Start up issues

[physicsfool]

Afternoon chaps,

As its Friday and i am sat procrastinating i thought i would get your advice. G has been a proper trooper since the head went back in June and no new noises or banging.

However.....

The first problem has reared its ugly head, this started Wednesday morning. When the engine is cold it starts slightly smoother, and sometimes on the first try, however when warm it takes a few tries, and requires a bit of throttle action to get going.
the dizzy cap and arm were new back in august and so were the leads, spark plugs and freshly cleaned injectors.

I have been driving very conservatively since the rebuild as i am slightly worried it running a tad lean (with the dewedged TB and work done on the head) however i am running a GT box so 60mph and 3000rpm. However the chip (g40002) has arrived from Andy and i will be fitting a piper cam along with a 65mm pulley. so that should cure that problem

battery looks fairly new, however i haven't put a volt meter to it yet, i just wanted a few suggestions for this weekends work list.

runs a treat once warm, although the idle revs have increased from about 1200 to 1600.

I will be checking the battery/alternator/starter motor and all associated wiring. As well as a check of the plugs to make sure they are the right colour.

Cheers in advance

[Andy]

Does it turn over quickly enough when it's struggling to start whilst warm?

If it's slow turning over, that points to starter; battery or wiring. If it turns over just as quickly when it's struggling to start, then I'd be checking the basics like ignition timing etc.

[physicsfool]

Yeah seems to turn over quickly when warm. Just requires a bit of throttle to finish the job. and usually cuts out after a few rotations on the first key turn

[z3i]

Idle seems really high even 1200. Should be around 950

[physicsfool]

Yeah i am waiting to put the new chip and setup in before i address that. will need to check for any leaks and possible causes

[Andy]

Is your ignition timing set properly?

[physicsfool]

Yeah set it back in August. +6! Been fine since I set it. Car was starting fine one day and the next day it was struggling. Will be retiming when i pop the cam on.

Could the timing change that suddenly?  

Saying that, I checked the charger on Tuesday evening to see if it was leaking oil (rebuilt 1 month ago). I did that by taking the charger to intercooler pipe off and starting it. Then revving a few times with a tissue by the charger outlet. Then reattached the pipe.
Could that have messed with a sensor or two?

[Freddy77]

Have ypu tried the blue temp sender mine wouldn't start when hot due to that being tits
Worth a try for a couple of quid

[physicsfool]

Ay, replaced it back in May when the thermostat housing seal went. It is non VAG though. £7 number from gsf. Could pop the old one back in and test it

[Andy]

If it's gone from being fine to running crap it's more likely that something's dying. I'd assumed from your first post that it'd always been difficult to start.

Blue temp sender, hall sender and coil are probably good places to start looking. Worth checking the wiring from the blue temp sender to the ECU as well - the wiring looms in these cars are getting pretty crusty these days!

[gaz g40]

Non bag temp sensors can be pretty turd aswell. Test that out theres a really useful guide on here how to do it mate

[physicsfool]

And here is the issue. Embarrassingly simple. But hidden away in its blak casing. Wouldn't have checked if it wasn't for you chaps. She is running sweet again.
Has highlighted some issues I need to resolve in the coming weeks. Thanks again all

[z3i]

Haha mine did exactly this

[Freddy77]

Had a feeling it would be that mine did exactly that, and the sensor was broken
Easy fix though

[physicsfool]

Struggling to refit the cable, keeps popping back out! Do I have to replace the whole plug or is there an easy way of getting the 2 pins out and recrimping the wires?

Apologies for my bad technical language today. Man flu is taking its toll