[1.6 fsi] - Misfire or something else

E

Evripidis

Member
Hi all,

I need some help in identifying a potential missfire.

I have replaced the engine with a second-hand one I got from a breaker of this forum:

1. I have transfered the injectors with new seals. They worked fine before and no misfires.
2. I transfered the cam cover.
3. Installed new thermostat housing and pipe.
4. Transferred the HPFP. Also known to work fine before.
5. The car has been sitting for nearly 2 years.
6. The engine probably a couple of months.
7. There is petrol at the HPHF. The tank shows empty and it has been sitting all this time but the petrol will light up with a lighter immediately.
8. No signs of fuel leaks.
9. I replaced all the injector and coil connectors.

I tried starting it 3-4 times noticing the following:

1. First time round, fuel would come out of the cat converter and running down the exhaust before the flexi.
2. Second time round this cleared but there was a lot of smoke coming from under the heatshield.
3. No leaks.
4. There was a lot of condensation coming out from where the exhaust joins to the flexi.
5. The car will sputter and try to die. If I rev it it picks up with a noticeable judder.
6. The judder is very bad when idling.

Unfortunately I have lost access to VCDS, and also VCDS lite. I just cannot get it to work on my laptop.

Any pointers are welcome before I scrap it.
 
Evripidis said:
Hi all,

I need some help in identifying a potential missfire.

I have replaced the engine with a second-hand one I got from a breaker of this forum:

1. I have transfered the injectors with new seals. They worked fine before and no misfires.
2. I transfered the cam cover.
3. Installed new thermostat housing and pipe.
4. Transferred the HPFP. Also known to work fine before.
5. The car has been sitting for nearly 2 years.
6. The engine probably a couple of months.
7. There is petrol at the HPHF. The tank shows empty and it has been sitting all this time but the petrol will light up with a lighter immediately.
8. No signs of fuel leaks.
9. I replaced all the injector and coil connectors.

I tried starting it 3-4 times noticing the following:

1. First time round, fuel would come out of the cat converter and running down the exhaust before the flexi.
2. Second time round this cleared but there was a lot of smoke coming from under the heatshield.
3. No leaks.
4. There was a lot of condensation coming out from where the exhaust joins to the flexi.
5. The car will sputter and try to die. If I rev it it picks up with a noticeable judder.
6. The judder is very bad when idling.

Unfortunately I have lost access to VCDS, and also VCDS lite. I just cannot get it to work on my laptop.

Any pointers are welcome before I scrap it.
Click to expand...
Remove all previous traces of VCDS from the pc.
Download and install free Lite, and the Ross-Tech USB/serial drivers.
Get VCDS working, then go back to the car
Mac.
 
If the replacement engine is connected to the original ECU, then the ECU will take time to "adapt" to the" new" sensors. Throttle body, flaps, Lambda etc.
Mac.
 
Hi Mac,

The judder was amplified mechanically by the car being on jack stands.

I precluded the timing being off or bent valves etc, because it appears to go away when revved as opposed to becoming worse. No CEL but I am sure it would come back if I let it run. I am running it with straight water (not tap) to make sure there are no leaks so I cannot leave it reach full operating temp. I will put coolant in it if it all goes well.

In a moment of clarity I replaced the oil cap with the old one and it appears to have made it somewhat better. I had replaced the gaskets on the old one, plus the new cap would seal better on its own cam cover which is not installed (because it came broken).

So it must be something related to the air intake or the PCV. I will try and investigate more today. Maybe take out the canister at the back and dress the o-ring with some RTV.

I also got some fresh petrol because it is really on the very low end of the gauge and maybe the pickup is not as good.

I also got vcds lite to work. An endless list of fault codes that I cleared. None of them came back but it was 11 o'clock at night and I could not start it up.

Evros
 
OK,

Ran the adaptations to the letter, i.e., let it warm up, etc. Done the throttle, egr, flaps but cannot find how to do the lambdas???

Also took out the PCV canister and ran a bead of black RTV round the edges.

It is somewhat better but still hunting.

I cannot take it on a spin because:

1. the tires are completely shot and will not hold air.
2. I lost the wheel key, it is a 10-point.
3. The tracking is way off and the rod ends need doing. Got a spare set in case this works out.
4. The car is SORN, i.e., illegal to driver over here.

Evros
 
Evripidis said:
OK,

Ran the adaptations to the letter, i.e., let it warm up, etc. Done the throttle, egr, flaps but cannot find how to do the lambdas???

Also took out the PCV canister and ran a bead of black RTV round the edges.

It is somewhat better but still hunting.

I cannot take it on a spin because:

1. the tires are completely shot and will not hold air.
2. I lost the wheel key, it is a 10-point.
3. The tracking is way off and the rod ends need doing. Got a spare set in case this works out.
4. The car is SORN, i.e., illegal to driver over here.

Evros
Click to expand...
Look in the VCDS label folder. The FSI/BAD label file is 036-906-013-BAD.lbl
Open it in Notepad. Look at Group 034/B034 and 036/B036.
Mac.
 

Attachments

Thanks Mac. I found your document earlier but did not realise what it was.

So, I have to perform basic settings on 34 and 36? I am not very knowledgeable with VCDS. I could only find a youtube video on this:


Evros
 
I've not done it before either, so can't help much.
I'll have a look at the two groups over the weekend, to give us an idea of what those groups should look like.
Take a look at the readiness codes, Groups 87, 88, &, 89, which will tell you which condition, if any are not set.
Post up what the readiness looks like, and I'll look out for them.
Mac.
 
