1.8T AMU/AEB: 17748 - Cam and crank sensor - P1340 - 35-00 - Incor. Correlation

[vtraudt]

1.8T AMU/AEB: 17748 - Camshaft Position Sensor (G40) / Engine Speed Sensor (G28)
Still fighting code
17748 - Camshaft Position Sensor (G40) / Engine Speed Sensor (G28) P1340 - 35-00 - Incor. Correlation
after engine build.

2001 Audi TT225
AMU block. New bearings, rods, rings, seals, oil pump.
Rebuild AEB head.
New VVT cam chain tensioner (not connected).
AMU valve cover (has vent, vs AEB no vent).
Existing Single Mass Flywheel (CM/Ringer Racing) and clutch.
New timing kit.
Existing Wideband O2 conversion to newer Golf ECU 8N0 906 018 K.

Replaced AEB cam timing plate (one window) to 4 window plate from AMU head.
Replaced AEB cam sprocket with AMU sprocket.

Done sofar:
- switched cam sensor 2 times
- test unplug cam sensor shows code
- test unplug crank sensor with engine running shut engine down (I am normally expect engine to run (off the cam sensor in limp mode) until shut off, but won't restart). Indicates to me that ECU cannot use or is not using cam sensor at all).
- verified timing. Cylinder (passenger side) physically at TDC, crank pulley TDC mark lines up. Cam sprocket mark lines up with valve cover mark. Camshaft 'squares' line up the cam holder bracket triangles.
- cam chain tensioner chain link count "15.5" see photo
- tried to find TDC mark on flywheel cut did NOT find (current waiting for Ringer Racing to inform if their Clutchmaster single mass flywheel have a TDC mark and how it looks like)

photos (note: in some photos, cam square mark is off the triangle because TDC moved a bit and/or chain tensioner compressed):

https://drive.google.com/open?id=19p...3nvWRY2hn4cPyR
https://drive.google.com/open?id=1Yd...-GF6bIkxbsAUNB
https://drive.google.com/open?id=1rp...vAo0Igk7NX4lEc
https://drive.google.com/open?id=1hq...wB5PnfSF0HDo4S
https://drive.google.com/open?id=1BC...irIEPsk8KHQ1mf
https://drive.google.com/open?id=1wD...RN7IFFES9at_8r
https://drive.google.com/open?id=1RV...SEeXp8H4z4arTb

[Seerlah]

I'm thinking short in the wiring somewhere. If you have a spare parts harness laying around, try and pull a matching connector for the cam sensor with terminal leads on the ecm sides. Find the correct pins to the ecm connection and swap that out for testing purposes. If dtc goes away after swapping wires all the way to the sensor, pretty much can conclude it is a short.

Only thing I can think of, other than cams themselves being the issue (doubtful).

[vtraudt]

[QUOTE=Seerlah;13230265[/QUOTE]
How about using oscilloscope and record cam/crank signal.

I dispute (for arguments sake) the 'short':
a) when unplugging the cam sensor, VAGcom immediately shows "cam sensor signal too high" (or similar)
b) when unplugging crank sensor, engine dies immediately (I am used to car continue running with crank sensor gone, running off cam sensor/limp mode. Just not restarting).

Did have a chance to look at the cam chain link photos? I don't trust my counting and counting method anymore (for obvious reasons, I have to question EVERYTHING).
Does the count look right to you? Would a link to short (15 instead of 16) throw the code and result in -23 KW in block 093?

[Seerlah]

Looks like 16 links to me. Rotate the assembly via crank bolt manually to have the cct in the upper position. Makes it easier to count the links. While in the lower position that 15 1/2 link that has you questioning can be seen easier as 15 or 16 links when the cct is in the upper position.

Also, engine simply will not run with crank sensor unplugged (ecm won't grant spark without it). But can with cam sensor unplugged. Just how these cars work.

[vtraudt]

Thanks. Had 2nd pair of eyes quadruple check timing. Conclusion (with some generosity): timing belt is 1/2 tooth of.
Changed timing by one tooth. REDUCED the number of belt teeth (or belt length) between cam and crank (clockwise/running direction).
Resealed valve cover.
Will run today or tomorrow, see if anything changes.

