Long cranking

[UrS4boy]

Check if injector's are good

I did this by parking the car up, and then removing the fuel rail with the injectors and everything intact. Placed glass jars over the open ends of the injectors and monitored them every few hours to see if any of the injectors leaked. Two or three of them did. I removed the injectors and took them all for cleaning and blueprinting (new pintles, etc). The fellow said it looked like there was a jelly-like blob inside the injectors and suggested that my fuel was too old and that I should purge the fuel tank, change the fuel filter and start over again with the new injectors.

[Mikes2]

Sounds like you have a leak.

Try priming the pump a few times before trying to start. if it fires up straightaway after doing this, you're losing fuel pressure.

What are the fuel lines like underneath

[UrS4boy]

Try priming the pump a few times before trying to start. if it fires up straightaway after doing this, you're losing fuel pressure.

How do you do that on an S2? The FP relay is triggered by the ECU after it has a signal from the G28 engine speed sensor that says RPM > 13. (At least that it is how it works on an AAN and 3B).

For an AAN you can power the fuel pump from the (+) post under the hood to the downstream side of the S17 20A fuse holder.



3B:

[RichLV]

Sounds like you have a leak.

Try priming the pump a few times before trying to start. if it fires up straightaway after doing this, you're losing fuel pressure.

What are the fuel lines like underneath

Fuel lines look like this:





They're new. No leaks underneath, doesn't stink of fuel. I'll try to prime the pump by removing the relay cover and sticking the switch together a few times.

[RichLV]

The car stood today for 2 hours and it was already hard to start. I'll yank the relay when I'll go home from work. And I have my old fuel rail still lying around, I'll swap the FPR from it to be sure, but it looks more like the pump check valve is stuck open, since I experience no running issues.

[mcandmar]

How do you do that on an S2? The FP relay is triggered by the ECU after it has a signal from the G28 engine speed sensor that says RPM > 13. (At least that it is how it works on an AAN and 3B).

Easy, open the fuse box under the bonnet, pop the cover off the fuel pump relay and engage it with your finger. Its a little trick i came up with to check for leaks after replacing fuel lines

[Mikes2]

or use the z bridge

[UrS4boy]

J17 Fuel Pump Relay Information and why it is so important

Easy, open the fuse box under the bonnet, pop the cover off the fuel pump relay and engage it with your finger. Its a little trick i came up with to check for leaks after replacing fuel lines

Not so easy with a C4. The FP relay is under the drivers side, inside.

And the "Z" bridge has nothing to do directly with the FP on a C4

J17 FP relay info: http://forums.quattroworld.com/s4s6/msgs/22583.phtml

J219 C4 Starter Interlock Relay: http://forums.quattroworld.com/s4s6/msgs/270532.phtml

FP relay is either a 208:



OR 372:



A "Z" bridge in place of the J219 starter interlock relay (relates to the type of central locking and alarm control module the C4 has):

[RichLV]

For how long should I hold it? I held it for about 5 seconds and it still was hard to start. I have the 208.

It also stinks of fuel in the vicinity of N80. Is it supposed to?


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[mcandmar]

2-3 seconds should be plenty. Smell of fuel isn't right, try disconnecting the vacuum line to the pressure regulator and make sure there is no fuel in there, i have heard of them rupturing and leaking fuel out through that fitting.

[UrS4boy]

N80 Evaporative Emissions Frequency Control Valve and Canister info

For how long should I hold it? I held it for about 5 seconds and it still was hard to start. I have the 208. It also stinks of fuel in the vicinity of N80. Is it supposed to?

The N80 is part of the Evaporative Emissions Control system which, in theory (and practise when the car left the factory) is a closed system, i.e. no leaks, no smells, everything is contained and fuel vapours (from the fuel tank) are collected and the directed to the intake manifold in a controlled manner.

I have been having what I called "a hot start" problem, with long cranking times after the first start (First start was always good which ruled out fuel pump check valves, etc.). As I thought it through, I started to suspect the N80 was sticking open. I have a borrowed one on my desk as I type that I was going to try. I don't know the answer yet but your mention of the N80 and smells and hard starting implies to me that our problems might be similar and that we both need to investigate our respective N80 systems.

N80 Evaporative Emissions Frequency Control Valve and Canister info:

http://forums.quattroworld.com/s4s6/msgs/21014.phtml

[RichLV]

Long cranking

I'll check the vacuum line.

I have more of a cold start problem. Once it has started I can shut it and start it again almost instantly. I remember removing the throttle body, and fairly strong stink of fuel came from the intake manifold. And right near the N80 port in the bottom there was a small puddle, by smell felt like petrol.

It stood for about 20 minutes and already had a long crank. The engine is around 90 degr. I shut it down and tried again and it started instantly.


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[RichLV]

Long cranking

I yanked the relay contacts together for approx 5 seconds, the pump operation was audible. Did not help. Still a hard start.

That N80 got me thinking. Could it be that it sticks open on shut off and uncontrollably leaks petrol vapors into the intake resulting in a very rich mixture on start-up? And when I'm starting it it basically vents the manifold and normalizes the mixture during the longer crank time and bubbling?


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[RichLV]

I got home and pulled the fault codes:

00561 - Mixture Adaptation
14-00 - Adaptation Limit (Add) Exceeded
00561 - Mixture Adaptation
14-00 - Adaptation Limit (Mul) Not Reached - Intermittent
00537 - Lambda (Oxygen Sensor) Regulation
08-10 - Control Limit Surpassed - Intermittent

Starting has worsened. I've disconnected the N80 from the rubber boot and plugged it with a bolt. I'll check in the morning if it's better without the N80.

[hunker7]

lambda has gone kaput?