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Discussion Starter #1 (Edited)
Hi there.
I need expert advice on this.

I finally plug the vag-com tool on my wife’s car after she got a few warning lights.
I got this code: 17956, boost pressure regulator valve, N75 open circuit, P1548-35-10 intermittent.

Well I cleared that and everything is back to normal. So just for « fun », I continued the scan and discovered that the ign.timing is at 18° BTDC at idle. What controls the timing and what could be the cause of such an out of tolerance reading?

Thanks!

Gunde

PS:1.8T,AWM engine
 

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Well, I know that a lower octane gas can affect (retard?) timing.
I noticed you said BTDC, which means it's pulling back on timing.
Are you running Hi-octane? Other things I'm guessing here...
could be the temperature outside? Dirty/fouled plugs?
 

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Rusty said:
No? Ah well, I'm just starting to get the hang of it.
 

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Gunde said:
the ign.timing is at 18° BTDC at idle. What controls the timing and what could be the cause of such an out of tolerance reading?
How do you know it's out-of-tolerance? Did you compare it with specs in the Bentley?
 

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Colin said:
No? Ah well, I'm just starting to get the hang of it.
Advance = spark happens sooner (i.e. before)
Retard = spark happens later (i.e. after)

Although "retarded timing" doesn't necessarily means it happens ATDC. For example, if the nominal timing for a given load and rpm is 20 BTDC, and the knock sensors activate for some reason and the ECU retards timing by 5 degrees, then you have retarded timing, although it's still happening 15 Before TDC.
 

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Thanks Rusty. :thumbsupbub:
 

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Timing at idle is usually the least of your potential worries, but that does sound a little advanced for idle. A couple logs I have show it in the 2-5 range. I'll check later today and post up.
 

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Discussion Starter #9
timing

Thanks for your help everyone!

I say it's out of tolerance because: I compared it to the reading on my car, and I can read normal value on the mea.blocks page.
Also, super unleaded fuel is used.
Any ideas?

Thanks again

Gunde
 

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Gunde said:
I say it's out of tolerance because: I compared it to the reading on my car, and I can read normal value on the mea.blocks page.
Lost you somewhere on the above quote Gunde. Maybe explain a different way.
 

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Discussion Starter #11
timing

I was answering some of the question asked above.
On my car, I read approx 6° btdc compared to my wife's car that reads 18°.
The car runs "ok" but lacks the quick pedal response of my car. She also gets codes once in a while (O2 sensor, n75 valve,) but the vag-com tool reads those codes as intermittent.

thanks

Gunde
 

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Which measuring blocks are you reading? IIRC, 002 or 003 or 005 (or something around there) has the "basic engine timing" in field 4. Block 020 has the knock-based timing retard for each cylinder. The basic timing is influenced by rpm, intake air temp, and coolant temp IIRC. You should see all zeros or at worst low single-digit numbers in block 020. The basic timing should fluctuate a bit, even at idle.

Does it stay at 18 BTDC during driving, or does it move around?
 

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...but the vag-com tool reads those codes as intermittent.


intermittent can be once every second ;)... as long as it's not continuous in duration.
 

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Discussion Starter #14
timing

Hi Pete1
I took a look again this morning and this is what I read:

measuring blocks, group 03,ignition angle (4th row)at idle:24° BTDC
throttle body angle 3.9%,intake temp 7°C,
coolant temp 36°

At 3000rpm I read 36° BTDC!!!
Block 020, the knock-based timing retard for each cylinder, is 0

As the battery on my laptop is Kaput, I don't have a long enough extension to take on the road...

Thanks

Gunde
 

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Took another look at block 003 @ idle and it seems to fluctuate between 9-21 degrees, mostly in the 12-16 range when idle sticks at 800 rpm. Not being able to log it on the road makes it real tough to draw any conclusions. I don't think 18 or 24 degrees at idle is a problem. The fact you see 0 retard also shows you're okay. The potential for problems comes under high load conditions and that's not idle.
 

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Discussion Starter #16
timing

Thank you very much for your help!
Very much appreciated.
I'll try to get my computer running in the car so I can take in situ readings.

Thanks again!

Gunde
 

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It still seems a bit too high for me... hmmm. Log some driving data when you get a chance.
 

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Discussion Starter #18
ignition timing

After a long search, I found a cut vaccum hose near the turbo.(from the main air intake to the evap canister, and cut by the heat shield of the airbox). I taped it just to see if it would make a difference. Well, timing is now at 9°BTDC and throttle response much better with less hesitation.
When something is running in a funny way on these cars, I guess checking the vaccum hoses is a good start...

thanks

Gunde
 

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:thumbup: Glad to hear the car is running better! :)
 

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how many degBTDC do u guys see at redline in a 4th gear pull?is ur timing retard =zero all the time?

(I did not start a new thread,just jacked this one,sorry)
 
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