Does someone know the meaning of negative numbers in block 093?

From other ECU logic: Negative means ECU 'is taking out'.
Here: Intake cam (cam sensor) is overadvanced, so ECU wants to retard by "-23 degree Kurbel Welle" (and we all know the unit of measure is not degree).
Here: meaning cam too far forward, take chain link out or reduce timing belt length/teeth from cam pulley to crank sprocket (clockwise)

Can someone confirm?

[Seerlah]

Can't confirm. But I drove for a few thousand miles with my timing belt being one tooth off before (I think after two teeth off the valves will hit the piston). Even had a blown tensioner that caused extra slack (luckily the early awm tensioners are forgiving when they blow, so you don't bend valves). Both incidents did not trigger any dtc.

Also, why isn't the vvt solenoid plugged in?

[vtraudt]

Can't confirm. But I drove for a few thousand miles with my timing belt being one tooth off before (I think after two teeth off the valves will hit the piston). Even had a blown tensioner that caused extra slack (luckily the early awm tensioners are forgiving when they blow, so you don't bend valves). Both incidents did not trigger any dtc.

Also, why isn't the vvt solenoid plugged in?

Is it possible that the VVT is causing the -22 in block 093? The number reminds me of logs of cars with VVT when VVT activates.
The ECU (wideband o2 from Golf, 032LP) and tune (no change from before engine swap) are not yet modified to allow playing with VVT.
My ASSUMPTION was that an unplugged VVT acts exactly as a non VVT tensioner? Do I need to power up the VVT? Or would that add another negative 20 to the already negative -22?

[Seerlah]

Don't know. But I was thinking that, and worth a try. Does the AMU not have VVT factory? Maybe resistor it out, if you know the right diode to use for testing purposes?

[vtraudt]

Don't know. But I was thinking that, and worth a try. Does the AMU not have VVT factory? Maybe resistor it out, if you know the right diode to use for testing purposes?

"VVT factory"?

Has anybody installed a VVT in a non VVT engine?
I do not get a 'VVT not connected" code from the ECU, so I assume the tune is certainly not looking for a VVT.

Anybody know the 'meaning' of negative values in block 093 (cam/crank correlation)?

[Seerlah]

Meant if the car had VVT or not when I said factory. Should have chosen better words. And yes, people have addded VVT to a non VVT engine (thenj3 did and even ran an 058 block in his 06A original equipped car. I picked up his old 06a block and built that, which is currently in my car).

Researched it for you, or tried. To my understanding from the link below, the KW is the degrees the cam is off. In the thread you will read that you ideally want it at 0 at idle, with +/-6 degree deviation from that at most to be in VCDS specs. But when I looked up the 17748 DTC on Ross Tech, they suggested that possibly the timing chain could be stretched. Something to also consider, as it is also mentioned in the thread linked below. I only read the first page (to understand measuring block 93), but you may be able to find your answer in the thread linked (12 pages long with a person having the same issue as you. different engine, but doubt that matters in this situation).

http://wiki.ross-tech.com/wiki/index...8/P1340/004928
https://audisrs.com/cam-timing-check...om-t21169.html

[Seerlah]

And as stated before I ran the timing "belt" one toothe off before without throwing a DTC and with a bad hydraulic tensioner creating slack. Can not recall if this were the same or separate incidents. But...my cam "chain" had the 16 links intact. With my understanding now about block 93, if I am understanding it correctly, being -23 degrees off is a rather large difference and would point more to the timing being off.

Maybe stretched chain makes you think it is 16 links, adding to the -23 KW? When in reality, it really is a toothe off with stretched chain?

[vtraudt]

Meant if the car had VVT or not when I said factory. Should have chosen better words. And yes, people have addded VVT to a non VVT engine (thenj3 did and even ran an 058 block in his 06A original equipped car. I picked up his old 06a block and built that, which is currently in my car).

