s6 not starting as it should

[220bhp]

My s6 for some unknown reason is not starting as it should. I don't think its the hall sender, as I have had this problem before and replaced it. This is different. It starts after a few turns, but wont run unless I feather the throttle. when driving I can feel the engine is not running as well as it should all the time. What ever the problem is its very intermittent. The car runs ok 90% of the time.
I intend to check it out latter today if I can. I replaced the fuel pump a few weeks ago with a new unit I wonder if this has anything to do with it. The car ran fine after I fitted it, with no issues.
Any help as always would be much appreciated.

[domas]

I would start by pulling the codes.

[UrS4boy]

Potential solutions to why your AAN/ABY/ADU isn't starting

In addition to the code pulling suggestion, you might want to consider the list in this post (below), including the MAF and the throttle position switch.

http://forums.quattroworld.com/s4s6/msgs/210191.phtml

[220bhp]

Thanks Dave I have looked through your post. The car will start, just a bit reluctant sometimes. I have ordered another vagcom cable and we will see what comes up.

[UrS4boy]

UrS C4, 200 20VT (3B) and S2/RS2 OBD1 Fault Code access port locations and info

Thanks Dave I have looked through your post. The car will start, just a bit reluctant sometimes. I have ordered another vagcom cable and we will see what comes up.

In the interim, you could pull the codes by blinking them out. See the link(s) in this post:

UrS C4, 200 20VT (3B) and S2/RS2 OBD1 Fault Code access port locations and info
http://forums.quattroworld.com/s4s6/msgs/90409.phtml

[HMS-S6]

Does sound a bit MAF

[domas]

so start the car with maf unplugged.

[220bhp]

Plugged in vagcome 00515 and 00513 with ignition on, engine not running. is it right that these codes come up if its done like this.

[twoqu]

The 00513 code is the usual speed sensor one that occurs when the engine is not running.
The 00515 code is associated with the hall sensor I am afraid!
If not an electrical fault which would probably mean a no start it could be a mechanical fault such as cam timing/pulley or worse the flywheel pin!

[UrS4boy]

G40 Cam Sensor info including 3B replacement

Plugged in vagcome 00515 and 00513 with ignition on, engine not running. is it right that these codes come up if its done like this.

As Robin suggested, the 00513 = G28 engine speed sensor, which always comes up when the codes are checked with the engine off.

00515 (Blink Code 2113):

•2113 (Blink Fault Code), 00515 VAG1551/2 Fault Code Number
(G40) Hall sensor in distributor (3B, early AAN engines) or camshaft position Hall Effect sensor later S4/S6 AAN engine). Distributor alignment, faulty sender, Mis-located sensor & distributor, Cam timing possibly incorrect on AAN engine, Check lower Crankshaft Gear keyway Symptom: Engine will not start, power loss, check engine light may come on during driving above certain RPM

You can check the G40 itself with an LED with its legs strategically inserted into two of the three connectors, as discussed here (Click on the G40 live label):

http://members.shaw.ca/speedtek/UrS%...ice%20Map.html

IF you need to change it, you can use this procedure:

http://12v.org/urs/Nate_P_CPS_How_To.pdf

[220bhp]

I have charged the battery again. Left the ignition on after vagcom The 00515 code. Camshaft position sender 20-10 malfunction in basic settings-intermittent.
Before going to the expense of replacing the g40 sensor, there are a few other things I should ask advise on.
I have tried to read the codes again, but I cannot. I only have vagcom lite and some Ebay cables. All I get is comport ok, no interface found. I will have another go today.
I tried to start the car ,as suggested with the maf disconnected, no difference . I will
say that despite the 00515 code. the symptoms do not seem to be normal g40 failure. it is more of a misfire. It starts but it is not keen to be revved. When it clears it seems to run on four. I changed the plugs, no different . Wiggling the injectors helps a little.
But I found unplugging them one by one did not make the same difference to the tick over. a couple made very little difference, the others made a lot and almost stopped the engine. It was dark by then so not the time to try. I will have another go later today. Am I right in thinking if it where the injectors at fault or the fuelling, Or even timing, It would have thrown a code. I cant help thinking it is related to the fuel pump
Issue. The pump had done a lot of miles and needed replaceing.

[newsh]

Did you replace the fuel filter too?

Check your black and white connectors are the right way round, with the cheap ebay leads it's possible to fit them backwards. Make sure the fuse is good.

[220bhp]

Which fuse are you referring to John .

[UrS4boy]

Try testing the G40 with an LED inserted into the connection pins, as suggested in the post I linked you to above. That will either rule out or confirm the G40 issue.

"The long lead (anode) should go to the 5V side and the short lead (cathode) to the CPS output side, with a (270 ohm (or more, e.g. 300 ohm)) series resistor on either side. With this configuration the LED is "on" when the open window of the metal cup passes through the CPS, because the CPS output is pulled low at this time. So the LED will be "off" during most of the camshaft rotation." Doron, 2013-05-10

http://forums.quattroworld.com/s4s6/msgs/240878.phtml

[macspring]

What was the fault in the end ?

Thanks.