[Mk2] [Turbo] judders and jumps when comin on boost

[chirlie]

Hi guys i took my car out today and was running fine, now all of a sudden when i put my foot down and gauge reaches the start of boost car just jumps about like kangaroo petrol any ideas ?? as totaly stumped

[chirlie]

Ok so now iv turned car off for half hr took for a drive and all is working again in the process of getting new cold start sensor as car was getting hard to start and run ruff when cold ,could this be my culprit

[djpkins]

no...the cold start sensor only works for 20 seconds when first started. The water temp sensor just above it can throw a spanner in the works or If you have a rev 2 they run like a bag of $hit if you have an air leak.

[chirlie]

thanks mate so is it this one i need
http://www.camskill.co.uk/products.php? ... 0s605p4331

or http://www.camskill.co.uk/products.php? ... 0s605p4332

thanks for any info

oops and ye iv got a rev2 tubby but nothing but trouble from HER

[Steve-O 2007]

hhmmmm sounds like it could also be an ignition problem. Check the Dizzy cap, rotor arm, HT Leads, Spark Plugs.

[djpkins]

The first link is the water temp sensor yes..this sends a signal to the ecu to tell the car how warm the water is, the second one is just for the water temp guage....my money is on an air leak though mate...I had the same problem, very poor running when coming on boost but absolutely perfect (for 95% of the time) when at low revs.
I replaced...plugs, leads, igniter, coil, water temp sensor, cold start sensor....all of which seemingly could be at fault. I tested the AFM and replaced the throttle position sensor to rule them out also...but the guilty party was a balloned and slightly split intercooler hose that was leaking air when on boost. The prob sounds like your severly over fuelling and it's true that these cars eat dizzy caps for breakfast so my advice would be to check all your ignition bits for signs of damage...But if it's only happening when on boost then I would think it's more likely to be a physical failure rather than an electrical part wearing out...if you have a multi meter you can test the AFM really easily...it's all in the BGB or you can search on here for my posts and see what the readings should be...of course the very first thing you should do is check for error codes , reset the ecu by pulling the EFI fuse in the engine bay fuse box for 10 seconds then go for a spin...when the prob occurs again pull over and check the codes once more...keep updating this thread and we'll eventually get there mate

[chirlie]

Thanks mate my dizzy and rotor arm are about a month old and cant see anything wrong with them, car seems to be running fine now . also checked my hoses and cant feel any air coming from them and are new to .but will check for error code if and when it happens again .

thanks again for all your help

[i got boost]

have you checked your plugs?