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Sorry to raise the ghost again but it's getting to me. Fine when cold but up to temp pinks under load. Timing's spot on, VW dealer diagnostic shows nothing. Using BP Ultimate (can't get Optimax). Dealer and trusted independent mechanic offer no solution. I've followed the thread on this site. Any new thinkng?
 

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Hello Arundo,

My Bora 1.6 16v (Oct, 2001) 58k has just started Pinking... I've not noticed it before and can't understand why it should start happening now (Past 2 weeks)? I hear it just after pull away from a start on a hill or under load / 2 seconds after releasing the clutch and pressing the gas pedel. It doesn't happen when the engine is cold.

Also when hot I hear what sounds like a controlled air pressure release (Strong hissing sound) when going down hills / flats without pressing the gas. It seems to discharge in 1 Second releases and 3 - 4 times, then repeats after 30-45 Seconds.

I used to run the Bora on Shell 98 RON and Tesco 99 RON super unleaded, but switched to normal unleaded Tesco 95 RON and shell 95 RON fuel for the past 6 months without any issues that I can recall.

The only things that I feel have changed in the past month are: I'm quite light on the gas pedel (Always have been), and my normal run to work has been brought to a snails pace due to road works. 45-55 Minutes to do 5 Miles! Up a very slight hill too! Handbrake job.. :-(

I'm thinking that Carbon deposits have been building up in the engine and causing the Pinking. But I'm not sure about this? Because after recently taking my car to VW service for a very small radiator leak (Rad seal fixed it for now), I was sure it did not over heat, So I'm happy it's not due to over heating). The Pinking started after my VW service garage visit... funny that hey!?

Last week I run a tank of Shell 98 RON through, but without any changes... So I've now opted for STD injector cleaner - Added to a tank of Tesco 95 RON.

My thoughts are:

Carbon build up, Vacum leak on fuel / air mix side, Sensor failure, VW service moved / knocked something while looks for all the common faults...

Will keep updating...

PS - Anyone... Any thoughts on the Hissing sound? normal right? Can someone comfirm that their Golf / Bora 1.6 16v does this?
 

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The only things that I feel have changed in the past month are: I'm quite light on the gas pedel (Always have been)
That's part of the problem. You really need to keep the revs up on the 16V. Boot it in 1st until you feel a shove in the back then shift quickly into 2nd and keep it revving.
 

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Thanks for the tip.. I've stuck a Post-it-note of the dash to help remind me to keep the revs up. I'll hold the revs at 2k before feeding the clutch in and keep pressing the gas until the clutch is full released... Noted.. cheers!

Yesterday evening, I prised off the big piece of plastic covering the engine to get to the spark plugs.. No screws on the big plastic cover... Just disconnect the breather hose on the left side, unclip the coolent pipe on the right and pull each corner (Rocking action) until it pops off.

My findings:

One coil very loose, loose enough to pop out just by touching it / a slight pull... It was the first coil near the clutch / gearbox end. This was the only coil that came out easily, the others had to be prised out with a flat end screwdriver.. a little at a time.. round and round until it pops off / comes off.

Removed / Checked all the spark plugs. The tips looked white with a very little grey / brown powder around the tips and side. I found a light black carbon around the end of spark plug threads. I removed all of the light black carbon of the spark plugs with light sand paper... carefully.

I shone a light into the spark plug hole and found light black carbon on the pistons crown. I'm not sure but I thought I saw very very small marks / scratch marks on the piston crowns. The light was poor so I could not be sure.. I thinking a little valve slap it taking place on the Pinking.. My thinking is pistons should have some back carbon in and around that area. Just how much is the next question?

[:O] Warning!! I had some REAL problems when removing 2 of the spark plugs. The spark plug tool I used kept getting stick in the suround where the spark plug sit. I had to use a little (1-2 small drops) of 3-in-1 oil to help free up the spark plug tool.

My advice is if you are thinking about taking the spark plugs out them MAKE SURE your spark plug tool fits ok!! If it's tight or remotely tight then forget it... I found the 2 spark plug holes nearest the Cambelt end were the most difficult. I was able to remove all the coils and plugs one-by-one without removing the coil cables. You have to remove all the little cable clips.. and be careful not to strain the cable / coil wires. I gave the spark plugs a quarter turn or less to fit them.

