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graffboy

6N2 Rough Idle

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graffboy

Hi guys, My car had recently been making a "tractor" like sound for some time. It started off small but got louder and louder and i find it really embarrassing to drive now :oops:

From doing some researching, I discovered it was (i thought) the exhaust manifold gasket, and it was definitely coming from that area.

My mechanical experience is pretty limited but i have a basic understanding of how engines and other components work. I like to get in about it and have a go myself. In the past i have done simple things on my cars like brakes shoes/ cylinders, handbrake cables. So i had a flick through the haynes manual and the gasket seemed pretty simple to change :thumbsup:

Upon getting the manifold off, i noticed there was some cracks around the pipes at the start, and the gasket itself didnt look deteriorated. Here are some pictures i took:

bhaqkg.jpg

30cr3x0.jpg

2zsz9kz.jpg

At this point i was pretty certain it was the manifold itself that's leaking and not the gasket.

But anyway i went ahead and installed the new gasket and proceeded to put everything back together. hoping for it to mystically sort itself haha! JK i knew it wasnt going to fix :(

When i went to start her up, the engine light was on and it was idling lumpy. sitting at ~800 and frequently dropping to ~500. I know obviously the manifold needs changed/ repaired. but it was never running like this before. here a video i took of it idling :(

Heres a few other pics i took, I thought these parts were abit oily looking but not sure if its normal or not :paranoid:

2ufez6a.jpg33kqgox.jpg

Also this little cappy thing didn't look right, i popped it back over:

ajntr6.jpg

Sorry for the long post, but i know the more info i give the better i can be helped :D

Hope someone can help me :thumbsup:

Edited by graffboy

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dixy

It may just be me, but I can't see any cracks? :?

By tractor nose, do you mean a deep loud exhaust note? Or a tappy diesel engine? If it's the exhaust note, then it is most probably a brocken flexi section on the down pipe. Mine broke clean off and it pissed all the neighbours off. I would have kept it like that but the mpg went up :)

Have a look underneath and have a feel around for blowing. I look around for a used downpipe, but because they have the cat on it, all the breakers yards wanted 85-100 for it and it will most probably blow again. I went on eBay and bought a stainless flexi section and had it welded on and it's better then new and cost £25.

As for the lumpy running, make sure the lambda sensor hasn't disconnected and that all the other connections around are secure including the temp sensor.

As for the throttle vody, that is nice and dirty. Take if off (4 Allen bolts) and get yourself a litre of petrol and a bucket. Use an old tooth brush and scrub the inside of it intilits spotless. Dry it off and refit.

There is also a breather pipe to the left of the manifold, remove this and clean it out with some petrol, again dry off before refitting.

Check the pipes going to the throttle body for splits, especially to the roo d plastic valve as this would greatly effect the idle.

When you refit the engine cover there are two pipes that need to go back on, make sure thenr on properly.

Once you clean the throttle body the car may well run worse for a while, this is normal as the ecu is adjusting itself. If it doesn't go away after 30 miles thenthe temp sensor may be faulty.

Also, on the mph engine the front lambda sensor is a big part of the fuel trim system, and is a different sensor to other polos (why Vw did this, I don't know) so if this is failing the engine will run crap.

Hth.

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dixy

Just watched the video and yes I would say its deffinarly the down pipe.

Get it jacked up and have a look.

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graffboy

Hi dixy, thank you for the reply

here is a closer pic of what i think is a crack (just at the opening of the pipe)

30ni5qr.jpg

I've had a check at the downpipe. I cant see, hear or feel any blowing from it, only thing I noticed was the braided wires have disappeared from the flex section :s

I can feel blowing when i put my hand next to the manifold. I did try to seal it up with some exhaust putty, but cant fully cover the underside of the pipes due to awkward angles. perhaps i should fully remove the manifold and thoroughly cover the cracks? probably better to just get a replacement from teh scrappies?

Thanks for your advice on the throttle body! :thumbsup: I'll definitely be doing that when i get time, love reasons to work on the car :biggrin:

Also, I checked all the connections and i hadn't reconnected the sensor on the manifold :facepalm: :oops: took it for a run, power randomly dips, like flat spots, but just randomly. Engine light has now went out :thumbsup: . Was idling ok when i parked up, still loud as f**k though haha!

what do you think the best thing to do from here? replace/ bodge manifold then go from there?

once again thanks for your reply! :D:thumbsup:

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nige8021

Get a replacement manifold, you'll never get a bodge fix to last.

As for the throttle body, I would'nt use the petrol method, get a can of spray carb cleaner (£1 on my local market) and a old toothbrush I did mine without even removing it from the manifold as I forgot to take the allen keys with me :lol:

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adam-

Sounds like the manifold is burst.

Pretty sure the ones on the Lupo are the same, the 1.0 ones, anyway. Nige should confirm.

Is the steel wire around the flexi not supposed to be there, though?

