poorly engine mk2 gti 16v

[neil68]

hello to one and all, just got my 4th golf (2nd gti) sorted a few bits what needed doing and now hit a right bummer of one   
driving home the other day 30 mph in 4th, 5th gear and hitting bumps/holes in the road the rev counter would jump upto 3000 then drop back down to 1500, went out the next day again 30mph drove 1/2 mile and the revs were flapping between 1500 and zero till i stalled (then had to push the beast!!!) managed to start the next day and get home the next day and take a look under the bonnet, every thing seems to look ok but I'm no mechanic, started up again (parked) but after a short while same problem again, revs were flapping this time between 900 and zero until it stalled (while this was happenin i heard some poppin noise from around the exhaust manifold area) i am now armed with a haynes manual and tools, and any suggestions from u guys/girls would be would be surely welcome.
ps, my car is a standard apart from tsw hockenheim wheels (need bbs ra's!) will get some pictures soon.

[Only_A_8V]

Hello there!!!

Don't know much about this sort of thing but i did have the same prob some time ago and all it was was a wire coming from the dizzy forgot what it was called but yeah it was just a doggy conn>

Not saying this is your prob but have a look anyway

[Rain]

start with dizzy cap and rotor arm, spark plugs and HT leads, make sure there in good condition and clean haynes has a spark plug guide on the back page, if its still searching then it could be a number of things timing being the first port of call, then if its still doing it check the oil/engine/water temperature if there normal then its probably the MFA which is very common and can be expensive to replace.

i think there is a digifant diagnosis guide in the haynes if not pm me and ill send you a link to one

[neil68]

cheers chaps, goin to get on with these 2mora,let u know how it goes 

[16v Matt]

ISV??

[Gambit]

sounds more like the hall sender in the dizzy

hall sender is the little electrical plug that you see on the left hand side of the dizzy.

overtime these begin to breakdown, its more apparent when the car gets real warm, i.e. is sitting in traffic. the car will splutter, misfire & even stall. the rev counter will bounce all over the place but this does not tally with the actual rpm of the engine. this is because the hall sender is sending a false signal back.

usually once the car is moving then there is enough airflow in around the dizzy to cool the hall sender enough for it to function correctly.

new hall sender is £30 from Euro Car Parts and you need to dismantle the dizzy to change it.

HTH,
Craig

[neil68]

hi, thanks to every one for reading my story and to all those who posted too!! turned out to be the coil that was busted, although the hall sender had had it too! rotor arm, plugs,dizzy cap and leads are only 300 miles from new so they were ok. there is a wire with blue n white housing which is adrift (needs looking at). took my car for a run today and every thing is wonderfull  :grin:  once again thanks...... this is a top site!!!!!!

[Gambit]

is that blue/white wire hanging aound below the dizzy?? that is the temp sender wire for the ECU. if it is disconnected then the ECU wont advance the timing on the dizzy so your losing out on power

the ECU will only advance the timing once the car is upto temp

[neil68]

the blue wire comes out of some housing with a red/black, brown/white, green wires, just below the dizzy. it has a connector on the end of it but am unsure as to where it should connect to.

[Gambit]

yeah thats the one im on about

if you look at the water outlet on the side of the head you will see 3 temp senders - the temp senders are all the same so it doesnt matter which wire goes on which sender - sometimes the spade connectors break off the senders so u'll need to replace them, only bout £5 from Euro carparts

the wires that connect to the senders are

green/red - ISV/cold start control
yellow/red - dash temp gauge control
blue/white - ECU control