Jonew Posted January 13 Share Posted January 13 Hi all bought an Audi a3 2L tfsi sline Quattro 55 plate as a project.. doesn’t start,cranking sounds like low compression so put my diag tool on it. only a few faults, 01314 & 01309 in brakes.. low battery terminal voltage in engine (replaced battery) so I did a compression test, the cheap Amazon kit was used, no compression on any cylinder. timing belt looks ok but haven’t checked the timing yet or the chain . I suspect head gasket but have very little knowledge on these engines.. as I say it’s a project and one I would like to repair.. any tips/advice would be appreciated (someone told me ecm/ecu is probably at fault but that won’t cause compression loss) tia Quote Link to comment Share on other sites More sharing options...
Steve Q Posted January 13 Share Posted January 13 An imobiliser issue will prevent it running as ECU imobiliser blocks the fuel pump. Are there any lights on the dash. Also is it worth getting a diagnostic check to see if any fault codes flag up? Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 13 Author Share Posted January 13 Hi yes there is lights on dash when I run a diagnostic check it flags up these but like I say the compression test is o on all cylinders also I’ve checked wiring and fuse box etc replaced the ecm relay also I feel there’s 2 issues with this car,ecm n possible head gasket Quote Link to comment Share on other sites More sharing options...
Steve Q Posted January 13 Share Posted January 13 How old is the battery, if the cars been sat and battery is fudged then it can cause unusual fault codes as a failing battery causes electrical gremlins Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 13 Author Share Posted January 13 I put on a brand new battery as the old one was totally dead.. the faults do clear except steering light but I’m not concerned about that at this point.. Quote Link to comment Share on other sites More sharing options...
cliffcoggin Posted January 13 Share Posted January 13 Are you really telling us there is zero compression on every cylinder? That would be more than a head gasket leak. Even worn rings and bores would give a little compression. If the valve timing is completely wrong I would still expect a little compression on one cylinder or some valves hitting the head. Are you sure there any pistons at all in the engine? Take the spark plugs out and use a long thin wire to feel the different heights of the pistons. Remove the wire and spin the engine. You should hear and feel the air being blown in and out of the holes. Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 13 Author Share Posted January 13 (edited) I found it strange also but I’ve never used this Amazon compression kit before so it could be rubbish n my other car is electric so cannot even test it.. I’ve had to remove the rocker cover because Some fool has over tightened the oil filler top and I found a bit of plastic sitting in the neck, I went to fish it out and dropped it.. there’s also an oil leak im trying to find as well under the hpfp, plugs look ok.. on cranking it sounds like low compression with that puff puff sound from the exhaust but again I’m not familiar with this engine. only engine fault on the diagnostic machine is air flow meter but I have that disconnected. the reason someone said ecu is because the previous owner clearly thought it didn’t start cos of faulty coil packs,they replaced the coil packs then gave up on it.. this car owes me nothing and im in no rush, just a project.. Edited January 13 by Jonew Quote Link to comment Share on other sites More sharing options...
Magnet Posted January 13 Share Posted January 13 Hello Neal, As Cliff says, you can forget about something as ‘simple’ as the head gasket. Head gaskets can blow between a cylinder and a waterway, or even between the cylinders themselves. Would all cylinders blow between each other, or would every cylinder be blowing across to coolant - no chance. My theory:- the chain/belt has jumped, the valves have contacted the pistons and bent the valve stems, resulting in valves being unable to close - hence no compression. Sorry to bring bad news to the door, but it sounds like stripping the head off ( then you will indeed have to change your head gasket). Examine valves and their stems, cams and camshaft, piston crowns, and conrods for potential distortion. If you look at it from the point that if this engine was only running at just over tick over - say 1000 revs. per minute when the belt/chain jumped, you can calculate the number of times the engine would have turned over in just one second - enough to do considerable damage. To be honest Neil, I think the last thing you need to be worried about is diagnosed codes. Surely it just too old to consider it an economical repair. Did you buy it super cheap? Kind regards, Gareth. Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 13 Author Share Posted January 13 23 minutes ago, Magnet said: Hello Neal, As Cliff says, you can forget about something as ‘simple’ as the head gasket. Head gaskets can blow between a cylinder and a waterway, or even between the cylinders themselves. Would all cylinders blow between each other, or would every cylinder be blowing across to coolant - no chance. My theory:- the chain/belt has jumped, the valves have contacted the pistons and bent the valve stems, resulting in valves being unable to close - hence no compression. Sorry to bring bad news to the door, but it sounds like stripping the head off ( then you will indeed have to change your head gasket). Examine valves and their stems, cams and camshaft, piston crowns, and conrods for potential distortion. If you look at it from the point that if this engine was only running at just over tick over - say 1000 revs. per minute when the belt/chain jumped, you can calculate the number of times the engine would have turned over in just one second - enough to do considerable damage. To be honest Neil, I think the last thing you need to be worried about is diagnosed codes. Surely it just too old to consider it an economical repair. Did you buy it super cheap? Kind regards, Gareth. The car cost me nothing, I wanted a project over the next year to keep me busy so am not bothered about the time I put in..it’s very clean and has fsh with 100k on the clock. apart from the not starting and steering light on it’s a nice car. i can source an engine no problem and I’ve a found few under £400 but I’d really like to try and fix this. i haven’t checked timing yet etc but I will next week, like I say someone said ecu but I just felt the cranking wasn’t as strong as it should be Quote Link to comment Share on other sites More sharing options...
