Difficulty starting and dodgy idle

Carbs; K-jet; Tanks; Lines; Filler necks, Senders; aftermarket fuel systems; Exhausts and Manifolds;air filters - standard and aftermarket
Forum rules
Hints, tips and guides for repair and modification - the FAQ section on the main website is worth checking first for information relating to common faults and technical help. Useful posts and guides will be added to the FAQ http://www.sciroccoregister.co.uk/scirocco-faq
d_jay1
Posts: 52
Joined: Fri Aug 21, 2009 12:10 pm

Re: Difficulty starting and dodgy idle

Post by d_jay1 »

or is the 5th injector just for adding fuel at startup?


User avatar
p in phcas
Posts: 127
Joined: Wed Apr 01, 2009 8:05 am
fill in the right answer: 10
Location: Slovenia

Re: Difficulty starting and dodgy idle

Post by p in phcas »

If it were one of today's chipped cars, I would say yes, disconnecting is would be bad and all sorts of sensors would complain. As this is "old tech" and it's all mechanical or electro-mechanical so the affect is small in this case.

1> Cold (very cold) starting could be affected. The 5th injector is effectively the enrichment part of the auto choke setup and therefore gives rich running for a time. After the WUR has 'warmed up' then it 99% shuts off the 5th injector
2> The secondary function is to add a little squirt of fuel when stomping on the gas. A quick enrichment when pulling away quickly. Without it you may experience some hesitation in some circumstances - I guess is depends if your F-Inj setup is correct anyway.

I have done both and would rather know the car will start first thing rather than a slight hesitation every so often. Or I could just replace my injector, but I'm too lazy to do that. :hugegrin:

Let us know how you get on with the new 5th inj and try driving it disconnected for a while to see the difference.


Scala in black - mine... all mine... bwah ha ha ha ha 'cough' mwahha
d_jay1
Posts: 52
Joined: Fri Aug 21, 2009 12:10 pm

Re: Difficulty starting and dodgy idle

Post by d_jay1 »

i should get the injector through tomorrow, so will see how i go. got one for cheap so figured it was the best option to sort it properly. i'm not sure if it's overfuelling or not fuelling enough, i suspect the latter as i need to push the gas to get it to start. will fit it and see how i go!


d_jay1
Posts: 52
Joined: Fri Aug 21, 2009 12:10 pm

Re: Difficulty starting and dodgy idle

Post by d_jay1 »

also someone had connected a long wire from the WUR to the 5th injector at some point, going over the top of the head. it was clearly not an original wire and didnt seem to do anything when it was disconnected/reconnected. i'm thinking someone used this to bodge a fix and now the 5th injector has totally gone, maybe from continuous overfuelling? i know sometimes people adjust them as they think more constant fuel equals more power.


d_jay1
Posts: 52
Joined: Fri Aug 21, 2009 12:10 pm

Re: Difficulty starting and dodgy idle

Post by d_jay1 »

i've just replaced the cold start injector with no luck. still has the same problem. when i removed the old one it was fairly crusty so i dont think the 5th injector is ever coming on. there was a wire from the WUR to the injector when i got hold of the car, and i'm now presuming that was a bodge to make the thing work. even with that wire it didnt come on though.

where do the wires to the cold start injector go to? i was assuming they went straight to the WUR, but they seem to be routed via something else first. i'm thinking that connection may be dodgy and stopping the signal from the WUR reaching the 5th injector. if thats the case, it could well be a fix for anyone else having the same problems?

i'm going to start the engine with the injector off to see if any fuel comes through. if not, thats certainly the problem.


User avatar
bluestreak56
Posts: 616
Joined: Wed Apr 01, 2009 11:59 am
fill in the right answer: 10
Location: West London

Re: Difficulty starting and dodgy idle

Post by bluestreak56 »

Glenn (Lenny125) replaced the WUR on Wildrider on Saturday.

The first one we tried to change to (newer looking one) ran like rubbish (worse than the original)
The second one we tried to change to (muckiest looking one) ran similarly to the one I had on there

A few adjustments to fuel mixture, engine revs and the timing and the car was running a WHOLE lot smoother.

