perry318888 0 Posted September 24, 2008 hi all, got my 1.6 gti a couple of months ago, it started fine after being stood for some time (6months-ish) but i still put it on a trailer to bring it home. its done 57k and just had the head gasket and cambelt done by the previous owner (well... some dodgy garage did it for him) hes a mate of mine and he stopped driving it because it was always causing him problems. im a qualified mechanic so i thought id take it off his hands and have a play with it... i serviced it first, changed all the wear and tear parts (brakes ect) and generally tidied it up. i then took it up the road on the trade plates from work to bed my competition pads in. it had a hesitation at about 2500 and 3500 revs every time you revved it, wether under load or standing still it did it! i had a leaking injector so i pulled them all out and changed the seals. i also checked the vacuum advance unit and changed the pipe, it made no difference! so i put it on the emissions tester and set up the idle, afm, air/fuel mixture.. everything - took it up the road and it was spot on, no hesitation and a lot quicker! very happy with it i went home and had a good nights sleep not worrying what it was anymore... until the morning! i turned the key and it turned over for a split second and died. tried again... died. so i tried again and gave it some throttle and it started and ran with no missfire whatsoever, but it wouldnt idle above 450 revs (so basically wouldnt idle at all!) but after 15 minutes of getting nice and warm it was a different car- back to as it was the night before when id set it up. i looked on here and found loads of info on idle problems, instantly i thought S.A.D sensor. so i cleaned it out thoroughly with carb cleaner and started the car and it made it a tiny bit better (550 idle!) i tested it by squeezing the pipes and it did affect it but nowhere near as much as i would have expected it to. so i then thought if its half working, maybe it getting the wrong info from the E.C.U? so i changed the water temp sensor. again a slight increase in idle but just not right. before i go and spend silly money on replacement parts that might not work, has anyone ever had the same sort of symptoms? any help would be largely appreciated! regards perry. Share this post Link to post Share on other sites
DamirGTI 344 Posted September 24, 2008 Hello ! The ECU doesn't have anything to do with the SAD , it's rather simple temp. sensitive device , inside the unit is a bimetallic disc which moves as the unit heats up from the heat of the cooling system and from integrated heater element .. anyway you can read more about the "thing" here : http://www.205gtidrivers.com/articles/e3-sad.html Now , if the idle speed is the problem (if it's too low as you say ..) and you've adjusted the idle screws on the TB , AFM , changed the ECU temp. sensor etc. then try advancing the ignition timing a little bit and see if it responds better (it should !) .. further on if that doesn't work satisfactory , bend down and take a good look at the front side of the SAD - you'll see a little 7mm screw on the SAD body , by loosing and moving this screw you can increase/decrease the amount of air (gap of the bimetallic disc inside the SAD) , and by that you can set it to operate at higher or lower rmp from cold ... loosen the screw and move it to the right to increase the gap (so that more air bypasses trough) or to the left to reduce gap (less air) ... remove the front air pipe from the SAD and you'll be able to see the gap adjustment which you've set , or you can remove it completely out (but it's really a bitch job !! ) and proceed with this adjusting on the bench , or still could try blowing trough the SAD pipe remove the end which plugs on to the big air inlet pipe adjust the screw a little bit on the right side an test blow trough the pipe .. If it still doesn't work properly afterwards check ignition system , especially the ignition amp (try with a spare one) and dizzy signal cable (the one which goes from the dizzy on to the ignition amp connector) .. Hope this helps ! Damir Share this post Link to post Share on other sites
perry318888 0 Posted September 29, 2008 hi damir, thanks very much that is very helpful. i will try the ignition advance first as its the biggest probability! regards perry Share this post Link to post Share on other sites
