fuse causing problems

Camped on the site Joined: Feb 20, 2009 Posts: 271

Have a 1993 2.3 10 valve auto ,its had running problems,it seems the rear box was a lot of the probs ,anyway when the car was running fine ,seems like a life time ago,, it started first time ,but always seemed sluggish the problem I have nowis the fuse [timing 2],,, I noticed a long time ago that this fuse was blown I put a new fuse in and the car fast idles ,or hunts ,remove it and the idle is fine ,but does not seem to have any power ,the car will not start now without it in ,but as I have said it makes the car run fast and erratic,what does this fuse actually do,what should I be searching for to sort this problem out any thoughts cheers

Needs to get out more Joined: Dec 03, 2010 Posts: 180

what number is the fuse

Camped on the site Joined: Feb 20, 2009 Posts: 271

hi the fuse number is 28 [engine timing 2],its written as [engine timing 11]on the fuse box cover cheers steve

Needs to get out more Joined: Dec 03, 2010 Posts: 180

the fuse is for the ecu, idle speed control valve, cold start valve and maybe other things, i'm no expert, i only looked up what the workshop manual shows,i dont know the engine, but idle sounds bad so maybe you could start by cleaning the idle speed control valve as these are well know for causing this type of problem, removing the fuse must make the ecu run in a safe mode and maybe thats why it has low power when removed. does sound like idle control valve stuck or failed, but could be lots of things , hopefully someone with more knowlegde can jump in and help you. do you know how to check for fault codes?

Camped on the site Joined: Feb 20, 2009 Posts: 271

Idle control valve is new ,so I don't think its that ,not sure how to check the fault codes any advice would be helpful cheers steve

Posted: Mon Jan 16, 2012 11:40 pm

If you have a timing light, checking the timing with and without the fuse may be worthwhile?
Haynes gives 15 deg + or - 1 deg at 720-860 rpm

fault code description here:

http://www.sjmautotechnik.com/trouble_shooting/100ecuf.html

Ignore the california model info, they have things different due to state law, and note that the NG ECU has volatile memory, it erases each time the ignition is switched off, so best to follow the warm up procedure given then take codes from the running car

Forgot to add, the diagnostic connectors should be located clipped to the front edge of the 'parcel shelf' under the dash - just above the driver's ankles. If not there, the shelf may need removing to find them.

Needs to get out more Joined: Dec 03, 2010 Posts: 180

have you checked vacuum leaks? i think you have to check for faults by blink codes, if you search this forum you'll find the info on how to do it, try this http://www.s2central.net/blinkhow.html

Posted: Wed Jan 18, 2012 9:37 pm

just out of curiosity the NEW isv you mentioned, that not a cheep chinky chongy one is it? £39.99 from ebay for example

Camped on the site Joined: Feb 20, 2009 Posts: 271

thanks for the replies ,there are no air leaks at all ,can only set the timing up on the strobe when timing 2 fuse is out ,if its in its to erratic to time ,as for the isv yes it was one from ebay i think its okay because if i disconnect it while its running ,the car calms down .i did also mention in another post about my running probs ,was that i found the rear box was falling to bits the fibre glass was coming out in chunks,when i removed the box ,the car ran a lot better it started first time with the box off,where as before it was a nightmare to chug into life,i put a new rear box on and it still starts okay ,but is not as smooth [with the fuse out ] as it was without the box,..,but timng 2 fuse has to be in for it to start,it still idles high with the rear box on , AND FUSE IN,but its all over the show,without the rear box on ,the idle [with the fuse in] is high or it just hunts,sorry If ths is getting a little confusing ,but the bloody thing is drivng me nuts,could it be something to do wth the back pressure? i had diagnostics last year which pointed to an air leak ,on no 4 injector ,i replaced all the seals on all injectors and could find no other leaks ,in fact spraying carb cleaner all around manifold etc ,makes no difference to the high idle so it seems not air leaks cheers steve

Posted: Thu Jan 19, 2012 5:21 pm

do you still have the old genuine isv? ive heard nothing but bad press bout them cheep chinky ones and they are made way out of spec. could be well worth trying a genuine one instead

you did say the car calms down when disconnected might be saying something

i had a fualty idle switch on mine and when diagnosing it with the isv disconnected the idle floated high and after a while would bounce up and down between 1000 - 1300 rpm really fast

Posted: Thu Jan 19, 2012 8:55 pm

I don't understand what the timing 2 fuse does or how it does it. I was hoping, that if you checked the timing with the fuse in and without, you could tell us what effect it has on the timing? eg. if you set the timing to 15 degrees without the fuse fitted, then fit the fuse, whatever effect it has, probably throws the timing off by a bit? I realise that the timing value alters with engine speed, if the engine is hunting you will struggle to get a stable reading, but could you determine what the average engine speed and average timing values are?

