# Mk1 TT Cam sensor error



## KeegsTT (Aug 10, 2015)

Hi Guys

So my car keeps giving me a cam position sensor error (17748/P1340/004928 - Camshaft Position Sensor (G40) / Engine Speed Sensor (G28): Incor. Correlation ), 
i have to date done the following

Replaced the cam position sensor
replaced the timing chain (it was off by 1 tooth) timing is now correct both chain and belt
fitted a new turbo (Gt28 Upgrade)

the car is tuned on a stage 3 Revo file but it wont boost past 13psi even though the MBC is set to 21psi, i have all the supporting mods to go along with the tune
red top coil packs, NGK level 8 plugs, Bigger intercooler, 4bar FPR, MBC, Forge 008 DV with blue spring, Forge Tip and the 550cc Injectors.

the car starts fine during the day just in the morning it struggles, the engine is fully rebuilt with forged internals and new valves. it feels like it doesn't have any vacuum on morning starts, even the boost gauge only moves after a few milli seconds, the car wont boost past 13psi but when it does it boosts hard but you can feel the limitation. i get a little white smoke out the exhaust that sort of smells like gasket mixed with a little oil (very difficult to explain) the turbo is stil very new only a few days old and i only covered about 150km (95 miles) but has smoked from the time i started the car. if i pull out the wastegate vacuum line the car then boosts fine but with no control on where to stop boosting, i have unplugged the MAF to see if that helps but no change.

any help here would be greatly appreciated.

Keegs


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## KeegsTT (Aug 10, 2015)

*Cam Belt was also replaced but could it be streched*

Ok so just though i would thro this out there, we did take the cam belt out a few times while doing the Rods so could we have stretched the belt. the belt is only a month or so old. this only came on after we did the rods and fitted the new belt, granted the chain was also misaligned from being stretched but once we corrected that the power was there just not getting full boost


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## Audi_Mechanic (Mar 24, 2012)

Might be a problem with the camshaft tensioner/adjuster.


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## KeegsTT (Aug 10, 2015)

*CamShaft Tensioner/ Adjuster*

we did check it when we changed the chain and it seemed fine.
i will take out the tapped cover and see if the timing is still fine or if it went out.
i also want to change the G28/ Crank sensor today and see if this helps.
thanks for the feedback.

i will keep this updated as i go along.


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## KeegsTT (Aug 10, 2015)

*Boost issue*



KeegsTT said:


> we did check it when we changed the chain and it seemed fine.
> i will take out the tapped cover and see if the timing is still fine or if it went out.
> i also want to change the G28/ Crank sensor today and see if this helps.
> thanks for the feedback.
> ...


ok so far we found a boost leak, gonna have to pull out the intake mani to get to it, well not really but it will save lots of time.
will get that going and see how far we get.


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## KeegsTT (Aug 10, 2015)

*Impulse Rotor*

Ok Guys

some news, i managed to find the Impulse rotor had some wear on it, ordered the new part from Audi will take 2 days as its a special order.
part number 06B 905 234A
will update after i install the part, am busy sorting out the boost leak now.


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## KeegsTT (Aug 10, 2015)

*Impulse Rotor*

Heres a pic of the rotor


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## KeegsTT (Aug 10, 2015)

*Update*

OK so i haven't been able to update in a while but here goes, so my error hasn't gone away and still persists.
car is going fine overall but i have a new issue

Mods just to remind everyone
GT28 Turbo
FMIC
4Bar FPR
Red Top coils and level 8 plugs (NGK)
Forge TIP
Cat Back Exhaust and DP
MB Controller
550cc Injectors
Revo Stage 3 map
N249 delete, Catch Can install, PCV delete
Forged internals
not sure what else i missed but ask and i will let you know
car boosts fine but wont get up to 1.5 bar boost without adjusting the WG fully to open at 1.5bar up.
i have also done the Diode mod, the N75 isn't in use but as soon as i get to 4k rpm the throttle closes, what could cause this?
i am going to change the Fuel pump to an 044 Bosch with a surge tank tomorrow but could my car be starving fuel to cause this?
up to 1 bar boost the car runs fine, pass 1.2 at 4k rpm the throttle closes.

any suggestions will help.


and i have double checked the cam timing and its 100% but the error code still persists.


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## KeegsTT (Aug 10, 2015)

*Help*

No one?
any suggestions will help here guys.
haven't done the Fuel pump today was a bit busy


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## Audi_Mechanic (Mar 24, 2012)

Don't worry about how it boosts, aim your concern on the timing issue first. Full boost pressure isn't going to matter if the ECM is inable to properly calculate proper spark/fuel timing.