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dixy

I can bet that your pre cat is blocked. Happened on mine also

If your is cracked or damaged then I would replace. I didn't know this at the time but you can fit straight through ones that don't have a pre cat. So from the 1.4 100hp etc. I cut mine open and removed the melted insides then welded back up. Instant power boost.

What's likely happening on yours is the gas can't escape down the pipe so it goes out through the seams, as these aren't welded there just pressed together.

As for the throttle body, if you can get card cleaner then. Do so, it's just I can't get a can for less then £7 near me and every time I get one someone nicks it. So for me a litre of petrol is around £1.30 so it's cheaper. Although you can use any defreaser so gunk jizer etc, as long as you dry it off thoroughly before fitting back.

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graffboy
Get a replacement manifold, you'll never get a bodge fix to last.

As for the throttle body, I would'nt use the petrol method, get a can of spray carb cleaner (£1 on my local market) and a old toothbrush I did mine without even removing it from the manifold as I forgot to take the allen keys with me :lol:

for the manifold, is it ok to just get a used one of ebay or from a scrappies? rather than a new one, seen them priced between £100-£200 :(

i going to remove the throttle body and clean it just for the experience :) thanks for your advice! :thumbsup:

Sounds like the manifold is burst.

Pretty sure the ones on the Lupo are the same, the 1.0 ones, anyway. Nige should confirm.

Is the steel wire around the flexi not supposed to be there, though?

oh interesting! that will expand the expand the motors i can hunt for at the scrappies (if i need to go)

sorry, you confused at the last sentence, (its not hard to do :retard: ) do you mean it SHOULD still be there? Or it should NOT be there over time?

cheers!!

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graffboy

Hi guys, update plus a few questions here.

Thanks for the suggestion of cleaning the TB :thumbsup:

got it off and cleaned it yesterday. While i was removing it i noticed some damaged hoses. took pics of them.

As my knowledge is very limited, I'm hoping you can help me out? :roll:

Underside of the TB before cleaning it: (yuuk)

f60f26cf-68f8-44a4-9bbd-240fe5b562b4_zps

Damaged hose 1: Crankcase breather i think? :retard:

3ab08530-b312-474e-b03b-d528e37e7e8f_zps

Damaged hose 2: connects to the TB. no idea what this, some emissions thingy i guess :retard:

a57eb42d-4a6c-4414-88d9-fc3639a17a10_zps

Also got a bluetooth OBDII reader the other day. Reset fault codes and took it for a drive.

It shows fault code: P0134 - 02 Sensor Circuit No Activity Detected

Had a look about the sensor and checked the wiring, then i discovered this.......

Broken wire:light blue marked #1

IMG-20130523-00192_zps928fdb24.jpg

Hoses: I don't know what they're called so don't know how to go about looking for replacements :retard: do they have specific part numbers?

Broken wire: Could i just reconnect it by soldering some wire? I don't own one and have never done it before, but this is a great excuse to give it a go! :D

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nige8021

Hose #1 is the crankcase vent pipe part number 030103474C breather hose

For the smaller hoses connected to the throttle body and the carbon cannister, I used this http://www.ebay.co.uk/itm/8MM-SILICONE-VAC...e#ht_2586wt_904 As the rubber ones from VAG were £25+ ea !!

On mine the RED pipe had a 1" split in it and this was causing the EPC to come on intermittantly, I replaced all the pipes in the picture with the tubing above

AUDVacummpipes_zpsb1f32529.jpg

If there is enough wire on the connector then you can do a solder repair, use some heatshrink sleeving to protect it

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graffboy

Thanks for your reply! :thumbsup

I'm having trouble finding the crank hose online :( Would it be easier to just contact the dealer? Or can i get generic replacement simmilar to the silicon ones you posted? :D

Not sure about soldering the wire back, seems abit tight. And since this would be my soldering debut :retard: , probably safer adding abit of wire in between.

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nige8021

The crankcase breather pipe will be a dealer or TPS to supply, but you could get some larger silicone tubing from the same place, would be a lot cheaper :thumbsup:

If your not sure about soldering the wire, you could go to a scrappy and get a replacement bit of the loom with the connector and then solder or crimp the wires

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adam-

Soldering is easy mate.

Buy yourself an iron, some flux and some solder.

I'm not convinced by the whole flux in the solder thing, I like the flux to clean the iron.

Cut the broken wire (if its not already). Trim back 5/6mm of copper and twist together. Repeat on the other side. If you're going to put a bit of wire in between, obviously cut a small section out and trim and twist.

Dab your fingers into the flux and rub on the twisted wire - it helps the solder flow.

With the iron on, hold the wire, iron and solder (haha), or get an assistant until you're comfortable.

Hold the iron against the wire, and the solder against the iron and the two should flow into each other, cover the shown ends with solder.

Repeat for all 2 or 4 ends.