Camped on the site Joined: Feb 20, 2009 Posts: 271

I can set the timing with the fuse out ,but once the fuse is in its impossible to even check the timing,the fuse seems to bring everything into play causing the erratic running ,perhaps the idle control valve I got from ebay is no good ,if. You disconect it while its running it does calm down ,really got no idea anymore cheers steve

Posted: Thu Jan 19, 2012 11:33 pm

i do have a genuine bosch isv here if you need it. Can you decribe exactly what the idle is doing? or what could be a good idea would b to video the whole scenario with fuse in/out etc isv unplugged etc - show whats happening on rev counter at each stage on a decent mobile phone/camera and upload it to youtube or facebook so we can see. Because at the end of the day a hunting idle could look like any number of things

There was a post a short while ago about someone who put one of them cheep shitty isvs from ebay and made his problems a whole lot worse to the point where he just put his old one back in

this one i have has been thoroughly cleaned as when i had my problem i bourght it to rull out a faulty isv which in the end turned out to be a faulty idle switch

tomorrow afternoon when i get home from work ill pull out this fuse on mine and see what happens

ive sent you a pm to your inbox

Camped on the site Joined: Feb 20, 2009 Posts: 271

thanks for that not a lot of good at downloading ,but do my best to explain,with fuse out the car sits at 800 rpm,constant ,with very little variation ,with the fuse in it either idles at about 1,200 rpm ,or sometimes hunts quickly ,if i then dis the isv,the idle settles down,but will not rev cleanly,, when i have felt the hose going into the isv you can feel the air is pooring into it,withe isv connected ,it seems to be pulling far to much air to me ,i have ruled out an air leak due to the fact that when the fuse is out ,the idle is constant cheers steve

Posted: Fri Jan 20, 2012 12:26 pm

relevant diagram is here:

http://s2-audi.co.uk/workshop/schematics/cabriolet/page31.png

track 71 shows a connection from fuse S28 via a black / blue wire to track 39

but you also need

http://s2-audi.co.uk/workshop/schematics/cabriolet/page28.png

for track 39. It goes to pin 14 of J21 (ecu)

blue / black is a common wire to fuse 12 and is the 12v supply to a lot of switched components.

Check to see if fuse 12 is damaged in any way

Check for a short to ground at fuse 12 and also fuse 28

Camped on the site Joined: Feb 20, 2009 Posts: 271

can find no fault on the electrics ,though im no expert ,it seems to point ti the aux air valve,staying open ,but why with the back box off ,every thing ie idle is smooth,okay with timing 2 fuse in ,its still idle high but smooth ,but as soon as the rear box is on ,once its warmed up it pops and farts a bit at the back end ,,,[a bit like me],and the tickover is a bit lumpy?,i have sprayed brake cleaner around all the areas where there could be a vacum leak and can find nothing ,,,time for a fag i think ,maybe 2 cheers guys

Camped on the site Joined: Feb 20, 2009 Posts: 271

hi everyone well an update on the car ,ithat air aux valve from ebay was crap ,your right they are two bob ,put an orignal on ,and bingo the idle was consistant ,some one should report them for selling rubbish ,anyway thought every thing was good ,then out of the blue it started running lumpy,discovered the hose that goes from the air intake down to the aux valve,it has a small pipe that branches of ,and this is split ,so went to audi to get another ,but they no longer make it ,,they show it as 3 seperate items ,but anyway they no longer do it now im stumped ,tried loads of breakers no joy ,whay now scrap it for a hose any ideas cheers steve

Posted: Thu Feb 02, 2012 10:59 pm

Steve give this guy a try http://www.vw-audi-specialists.co.uk/intro.html

Posted: Thu Feb 02, 2012 11:50 pm

glad your finally heading in the right direction Very Happy

message audibits2 on ebay as he was breaking a 2.3e bout a week ago.

his number is 07809222346

probably best to ring him and try and describe it or maybe get a pic of it so you can email it to him

if your not sorted by sat ill ring this place by taunton or bridgewater that breaks old audis and see what they got as i need something myself

if poss have you got a pic you can put up on here of the pipe so i no what im asking for

Needs to get out more Joined: Dec 03, 2010 Posts: 180

are you sure this hose only split AFTER you fitted the the original type valve? everyone keeps slagging this stuff off and WOW there are other problems?
if the split hose is opening under certain conditions you wouldn't know about it. my personal opinion is that people dont check things properly before they are willing to write things off as no good. have you checked the ebay air aux valve now you have fixed the split hose??

Camped on the site Joined: Feb 20, 2009 Posts: 271

merton in answer to your question ,yes i must have checked eveything a thousand times the pipe in question has been on and off so many times to check it for any splits,the small pipe that branches off and goes into the inlet manifold,is the one thats letting air ,it has split where the jubilee clip is,so yes it may have been a weak point but was not letting air before , i let the car dle for ages ,then drove it and all was fine ,it was the following day that the problem occured ,as for the air aux valve ,it is most certainly the idle fault ,if you have read the post you will see that with timing 2 fuse in ,it ran high tick over ,and lumpy when i replaced it ,it idled as normal after warm up ,i put the ebay one back on again just to satisfy myself this was the problem ,and the tick over increased as before and ran lumpy when warm . put the original one back on and it was fine ,obviously before the pipe split, there have been other reports of these valves from ebay not working correctly ,and if someone had not pointed this out here on the forum ,i would still be going up a blind alley

Camped on the site Joined: Feb 20, 2009 Posts: 271

cheers jamie ,i have already sent him a message ,yes i can send you a pic ,ot sure how to send pic here ,but could send to your email thanks mate steve

Posted: Fri Feb 03, 2012 8:49 pm

which part are you referring to in this pic ?

Camped on the site Joined: Feb 20, 2009 Posts: 271

the items are listed as 12,,19,20,21,the diagram shows these as seperate items ,but the hose is all in one on mine ,as i said i went to audi ,and they said none of the items are available anymore,its the smal pipe that branches off which has the split,but as this pipe is rubber welded to the larger hose its impossible to try any kind of repair cheers steve