1.4 petrol low compression or dealer fast-one?

Hello, this is my first post as a new A2 owner. I have just bought a white 2002 1.4 petrol as a first car for my wife but have yet to collect the car for the following reason. When I went to see the car, the owner informed me that the engine warning light had just come on the day before. I drove the car and it drove fine with a perfect tick over. I agreed to buy the car under the provision that the problem was fixed. The history folder contained a recent bill for £2500 including a lot of engine work from a main dealer including a head gasket change. The car has covered only 3000 miles since the engine work. The car has been dealer maintained to date and has covered 100K miles.
The cam belt has just been changed by a local mechanic in view of the sale. (I would have thought that a head-off repair would have included a new belt at the same time?)
The previous owner took the car to the dealer who did the previous work for a diagnostic check. Apparently it was running roughly with a poor tick over on the way over. The dealer first said that it was a spark plug problem and later carried out a compression test stating that one cylinder was low and this caused the engine light to come on. He refuses to do any warranty work based on his previous recent repair because the cam belt was changed by someone else.
When the owner picked up the car, the light was off (reset?) and the car was running fine with no hesitation. The dealer wants to now charge to remove the head to check for a badly seated valve. The owner is a young lady and the dealer diagnostic seems odd....A worn valve cannot cure itself and the problem gives the impression of being minor and possibly electrical. The very conscientious owner insists that she will get the problem sorted out for me, but I do not want to see her getting ripped off. She will take the car to another main dealer for a second opinion before committing to any repairs. She was not given and fault codes and was treated poorly.
Does anyone have any ideas to the problem and is low compression a problem with these engines?
Thank you in advance for any suggestions.
Philippe
 
Philippe,
Is there any chance you could plug in a cable and scan for faults?
If you could get the fault list it would be useful. VCDS-lite can be used with a generic OBD-II cable which should be fairly cheap and easy to obtain.
I see no reason why the cam belt being changed by another mechanic should cause a refusal to investigate and fix the problem. Shouldn't the repair by a main dealer be guaranteed regardless of other unrelated work being done elsewhere?

John
 
Hi there - perhaps the dealer suspects that the mechanic who did the cam belt change did not correctly align the pulleys thus allowing the valves to hit the pistons and possibly bending a valve and causing a seating issue. This would be confirmed on strip down

Regards david
 
Hi there - perhaps the dealer suspects that the mechanic who did the cam belt change did not correctly align the pulleys thus allowing the valves to hit the pistons and possibly bending a valve and causing a seating issue. This would be confirmed on strip down

Regards david

Thanks David. I did consider this, but the car was running perfectly and still does but with the warning lamp on. Do these engines use single coil packs per cylinder or just one? Could a coil pack breaking down cause intermitent running hence the lamp warning, or do they just give up in one go?
 
Hi - if the previous owner found low compression on one cylinder this is nothing to do with a coil pack issue but more of a mechanical issue with valves or pistons. Early petrol engines like mine (1999 - 2001) used a single separate coil unit (Aua engine code) - this changed to four coil packs in early 2002 I believe ( Bad engine code) which seem to be more prone to failure.

Regards david
 
Hello, can someone kindly tell me what sort of compression readings I should expect to see for a 100k mile 1.4 petrol engine?
I know an equal balance between the cylinders is more important, but I would appreciate any ideas as to a base figure.
I am a good mechanic, but have never worked on an A2 before. Do I need any special tools if I need to remove the head?
Many thanks, Philippe
 
Hi there - I have a 2001 1.4 petrol fitted with Aua engine - checked in my factory manual and when new compression pressure should be between 10 and 15 bar and no more than 3 bar difference between cylinders. It also states wear limit as 7 bar.

Hope this helps -david
 
Thank you David, very helpful. For anyone following this thread, here is the latest update. First Audi dealer who changed the head for a new one three thousand miles previously did a compression test and stated that No.2 cylinder had a problem, hence the rough running and engine management light on. Second Audi main dealer came to the same conclusion. Independent garage changed the coil and ht leads and the car runs better. Engine light came back on. Owner took the car back to the original dealer dealer and asked for the error codes and compression readings. Dealer could not supply this information as his printer was not working, but offered to redo the compression test....I suggested that the owner use 98 octane fuel. The car is now running fine and the light is off. I presume that the audi diagnostic equipment 'turns off' one cylinder at a time when doing a compression test / rpm drop to compare % power readings per cylinder, rather than remove a plug and physically fit a compression tester? Hopefully the car will be running fine with the light off when the main dealer repeats the test. My suspicion is that the low compression conclusion is masking either an intermitent ignition or injector problem and not a mechanical problem. To be followed.
 
Not sure if it has changed over the years but the 'compression test' used to simply measure starter current required to spin the engine over compression on each cylinder. The cranking current would then be correlated to reference test data

Cheers Spike
 
I received the compression test results today and apparently they were taken with a regular compression tester. This was done by the main dealer who wants to remove the head for inspection, eventhough he fitted a new head 3000 miles ago.
I still do not know why a new head was fitted.
Cylinder 1: 13.2
Cylinder 2: 12.5
Cylinder 3: 13.5
Cylinder 4: 13.8

According to David's post, the car is well within limits. Cylinder 2 is lower, but still seems respectable for a 100,000 mile motor. My local Audi dealer seems to think that the Engine warning light is most probably due to either a lambda sensor before or after the cat giving a bad reading or an injector playing up and giving too much fuel, which could result in bore washing and advanced wear on No.2

