HELP - URS4 Not Starting...no spark...immobilzer??

[lcsmith]

Update;
Couldn't get it to start at all last night, to test anything while running...

Took out the G4 and G28 sensors down at the flywheel, tested the resistance across them which came out at roughly 915 ohmns and 925 ohmns, while wiggling them to see if there was a broken wire that would affect the reading........nothing, seemed fine.

Tested all the wiring to / from coil packs, all ok, no broken wiring.

Tested the cam position sensor (G40) at the 2nd pin of the plug with an led tester, the bulb lit up when the ignition was turned on then went off and didn't come back on or flash while we were turning it over so that would lead you to think that there is no signal coming from the sensor. There was no change in the results whether the sensor was plugged in or not........

I'm going to talk to a friend who has the same car and perform the test on his car to compare.


Any suggestions on suppliers for this sensor (G40) and cam belt kit?

[lcsmith]

Update;
Phoned up Quattro Corner this afternoon and he was VERY helpfull!

So I ordered up;
Cam Belt - £18
Tensioner - £25
Cam Position Sensor - £100

All in stock, and in the post..............so tonight I'm going to strip down the front end ready for the parts arriving.......

Cheers!

[S2central.net]

Sounds like some fine diagnostics with an LED on G40 - well done... sure smells like the root cause.

[lcsmith]

Well thanks for all your help & info so far!

If it wasn't for you lot I would have been totally lost and probably ended up putting into a garage = ££££££££ BIG BUCKS ££££££££

So add that saving to the savings I'm having with the coil tubes group buy, and the savings from quattro corner compared to audi.........well basically....drinks are on me!

[lcsmith]

OK Update time;

Took the front end apart and radiator fan was on his last legs, fan belt was knackered, and the timing belt was totally knackered, surprised it hadn't gone! So changed all that, new cam position sensor fitted and finally managed to get it all back together yesterday, turning over but not starting......

So am I thinking to get a shot of the POS's & Coil Packs from my friends URS4 to give that a shot, I did test my ones for broken wires, but that doesn't mean to say that the POS's or Coil Packs aren't to blame.......failing that........I could swap G4 & G28 from my pals car at the same time, to try that............

Any other suggestions.......................?

[S2central.net]

Are you seeing pulse with the LED on the new camshaft sensor - at pin 2 ?

Are you seeing 5V across pins 1 and 3 on the cam sensor ?

Don't change too many things at once or you will confuse things further. I seriously doubt you have two dead POS and five dead coils - there is something else afoot here.

Have you possibly swapped the connectors at G4 and G28 over by accident ?

Have you checked the flywheel pin for G4 is still there ?
There has been the very odd occasion where the pin falls off and so you get no signal at G4...

Could talk about this for weeks. See if you can borrow a two channel oscilloscope and we'll have this sorted out in half an hour !

[lcsmith]

Are you seeing pulse with the LED on the new camshaft sensor - at pin 2 ?

Are you seeing 5V across pins 1 and 3 on the cam sensor ?

Don't change too many things at once or you will confuse things further. I seriously doubt you have two dead POS and five dead coils - there is something else afoot here.

Have you possibly swapped the connectors at G4 and G28 over by accident ?

Have you checked the flywheel pin for G4 is still there ?
There has been the very odd occasion where the pin falls off and so you get no signal at G4...

Could talk about this for weeks. See if you can borrow a two channel oscilloscope and we'll have this sorted out in half an hour !

I will test the new cam sensor as you've described.....

as for changing things over, I will only be swapping one thing at a time and putting it back before changing another, I wouldn't have thought that 5 coil packs would pack up either but didn't know if one coil pack failed they all still worked, or if one POS failed they both wouldn't work, I'll have to do some reading on how they fail and what the symtoms can be.......

G4 & G28 have different coloured plugs at the bulkhead (one white and one black), so you don't mix them up, and when I removed the actual sensors i didn't take them off their bracket so they can't be mixed as the bracket only bolts on one way.

I wouldn't have thought that if the fly wheel pin had fallen off the car would have intermittantly started and sometimes hadn't before, but I will manually turn the car over and have a look to check its still there!

THE FIGHT RAGES ON!

cheers for now.

[S2central.net]

It has all the symptoms of cam sensor failure - but equally something stupid like a broken earth strap or loose connections on critical sensors will give this kind of grief.

The POS is a 3-channel thing... Three independent channels per POS. Any one can fail but it only affects one cylinder.

There's four plugs that connect the coilpacks to the loom. The two white plugs are just 12V - protected by Fuse 32. The two black (or black and brown) plugs connect to the POS outputs.

[lcsmith]

Well over the weekend I got a shot of my friends car to swap bits across and swapped both the G4 & G28 sensors from his car.............nothing put them back on his car and it started and was running fine, so..........

swapped over the coil packs............nothing put them back on his car and it started and was running fine, so...........I now have no idea!


