QuestionQUESTION: Hi Naushad
I have the same problem as the anonymous, Date: 3/31/2008
Subject: Help, 96 A4 Wont start...
I read through your tips and here is my story:
I have an Audi A4, 96 Auto V6 2.6L, clocked just over 250,000 Kms! Petrol, I use regular unleaded. Anyway - it's been great until recently it just won't turn over enough to start the engine. It takes many turns of the key and sometimes I just give up. It seems to be much better in warmer weather, it takes less turns. I have just had a major service done (so I'm going to assume that all the things like air filter, sparks etc are all OK)and still the problem exists and the mechanic changed the oxygen sensors, because apparently that's what the Audi computer spat out. But still the same problem. I have spent 0ver 1600 dollars so far and still no result! I'm a bit hesitant to send it back in if the mechanic has told me he's not sure what it could be? Should I go to an authorised Audi service centre? He recommended I use a higher octane petrol, like premium - is this just crap or will it really help? I did notice the level of the oil was high on the dipstick so I drained the oil a bit to see if would help... Could the high level of oil for a long period have damaged the cat converter or something related? Thanks for your help!
ANSWER: Hmmm, well sounds like you got the basics covered.... As long as good quality parts have been used then there should be no problem.
You say the engine doesn't turn over enough, Does it turn over quickly or is it sluggish, Majority of hard start faults in petrol engines are caused by the battery. If the battery is ok then maybe the brushes in the starter are worn out and the starter doesnt have enough power to kick start the engine over, as a guide the starter has to turn over at approx 500Rpm to start the engine. could explain the hard start when cold, the engine oil is also heavier(viscosity) when the engine is cold and provides more resistance so if the starter is weak then......
Replace the battery first (before you by a new one) and see if theres a change. if not it might be a good idea to have the starter removed and inspected.
What did the major service cover?? were the timing belts replaced?? (Audi recommends every 120,000kms) Most workshops charge for a major service but dont really check everything. Worn timing belts can affect the timing of the valves and also the ignition.
As for the fuel grade as long as you cant hear pinging( a rattling that sounds like tin cans being hit) then I doubt you have a problem. the noise should be apparent when the vehicle is started (when the timing is advanced) or when the vehicle is under load like hill climbing in higher gears. if you have noticed this then you will have to change to a higher grade. most Audi's are adjusted to use fuel of about 94 ron. the exact grade is in the technical data booklet that came with your vehicle.
try out these tips and let me know how it goes.
---------- FOLLOW-UP ----------
QUESTION: Naushad, thanks for the tips. I actually got a brand new battery the week before the major service. I'll re-check the connections as a precaution. No, the timing belts weren't changed. And when it turns over, it starts fine. It just doesn't engage the engine to actually get the engine going. Yes, I have noticed pinging - I'll change my fuel grade as soon as possible and let you know. And what of the high oil level I suspected - do you think that may have contributed to any problems? Thanks.
Answer Ok im confused, what does ' it doesn't engage the engine to actually get the engine going' mean?? is the bendix engaging the fly wheel?? does it produce an unusual sound( like a shriek)when the starter is engaged? if it does then your starter definitely needs to be checked. also the teeth on the fly wheel will need to be checked for damage.
I'd get changing those belts as soon as possible even if they aren't the cause of your current predicament, before they cause expensive damage, you wont have any warning when they give out and could end up replacing the whole engine. of course assuming you replaced them 120,000Kms ago and replaced them with the original replacement parts.
How long have you noticed the pinging?? in the long run pinging can cause irreversible damage to the internals. Pinging by the way is caused by the fuel exploding inside the combustion chamber which means excessive pressure inside the chamber which is going to look for the easiest way out, usually through the piston crown!!! have a compression test carried out just to make sure everything is ok and that low compression isn't causing the hard start. Check that all the cylinders pressures are fairly even.
As for the excessive oil I doubt it contributed to the current problem, excessive oil causes excessive oil pressure in the crankcase and usually causes oil leaks as it looks for weak points to vent that pressure out, sometimes through weak gaskets and seals and sometimes through the piston rings and out through the exhaust where it soaks the CAT converter causing symptoms like lack of power and higher fuel consumption.
