I'm running a mk2 polo gt conversion with schrick 248 cam and tappets I've rebuilt the head and ever since the engine refuses to run right when I go to excelerate it revs up a little then dies I've replaced the blue sensor tried different Ecu's throttle position sensors a new fuel pump relay new fuel filters new coil pack new dizzy new leads new rotor arm and cap new spark plugs new spark plug leads different injectors different throttle bodies only things I haven't tried are a maf and a new fuel pump mainly because there expensive and don't want to buy them until I've gone through anything else it could possibly be any advice would make my week thanks for reading Simon

Have you checked the cam and ignition timing to make sure they are ok?

When the car is warm and idling, unplug the blue temp sensor, the revs should rise to 1200ish rpm if the ignition timing is correct and the ECU is happy and all the sensors are good.

Make sure it's not just poor earthing as GT's are finicky about this. The easiest way to check is bang a jump lead between the engine and battery negative.

Then set your timing as detailed here - http://www.clubpolo.co.uk/forum/index.php?showtopic=109802 - you'll need an advance gun and it's a bit of a ballache but it works.

Wow cheers guys I will check the timing next time the cars on the ground I never knew half the stuff I just read on setting the timing properly on a Gt shows what I know thanks again guys really appreciate it should hopefully fix my issues I will get back to you with the out come tomorrow

So it it turns out when I unplug the blue sensor when it's at temp it doesn't do anything it's says it should change the engine revs but it never changed so am I right in thinking that where's something more wrong with my engine than I think ? Could it be the blue sensor is faulty

Could just be that the ignition timing is off. I'd check that first before you go replacing bits.

Do u know I can clear fault codes of my Ecu /reset it it might possibly be in limp home mode ? Cause the blue plugs been unplugged when I've started the engine could it being in limp home mode cause it to not rev up ?

The ECUs in these are very basic, having everything plugged in and going for a 20 minute drive will clear the ECU, providing everything is OK.

Maybe even the old trick of leaving the battery disconnected overnight might work....don't quote me on that though.

But yes some code readers do work, others don't. I've found the fancy Snap-On ones work a treat but not everyone has access to those. Years ago I remember using one of those cheap eBay VW code readers and that read and cleared codes. You'll need the 2x2 adaptor plug too.

Cheers for all your help so far guys the car seemsto be running pretty good only issue I seem to have now ever since I cammed it it won't start once warm :/ any ideas cause it's got me stumped cheers again guys I shall upload a video later on it does sound good I forgot how nice it sounded :)

I chased a warm start problem for literally years, turned out to be the battery, can't explain why! When it's warm and won't start try disconnecting the blue temp sensor, then start the car, mine used to start but died soon after without reving it. Stop it, then reconnect the sensor and try starting it again.

If it starts and runs fine then replace you are battery before u replace everything else like I did!!

Alright spot on cheers bud I shall go buy a new battery in the morning and see where I get cheers bud :)

When you crank it over when it is warm is it slow to crank over or just the same as normal?

Also have you checked the voltage to the battery when the car is running?

Cranks over normal and I haven't checked it yet but I have a brand new battery I can borrow to test out the theory so worth a try right ?

If you need a code-reader, try a 'Vgate Scan VS450', they can be picked up online for around £30 currently, though you may need the little adapter for the Polo loom bought separately.

I've been using one since I first replaced my blue temp sensor.

Found in my case that the engine ran much better with proper pull-away torque by clearing the code after blue sensor replacement. Didn't try running it until the code cleared by itself.

bump for an old thread...i have a gt that wont start hot , cranks but wont go....fine if you restart instant after turning off , goes after 30 mins or so 

I had this, was a fucked distributor 

22 minutes ago, OVOMartyn said:

I had this, was a fucked distributor 

 

what exact symptoms please ?  fed up spending on this lol

5 minutes ago, steveo3002 said:

 

what exact symptoms please ?  fed up spending on this lol

I would drive it until it got hot and it would cut out and would start after and cut out would only run after cooling right down 

did you just guess at the dizzy or test it somehow 

Dying Hall sender when hot can cause random cut out and hard restart until cooled.

 

 

On 12/09/2015 at 13:12, kwijibo_coupe said:

Have you checked the cam and ignition timing to make sure they are ok?

When the car is warm and idling, unplug the blue temp sensor, the revs should rise to 1200ish rpm if the ignition timing is correct and the ECU is happy and all the sensors are good.

 

mine does this...revs to 1100 or so 

 

thing is i though the idle was to be set with the temp sender off ...so should it it turned down to 900 ?