Summary of things thats been done / checked (and thats double/treble/quadroople checked);
All Fuses / Relays,
ECU is DRY and all plugs are firmly connected,
All plugs at bulkhead are connected,
Immobiliser is turning itself on and off (it doesn't allow the car to be turned over, but I can turn it over fine),
Replaced cam position sensor (G40),
Ruled out G4 and G28,
Ruled out Coil pack failure,
Set timing and replaced belt.


Symptoms;
No Spark,
I have Fuel,
Turns over.


Could it be the ECU? Could I swap the ecu from my pals car without requiring reprogramming?.................s2central - can you test my ECU? How Much?

Only other thing is the pin on the flywheel - although either its there or it isn't, this started off as an intermittant starting fault, that wouldn't be the case if the pin had broken off, it just wouldn't start at all............anyway

Cheers for now..........

[lcsmith]

Right...........

Tuesday Night;
Checked that the timing wasn't out, but it all looked fine.
I tested my new cam position sensor, and its working fine (the old definately didn't work!), so I do think the cam sensor was knackered.
We had spark and fuel, and we knew it wasn't the coil packs or the G4 and G28 sensors. So I thought well maybe we've managed to get two of these plugs on the bulkhead mixed up, so I swapped over the two plugs from the coil packs going into the POS's, started straight away, it was running smooth, so the timing was right, and it sounded great!..............so I thought well I'm not going to get too excited, turned it off and it wouldn't start again, so I thought well maybe that POS's are knackered..........so I read up about them and found out that the ones of a V6 can do as a replacement............


Last Night;
I got a hold of a POS from a 2.6 V6 that was breaking and tried swapping that with one of my POS's then the other............no change.
Then I checked if I had spark with my POS's plugged in one way then swapped round, then with the new V6 POS.................no spark...........nothing!
I still have fuel, but now I don't have spark..........how the hell can that be (the cam position sensor's still working)

Anyway I started thinking about it, the actual engine itself doesn't need that much to make it run........3 sensors, coil packs, POS's, earths, fuel, Fuses / Relays, Immobiliser disarmed, ECU......


Could this be the ECU giving me bother here?
Can I swap another ECU onto my car without and frigging about?
Where can I get MY ECU tested and fixed if neccesary?

I'm really just getting to the end of my tether over this one, I'm even having horrible thoughts of breaking it up to put on the dreaded ebay, its ok though the local preist is coming round today to exorcise that thoughts out of my head...............but joking aside it might come to that!

[lcsmith]

Well I removed the ECU, and the back of it has scraped marks where it looks like someone has pryed off the tabs with a screw-driver to get the back off......so

I sent it to Blue-Streak for testing, and they've just phoned to say its faulty and they're not sure whether they can repair it or not, anyway they've quoted £182.75 + Delivery to rebuild it if possible and they'll have it ready for the end of the week.....

So it looks like I've finally found the problem.......hopefully

Well the way I look at it is that if I've fixed the cam sensor AND the ecu, surely there can't be more faults at the same time!............two faults simultaneously is bad enough!

I'll keep you informed.........

Cheers

[lcsmith]

Blue Streak have just phoned to say that further inspection of the ECU has shown that it has been immobilised...............by....you got it - the f*cking immobiliser, so theres nothing wrong with the ECU and they're sending it back and charging me nothing apart from the carriage.......sweet!.......free test

BUT, the technician tells me that these immobilisers can work on say three circuits (eg - turning over, spark & fuel), so for all I thought that the immobiliser was deactivating itself when I put the chip in the dash by allowing me to turn the car over, one of the other circuits could be broken.......ie spark...

Anyway the ECU is on its way back and I've booked the car into a Car Electronic Engineer and they're going to check it out and hopefully rip out the Immobiliser and all related sh*te.......so it looks like it was the Immobiliser all along.....my hunch was right!

[S2central.net]

Are you talking about factory fitted IMMO or aftermarket device ?

Best talk this one thru privately on PM - I don't like divulging any IMMO info on public forums.

[twoqu]

Hi!
In my opinion you should trace every wire from that aftermarket immoboliser and chop them! If they are soldered connections and you want to reconnect the immo at a later date then leave a bit of wire.
Can't see how these ecu specialists can tell the ecu has been immobolized as they do not get locked. Post the ecu number as there are two versions, non immo and immo. I would have thought the immo version would have been phased in with the introduction of the S6. Anyway, if you had a factory immo equipped car then there probably wouldn't have a problem.
Ok, so it looks like somebody has opened the ecu before, perhaps to upgrade the chips. I doubt whether that particular aftermarket immo has additional circuitry which would require opening the ecu. I understand that the factory immo system uses a pulsed signal into the ecu thats why there are two ecu versions.

[S2central.net]

Agreed with twoqu above... SOunds like the aftermarket ECU is the root cause. I sent a PM to help work this further.