So my ASSUMPTION is confirmed: a VVT cam chain tensioner that is NOT connected behaves the same as a non VVT. And uses the same chain (not a longer or shorter chain compared to non VVT).

[Seerlah]

Yes, you are correct. But never said anything in relation to what you are saying. I was assuming that having it disconnected could possibly cause your issues (not sure how the ECM would react with that electronically disconnected). I no longer think this, after reading that thread linked in the post above.

The AMU and AEB uses the same cam chain as far as I can tell with part number 058109229B.

[vtraudt]

Another aspect:

The proof if cams are in the right position is the machine squares in the cam lining up with the triangle cam marks on the cam holders. In may case, they do.
BUT, the position position of the intake cam relative to the exhaust cam (and in direct consequence the cam pulley (keyd to the cam) and crank, both at their TDC mark) is influenced by the position of the tensioner (collapsed/compressed or extended).
I don't know
a) how much the change is (but will observe/document next time the valve cover comes off. By trying to let the tensioner fully extend if possible, and by compression (use the tool), and see how much the squares move relative to each other.
b) I assume the 'natural' position is extended (keeping chain tightly tensioned).

In other words: could a tensioner that does not fully extend (and either remains collapsed (not getting oil pressure) or not strong enough (not enough flow or pressure or leaking internally) to fully extend) cause the -22 "degree" in block 093?

[Seerlah]

Disclaimer: I am incorrect in my posts from here forth, for those who read this thread!

When looking at your pics in post 1 more, it looks like you placed the two cams off one toothe from each others. Didn't notice this earlier and looks like you need to rotate the intake cam one toothe back. You still have the 16 links, but your notches look one off. I'm pretty convinced you timed the cams one toothe off, but can always be wrong. If you can post pics of all the timing marks at TDC, that would be helpful? IIrc, when everything is aligned correctly the intake cam will have the notch just lightly off (still directly in front of the arrow, but offset a bit), while the rest of the marks will be spot on.

[Seerlah]

You may be able to get away with rotating the cam without taking much apart. If you remove the tensioner, you may have enough slack on the chain to rotate the intake cam by whatever tool you want on the rough part of the cast. Not sure what I was doing on my car before, but I rotated the intake cam this way with vice grips on the rough cast section of the cam. Doesn't hurt anything.

But yeah, you are def one tooth off (the more and more I looked at it, I realized the notches would be symmetrical if you rotate the intake cam one tooth back).

[vtraudt]

You may be able to get away with rotating the cam without taking much apart.

Yes, I can add/reduce number of cam chain links.
Are you saying that the chain link count is NOT 16, but rather 15 or 17? If so, which?

At that point, I probably would also replace the VVT with a non VVT tensioner; doesn't seem to be a lot of VVT on non VVT heads out there (only the other way rund, people throwing VVT out and going to non VVT tensioners).

[Seerlah]

Your 16 links are spot on. But the notches are not. You need to rotate the sprocket on the intake cam gear one toothe back on the chain. You will still have the 16 links in relation to the arrows, but the cam itself is off in relation to orientation. You can have the cams aligned way off and still have 16 links. Bring the sprocket on the cam one toothe back on the chain and you should be good.

Circled is where you want the notch. Then it will be in the same spot as the exhaust cam. You are one toothe off.

[vtraudt]

When looking at your pics in post 1 more, it looks like you placed the two cams off one toothe from each others. Didn't notice this earlier and looks like you need to rotate the intake cam one toothe back. You still have the 16 links, but your notches look one off. I'm pretty convinced you timed the cams one toothe off

Timing belt tooth off?

I will check other photos (the above only for chain link count, no attention paid to actual position/TDC).

But, I recently - after getting a 2nd pair of timing experienced eyes - decided trail/error by moving what we perceived maybe a 1/2 timing belt tooth off to move the timing belt 1 tooth. Block 093 did not really change (may from -23 to -22?).