The cam/crank position correlation code will come up if the ECM detects that camshaft and crankshaft timing doesn't match. The crankshaft is directly measured by a magnetic sensor and the intake camshaft is monitored by a hall sensor. The intake camshaft isn't directly run by the timing belt/crankshaft; it is driven by the exhaust cam via a chain which is tensioned (or adjusted if equipped) by a hydraulic unit. If you know for sure that the exhaust camshaft has correct static timing with the crankshaft via the timing belt offset sprocket marks, and that intake camshaft timing is correct with exhaust cam via timing chain #of rollers & offset marks, then you would have to suspect that there's a problem with the chain tensioner/adjuster unit while the engine is running. Or an electrical problem with the crank/cam sensors, engine wire harness, or ECM. 

You need to check engine oil pressure to make sure you don't have a clogged oil pump pickup. How does the cylinder head look with the valve cover off, pretty dark brown from not being serviced very often or light brown from proper maintenance? If it's getting kind of dark or you have low oil pressure, remove the front and rear camshaft bearing caps to see if excessive wear is present. If the chain tensioner/adjuster unit (does your chain tensioner have an electric solenoid on it?) doesn't receive proper oil pressure, it won't maintain proper intake camshaft timing and set off that correlation dtc. If the tensioner is failing mechanically, it will set the dtc and there's no real way of checking it beyond replacing/swapping it to see if it corrects the issue. I dealt with a bad cam adjuster/tensioner unit on a customer's B6 1.8T A4 which was well maintained, had good oil pressure, and static timing was good. Adjuster/tensioner unit looked okay, no signs of oil sludging with the engine, no abnormal wear on the chain guides, but ECM kept storing a cam/crank correlation dtc. New adjuster fixed it.

You can use a DSO to monitor the cam and crank sensor signals at the ECM. If the signals are okay, voltage drop on cam/crank sensor circuits are okay, verify that there aren't any power/ground circuit problems, engine oil pressure is okay, engine static timing is okay, you know for sure that the cam adjuster/tensioner unit is okay, then you'll have to suspect that either the crankshaft sensor wheel is misaligned or damaged, camshaft sensor wheel is misaligned, intake and/or exhaust cams are faulty somehow, or the ECM took a crap.


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## KeegsTT (Aug 10, 2015)

You need to check engine oil pressure to make sure you don't have a clogged oil pump pickup. I will check the oil pressure today but i don't see it being a problem, the oil pump is brand new (we a few months old) the oil is changed regularly twice a year.

How does the cylinder head look with the valve cover off, pretty dark brown from not being serviced very often or light brown from proper maintenance? its clean and tidy the complete engine has been overhauled 3 months ago

If the chain tensioner/adjuster unit (does your chain tensioner have an electric solenoid on it?) doesn't receive proper oil pressure, it won't maintain proper intake camshaft timing and set off that correlation dtc. If the tensioner is failing mechanically, it will set the dtc and there's no real way of checking it beyond replacing/swapping it to see if it corrects the issue. I dealt with a bad cam adjuster/tensioner unit on a customer's B6 1.8T A4 which was well maintained, had good oil pressure, and static timing was good. Adjuster/tensioner unit looked okay, no signs of oil sludging with the engine, no abnormal wear on the chain guides, but ECM kept storing a cam/crank correlation dtc. New adjuster fixed it. Makes sense, the chain is new and the cam sensor and crank sensor are new, it does have the electric solenoid. i suspected that maybe an issue but your exp has now confirmed this to be a possibility, i will get one tomorrow and revert.


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## KeegsTT (Aug 10, 2015)

*cam tensioner changed*

Ok so i changed the cam tensioner and still no luck same error keeps coming back P1340, all the marks line up 100% and everything is new, gonna change the oil on Monday and see if that helps, 

currently using Castrol 5w40 magnatec professional fully synthetic so it maybe the car doesn't like the oil, will also do a oil pressure test to ensure that the oil pressure is in fact in line with the specified measurements even though the oil pump is new.

i am now stumped anything else that i should look at maybe?


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## Audi_Mechanic (Mar 24, 2012)

:facepalm: Damn Audis, always gotta have some melon scratcher of a problem. Drive it off a cliff. Well, the engine runs so if timing is off, then it's not so bad that it bends valve. But is timing actually off?

Is the cylinder head correct for the engine block? Correct cams? Correct timing belt pulley/gear system? Correct tensioner for that cyl head (check part # to make sure you weren't given a V6 or V8 adjuster)? 

Have pictures of your timing marks at the both belt gears while at TDC? As well as a picture of both cams at TDC with their timing marks at rear of cams in or near the windows with 16 rollers spacing them?