NB - Keep track of small tools / plastic clips near the spark plug holes when there are out.. If something drops inside the spark plug hole you're stuffed!!

I gave the Bora a little run after putting the spark plugs and covers on, but no change... Pinking when hot on hard / light-to-hard pressing of the gas pedel [:(]

My thoughts:

I think the Carbon has build up has reached a point where it's causing the Pinking to get worse / extra carbon build-up. So I think a different style of driving / fuel mix is needed (As suggested) to help burn off the excess carbon. Keep up the revs / high revs while driving / no blipping of gas pedel.

Q - Does anyone know of a Good / BUT safe way to remove the excese carbon? I have STD Injector cleaner added to the petrol at the moment and I'm waiting for it to work through the system. I will then switch to Shell 98 RON super unleaded once this tank of petrol is used up. I heard you might need 4 tanks worth before it clears the Pinking?

Q - There must be a strong injector / cylinder clear out there.. Name / brand?

Q - I read in the Bora hand book / Haynes manual that you can reset the Bora's computer fuel / air timing back to the basic setting / learn mode, by truning the key to position 1 or 2 and waiting for 1-2 minutes then switch off, then start the engine and drive it for a few miles. Can I use this to help reset the fuel / air mix timing? I now can't find the text I read about how to reset the computer to be sure I have done the job / reset the computer correctly?

Help? Does anyone know the procedure to reset back to basic computer settings?
 

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I know of a cleaner that is sprayed directly into the inlet manifold and the entire contents of the can is sprayed into the manifold. Can't remember the name but they sell it at Halfords. Made a big difference in my Mk3 GTi, took ages to restart though as the manifold was choked full of the cleaner and when it did kick after 10mins a huge black/blue cloud of smoke came out through the exhaust and the performance and fuel economy was excellent.

Another pinking solution could be by changing the leads? Leadsdo tend to only last about 3 years max as they deterioate through heat etc and as the leads break up, they arc and cause misfire etc. This happened when my old car was warm and the misfire occured at certain revs ie lower rpms. This could be a solution as the VW service computer does not seem to pick up a fault when the leads are arcing.

As for resetting the ECU, the best way is to disconnect your battery for 10 mins which then resets the ECU back to factory settings.
 

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Cheers for the update...

After removing the Air box and openned it (Many Many screws!), I found that the hot air flap in the closed position put the original installation seal was gone, it had in fact breaking up and had separated into smaller parts in the airbox system. I was worried that without this seal in place it would not be able to block off the hot air. This will cause hot air to enter into the air box all the time.

So I made a better seal by cutting down the middle a piece of three cord mains flex cord. I then pushed them (Three pieces onto the edge of the plastic flat and glued it down with some epoxy resin. I hope it holds and does the job of holding back the hot air after it's not needed anymore. I tested it with a hair dryer and it worked ok.

I tried to check First O2 sensor just off the first manifold down pipe. I disconnected it and found 5 wires attachd to the probe and connector. I measured all the O2's wire output while disconnected on resistances measuring meter (Hi / low ohms setting). But could only find 22k ohms between two pins, and nothing on any of the other wires. I was looking for Heater circuit wires for the probe.

Q - Does anyone know what the five colours are on this O2 sensor? Signings / expected Ohms?

Cable colour : Blue, Yellow, White, Grey and Black.

I have the 1.6 16v 2001 - AZD Engine with 5 speed manual box.

I would like to check the O2's heater Ohms? Being a heater I'm thinking it might be lower than 22k ohms?

Q - Which is the signal wire/s too?

I still get that Hissing sound when comming to a stop on a roundabout / lights. The car is in gear with no gas pedal pressed and the clutch not pressed. I get what sounds like a controlled release of air in short bursts of 1-2 seconds and repeates every 30-40 Seconds but only when you have your foot off the gas pedal. Anyone know anythink about this / heard this noise?
 

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Updates on my Pinking issue..