OK, I have performed 3-4 heat cycles.

Looking promising.

1/4 of a tank full with whatever was left in it from 2 years ago.

LOTS of condensation coming out the exhaust, not sure it's got anything to do with it. A lot more than what I get out of other vehicles that I use so I am wondering if the rev hunting has got anything to do with humidity in the tank.
 
Evripidis said:
OK, I have performed 3-4 heat cycles.

Looking promising.

1/4 of a tank full with whatever was left in it from 2 years ago.

LOTS of condensation coming out the exhaust, not sure it's got anything to do with it. A lot more than what I get out of other vehicles that I use so I am wondering if the rev hunting has got anything to do with humidity in the tank.
Click to expand...
It needs, and deserves 20 ltrs of fresh Super Unleaded.
The old stuff will be very low octane, as all the volatile components are long gone.
Mac.
 
I put 15 or 17 but the tank shows about a quarter I could be wrong. The best I can get is 98 over here and is all I use in everything that burns petrol.
 
Hi,
Firstly, great to hear you have been bitten by the FSI.
Now open your wallet and do as it commands.

False air is what I got to say to your problems. Politely of course.

You have started to fix your vacuum leaks on the crank case breather and oil cap. I encourage you to continue and systemstically work through the car replacing old for new with every seal and gasket metal or rubber where ever you find a joint between two components that are part of the air intake system or hold pressure from escaping or being drawn into the camshaft case and crank case. For example the dip stick tube where it fits into the crankcase and the actual stick itself have rubber o-rings.
My modification, a hosepipe jubilee butterfly fastnener.
20241002_090332-COLLAGE.jpg


Great work @Evripidis

Glad you didn't scrap it.

Good luck

:)👍

False air example, I did a write up focusing on the 1.4 Petrol.

D

Thread 'Engine Management Diagnostic False Air AUA BBY'

Hello to all,
I hope you're well and have been enjoying your car(s).

Introduction​

Over time, management systems that control the fuel-air mixture in internal combustion engines have evolved. Computerised engine management systems have decreased pollution levels from exhaust pipes by enhancing combustion control and the utilisation of efficient catalytic converters. While engine sensors continuously relay information to the ECU, a poorly maintained subsystem may lead to erroneous fault indications from a sensor.

Observation
It is improbable that the sensors are causing a...
  • Like
 
Last edited:
A few simple things that could cause the rev fluctuation and that I would check are that

The oil dipstick is inserted and located correctly and making a seal (ease it out slightly with the engine running and then securely push it back in again to see the difference)

The petrol cap has a good clean non-perished rubber seal and replace if in doubt as they are cheap

The coil packs are all good and genuine, Bosch or NGK, switch them around to check if you have a new or known good spare

The fuel tank breather valve is functioning correctly, again easily replaced and facing you when you remove the bonnet. Made by Bosch and only around £20 or so new (let me know if you need the part number)

Obviously these are basic things but not necessarily picked up by Vag Com 👍
 
PlasticMac said:
I've not done it before either, so can't help much.
I'll have a look at the two groups over the weekend, to give us an idea of what those groups should look like.
Take a look at the readiness codes, Groups 87, 88, &, 89, which will tell you which condition, if any are not set.
Post up what the readiness looks like, and I'll look out for them.
Mac.
Click to expand...

Most of the readiness bits are red. I haven't driven it for too long. Only round the block at slow speed. Uninsured, no MOT and SORN. Also the tires will burst any minute now.

Not too sure what to do with this.
 
Evripidis said:
Most of the readiness bits are red. I haven't driven it for too long. Only round the block at slow speed. Uninsured, no MOT and SORN. Also the tires will burst any minute now.

Not too sure what to do with this.
Click to expand...
I suppose most of the readiness bits need an extended drive, warm up cycle etc.
All a bit uncharted territory.
What DTCs do you have now?
Maybe log, or at least monitor, a few groups, such as 140 for fuel pressure, with ignition on, engine off, then engine running.
Mac.
 
Not too sure. Putting tires on it, even without insurance, etc., is still an additional cost that might end up going down the drain.

The outlook is good so far as far as the cooling system goes, touch wood.

I noticed that the interior light will flicker when the revs drop while juddering.
 
Evripidis said:
Not too sure. Putting tires on it, even without insurance, etc., is still an additional cost that might end up going down the drain.

The outlook is good so far as far as the cooling system goes, touch wood.

I noticed that the interior light will flicker when the revs drop while juddering.
Click to expand...
I know you're very knowledgeable with the FSI Evripidis (far more than me) and the things I've suggested are not technical and only basic but sometimes the basic/silly things can be the cause a lot of problems.

Have you ensured the battery is in good condition and fully charged and have you removed and cleaned (and I mean cleaned/sanded) the main earth behind the headlight as the light flickering sounds like this could possibly be the cause? 👍
 
@A2Z Indeed. I re-checked all that you have suggested. The dipstick is RTV'd in the sump and the upper connections are tight. So as the second filler cap. What I have not checked is for any holes in the tube.

I also did fit check the purge valve with a stethoscope. It does not click and I also unplugged it which cause a CEL to come up.

I am not sure if I do have a leak at the exhaust manifold (upper cat).

I replaced two out of the four coils. Nothing wrong with the old ones, they just seemed a bit weathered on the inside. I replaced them with the ones that came with the engine, that where in a better condition.

The battery is suspect. I got a brand new bosch battery yesterday for my dad so I might try it out.

Evros
 
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