cliffcoggin Posted January 13 Share Posted January 13 Neal. Gareth's theory is a good one, in which case repair could cost much more than £400 if the pistons and rods are damaged. Your mention of plastic stuffed into the oil filler pipe sounds like somebody tried to stop excess crankcase pressure blowing oil out, which is exactly what one would expect from a blown engine. Forget about ECU, warning lights and diagnostics until you have established whether the engine is sound. 1 Quote Link to comment Share on other sites More sharing options...
Magnet Posted January 13 Share Posted January 13 Well let’s put it like this Neil - I think you can forget about the ECU until you have an engine that has adequate compression. Kind regards, Gareth. p.s. What is the history of this car, and its mode of failure? Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 13 Author Share Posted January 13 6 minutes ago, cliffcoggin said: Neal. Gareth's theory is a good one, in which case repair could cost much more than £400 if the pistons and rods are damaged. Your mention of plastic stuffed into the oil filler pipe sounds like somebody tried to stop excess crankcase pressure blowing oil out, which is exactly what one would expect from a blown engine. Forget about ECU, warning lights and diagnostics until you have established whether the engine is sound. No I could see the broken part on the filler cap n the part in the neck, no one put it there.. I understand what you guys are saying and I know the engine could be toast, but what are the chances it’s ecu as well?. Quote Link to comment Share on other sites More sharing options...
Magnet Posted January 13 Share Posted January 13 Hello Neal, Sorry to say it as I (in bold) see it, but I really can’t see any point in concerning yourself with potential ECU issues at this stage - as has been pointed out. The ECU controls the engine, but the engine appears to be unserviceable, so until you repair/replace it, the ECU doesn’t matter. All I can suggest is that if you still consider the ECU to be at fault, then you will need to send it off for specialist assessment - and repair, if found to be faulty. Kind regards, Gareth. Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 13 Author Share Posted January 13 Will investigate the engine further next week and will probably keep this thread updated.. im looking forward to figuring this one out and seeing where it takes me.. I spoke to an ecu guy that said he can get an ecu and do the programming etc at a reasonable price so I’m not overly concerned about that but I totally agree the engine needs looking into deeper was just trying to get a heads up on what to expect Quote Link to comment Share on other sites More sharing options...
cliffcoggin Posted January 13 Share Posted January 13 How many times do we need to repeat "Forget about ECU, warning lights and diagnostics until you have established whether the engine is sound." Quote Link to comment Share on other sites More sharing options...
Magnet Posted January 14 Share Posted January 14 Hello Neal, I can now see that your earlier post about a performance back box - which Steve indicated would cost you £500/£600 - was relating to this same non-running car. Without wishing to be over critical, but you are talking about ‘toys’ on a 19 year old non-running vehicle, when to get it running is likely to cost you in excess of its worth. Personally, I find all of this to be worrying, yet we will aim to offer advice as best we can, as you attempt to progress with this. To me, it smacks of money no object, but….. Please bear in mind that this is my personal view and may/may not be shared with with all on here. Kind regards, Gareth. 1 Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 14 Author Share Posted January 14 As I say it was a project I’m a carer and am at home most of the time so to occupy my free time I’d thought I’d try and rebuild a car.. nothing more nothing less.. anyway I’ve stripped it down and the timing is all good, belt needs replacing but all good with timing.. im going to send the compression kit back as it is most likely faulty Quote Link to comment Share on other sites More sharing options...
Darryl Hill Posted January 14 Share Posted January 14 See if you can get a local mobile mechanic to come and do a proper compression test, unfortunately I am no longer mobile otherwise I would have offered to come over for the cost of fuel, ignore the ecu until you know that the engine is good, you say the timing is good but you are going to replace the belt, wait until you have had a proper compression test done before attempting the belt, if you can't get a c/t done see if any one has a bore scope you could borrow just to check each cylinder and the valves Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 14 Author Share Posted January 14 1 hour ago, Darryl Hill said: See if you can get a local mobile mechanic to come and do a proper compression test, unfortunately I am no longer mobile otherwise I would have offered to come over for the cost of fuel, ignore the ecu until you know that the engine is good, you say the timing is good but you are going to replace the belt, wait until you have had a proper compression test done before attempting the belt, if you can't get a c/t done see if any one has a bore scope you could borrow just to check each cylinder and the valves I won’t replace the belt yet.. im going to send the c/test back and borrow one from a friend. Quote Link to comment Share on other sites More sharing options...