Here is the cam chain again. From the looks, showing a compressed tensioner. Exhaust cam square left of mark, intake cam square right of mark.

https://drive.google.com/file/d/1I-m...ew?usp=sharing
https://drive.google.com/file/d/1PIP...ew?usp=sharing
https://drive.google.com/file/d/1EN9...ew?usp=sharing
https://drive.google.com/file/d/1uUt...ew?usp=sharing

[Seerlah]

Yeah, your cams are off. Just rotate the intake cam to have it sit one toothe back on the chain. You will still have the 16 links, but now the actual "orientation" of the cam will be correct. Don't touch the exhaust cam, as that is timed with your belt (should be if done correctly). You need to bring the intake cam one toothe back on the chain.

[vtraudt]

Yeah, your cams are off. Just rotate the intake cam to have it sit one toothe back on the chain. You will still have the 16 links, but now the actual "orientation" of the cam will be correct. Don't touch the exhaust cam, as that is timed with your belt (should be if done correctly). You need to bring the intake cam one toothe back on the chain.

If I rotate the intake cam back (counter clockwise) to align the marks similar to exhaust cam position, I will take 1 chain link out so it would be 15.
If link count was previously CORRECT, it will then be WRONG.

The same effect takes place when extending the tensioner (in the photo, seem like it is compressed): pushing the piston UP will pull the intake cam back. Figure the width of the square (gut feeling from past).

So maybe: the tensioner does not extend, staying collapsed (because not connected, or because no oil gets in), resulting in intake cam being allowed to far forward (clockwise).

Does anybody know (I don't remember) if VVT uses the BOTTOM piston to change the position of the intake cam by roughly 20 degrees?

[Seerlah]

If I rotate the intake cam back (counter clockwise) to align the marks similar to exhaust cam position, I will take 1 chain link out so it would be 15

No, you won't. Chain is moving nowhere and will still have 16 links in regards to the arrows. You need to bring the sprocket back to sit one toothe back on the chain to have the notches line up correctly. Either do that, or never fix your issue. You want to correct the orientation of the cam, by bringing it back one toothe on the chain.

Your intake cam could be 180 degrees off and still have 16 links. Can be 87 degrees off and still have 16 links. Does not matter (leaving interference out of the point). It's the orientation of the cam you need to correct. The link count is not my concern here, you have that correct. But you have the sprocket one tooth off on the chain (orientation). Just do it, and you will see the 16 links will not change. But then you will see your notches will line up and DTC should go away.

[vtraudt]

No, you won't. Chain is moving nowhere and will still have 16 links in regards to the arrows. You need to bring the sprocket back to sit one toothe back on the chain to have the notches line up correctly. Either do that, or never fix your issue. You want to correct the orientation of the cam, by bringing it back one toothe on the chain.

Your intake cam could be 180 degrees off and still have 16 links. Can be 87 degrees off and still have 16 links. Does not matter (leaving interference out of the point). It's the orientation of the cam you need to correct. The link count is not my concern here, you have that correct. But you have the sprocket one toothe off on the chain. Just do it, and you will see the 16 links will not change. But then you will see your notches will line up. Once again, you need to change the orientation of the cam (basically, you clocked it wrong).

The links are counted from the mark ON THE CAM. That is how you change the link count between intake and exhaust.

Simply rotating the one cam (possible when using slack in chain tensioner) doesn't change the timing, it only temporarily changes the tension on the chain/tensioner. Will return to its natural position when engine runs.

If you DO rotate the (intake) cam (let chain links slip over the sprocket teeth), the link count IS changing (since links are counted between the marks on the cam, not mark on the cam holder).

In other words: for chain link count, can move the cams anywhere you want. In fact, you can take them out of the engine, get the chain link count done, mark the links and teeth. Then (ideally 2 sets of hands) insert the tensioner, and put/wiggle the whole thing into the head. No need to pay attention to where the square exactly are (but you want them near the top).

[Seerlah]

To make it easier to see what I am talking about, you are basically sitting with 17 links between the NOTCHES...and 16 links between the ARROWS.

Here are cams properly oriented, with notches matching the arrows. See how that differs from yours? Simply bring it back one tooth on the chain, and then you will have what is in the pic below.