There is a basic setting that will allow you to test camshaft adjustment, I think block 94 but i'm not 100% sure that's the correct block number, haven't done it in a while. If it fails then your issue lies with the adjuster somehow. Sorry I didn't mention this test earlier, it gets hard to remember stuff for the older cars when you're constantly having to learn new stuff for the newer cars. With the timing error, you might not get accurate results with that test so keep an open mind.

So if you know for sure that you have proper static timing, and the crank/cam sensors are okay, and cam adjuster/tensioner is new, new cam chain, then maybe you have a very unusual problem. Like maybe the sensor wheels on the crank or cam are installed incorrectly, or maybe the crank sensor wheel is damaged and throwing off the tdc window. Maybe you have an ECM problem. Check oil pressure, cam tensioner/adjuster won't operate properly without adequate pressure.


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## KeegsTT (Aug 10, 2015)

*oil pressure*

Going to do the oil pressure test tomorrow as well as the new fuel pump install, car will be parked for a while but once i am done i will test and provide feedback.
i have measured the measuring block 090 and the intake cam position is sitting at -5kw to -6kw on idle. is this normal? what should it be.
going to also disconnect the tensioner solenoid to see if any of the values change, maybe the solenoid isn't getting power 
need to find a high enough cliff


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## KeegsTT (Aug 10, 2015)

*Oil Pressure*

So i check the oil pressure an it is 100% spot on.
Idle is at 1bar
3000rpm is at 4bar.
16 rollers between cams,
cam pick up is new, 
gonna check the crank pick up and the crank position.
is there a particular trick to setting the crank timing?
i read somewhere the we shouldn't use the flywheel position to set the crank timing.
at least we are narrowing things down further.


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## vagbahn (Dec 13, 2009)

Check your crank gear pulley to see if the key-way slipped ? Has the cylinder head been milled more than 20Ks ? Using stock cometic head gasket ? Check timing gear (chain side) for rotation on shaft ? Was the crankshaft reluctor wheel damaged or removed and reinstalled ? 

Hope any of that helps


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## KeegsTT (Aug 10, 2015)

*Key Way setting*

Hey Bud thanks for the advise, what's the best way for us to go about checking this?
the motor was rebuild so it was stripped and reassembled so there is a possibility the Crank is not set up correctly.


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## 20v master (May 7, 2009)

KeegsTT said:


> Hey Bud thanks for the advise, what's the best way for us to go about checking this?
> the motor was rebuild so it was stripped and reassembled so there is a possibility the Crank is not set up correctly.


The keyway that aligns the timing belt cog would have to be pretty worn to cause this, but it's possible. Basically you have replaced everything hardware wise on the electrical side. The easiest thing to do at this point is remove the crank position sensor, pull the spark plugs out, with trans in neutral, and slowly turn the crankshaft to observe the crank trigger/position wheel. If it's the "window" style wheel as opposed to the "toothed" wheel, it very easily could have been damaged during your build, knocking out one of the dividers between the windows, making the ECU unable to determine crankshaft position, hence your code. The next step would be to remove the timing cog and verify the keyway isn't badly worn, but that's a lot more work to remove the timing belt. After that, send me your email address in a PM and I'll send you the OEM harness troubleshooting guide for the cam sensor. That's a long shot but you can at least verify no damage to the harness there.


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## vagbahn (Dec 13, 2009)

Depending on the transmission it might be easy to check the TDC alignment mark on the flywheel. After you've verified the mark on the flywheel, check the mark on the timing cover/belt pulley. If there is any deviation it would warrant a tear down of the timing belt and crank gear. If it's slipped you might get lucky with a gear only, but if the crank was damaged you'll need to install dowel pins. Integrated Engineering sells a kit for the TDI but you can do it yourself if you are confident ...You have to get it right or the crank is junk.


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Image uploading. Refresh page to view


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## doctordubs (Feb 28, 2015)

So many guys caught out by 20v timing lol. No offense keegs. Il bet the inlet cam is out. Guys preload the chain tensioner incorrectly. You think all is ok till it starts up and the oil pressure fills tensioner, this is where it pulls the timing out. 

Sent from my GT-S5280 using Tapatalk


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## KeegsTT (Aug 10, 2015)

*Cam sensor*

i agree with you i also think they have been tensioning the tensioner correctly, so we now stripped the inlet cam out to compare it to another cam i am getting tomorrow. i want to see if there are any differences between the 2. 20v timing is a nightmare.


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## doctordubs (Feb 28, 2015)

Do you knw wich marks to use when installing chain and tensioner? 

