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Re: Cam sensor troubleshooting

Posted: Tue Nov 15, 2011 4:03 pm
by FrankCorrado
Did a leads swap, same issue.
Did a sensor swap again with my other sensor and after cranking 11 errors engine stalls. Swapped to my 1st sensor, works. But I still get the errors here and there while driving and I get a little more when engine is hot.

Am gonna buy a 3rd sensor, this one being fully new.

Re: Cam sensor troubleshooting

Posted: Tue Nov 15, 2011 4:38 pm
by Basil
Very good idea, I see cam and and crank sensor "issues" on OE systems almost monthly. They can "almost" work but cause missing and bad / no starting. Those that run in contact with hot cam box oil seem particularly liable to problems, perhaps unsurprisingly. I have seen this enough to always take a scope recording of both sensors when there are odd hiccups with no definitive fault codes on OE older ecu's. I trust my limited oscilloscope knowledge better than fault codes on older cars. Good luck, you sure deserve a break with this. I would loved to have seen a scope recording direct off these cam sensors.

Re: Cam sensor troubleshooting

Posted: Tue Nov 15, 2011 4:47 pm
by FrankCorrado
Monthly? You work in a shop? :)

Yeah it's sad I don't have hands on an osci somewhere. I know nothing about that stuff, though.
But as you may know, or not, yes it's a hot cam box filled with oil. Now that I have cranked, stalled with 11 errors, swapped the sensor and cranked and it worked, that obviously tells me it's the sensor. It's the second time in 2 shots I experience this with these 2 sensors of mine. Time for a 3rd sucker. :)

Kev, or other VR guy, with the OEM ECU, if it detects cam errors, what does it do? Does it switch to batch automatically and lights up that stupid Engine Light on the dashboard throwing out a fault code on the vag-com? Why wouldn't DTA do that too? This way the engine could still run smoothly instead of cutting fuel at 200kpa or stalling the engine. :)

Re: Cam sensor troubleshooting

Posted: Tue Nov 15, 2011 5:38 pm
by Basil
I work on a lot of road cars but mainly do race engines and race chassis stuff. If it's any consolation VAG cars seem to give me more electronic hassle than all the Jap stuff put together, so more than one oil bathed cam sensor playing up is no great surprise. If you play with ecus and modern car electrics you NEED an oscilloscope. Decent USB laptop ones are cheap nowadays. Whilst something like an automotive Picoscope is nice, with pre compiled set ups for lots of stuff, a basic one will do almost as much, with a little effort and cheating. (Picos excellent help files in their freely downloadable software show how each setting is derived, in the laptop screenshots ;)) I am no electronics guru, at all, but already I am wanting a proper battery powered standalone `scope. Still very much learning, but couldn't do without one now.

Re: Cam sensor troubleshooting

Posted: Tue Nov 15, 2011 5:53 pm
by FrankCorrado
Well you know what, that just reminds me my uncle is a teacher in electronics and has all kind of electronic gizmos, I'll ask him about that, tnx. :)

Re: Cam sensor troubleshooting

Posted: Tue Nov 15, 2011 6:11 pm
by Basil

Re: Cam sensor troubleshooting

Posted: Tue Nov 15, 2011 7:27 pm
by FrankCorrado
Will read. Tnx. :)

Re: Cam sensor troubleshooting

Posted: Wed Nov 16, 2011 5:58 am
by VR6Turbo
FrankCorrado wrote:Kev, or other VR guy, with the OEM ECU, if it detects cam errors, what does it do? Does it switch to batch automatically and lights up that stupid Engine Light on the dashboard throwing out a fault code on the vag-com? Why wouldn't DTA do that too? This way the engine could still run smoothly instead of cutting fuel at 200kpa or stalling the engine. :)
It does exactly that. It switches to a batch injection fuel map and a heavily retarded timing map.

The DTA can do that as well if Allan writes some software for it. We could add a parameter in General Engine settings (under the existing sensor failure defaults) to load a 2nd map if the cam sensor fails.

The OE ECUs take contingency very seriously and for every day life, they are unbeatable for a road car engine. Standalones take no prisoners! But that encourages you to go the extra mile with wiring quality.

I have to say though, I just don't buy the fact you've got 2 duff sensors. I used the same cam sensor on mine for 60K miles with no errors at all, other than the startup ones you always get.

Crank sensors which generate their own voltage output can deterioate with age and become a bit more sensitive to the gap and swarf etc, but digital sensors with a chuffing great 12V spike..... I don't buy it Frank, sorry. I still say you've got a wiring fault here mate.

Consider the facts. Two identical engines running identical sensors and identical ECUs. One has no signal errors and the other has several. What's the only variable between the two setups? Wiring :D

Re: Cam sensor troubleshooting

Posted: Thu Nov 17, 2011 1:59 pm
by lumley32
frank has your S80 got the extra earthing lug next to the power connector?
the older ones dident have this and i think im right in saying there were some ref/sync problems because of it!

just remembered and thort it might be connected!

Re: Cam sensor troubleshooting

Posted: Mon Dec 12, 2011 6:25 pm
by FrankCorrado
lumley32, site never sent me a mail that you responded, sorry.

How many earthing lugs should there be? I got the ECU in Spring 2010.

But good news!!!! I got my new sensor last week and today was the last possible day to drive the car in 2011, so I did it. And it worked!!!!!!!!!! No errors. I really have 2 faulty sensors!!!! Incredible... but so happy it was not the wiring as I did all sort of testing and it proved to work. Still surprised the sensor could fail like this.