After suffering badly from Pinking for the past month or two on low engine revs and gear changers. I opting to use some extra help to clear out the carbon buildup. I'm now some 100 miles into using STD injector cleaner mixed into a tank of petrol. The Pinkings is getting a little less audiable and the extra pickup is more noticable. But still she Pinking.. but some what less than before. I guess the injector cleaner is doing it's job slowly.

In the meantime, I removed the Throttle housing for cleaning. I found what looks like to me like a butterfly air inlet / fly-by-wire accelerator module.

[:O]NB - My Throttle houseing doesn't match the picture in the Golf / Bora Haynes manual.. but then we all know what to expect from Haynes manuals, so know surprises there!

My Throttle housing is held in place with four bolts and a wiring connector that's used to control the unit. Remove the air box to gain access to the Throttle housing, then remove the four bolts and wiring connector from it. This will allow the Throttle housing to come off in one piece. Recover the rubber o-ring between the Throttle housing the EGR sub part. It's only a rubber o-ring so you'll not need a new one unless it's damaged in some way... bit unlikely thou.. but check the o-ring anyway.. An air leak where the o-ring is will make the car run rough!

Cleaning the Throttle housing - I use an old toothbursh, a flat edged screwdriver and a can of Brake Disc cleaner to clean out the Throttle housing, I guess petrol could be used instead for cleaning. I found the leading edge of the butterfly black with a build up of dirt / gunge to the outter edge / lip. You must remove this build up of dirt, as this restricks the air flow into the engine which can effects the air / fuel mix leading to rough / erratically idle! I use the flat edge of the screwdriver to lightly scratch off the dirt on the edge, careful not to damage or scratch the metal parts. I re-assembled and checked the o-ring / bolts / wiring were back in place correctly. I used a little KY gel on the o-ring to help stop air leaks. KY gel doesn't rot rubber[;)]

I found the cleaning of the Throttle housing had a BIG difference in the engines pickup and driveability.. Much more pull through the gears. She still Pinkins thou.. I'm guessing the extra carbon needs removing, The injector cleaner will hopefully continue to do it's job.

Tomorrow, The Bora will go to VW service to be checked... mainly to check the computers log for errors / advise on this Pinking.

My thoughts :

Because the AZD engine doesn't have a MAP sensor, I think the engine management system relies heavily on the O2 sensors and the coolent sensor for much of it's information on how much Air / fuel mix is needed. I suspect it's a fast closed loop circuit that relies heavily on the O2 sensors working in tip top condition. A little soot or dirt on these sensors could lead to an unbalance in the system very quickly.

Tonight, I hope to remove the first O2 sensor for cleaning... I'll also look at the EGR Valve for checking / cleaning.

What puzzle me is how the revs drop off when pressing the gas pedel.. what I mean is you press and try and hold the revs at say 1700rpm from idle. When the revs get to 1700-2000, the revs then drop off by 500-750rpm. This happens even if you keep the gas pedel steady. I thinking this is the root cause of the Pinking / loose of power... the computer is pulling back too early on the fuel supply / air mix for some reason which causes the engine to loose power / possible Pinkin!! I'm not sure why this is happening... Any thoughts anyone? It must be the O2 sensor possibly reaching the end of it's life / in need of a clean?

Q - Has anyone cleaned a O2 Sensor before? Did it make much difference?
 

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Where is the MAP sensor? Is it the same unit as the butterfly Throttle houseing? I never thought it's could be used to sense the air pressure / vacuum change. It's a shame it can't be opened!

I'll move the butterfly back and forth / lubricate it. See if that makes a difference.. It did feel quite stuff when I was cleaning it..

Anyway, the MAP looks costly...? ????
 

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Just got back from the VW garage. The tec took my car out for a drive then hooked it to the computer in the workshop...

30 minutes later came back to me and said... No pinking and no errors logged. Then the sales man said stop using Supermarket fuel...

Anyway, I'll continue to use Shell RON 98 from now on and keep up the revs... See how it goes in say 1-3k miles...

Will keep looking for a strong injector / cylinder carbon cleaner...
 

