| Author |
Message |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 121
Reg: 07-2005
|
Hi all,
I was driving my TT home the other day, sitting on 110 on cruise control, when i heard a sound like i'd blown a tire, and it started handling like it too. As i went to pull over the engine cut out.
Checked all my tires first (nothing blown) and then went to restart she turned over once and sounded like something was sticking. Ended up getting it towed home and i still cant figure out whats wrong, fuels half full, oils fresh and new (oil change 500km ago)
It turns over but no start.
I'm going to replace the fuel filter tomorrow, but any other ideas?
Cheers |
Dave Rose
DieHard
wa
uzz31 v8
Posts: 987
Reg: 03-2007
|
Hope i am wrong!! sounds like a cam belt letting go.......does it sound strange when the engine turns over ? you can always remove cam cover to check . |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 122
Reg: 07-2005
|
yea it almost sounds like A not getting enough fuel, and B like its not turning all cylinders. But on the other hand it turns over, and just doesn't fire. |
Dave Rose
DieHard
wa
uzz31 v8
Posts: 988
Reg: 03-2007
|
Yes Tom it will turn over but the camshafts dont ! tends to make the strange noises as valves are not moving as i said remove the cam cover , i really hope i am wrong .But its not the end of the world ......good luck. |
Matchy Loi
TryHard
VIC
GTT
Posts: 349
Reg: 06-2006
|
I know it doesn't explain the bang really, but for a start check your spark plugs/leads/ as it could explain the lack of spark?
Then check your belts like Dave suggested.
These pretty much are the two easiest things I can think of that I would personally do. |
Daniel Clarke
Goo Roo
NSW
TT 2.5L 6 cylinder
Posts: 5571
Reg: 03-2006
|
Cam belt doing 3000rpm then snapping inside cam covers would explain Bang !
Tom, Remove the upper cam timing belt cover, should be 2 or 3 bolts, easy to remove and check to see if the belt is in ok or not . |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 126
Reg: 07-2005
|
Hi All, This is getting to be a very strange problem. Cam belts ok and all indicators on cams line up as supposed to. Fuel pump ecu appears to be u/s, so I tried the fp/b+ bypass. The pump now runs at 10.5v when the bypass is in and the fuel can be heard moving in the fuel rail.
New Iridium plugs,spark at #1 and coils all look recent and in good cond (but better check the rest now)and a New fuel filter.
The engine sounds as tho' its trying to start but can't/wont. Immobiliser doesn't appear to be a problem as I have spark and this one stops everything when it's armed.
Next step is check the injector operation (how?), fuel pressure reg and lift the cam covers for a look.
Can't explain the blown tyre noise tho'.
Any other input would be appreciated. Thanks Tom |
Rob Rojo
Goo Roo
NSW
TT
Posts: 2946
Reg: 12-2007
|
Didn't just kill the cat converter? |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 127
Reg: 07-2005
|
Rob, When I bought the car it was supposed to have an SS cat - operative word being "supposed". It looks as tho a bit more strip down is gonna be required. Thanks Tom |
Rob Rojo
Goo Roo
NSW
TT
Posts: 2951
Reg: 12-2007
|
If its SS then I doubt it will be it but if its not as described and is ceramic it could have just let go and blocked the exhaust completely.
There is also the possibility that it has lost an exhaust wheel from one of the turbos and has blocked the exhaust which would also explain the bang.
Try starting it with the mid/cat pipe removed. |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 128
Reg: 07-2005
|
Problem is now getting weirder.Is it likely that the Igniter or ecu is failing slowly? I tried checking the spark in #1 - that was ok. Went onto #2 - ok as well but a diminished spark. By the time I got to #5 the spark was quite weak. Also the plugs were clean and showed a bit of fuel on them - except #5 which was covered with soot.Tried #1 again and now no spark.
All the cam lobes are ok and both exhausts smell of fuel. |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 130
Reg: 07-2005
|
Anyone got any other ideas - please fellas! |
Rob Rojo
Goo Roo
NSW
TT
Posts: 3010
Reg: 12-2007
|
Try another ignitor |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 131
Reg: 07-2005
|
Thanks all,
Just went into shock tonight after doing a compression test.Obviously cold test but the readings were almost consistent.-75,85,110,85,78,60.
This car had great pickup and boost until then.
The ignitor swap (and hopefully an ecu) was to be done tomorrow, but now maybe looking at the adjustable exhaust cam as well. Trouble is the marks all line up and the index didn't look to have moved.
