be leaky injector seals (mainly) with the brake booster hose having the common splits behind the silver foil heat shields. I also had a dodgy non-return valve near the vacuum reservoir Pierburg 046905291A. I do get the odd catalyst code but clear it, but have bookmarked this one because it has the heatshield mountings 1J1131701EX - Direct fit catalytic converter 77017 | eBay. Also just had my lower wishbones replaced - cheap as chips and didn't bother with special compliance bushings ( from the TT Mk1 and S3 of the era) - just go with decent brand name wishbones instead of the bush alone.

Also, finally I do think that VW crimped the grounds like your first pictures - pretty sure they are factory
 

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Discussion Starter · #7 ·
That's interesting on the injector seals, kinda makes me wish I'd pulled the manifold while it was apart now but I don't think there's much going on there. Guess I could give the injectors a spray with brake cleaner see if that makes any difference to the idle. Non return valve seems to have been sound (pulled a vac on the reservoir and it held when removing the pump).

Given the wiring issues & strange O2S heater readings I am leaning toward a damaged/spiked ECU more than anything, also it's never thrown a cat efficiency code despite having the downstream sensors working (although we've probably not driven it enough to throw one). The only recurring codes at the moment are an occasional O2S heater code and a very random, maybe 1 in 20 starts of the engine, P0343 (IIRC) Cam sensor bank 1 lost signal (which reminds me I need to look into that as we do have a fairly long crank time & that's not going to help it run it's smoothest)

Thanks for the heads up on those cats, they look reasonable if my cheap self can't find used lol. I'd prefer to keep the OEM wishbones and just replace the bushes, partly because stingy bastid but mainly because the ball joints are like new too.

Cheers for the response & ideas, I do appreciate them.
 
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