Cut a little heatshrink, place over the wire quite far down (otherwise it'll shrink because it's close to heat). Place the wires side by side:

_________ wire 1

_________ wire 2

And apply a little solder until they're all joined. Slide the heatshrink over and heat with a lighter until shrink.

Rinse and repeat.

Or, practice first. :p

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graffboy

What about the wire? What should I get? Went to maplins and realsed I have no idea what to get haha! I've got the iron amd some solder, just no idea what wire to get. And the heatshrink, bui that will depend on the size of wire right? Haha I'm such a noob :D

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adam-

The same kinda thickness as what's already there man..

And yeah, heatshrink obviously bigger than the wire. It shrinks..

Get some flux too, it'll make the solder flow so much easier..

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graffboy

Haha yeah but they had different ratings, like 6A or whatever, not sure what rating I need?

Flux is in the shopping list, cheers :D

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dixy

The breather pipes are such a common thing on the 6n2 and is a headache when you mix the f*ckers up it as nige said it's vest to use some of that hose, you can heat it up with hot water and bend it into shape then put into cold water and it holds.

I bought mine new from Vw at over £30 for a few hoses 3 months ago and they are on the way out again. I dont reconend it.

As for the crank brether hose in the pic, it doesn't look to have gone through yet, so remove it , clean it and use some electrical tape etc round it to protect it from whatever is rubbing it.

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graffboy

I ordered some silicone ones for the small ones like nige said.

The larger crank one has a tiny hole in it, I'll phone VW today and see how much they're wanting for one.

What about this wire, any idea what rating I should get? Or just get the highest rated that's the same size. I'm in work the now, going to head up after and get it :D

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Hodge_Polo

Did you manage to sort the wiring for the lambda sensor? I have had to order a new sensor as I'm getting an error code which indicates either sensor or cat failure, I'm going to go down the route of replacing the sensor first. My engine is running rough and has flat spots so I'm hoping the sensor change will resolve this.

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dixy

These engines use a wideband sensor so they are not regular ones. Changing it will make the engine run totally different and be a lot more economical. BUT check the wiring under the plastic conduit first, as it could well be damaged and give a false reading.

As for the wire guage I would think 3a or 5a would be plenty thick enough Sergey are low voltage wires. You may not even need to extend it, remove the plastic cover as that wire nay be long and stuck under the cover.

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graffboy

Fixed!! :D Cheers for the help lads!!

Soldering went ok, i just put a small piece of extra wire between the two, then heat shrink'd it.

IMG-20130528-00200_zpscc28ffd1.jpg

Got a new manifold from the scrappies for £40, still had the pre-cat sensor on it :thumbsup:

Pretty easy to fit, had small bother with down pipe bolts. Manged to get them off with a sketchy power bar made from a spark-plug socket head and some socket extensions :lol:

When the manifold was off, i decided to change the oil and filter, since its so easy to get to with the manifold off.

The filter felt like it was welded on! and after about 45mins of wrestling, it was off and not looking too happy tbh:

IMG-20130529-00203_zps114b394c.jpg

So now the tractor noise has gone, and i can drive around without being embarrassed :D

heres a video of how she sounds now:

I've still got some questions though :( and rather than start a new thread ill just ask in here.

There's a kinda knocking noise from the engine, in the video above. seen quite a few people asking about this and most get a 'not broke dont fix it' answer :p I just want to know what it is?

My whole down pipe and cat section look like a burnt colour. as if they have overheated, the backbox is fine. the braided part of the flex-pipe is gone. Is the normal or do i have a faulty cat? anyway to test?

My accelerator pedal has started vibrating when driving, doesn't happen at idle. I've checked to see if i can feel it through the clutch and brake pedals but it only feels like the accelerator.

Just want to say thank you to everyone that helped me here!! really appreciated it :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup:

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adam-

That really sounds like engine knock..

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graffboy
That really sounds like engine knock..

done a quick google to help me understand it :retard:

Its to do with the mix igniting at the wrong time?

Do you think a clogged cat could do this? Sending pressure back into the cylinders?

As we already know my knowledge is small but I'm eager to learn more. So apologies if the cat is a stupid suggestion :D

random thought: could a clogged cat cause the manifold to crack? theoretically makes sense in my head. but what do i know :)

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adam-

I don't wanna make it sound worse than it is - but if it's engine knock (you've Googled "pinking", it's basically when the engine is so hot that the fuel that's injected ignites because of high cylinder temperatures, and not when the spark plug tells it to spark.

But I'm worried that the knock is because of a worn bearing between the crankshaft and the con-rod.

The knock will get worse and then you'll need new bearings or at worse, a crank.

It depends though, it's hard to tell with a video..

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Jackobjason

Once you re-fresh the accelerator the car may run more intense for a while, this is regular as the ecu is modifying itself. If it doesn't go away after 30 kilometers then the temperature indicator may be defective.

Get a car rental services for vacations

Edited by Jackobjason

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