Magnet Posted January 14 Share Posted January 14 Thanks Neal, Although I can understand you now doubt the compression gauge, I think I recall you mentioning that the engine spins over on the starter as if there isn’t any compression. Anyway, I’m sure you will sort it. Kind regards, Gareth. Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 14 Author Share Posted January 14 3 minutes ago, Magnet said: Thanks Neal, Although I can understand you now doubt the compression gauge, I think I recall you mentioning that the engine spins over on the starter as if there isn’t any compression. Anyway, I’m sure you will sort it. Kind regards, Gareth. It just doesn’t feel strong on cranking but it’s been along time since I paid attention to a petrol engine, I currently have an electric vehicle .. but yes this is the reason I wanted this car, to test me,to rebuild if possibly and eventually get it too it’s former glory appreciate the support 1 Quote Link to comment Share on other sites More sharing options...
cliffcoggin Posted January 15 Share Posted January 15 15 hours ago, Jonew said: It just doesn’t feel strong on cranking but it’s been along time since I paid attention to a petrol engine, I currently have an electric vehicle .. but yes this is the reason I wanted this car, to test me,to rebuild if possibly and eventually get it too it’s former glory appreciate the support Fair enough, but let's start with the basics before moving on to the electronics and other ancillaries. That means a more complete description of the symptoms than you have revealed until now. You said the engine "doesn’t feel strong on cranking". If by that you mean it cranks too quickly and does not sound as if the starter is working hard, then I suspect you have little or no compression. Is that correct? Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 15 Author Share Posted January 15 40 minutes ago, cliffcoggin said: Fair enough, but let's start with the basics before moving on to the electronics and other ancillaries. That means a more complete description of the symptoms than you have revealed until now. You said the engine "doesn’t feel strong on cranking". If by that you mean it cranks too quickly and does not sound as if the starter is working hard, then I suspect you have little or no compression. Is that correct? It cranks (starter certainly sounds normal) normally as I replaced the battery but I felt the noise from exhaust and the sound from the engine could be low compression then I did a c/t test but obviously it read 0 so I started checking the timing . im going to put it all back together today then repeat the c/t but with another tester. someone mentioned the ecu because there was coil packs in the boot and they suspected no spark.. too many chefs i think is the phrase but absolutely going back to the start on this one today I’ll post a video on the cranking etc in the few days . Quote Link to comment Share on other sites More sharing options...
Magnet Posted January 15 Share Posted January 15 Thanks again Neal, Indeed - I think the broth is in grave danger of being spoilt here, and despite the fact that the car came to you cost free, these things have a funny habit of eating money, even if you adopt a logical approach to their repair. You will of course be able to gain as many opinions as the number of people you ask, but you have to question your own logic, by buying-into the possibility that the car has ECU issues, because someone notices some HT leads in the boot! Daft. Internal combustion engines need compression, ignition at the right time, and fuel. In an attempt to try to save you money Neal, please promise us you will only deal with eliminating each of those in their correct order. It’s not out of the question that your compression gauge is totally inaccurate ( or indeed you are using it incorrectly), but couple that with your suspicion that the engine is turning over too freely, logic would suggest that the the compression may indeed be low. Anyway Neal, keep trying, and please let us know how you get on. Kind regards, Gareth. Quote Link to comment Share on other sites More sharing options...
Jonew Posted January 15 Author Share Posted January 15 15 minutes ago, Magnet said: Thanks again Neal, Indeed - I think the broth is in grave danger of being spoilt here, and despite the fact that the car came to you cost free, these things have a funny habit of eating money, even if you adopt a logical approach to their repair. You will of course be able to gain as many opinions as the number of people you ask, but you have to question your own logic, by buying-into the possibility that the car has ECU issues, because someone notices some HT leads in the boot! Daft. Internal combustion engines need compression, ignition at the right time, and fuel. In an attempt to try to save you money Neal, please promise us you will only deal with eliminating each of those in their correct order. It’s not out of the question that your compression gauge is totally inaccurate ( or indeed you are using it incorrectly), but couple that with your suspicion that the engine is turning over too freely, logic would suggest that the the compression may indeed be low. Anyway Neal, keep trying, and please let us know how you get on. Kind regards, Gareth. I wanted a challenge and certainly have one, I have a budget in mind and the end goal would be to see it back on the road and possibly running faster than before but I’m also not stupid. its the reason I joined this forum, to listen to people who know these engines better than the tyre kickers I know . i will keep this post updated and I hope to have a diagnosis by the Tuesday at the latest .. Thanks for the support 1 Quote Link to comment Share on other sites More sharing options...
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