I would appreciate your feedback! Many thanks, Philippe
 
Hi those values look fine to me. One thing to keep in mind is if the battery is old and slightly down on voltage-on a cold day this could affect the values coming back from the exhaust sensors. Many 1.4 owners do experience engine management light issues from time to time usually cured by throttle body cleaning--i would be very much loathed to having the head off.
If you still suspect low compression due to piston/bore wear. Get a leak down test done that will confirm for sure but with the figures you have it is not much down. go to you tube and search leak down test.
hope that helps a little. cheers mike
 
Thanks Mike for the reassuring post.
Having waited a month for various garages to not diagnose anything concrete, I picked up the car last night from the previous owner. The car was taken for its French MOT before I picked it up and it was running fine with the EML off. During the test the light came on and then duly failed the test with a Lambda pollution reading of 1.422. The previous reading from 3 months before was 1.002.
I was picked up by the previous owner in the car and it was running fine even though the EML was on.
After completing the paperwork, I left to drive home. Upon starting, the EML started to flash and the car would not rev more than 2500 or go quicker than 60mph.
It felt like it was running on three cylinders, which was confirmed by the exhaust note. I limped the car home.
This morning the EML was on, but not flashing. The car now runs great on all cylinders.
The only error code reported is P0302 which comes up as "cylinder 2 not firing properly". The coil pack and ht were new last week.
If a lambda sensor detects a problem, is it capable of telling the ECU to put the car in limp home mode? If so, can it affect only one cylinder?
I am more and more convinced that I have an injector problem.
Are there specific error codes for the injectors? Can an injector go bad or partially seize when it gets hot?
I've ordered an injector, but my mechanical knowledge is based on classic cars.
Is there anything special involved in replacing an injector? Any special tools needed?
And as final question, does anyone know if I can get a workshop manual in a standard pdf form without having to run a windows program as I'm a Mac user.
Many thanks in advance for your input and help. I am sure that it will be a cracking little car once this problem is sorted.
Best regards from a soggy France. Philippe
 
on the 1.4, if the lambda reports a problem, the ECU switches to a default map (i think). The car still runs, will rev as much as it can and can certainly do far more than 70mph. I had pre-cat lambda issue before I replaced it, the car simply consumed more fuel while the light was on. It also won't affect just one cylinder on the 1.4.

I also suspect it isn't an injector problem, unlike the 1.6 FSI, the 1.4 isn't direct injection so it should not affect just cylinder 2. I would be tempted to swap the coilpack/HT lead (or even the sparkplug) of cylinder 2 with another healthy cylinder and see if the error code shifts to another cylinder.

If you're on a Mac, you can either run Bootcamp or a VM to install windows to run the workshop manual. Bootcamp is free, so is VirtualBox. There are other paid-for VMs which are very good too.
 
I took the car out again for a cautious drive and treated it to a tank of 98 super unleaded. The EML was on. It was running on all four cylinders but from time to time the tickover was a little lumpy.
I picked up an injector cleaning product and when I started the car again the EML was off. I had read that heat sink can cause the windings in an already tired injector to make it perform even worse, so was expecting a flashing EML (like last night) when I went to start it again.
Last right it was running on three cylinders and today it all seems normal again.
Are these 1.4 petrol engines meant to be particularly smooth or just like any other small displacement 4 cylinder car? Mine doesn't feel at all refined and quite harsh and thrashy from tickover. Any thoughts?
 
The lambda sensor can cause engine light. Using different fuel can also make the lambda induced engine light to go on or off. When my front lambda was not well, shell v-power usually turns it off but normal 95 and even other brand's 98, 99 102 won't make it go away.

My engine is virtually silent at idle, unless the environment is dead quiet, you don't notice the engine is started when you sit inside the car. When free rev-ing, it should be smooth all the way to the red line. In-gear, the acceleration is slow at low rpm and significant power from 3000rpm and tails off slightly towards 5000rpm. Again, it should be smooth.
 
Thank you for your advice. At last I think I am getting somewhere....
I started the car this morning, everything was fine and it had even stopped raining. No warning lights and it was running smoothly and quietly on all four cylinders. Decided that Dad would take the family out in the 'new' car already nicknamed 'Duplo' by our two year old because of its lego block shape.
I let the engine warm up while faffing around with child seats. I then heard the ominous 'popping' from the exhaust indicating that i was back on three cylinders....
I started the car later in the morning, EML blinking, then running on four cylinders with EML on but not flashing.
I've only had the car a day but decided to check out under the bonnet.
Started the car up again, running on three, EML flashing.
I disconnected what I believed was No.2 injector (closest to the cambelt?) as the DTC code pointed to inconsistent firing on No.2, no change. Reconnected it, no change.
I then did the same for the other injectors and each time the car ran slower and rougher until I clipped the connector back on.
Deduction: Either No.2 injector is playing up, or the ECU signal is not getting there.
I am a complete novice to A2s, but think I have found the fault in less than five minutes of applying simple logic.
Have we really arrived at the stage where a modern day mechanic cannot diagnose a problem without his plug in 'computer says no' diagnostic equipment?
Two main dealers wanted to remove the head to investigate further.
Hopefully, I can post a positve result in a few day time.
Thank you everyone for the help to date.
Philippe
 
There's no money in diagnosing a problem quickly. If you take the engine apart you can charge for lots of labour...
 
Good work just one thing the cylinders are numbered from the cam belt end --so closest injector is number one. Sounds like injector or wiring to it is not correct. The injector loom as far as I'm aware is not an issue on the petrol 1.4 just the diesel versions is it known to break down.
Good progress though cheers mike
 
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