mk2 golf various probs

[tris]

hi, ive got a mk2 golf, 1.8 gti 8v on a f reg. only owned it 3 weeks and still loving it lol. first prob i have, temp gauge on dash not registering any thing...have hot air coming out of heater so assuming no air locks,not heard rad fan kick in, and cant find blown fuse, taking it could be senders or gauge?
2nd prob, fuel gauge only goes upto between red and 1/4 full, even when filled tank to brim, guessing the float in tank stuck or full of fuel? any ideas where could get new sender from been quoted bout £60.
lastly, sitting in traffic or when slowing down  to junction etc, the revs increase on own from 1000rpm upto aroun 2000rpm, blipping throttle doesnt fetch em down only increases them. other than these few hitches, it drives and feels f***ing amazing, god i love my golf!!! lol. any help or pointers much appreciated
tris

[danny_p]

check erath straps to the engine rocker cover    also worth checkign that temp sensor is plugged in.

[cняis]

temp guage problem is the black temp sender in the plastic water flange housing in need of replacement (front of engine near the head, there are 2 senders situated in line)

dont change it when the engine is warm!  ouch. also fit a new rubber o-ring.

high revs at idle in traffic could be any manner of things, i had a dodgy idle stabilisation valve (ISV) which caused the revs to sit at 2.5k rpm on warm start ups. this is located just above the head on a bracket, its about 4 inches long and cylindrical. just unplug the electrical connector, undo the 2 jubilee clips and remove the vac pipes. once off you can clean the ISV out with carb cleaner, but if its very knackered it might not work 

[VeeDubGTI16v]

does the 8v have a microswitch on the throttle body like the 16v that closes when you take your foot off the accelerator? id check thats ok for the idling problem

[tris]

hi chris, yea ive seen the sender you on about, but wasnt sure which one. did have dash out yesterday to make sure no bad connections on dash but its got like a printed circuit ribbon all round the bach off dash??? also seen isv you mention, did spray all throttle cable with lube incase was sticking...and yea it does have microswith on the body veedub, but cant tell what it does as nothing seems to get close to it to actibate it??

[VeeDubGTI16v]

get someone to press the pedal while you look, the switch should click open and closed, if not maybe the spring needs playing with/everythings dirty etc. have a fiddle!

[sdall30]

I've hear the "cleaning the ISV" with carb cleaner a few times now but am still unsyre what's invloved (sorry for being a numptey)
is it just a case of removing the hoses, filling it up with carb cleaner shaking it about for a bit then draining the cleaner out or is there a bit more to the process ?

Help/advice appreciated

[rubjonny]

the idle switch is underneath the throttle body, you should hear it click when throttle is shut. the one on top is the wide open throttle switch.  Before you adjust anything make sure the throttle hits the stop firmly, if not the cable might be too tight, also check the wiring to the 2 pin plug behind the throttle body, often snaps here.

for the temp issue, disconnect the black plug and bridge the 2 pins together with a length of wire, then check the dash gauge with ign on. If it shoots up to max then you know the wiring/dash is ok and you just need a new sensor!  If not you have a break in the wire somewhere or the dash is broke.  You can check if its the earth wire at fault by running a length of wire from the battery -ve to the red/yel wire and re-checking the gauge, if it works now you have narrowed the fault down to the brown wire.  You can either try to find the break or just run a fresh wire from that pin to an earth somewhere!

Check the brown/white wires to the rocker cover/water flange on the side of the head, IIRC this is where the sensor is earthed.