16v not starting when luke warm - Poss Solved?

[.A.N.T. 0]

Right,

I'm starting to get fed up with the car letting me down and refusing to start for no apparent reason. 16v engine.

 

Seems to do it after I've been driving then have left it for one hour to 3 hours. Then it will not start. Turns over, even on a jump so it's turning over as fast as it can. There is a spark, but no sign of actually firing. There's petrol there, as after a while it floods and stinks of petrol.

 

There's a few things that haven't worked for a while on it, so I'm wondering if this will make a difference. Over the summer, the oil temperature sender starting fluctuating wildly between 80 and 135 deg, moving between them in 5 deg jumps, up and down regardless of in traffic or out on the open roads. Now it is just blank in the mfa (it shows --- I think)

Also, the outside temp sender is no longer sending, so that is also showing as a blank in the MFA.

 

I'm wondering if the ECU uses either of these measurements to calculate fuel ratios etc, so when the car is warm, it's trying to start it as cold.

 

It's the only thing that I can think of, as once the car is completely cold (ie, the next day) it starts fine. It also starts fine when hot, 10 minutes after stopping, or just in a petrol station. It doesn't fail to start all the time, but it appears to be getting more frequent.

 

HT leads are silicone blue and nearly new, the dizzy and rotor are pretty knackered so I'm getting a new one of those this weekend.

 

Basically, I can't carry on with the car like this as I need a reliable motor to get me about... (

 

Cheers for any input on why it's happening...

 

Ant.

[Rustynuts 0]

Is it running on K-Jet, from your sig I assume it is. Your symptoms sound like the classic fuel accumulator failure. This works by retaining pressure in the system after the engine is turned off. This prevents the hot fuel evaporating in the system and thus allows the engine to fire up. The reason that your car will work after leaving it to cool is that the pressure in the system is not required. I believe that the accumulator is part of the fuel pump housing, someone will put me right if I am wrong here.

 

Incidentally, the ECU is a simple mechanism for maintaining the ignition and does not control air/fuel ratio in any way

[krnau 0]

Is it running on K-Jet, from your sig I assume it is. Your symptoms sound like the classic fuel accumulator failure. This works by retaining pressure in the system after the engine is turned off. This prevents the hot fuel evaporating in the system and thus allows the engine to fire up. The reason that your car will work after leaving it to cool is that the pressure in the system is not required. I believe that the accumulator is part of the fuel pump housing, someone will put me right if I am wrong here.

 

Incidentally, the ECU is a simple mechanism for maintaining the ignition and does not control air/fuel ratio in any way

hi there. is there any way to test this part? I am having some problems with starting up, like ant's one.

[the delta force 0]

Exactly the same with my valver....

 

Cold start - Perfect

Left for an hour or so - struggles

[NS16V 0]

I had a similar problem with KR engined Corrado, it may worth checking the distributor, mine needed new Hall effect parts and rotor arm, the problem was sorted by my local VW specialist and has been fine since.

[.A.N.T. 0]

I had a similar problem with KR engined Corrado, it may worth checking the distributor, mine needed new Hall effect parts and rotor arm, the problem was sorted by my local VW specialist and has been fine since.

 

New dizzy cap and rotor arm are on order as they're pretty old...

 

 

 

 

Thinking about a test for the accumulator. As it is designed to retain pressure, if I drove the car to heat it up, then left it for 20 minutes - if it's working there should still be pressure in the pipes, if it's failed then there shouldn't be any. So could I detach one of the fuel pipes 20 mins after arriving home and see if it spurts petrol out or if it dribbles...

I know it's not very safe, but if there's no spark around it should be ok...?

 

 

Useful page - http://www.diagnostic-assistance.co.uk/mech_inj.htm

[mattnorgrove 0]

Does the rad fan still run on after you've turned the engine off?

 

My old valver had this problem, turned out the afterrun had been disconnected. Reconnected and it was fine. It helps stop the fuel evaporating after shutoff.