Roll on! |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 132
Reg: 07-2005
|
With all the above its hard to understand that I seem to have lost a Fuel Pump ecu, an exhaust cam and an ignitor/Engine control unit all at the same time - and all at the legal driving speed. Bah |
Rob Rojo
Goo Roo
NSW
TT
Posts: 3012
Reg: 12-2007
|
Something is definitely not right there, compression should be around 175 or so.
As somone mentioned before could be your timing belt has slipped |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 133
Reg: 07-2005
|
All three timing marks line up tho, and the belt looks to be in good condition.
I think Manny had a problem with cam gears some years ago. |
Peter Nitschke
Junk Filterer
South Australia
UZZ30 UZZ31
Posts: 11147
Reg: 11-2004
|
From memory, his cam gears chewed the belt. |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 134
Reg: 07-2005
|
I thought his problem was that the securing arrangements for the relative parts were pretty poor and the index was slipping. As well as eating belts.
Will have to dig into the archives for a check. |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 135
Reg: 07-2005
|
So, Did a couple of wet compression tests this morning.
1st run 145,110,125,153,180,120 - ok maybe stuck or u/s compression rings
2nd run 168,142,170,232,240,235 - wtf, 1&3 seem ok, 2 needs a bit of tlc, but 4,5,6??
I had a change to a screw-in type fitting for the tester as the push-on was being forced off by the pressure.
Repeated the test and readings close to same. The last 3 cylinders are acting like a compressor with the discharge v/v shut.
Now I think I'm looking at the aft turbo - might help to explain the initial "Pop" noise and the flat tyre effect.
If it was the cat blocked then surely it would affect all pressures.
I'm running out of options before a major strip but if anyone can offer another idea to try I'd be grateful. |
Cameron Laufer
DieHard
Queensland
 Built 1.5j 425.8rwkw & LPG 1jzgte 204rwks @ 10psi
Posts: 849
Reg: 12-2007
|
Your compression tests are up to sh1t, I would be doing a leakdown test and dropping a borescope down the plug hole to discover scored bores from bad afr's. The comp test should be around 175psi dry (and with in 5-10psi of each other) there is no way there would be a stuck compression ring on a car they gets driven often, it take years of sitting around for a ring to get stuck. |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 140
Reg: 07-2005
|
Que, you wanna try that again in English. I know they're up the sh1t thats why I'm asking for some assistance. It does say u/s rings as well. The compression tester is a professional unit and the gauges are calibrated.
I did have a better opinion of you before this.
And yes, a leakdown test is for tomorrow. |
Daniel Clarke
Goo Roo
NSW
TT 2.5L 6 cylinder
Posts: 5720
Reg: 03-2006
|
When doing the comp test are you removing all spark plugs and doing it with the Throttle held Fully Open ? Have you removed the EFI fuse to stop fuel going in whilst doing the test ?
Are you starting at number 1 and moving to number 6 ? Would explain why it increases the further along you move maybe ? |
Tom Cousin
TryHard
Victoria
GT Ltd V8, GTT-L
Posts: 141
Reg: 07-2005
|
The only thing that wasn't done was remove the efi fuse. Still, going back to #1,2,3 they were low when the test was repeated. Leakdown test this w/e. |
Cameron Laufer
DieHard
Queensland
Built 1.5j 425.8rwkw & LPG 1jzgte 204rwks @ 10psi
Posts: 850
Reg: 12-2007
|
Tom I don't really care what your opinion of me is, But here is my question is to you, Why are you looking for other problems
Tom Cousin wrote on Thursday, December 10, 2009 - 12:50 pm:Now I think I'm looking at the aft turbo - might help to explain the initial "Pop" noise and the flat tyre effect
When you have already found a major problem? Low Compression.
Find the cause of this first.
The next step would be to find out why there this low compression on these cylinders, so performing a leakdown test would be your answer, listen to where the air is leaking, remove hose from throttle body and have butterfly open, remove oil filler cap and also be prepared to place your ear upto the exhaust tip to find some answers. Hearing the leak from the throttle body would be intake valves, leak from exhaust would be exhaust valves, and hearing or feeling air from the oil filler would be a ring sealing issue, causes can be a number of things form worn rings/bores, scored bores, melted pistons, to name a few.
Also the blown tire feeling could be a transmission failure. |
James Buchan
DieHard
Vic
V8
Posts: 937
Reg: 10-2008
|
Tom, any updates? A mates car had the exact same thing happen.. |
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