Possibly cured my starting issue, need advice/explanation

[paradisiac82]

Ok, so, this is me showing how little I understand about engines. My assume was, turn on ignition, fuel pump pumps fuel to engine, glow plug/coil light comes on until the plugs reach temp and then go off, then turn the key to start car, engine starts. I'm sure there is more to it but thats my basic understanding (I know air/fuel mixture is all done so it can burn to make power too). Now as some of you are aware since day 1 I have had issues with my car, most have been fixed but the starting issue has remained.
I'm not sure if its the warmer weather, coincidence or something else going on, but I would like a possible explanation. Normally coil light goes off in seconds (as it has today), but......I have left it 30-45 on ignition before trying to start it and it has started every time today (about 5 times with gaps ranging from 20 mins to 4 hours), no hesitating, stuttering or anything, just started. Is it possible that although the coil light has gone out the extra time I have left it has still been warming them? Or does the pump still keep pumping the fuel until car is started so leaving it this little bit longer is allowing the fuel to get round properly? Obviously will do the same tomorrow and see if same results, if it works fine, then obviously its 'fixed' and just needs longer before turning over.

[topher]

glow plugs won't even be turned on in this weather (i think its coolant temp of less than 7 degrees when they switch on) and the fuel pump only primes for a couple of seconds then turns off again until you crank the starter motor. If waiting 30s before cranking has got around the issue then the cause lies somewhere other than glow plugs and fuel pump!

[paradisiac82]

glow plugs won't even be turned on in this weather (i think its coolant temp of less than 7 degrees when they switch on) and the fuel pump only primes for a couple of seconds then turns off again until you crank the starter motor. If waiting 30s before cranking has got around the issue then the cause lies somewhere other than glow plugs and fuel pump!

any ideas what else it could be if this cures it? have just been out and moved the car after its say for 4 hours and started 1st time with this same delay routine, so I'm hopeful this is a start to curing it, will find out for sure if it does it over a longer period.

[topher]

Not sure I've not kept up to date with your symptoms. Plus I have to diagnose faults like this for a living and it can be tricky enough with the car in front of you and all the diagnostic tools in the world... doing it over the internet is a bit meh.

[paradisiac82]

Not sure I've not kept up to date with your symptoms. Plus I have to diagnose faults like this for a living and it can be tricky enough with the car in front of you and all the diagnostic tools in the world... doing it over the internet is a bit meh.

Yeh I get your point, has been suggested could be the coolant sensor, this was faulty when I bought the car so replaced it with a cheap HAAS one, maybe this isn't working correctly, although would leaving the ignition on longer effect this? my knowledge isnt great. Car is driving fine, idles a bit rough, got black smoke when changing gear at high revs (although seems to of stopped since using some red-ex) and get a puff of white smoke on startup but nothing noticeable when driving. compression is/was down on cylinder 1 (hoping this is worn cam lobe) but has been suggested in the past it could be faulty injectors causing the starting/idling issue.

[paradisiac82]

Still starting first time without issue, and now turning over as soon as coil light goes out so really not sure why all of a sudden its decided to start working

[Nino]

I could be wrong here but if your saying that everytime that you leave the igntion on for 30 sec or so the car starts, first time, everytime then, that would rule out the Fuel pump in my eyes.

And its more of a priming issue,

Could be many things but you could rule out what is normally the main cuplprit for this fault on the Mk4 platform.

Remove keys from the car and put your side lights on, open the drivers door and you should get the following.

• Should hear a beeeeeeeeeep sound.
• Flood light on the door should come on.
• Interior lights should come on.

If 1 or one of the 3 above happen you have ether a faulty door module for fuel pump relay.

When a car has been standing for a period of time, (hour or more i think) when you open the drivers door, the module sends a signal to the fuel pump asking it prime. A common fault is the door moule failing, meaning that the puel prime does not prime.

This would make sense as you engage the ignition which does the same kind of thing.

Black smoke while driving is a sign of bad carbon build up, I'd reconmend that you have the car terricleaned. Redex is utter crap.
White smoke could just be condensation, pay close attenion that its not got a hint of blue as that "could" mean your valve stem seals are on their way out.

Hope this helps.

[paradisiac82]

I could be wrong here but if your saying that everytime that you leave the igntion on for 30 sec or so the car starts, first time, everytime then, that would rule out the Fuel pump in my eyes.

And its more of a priming issue,

Could be many things but you could rule out what is normally the main cuplprit for this fault on the Mk4 platform.

Remove keys from the car and put your side lights on, open the drivers door and you should get the following.

• Should hear a beeeeeeeeeep sound.
• Flood light on the door should come on.
• Interior lights should come on.

If 1 or one of the 3 above happen you have ether a faulty door module for fuel pump relay.

When a car has been standing for a period of time, (hour or more i think) when you open the drivers door, the module sends a signal to the fuel pump asking it prime. A common fault is the door moule failing, meaning that the puel prime does not prime.

This would make sense as you engage the ignition which does the same kind of thing.

Black smoke while driving is a sign of bad carbon build up, I'd reconmend that you have the car terricleaned. Redex is utter crap.
White smoke could just be condensation, pay close attenion that its not got a hint of blue as that "could" mean your valve stem seals are on their way out.

Hope this helps.

Not sure if this helps but the car now starts as soon as coil light goes out, no need to leave it 30+ seconds anymore.
Its hopefully going in to see why the compression is low on cylinder 1 in a couple of weeks so will know where I stand on that, hopefully something cheap.[/list]