 

The connector for it is on the front left side of the head, as you look towards the rear of the car.

 

Might be worth a look...

[.A.N.T. 0]

Does the rad fan still run on after you've turned the engine off?

 

Haven't heard the fan turn on since about early september! I'll have to leave it running for a while then when I get home. Which is probably a good thing as the interior is wet and could do with some warm air on it!!

 

I'll check this out as well, though the switch I think you mean is connected.

 

Would be useful to have a diagram of what all the sensors on the head do. I've always wondered about some of them...

[.A.N.T. 0]

One other question with the above hypothesis;

 

If the fuel has evaporated, isn't it replaced once the ignition is on and the engine turned over? Why does having evaporated fuel stop the engine from starting?

[krnau 0]

Does the rad fan still run on after you've turned the engine off?

 

My old valver had this problem, turned out the afterrun had been disconnected. Reconnected and it was fine. It helps stop the fuel evaporating after shutoff.

 

The connector for it is on the front left side of the head, as you look towards the rear of the car.

 

Might be worth a look...

 

this is controlled by a thermo sensor in which's place I have a screw :lol: :lol: so no, mine doesn't. HOwever, when I switch off the car, I instantaneously move the key to the 2nd position so that the fan runs. Once the fan stops, I remove the key. and I have noticed that since I am doing this,my car starts up easily.....

 

 

I have a KR VW diagnostic manual (my wife took it from VW :lol:), but it is in spanish :?

[Jay23Sx 0]

I've had various problems along these lines with my valver and it boiled down to two things:

 

1) Weeping Injectors - they keep dripping fuel into the engine after the engine has been switched off, effectively flooding it and causing starting problems until the fuel has evaporated. I didn't have a weeping injector, but one that poured fuel out.

 

2) Distributor - the nice people at GCS actually got my car to run perfectly yesterday (Yay!) so I'm back on the road. It only cost £45 inc VAT as all it needed was a re-tune (apparently it was seriously out on all counts). However they also told me that if the problem comes back, including failing to start when warm, then I need to replace the distributor to solve completely.

[.A.N.T. 0]

It's been a couple of weeks now, and though I've not been driving it daily, when I have it's started ok.

 

What I did was firstly replace the starter motor with one which engaged each time rather than just spinning without turning the engine on every other turn. The old starter was also pulling about 180 amps which could be causing a weak spark (as the spark produced when cranking was tiny compared to the one created when we shorted the hall sender)

 

It still wouldn't start though, despite it turning over quickly, so next on the list was a new dizzy (with new Hall sender as it's cheaper to get the dizzy than just the hall sender) Noted where it was on and put the new one on in the same position and it fired up first time, though was very lumpy for a few seconds.

 

Now, touch wood, it seems to start on the button every time... (famous last words!)

 

thought this might help people with similar issues...

 

Also, curiously, the battery seems to be about 1v higher. Before, it was running about 12.2v while the engine was running but now it's upped it to over 13.5, 14v with nothing switched on... (I have a voltmeter as the display on the stereo, very handy). Bit strange...

[dgarwood07 0]

AAHHHHH mine does this i hate it! Starts fine on a freezin morning but not when i have been out in it the left it for few hours!!! :( :(

[.A.N.T. 0]

Check the spark when it's turning over.... Not sure why it would fire from cold and not when warm, but it's worth a try... Mine seems to be ok now... 8)

[dgarwood07 0]

Check the spark when it's turning over.... Not sure why it would fire from cold and not when warm, but it's worth a try... Mine seems to be ok now... 8)

 

This is gonna sound so dumb but how you do that??lol :? :?

[krnau 0]

Try and disconnect the cold start injector wiring plug.... I have done it and it seems to work almost ok now! It is said that this happens because of a leaking CSI injector...

[dgarwood07 0]

Try and disconnect the cold start injector wiring plug.... I have done it and it seems to work almost ok now! It is said that this happens because of a leaking CSI injector...

 

oK i will give that ago! I think i need a new isv but not sure if this would effect it startin??