strange over rev,loss of power,small backfire

[sean1380 0]

now then chaps im new too the rado scene n not really got much in the way of understanding of how it all works on my g60 but gettin to grips with it

 

i have a 1991 g60 with remap to suit smaller pulley and bbm outlet,boost return delete

 

thing is,when im drivin and change gear the revs dont drop,when i come to a halt at lights it revs up by itself untill i blip the throtle the it idles at 1200rpm

 

whys it idling this fast??should it be doing this?its done it since i bought the car but dont think it should be like this should it? :scratch:

 

also today but every now and then when i put my foot down it splutters and a small pop comes from the zorst but then after a while itll clear n itll be ok or if i switch ignition off then back on its ok

 

usually does this when i first start it up tho

 

any ideas?? :confused4:

 

i remember on my old e30 it kinda did the same and turned out it was idle speed control valve,im guess the rado will have 1 will it?

 

cant afford a garage bill so ill av to try sort it myself

 

mucho gracias

[Rustynuts 0]

You are spot on with the idle valve, these are renowned for playing up. On top of the engine you will see a small cylindrical valve, thats the critter. Could be worth trying to clean it before swapping. Sometimes this works, even if it is just a temp fix

[sean1380 0]

cheers :)

 

so do i just take it off n douse it in clutch n parts cleaner fluid n try gettin any crap out of it then? if it still idles high is there anyway that i can turn the idle down like on the throttle body etc or is it running on a pre set settin on the map??

[sean1380 0]

well i took then vdo is it? off the car,cleaned it and soaked it in brake and clutch parts cleaner

loadsa black much came out of it n i let it dry out

re-fitted it and its still over revving

 

when im changing gear it revs up too 2and when im slowing down it still revs up by itself

 

iv not had then small back fire popping noise and stuttering tho

 

am i gonna av to get it looked at on a dianostics?? :scratch:

[MattWilde 10]

diagnostics won't work on it dude, the ecu isn't advanced enough to have fault codes. The idle adjustment screw is on the back of the throttle body, from memory it's a small brass screw and shouldn't be too hard to find.

Also try the blue temp sender, with the engine warm and idling as stable as poss unplug the blue temp sender clip (on the water pipe housing on the front of the block, should have two senders, one black one blue) the idle should change noticably. If it doesn't a new one is needed, get a genuine one not a GSF one though.

There should be a black vacuum pipe running from the back of the throttle body to the ecu, this cable must be in good condition and exactly(!!!!) 1 metre long, it's not expensive to buy just ask for 110cms and measure and cut to 1 metre at home to make sure.

Lambda probe could do with investigating but I guess you'll need a multimeter and some figures to correspond to and I can't help with that I'm afraid.

 

Hope this helps!

[sean1380 0]

nice1 fella im gonna av a look at that 2mo

 

i thought there must be an idle control screw i could just turn down abit like on a carb but it thought that little box of tricks would av fault codes etc,so its not that advanced eh,i thought all ecu's did,i suppose technologys more advanced since then i guess

 

ill check that blue plug as iv seen it,i was wondering what they do,what does the black one do??anything to do with engine temp sensor as myu guage on dash aint working

 

is the 1m pipe the one to t off for a boost guage??how come its gotta be exactly 1m?for the correct pressure in that lenght of pipe?

 

does anyone know what resistances i sould be gettin accross my lambda then??iv got a multimeter,what settin?12volts dc??

[MattWilde 10]

The blue plug sends the water temperature to the ecu and the black one sends the signal to the dash, if your gauge isn't working then it sounds like you need a black temp sender too! (I keep a spare blue sender in the car for just such purposes, tempramental little gits)

 

The 1m pipe goes to the ecu and basically tells it how much boost there is, along with the blue temp sender and the lambda probe the ecu keeps the car running well. If the pipe is too long/short or has any holes then the reading will be out and the ecu will fuel appropriately. As you can see, if the temp sender and the pipe are stuffed then the car won't know what's going on!!

[sean1380 0]

well the pipe looks in good nick with no hole or any looseness

 

couldnt find the idle screw so didnt play with that

 

im guessin i need both the black and blue sensor then

 

anybody know any part numbers?????? :scratch:

do i get these from the stealership or will my local motor factors be able to get me one???

 

when i disconnected the blue one today the revs slightly rose abit but nothing noticable happened n still idled at 1500rpm

 

been smellin the fuel :gag: today when i was giving it some licks

[sean1380 0]

well it was chugging away this morning again

 

i went to the stealers for these two sensors black and blue and got quoted 48quid

 

part numbers

6u0919501b

025906041a

 

is this about right or might i be able to get them cheaper elsewhere???

 

they dont like doing things for u down at lancaster vw they make u feel like yur scum for asking them for help n just to get lost n not bother them again

[sean1380 0]

i measured the fluffy black vacum pipe to the ecu from the inlet manifold today and it was 90cm

 

now i know its gotta be exactly a meter so might this be the problem for my over revving?? its starting to do my head in that much i just wana set fire to the thing n call it a day to be honest

 

iv got no money to take to garage yet untill i get a job so any other things i can try looking at that might help would be great folks

 

cheers :salute:

[MattWilde 10]

Hey, thankfully for me I've not had a problem with that vacuum pipe so can't be 100% sure on symptoms but I have been told that it has to be EXACTLY 1 metre long, 90cm would mean a definate raplacement, can't promise it will fix the prob you have at the moment, but that may be masking a problem caused by the pipe so change it anyway. If the blue temp sender swap hasn't worked try giving the ISV a clean with petrol (carb cleaner will work but some say it damages the seals inside) and next would be checking that the wires to the blue sender and lambda sensor. The engine bay gets very hot and after 18 years these wires geet brittle and will then cause the same problems as a duff sensor. Hope you get it sorted dude, could try asking on the dubforce forum too, keep your options open!!

[sean1380 0]

well ill try tracking down some piping too,is this the pipe i come off for a boost gauge inside the car too??

where might i get some from??

 

i replaced the black and blue sensor today n made no difference at all....might it be lambda sensor then as wiring seems ok???????????????????

 

really quite annoying,its over fueling that much can just take foot of pedal n drive itself around town un hill too in lancaster like herbie!! :scratch:

 

costing me alot in fuel tho so its not funny anymore :pale: as i dont av a job n av to borrow money so everyone knows how bad it is n keep on at me too sell it

[sean1380 0]

well just drove 2my girlfriends house n now and it just flashes up warning light on the temp part but gauge still doesnt work,stiil over rev's so im lost

 

might it something to do with the map??

[MattWilde 10]

Sorry dude, last options i know are to check ALL the earth leads and points, make sure they are all there and and nice and clean. Then the lambda sensor, after those two I'm lost too. But if it's badly overfueling try not to drive it as you'll wash out your bores and that costs alot more to fix

[sean1380 0]

well i cant really drive it any less as iv got no other transport n not going bak to public transport with those other nutters again!haha

 

ill have to risk the bores n get mini sorted so can pull it off the road get more stuck in

 

ill get another lenght of pipe for now n new lambda sensor if not then i think i might just av to get it too a garage

[sean1380 0]

well iv removed my isv n all is running fine n dandy

 

but should it not be running with it??

 

can it cause damage to run without it??