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Anyway, the MAP looks costly...? ????
Don't know if I misheard but the first time I had one fail, I was told they are ?300, hence I was glad it failed under warranty - then when the new one failed, also under warranty, I started to worry how many x?300 I would be forking out after the warranty period. Since the warranty expired, no problems with MAP sensors, ignition coils, lambda sensors, EGR valves or misfiring (all of which it did under warranty) and even had K&N panel filter and now induction kit for two years which some people swear kill air mass sensors. I can only say my car now runs smoother than ever and I'm loving it.
 

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Hi there,

Glad your car is running smooth.. it's good to hear that the 1.6 16v is capability to running smoothly! It gives me hope! The MAP being the most costly part, I'll keep it in mind until it comes to the crunch.

I took the 1st stage O2 sensor out and cleaned it up.. Disc brake cleaner... gave it a good soaking and re-fitted it. Not much to clean thou.

I got a little fright [:O] on re-starting the Bora... Engine was jumping around a bit for about 1 minute... hunting, choking and up and down the revs. Once it calmed down I took it for a spin.. engine now normal, but still Pinking / strange metallic noise.

Q - Does anyone know how these MAP's work? I can only see a butterfly part inside. How does it detect the air pressure?

I'm thinking it uses a spring loaded variable resistor / motor attached to the butterfly part. It must measure the extra air pressure passing over the butterfly while holding the butterfly open for the accelerate? Could there be a weak spring / bad variable resistor inside? I know variable resistors get scratchy / noisy when worn. A bit like a bad volume knob in a stereo.

Q - Has anyone ever opened one of these MAP sensors? I see there's a metal band around it sealing the unit. Is it easy to open / prise up the metal band?
 

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I ran 95 RON for the first 9-12 months of owning the car, this was when I knew nothing about cars, but then changed to a strict diet of Optimax. It used to very easily make metallic rattling noises on the 95 stuff, not any more, only if I'm in too high a gear for the current load. The last couple of months I've been experimenting with STP octane booster as well, and it reduces this phenomenon even further.

Can you make a small sound clip or even video clip showing the rev counter to show how/when this noise occurs?

P.S. A decent stereo would use a voltage controlled amplifier [;)]
 

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Update... On my quest for smoother running and pinkin free motoring.. Or is it just wishful thinking?

700 miles on STD injector... still pinking but less so..

Yesterday... it was a nice sunny evening after a hard days work.. So got the tool box out and head for Bora... I left the hammer in a garage just in case I got tempted... boy, I'm sure it would feel good for say about ten minutes!! Deep breaths... deep breaths.

I took off the temp sender in the air inlet manifold.. it's on the left hand side on the inlet manifold. It's a light hard to take out but a managed okay. It has four pins on the sensor and thermistor at the very end. I measured the sender and it seemed to be working fine. It was responding to changers in Temp... the resistance was going up and down with heating and cooling. The sender was quite black with oil, so I cleaned it and put it back.. It runs a little smoother but still pinkins... Anyway, I'm happy the senders working but without knowing the spec I can't be sure. For now I'm happy it's working.

Next I moved on to the " Controlled hissing sound " I hear on lifting off the gas pedel.. It happens when approaching roundabouts... It sounds like a valve is opening and closing but only when I come off the gas pedel.. Strange because I've not heard that sound in months gone by.. only after the Pinking started. So I'm thinking it's linked somehow... Poss reducing manifold pressure and effecting the air / fuel mix.. Now I'm thinking is something is controlling this hissing or release of air pressure... what? ECU and why? Is it something over pressuring and safely venting or is it something controlled by the ECU?

I checked vacuum hose from the inlet manifold and brake servo unit. I found the link.. small rubber connector not very tight / good seal, So I removed and put a little KY gel to get a better air seal. I could not hear the hissing sound yesterday and today.. Poss too much traffic / road noise...will need a quiet road to test... Late at night is best.. I'll continue to monitor.

My thoughts:

1. Remove the EGR valve and clean.

2. Check brake servo unit / read up on how it works / How to test for leaks?

3. Check second O2 sensor.. There's a small box under the car that the O2 wires disappear into... Check this / remove / clean O2 sensor.

