yeah he cooled it on the fan and checked it over fiarly well cant remeber his explanation but it was to do with the vac when revved...he snapped the throttle and pointed to whatever the gauge did..it wasnt at 48 , but he said said if he did make it 48 then it wouldnt be safe at cetain circumstances he didnt mention why it was like it , and i dont know why he didnt put it right with shims or whatever
well the vacuum connection allows the wur to drop the control pressure even further when under heavy load. i remember when i did mine that if i revved it the control pressure would drop slightly on the guage - as expected. i'll refrain from making any guesses as the exact details of the advice you got. but it must be either too much change or not enough. i would be really interested to know myself! just in case my mod is no good! perhaps a cheeky phone call might elucidate an answer from stealth?
just a thought, but how well does it start if you have the isv disabled (by disconnectiong the famous red/black wire to the coil)?? i mean, if you use the old fashioned foot-slightly-on-throttle technique?
well (conjecture comming up so we careful!) here's my thinking ... i recently wired an isv from scratch and learnt a few things along the way. for a very brief period after cranking, the signal from the coil to the isv controller drops from ~12v to ~6v. this seems to effect an initial 'wide open' isv, to help starting. the manual for a 16v says you don't need your foot on the throttle to start it, but the manual for an 8v mk1 (no vacuum feed to the wur on these) says you should have your foot on the throttle a little. now, given what stealth said about your wur i would imagine that your wur is responding too much to the vacuum feed. this would explain why he wasn't willing to reduce its base setting any further. so perhaps when cranking the isv is oppening right up, letting too much air in (how high does it rev (max) from just turning the key?) and causing the control pressure to drop too far - thus making the mixture too rich??? i know that adjusting my fuel pressures made a different to how high and for how long my revs would rise when starting so the are probably related. i know you've tried several wur's, so i'd start to suspect the vacuum system itself. you could try starting the car with the vacuum feed to the wur disconnected and blocked is suppose, but i'm not sure how you would get too much vacuum? like i said, just conjecture. probably a wild goose chase, but half a loaf ...
hmmmm kinda makes sense, although i had a spare wur at stealth and he said it wouldnt make any differance when it was running noramlly, it revved pretty hard from cold start...maybe 2000 ish or slighly more
yeah, i didn't think it was the wur, i though it was the vacuum feed. but like i said, i'd be puzzled as to why the vacuum would/could be too strong. i would definitely try disconnecting the vacuum feed, just to see what happens. Edited by: GTI
Ok will do, all i was trying to get to was maybe the fuel pumps are breaking down slowley and this is why the fuel is struggling to get the the engine, making it stall?? Ill see if it solves mine, and let you know.
Thats fairly high, mine never really goes above 1500rpm on a cold start. I've found that 49PSI is the sweet spot when setting the WUR, both on my mates 2.0 and my 1.8. It tends to be quite sensitive around this area - i.e 48 can make them run very rich when cold, whearas they can run perfectly smooth at 49. I've also noticed that when revving the engine, the gauge does go up by 1-2psi on both our cars, cant see what problem thats going to cause though
1-2 psi is what i get too and iirc we're using the same guage, aren't we smithy? (from www.fuelsystems.co.uk?) when i first set up my isv it would rev over 2k, but after setting my pressures and adjusting my mixture it settled down to 1.5k - just like smithy. i'm starting to think that my vacuum idea might be quite realistic!
Small update from me. Last night I blew out the lines to the WUR from the metering head and managed to snap one of the WUR banjo bolts off... Spare one on the way though - thanks GTI Also, I removed the fuel pressure regulator, little spring loaded valve thing that unscrews from the metering head, 16mm head I think. It had one washer on it presumably to seal it into the main thread and the actual valve part had one little washer (shim?) on it too. Does this mean it hasn't been 'shimmed' as one washer is standard? I noticed it was very clean anyway and seemed to have a newish rubber o-ring so it looks in good order, put it back together. Once I fit the line back on the WUR with the replacement banjo bolt I'll give the car a try and report back. My thoughts are still that the accumulator may be faulty as the car started cold ok/idled smoothly straight after I blew out the return fuel line the other day but then went back to being cr@ppy the day after. Presumably the system pressure isn't being maintained after the car is left standing? Is it possible there could be an air lock somewhere? My next idea might be to get a pressure gauge and start checking over the readings and hopefully not shear any more bolts off!
that fpr sounds normal (mine was the same as standard). have you visually inspected your accumulator? checked for leaks? tissue paper is very useful for this btw.
If it is loosing presure during the night(or long hours), have you checked if you have fuel in the combustion chambers? Your injectores could be leaking.
GTI - no, not checked out the accumulator yet, will have to get the jack and axle stands out out and have a look. Hidro - Injectors have been tested and have new o-rings so hopefully are okay
okay update from me fitted another isv controller, and the idle much nicer still revs to 2000 on start up..and id descibe the cold running as ..erm it feels physicly weak and stalls really easy, i think the fuel pressure needs a tinker now i called stealth about why he would do the mod, and they werent too helpfull said it prob ideal anyway, but i remeber it werent at 48psi
good news about the isv controller! what were the contcts on the old one like? furry? shame about stealth, but you can understand why they would want to keep their specialist info to themselves. have a play with a fuel pressure guage and becomer an expert youyrself . i just wish i had a gas analyser too compliment my guage ... btw, pig - you have my favourite sig. but, i've been keeping that to myself for some time.
the old isv contact were mint thing is vince at stealth readily talked about what was happening on my car, but for some reason i never asked how it should be fixed its not exactly top secret stuff is it i drove 2hrs each way for him to set the c/o which was already right and bump the timing to 8 deg..considering how people rave about them i was disapointed, maybe theyre more suited to highly modified cars glad you like nelson
Pigbladder - Glad to hear your car on the mend one way or another! For info: mine revs to about 1500rpm initially on start up which I think is normal. I think my ISV controller must be ok as it was idling lovely and smooth the other day after I blew out the return fuel line, sure my problem is fuel related rather than electrical. Will investigate further this weekend
stu..i feel the fuel line cleaning did help.maybe just in my mind though it might be worth you having a go with a proper airline have you checked the ohms of them head sensors?? i think cleaning them sorted my start then stall issue, and check your throttle switch with a multimeter
the throttle switch will have nowt to do with it. as far as i could tell when i wired my isv, it's only there for the overrun cutoff valve. my throttle switch isn't connected at all. stu, did you get dem bolts yet? Edited by: GTI