[vtraudt]

To make it easier to see what I am talking about, you are basically sitting with 17 links between the NOTCHES...and 16 links between the ARROWS. You count the links between the arrows and not the notches.

Nope.

You count chain links 'on the cam'. The notches are on the cam. Take the cam hold downs off, and do the link counting.
You can set timing chain timing with the cams off the engine.
The arrows are used for setting the timing, but not chain links. Because cam chain slack/tension, etc would influence the count; not so when using the squares.

Later, when you put the timing BELT on to do the timing, THEN you want to make sure that arrows/triangles are on the squares, and exhaust cam pulley mark lining up with valve cover. And crank pulley mark for TDC lining up with housing mark.

[Seerlah]

Yeah I know, my anger is getting to me that you simply aren't seeing it and simply spoke non sense. But bottom line is either listen to my advice or never fix the issue. You don't have 16 links between the notches, you have 17. And you have 16 between the arrows.

But this is starting to bug me out. Maybe you do have 16. But you need to figure why your notches don't line with your arrows (ie stretched chain).

[Seerlah]

Spent the last couple minutes looking over your pictures, and you do have 16 links between the notches. My apologies. But you still don't have the notches lined up to the arrows. You need to correct that and you correct your issue.

I keep coming back looking at the pics and this has me really confused. If you can't get your notches to match the arrows like I posted above, I don't see the issue being fixed. And been sitting here brainstorming how the notches can be so far off from the arrows. Can't figure it out besides the chain stretched. Chains are the same between AEB and AMU so lengths are the same. Only other thing I can think of is a stretched chain.

[Seerlah]

Once again, I apologize for being wrong. Not that I like being right, but I hate being wrong. Would rather say I don't know than be wrong. With the notches being off I thought it was 17 links till I actually counted them. 16 links should make the notches match, as you already know. That is where the confusion came from (me not counting the links at first).

If it were me I would try different cams, chain, and CCT if it yields the same result. Sucks, but it seems you are in a rut. And what sucks more, this would be to only test if the notches would line up to the arrows (that difference between them is too much and what looks like is causing your issue). If they do, then there was something funky with those components. If not, then you are stuck at square one. But it is worth a try if you have extra parts laying around. I assume you want that car out the shop.

[walky_talky20]

Hi Guys. Mitch asked to come by and check this out. I'll do my best to help.

- The cam notches will only (only, only, ONLY) accurately line up with the arrows at the VVT Full Retard position. #AlwaysGoFullRetard
- Checking that the notch lines up with the arrow on the exhaust cam is a useful quick check that your camshaft keyway isn't screwed up (assuming t-belt system is all at TDC marks), or your exhaust cam isn't twisted (that doesn't really happen).
- Checking that the notch lines up with the arrow on the INTAKE cam is generally considered useless because of VVT chain slop. So you just check your 16 links and be done.
- HOWEVER, if you really super-much want to see those arrows align there are 2 steps to do it (We'll call them step A and B)
STEP A - Put exhaust cam at exactly TDC. Use valve cover and belt sprocket marks. Maybe have somebody hold it there for you.
STEP B - Grab the intake cam with a pair of vice grips (on a rough cast section) and force it fully counter-clockwise (that's to the left, bro). Fully tight chain on bottom. All slack up top.
- This is VVT "Full Retard" (or "Zero Cam Advance") position. You must force it manually due to zero oil pressure. Check your marks. Win.


That said:
- The chain timing looks fine in all these pictures
- Save for the fact that the exhaust cam is shown not exactly at TDC position. I'm assuming that it was just moved, and that's not the problem here.


Onward:
- Have we determined Crankshaft TDC manually by using a dowel (or what-have-you) put down cylinder #1?
- Let's see some photos of belt timing. Nice straight-on shots of marks to avoid parallax error.
- Where did this VVT tensioner come from? Skeptical Cat is skeptical.
- If you are not using VVT, I would like to see a non-VVT tensioner in there. It just removes variables.
- I agree about scoping the signals (if we can't find anything physically wrong here). I'm sure we can come up with some healthy waveforms to compare against if it comes to this.