4. Arrange another road test with VW dealers.. Road test with Diag tool connected... poss?

The main reason I'm checking all these things is Stealers... The last Audi A4 I had cost me over ?4000 to fix an engine running issue [:(] It was 2 leaky o-rings on the fuel injectors in the end! About ?7 in parts!! [:O] then 3 months later luck has it some prat hit the back end which sent the Audi to heaven [:(]

Sometimes the fault or cause is so simple you would not believe it!
 

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Update..

I removed the EGR valve and found a little carbon on the valve.. I cleaner and working the valve head back and forth to free up any sticking parts. It seemed fine to me..

Next I checked the second O2 sensor.. check the wiring plug (Small black box under the car..) just under the Bora on the front drivers floor pan or section. I found the heater of the O2 sensor to be normal at 8 ohms. I was unable to remove the O2 sensor because it's tight up against the exhaust.. Will have to leave that one for now.

I noticed a little water leaking on the exhaust section where the CAT meets the 1st stage exhaust box (Joining sleeve)!! Seeing water there can only mean one thing... A leaky exhaust!!

I can't believe I missed this one.. but then you only see the water for a short while before it's burnt off.. So I guess I over looked it a few times..

My thoughts are :

A leaking exhaust will cause all sort of issue with reading on O2 values and cause fuel / air mix on the over run or foot off the gas pedel, this will allow air to be sucked back into the exhaust and interfearing with the O2 sensor reading / Temp. The ECU will then add little more fuel to compensate... too rich / Pinking and cause extra carbon build up over time...

Will remove / replace the exhaust sleeve and see what happens.. fingers crossed. Getting a good seal in an exhaust can be difficult.. and it's very important that there are no leaks on your exhaust / lean burn engines... especially lean burn engines like the 1.6 16v!

Recap on my issue :

Pinking on 2/3rd gear accelerating (Light or hard).

Engine very slightly hanging on to the rev's on over run. It feels like extra fuel is being burnt / engine still pulling with foot off gas pedel.

Feels like the engine still slightly accelerating when you have your foot steady on the gas pedel.
 

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Hi, we bought a 1.6 16v Golf (engine AZD year 2002) a couple of years ago and I've always been surprised by it's lack of power when warm and tendancy to pink. It's the only car I've ever owned that I ended up with my foot flat to the floor with regularity! Some days the car was OK, other times it would pink badly under the same driving conditions and the same journey - e.g trip to work

In the 2 years we've had it it's suffered all the standard VW faults - failure of brake light switch (twice), failure of coolent temp sensor, window dropping into the door thanks to broken plastic clip, battery replacement after it started causing all kinds of ECU errors due to low voltage levels.

We always use 98 Oct fuel and have tried additives + injector cleaners etc. I changed the air filters, plugs, temp sensor and have taken it to VW (3 times) and a VW specialist tuner. As their diag equipment showed no errors (other than brake switch and coolent sensor), they couldn't give me an explanation, so I ended up buying a vag-com and 3rd-party lead out of desperation. Cleaned throttle body and reset ECU.

Still pinking.

After Googling and scouring forums etc, this one gave me some help - thanks Steppy.

We live in Madrid where the temperatures get up to 40 deg C in summer and below zero in winter. Taking the air box off and looking inside, I found that the flap that mixes hot air (from exhaust) and cold ambient air didn't budge, regardless of heating it (hairdryer, boiling water) or freezing it with icer spray. (The rubber seal around the flap had already disintegrated due to the extreme heat). This means that the air entering through the air filer was really hot once the engine warmed up - far too hot. I've since made sure the flap stays shut to block any hot air from over the exhaust manifold entering into the air cleaner.

No more pinking (only occurs very briefly if the car has been idling in traffic - it also occurs on Mark V Golf 1.6 FSIs that I've driven) expected power has returned and have had no problems this winter nor higher fuel consumption. I suspect the intermittent pinking problems before were caused from this flap occasionally working correctly and then packing up completely.
 

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Same problem and the air box flap was also broken so stuck sucking in hot air!!!!!! only sorted last night sodon't know how well it is cured but it has decreased it massively, i disconected the pushrod from the flap so the rod wedges the flap shut so only sucking cold air all the time! oh well not bugging me so much now
 
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