Sent from my GT-S5280 using Tapatalk


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## KeegsTT (Aug 10, 2015)

*Guide lines*

i would appreciate some tips or instructions, we maybe doing it incorrectly from the start.
we have tried all the tips we found on the net but we could just be doing it incorrectly.
we have used the 16 teeth system with the cams on the mark but that hasn't been any good


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## Audi_Mechanic (Mar 24, 2012)

If everything is mechanically okay with the crankshaft, you want the timing mark on the crank pulley to line up with the mark on the lower timing cover. The exhaust cam belt gear has an offset timing mark that won't line up perfectly with the timing mark on the valve cover; all you need is to have the tooth with the timing mark to line up with the valve cover. From there, you want 16 rollers to seperate the intake cam from the exhaust cam with the tension tool removed from chain tensioner/adjuster unit. The timing marks on the rear camshaft bearing caps won't line up perfectly with the timing windows on the chain gears of camshafts (at least that's how I remember it), they will be offset. I think the intake cam will be more offset and won't line up very well; the key is the 16 roller spacing. 

Earlier I asked a question,


> Is the cylinder head correct for the engine block? Correct cams? Correct timing belt pulley/gear system? Correct tensioner for that cyl head (check part # to make sure you weren't given a V6 or V8 adjuster)?


 Have you addressed these yet? Reason why I asked is because a while ago I tried helping someone else on vortex with a similar problem but they insisted that their timing marks must line up perfectly when they usually don't (not on an engine with a lot of miles at least). I think they eventually figured out that the cylinder head they were using wasn't matching up properly with the cams or cam adjuster/tensioner or something like that. When I find the thread I'll post a link, it may be helpful seeing how it has some schematics.


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## Audi_Mechanic (Mar 24, 2012)

Found it! http://forums.vwvortex.com/showthre...oner-and-belt-Still-having-a-hard-time-timing


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## KeegsTT (Aug 10, 2015)

*Timing marks*

Hey bud

yup we checked the crank side and they line up 100%, this is how we got it lined up.
piston 1 all the way up with the exhaust gear lined up to the valve cover, we then checked the inlet cam should line up to its mark but that gives us 15 teeth.
i know that's completely off by 1 tooth i removed the inlet cam just to make sure all is in order with the gears as no matter what we do the marks wont line up 100% which s far as i know and as you mentioned correct, the 16 teeth is key.
i will check the crank pick up to see that all is ok, the key way is also spot on, i have had 2 other mechanics come thru and double check that we have done everything ok, rite now i suspect the cam gears to be the issue or something not fitted correctly, will take some pics and post later.
gonna read thru that thread you posted as well, thanks for the help guys its much appreciated


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## KeegsTT (Aug 10, 2015)

*Cam Pick up*

Ok so i think we sorted our problem out, well i still need to do a little more testing but i think we sorted the issue out.
seems that when we fitted the cam timing cap we over tightened it and the cap moved so the car always picked up the timing as off.
i still need to drive it around a bit more to confirm, from my initial test the car is going fine but the throttle pulls back a little after 5000rpm 
gonna fit the inline fuel pump now and see if that makes any difference


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## doctordubs (Feb 28, 2015)

Ok ur aware of the notches in the cams and the arrow s on the cam caps by the tensioner side?? They obviously must align, install the cams, as close to the arrow/notch alignment. Now release the tensioner retract tool, where the cams have the hex casting slide 2 spanners on. Holding the exhaist cam on its mark, turn inlet cam in anti clockwise direction. The top guide should move up, when the slack is taken up the 2 notches must align with the cam cap arrows. Thats how iv done it for years. 

Sent from my GT-S5280 using Tapatalk


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## KeegsTT (Aug 10, 2015)

*Cam shaft alighn*

Thanks for the trick bud, from my initial drive the car did feel a lot punchy from low revs vs. before when it was fairly dead until i came into boost.
the only thing i noticed a get a little pop when i come off the throttle a few loud ones but mostly smallish ones, been getting those quite a bot lately but i also have no exhaust boxes, i have a rear box but its been gutted out, i got the car like that so i am gonna change them in the near future, car isn't too loud or anything if anything its sounds quite nice. also i have 550 Injectors with a bigger turbo, these pops only came when i installed these

i am still only getting 1.2bar boost 17PSI, car is mapped to 1.5bar 21PSI but i can bump up to 1.6 - 1.7 bar easy.
actuator is new and adjusted quite tight and i am using a MBC with the diode mod. if i disconnect the MBC i get full boost so maybe ii need to adjust the actuator a bit more but thing this may cause more harm as the last time i adjusted the actuator it only opened at 3ar boost under load test with a compressor.


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## KeegsTT (Aug 10, 2015)

*FIxed*

ok so we removed the intake cam and found the cam pick up was over tightened and the wheel moved.
not how this happened but i guess if you don't double check things this is what happens.


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