The morning start issue is still there but at least the car is not cutting out now.

Also hasnt stalled yet in neutral and 1st / 2nd at low revs but I shall report back my further findings the more I drive it.

Also I hasten to add my fan belt has been squealing for some time - any of you also have this as I think it may contribute to the issue..
Last edited by bluestreak56 on Fri Oct 09, 2009 10:39 am, edited 1 time in total.


Image
d_jay1
Posts: 52
Joined: Fri Aug 21, 2009 12:10 pm

Re: Difficulty starting and dodgy idle

Post by d_jay1 »

mine is fine when its warmed up, not stallling issues and it runs dead smooth, will take a good look this week and report my findings!


ianaudia4
Posts: 3800
Joined: Wed Apr 01, 2009 4:35 pm
fill in the right answer: 15
Location: Central London and Essex

Re: Difficulty starting and dodgy idle

Post by ianaudia4 »

The alternator belt squelling means it neeeds tightening mate.


1984 MK2 Havanna brown Storm
1989 MK2 Alpine white Scala injection
2006 Audi A4 3.0TDI quattro (the beast)
User avatar
bluestreak56
Posts: 616
Joined: Wed Apr 01, 2009 11:59 am
fill in the right answer: 10
Location: West London

Re: Difficulty starting and dodgy idle

Post by bluestreak56 »

Small update - havnt driven the car in the last few days so went to start it today.

Same issue as before swapping out the WUR - Turns over first time, struggles to hug 1000 revs, drops & cuts out.

Start the 2nd time, turns over first time, struggles a bit but survives..


Image
GTXTRA
Posts: 3392
Joined: Mon Mar 02, 2009 10:38 pm
fill in the right answer: 10
Location: London

Re: Difficulty starting and dodgy idle

Post by GTXTRA »

Ro, take it to the Phirm for Tim or Paul to do one of their first time visit checkovers/diagnosis - see AndyJ recent thread. These are free for first time visits and the guys let you know exactly what you need to worry about or, just as importantly, what is all ok.


Serial Rocco-ist.........
d_jay1
Posts: 52
Joined: Fri Aug 21, 2009 12:10 pm

Re: Difficulty starting and dodgy idle

Post by d_jay1 »

not sure if this is the cause, but after much fiddling i found that my auxiliary air valve was stuck in a slightly opened position. i'm swapping it out for another one as i had similar starting issues. I'm wondering if the lack of extra air at startup was causing difficulty to start and idle. i'm also going to check that the 5th injector is actually delivering any extra fuel on startup overt the weekend.

i'll let you know what i find, but it might be worth checking the AAV to see if its stuck closed or open (i would imagine closed).


User avatar
bluestreak56
Posts: 616
Joined: Wed Apr 01, 2009 11:59 am
fill in the right answer: 10
Location: West London

Re: Difficulty starting and dodgy idle

Post by bluestreak56 »

GTXTRA wrote:Ro, take it to the Phirm for Tim or Paul to do one of their first time visit checkovers/diagnosis - see AndyJ recent thread. These are free for first time visits and the guys let you know exactly what you need to worry about or, just as importantly, what is all ok.
Thanks Sean, I'll plan that with Glenn for the next time I'm down - we did try and go last week (Sat 3rd) but got lost for a few hours instead! Next time we'll take printed instructions and im updating my sat nav!! :hugegrin:

Cheers d_jay but I dont think valvers have an aav .. might be useful to the 8v chappies here though


Image
GTXTRA
Posts: 3392
Joined: Mon Mar 02, 2009 10:38 pm
fill in the right answer: 10
Location: London

Re: Difficulty starting and dodgy idle

Post by GTXTRA »

bluestreak56 wrote:
GTXTRA wrote:Ro, take it to the Phirm for Tim or Paul to do one of their first time visit checkovers/diagnosis - see AndyJ recent thread. These are free for first time visits and the guys let you know exactly what you need to worry about or, just as importantly, what is all ok.
Thanks Sean, I'll plan that with Glenn for the next time I'm down - we did try and go last week (Sat 3rd) but got lost for a few hours instead! Next time we'll take printed instructions and im updating my sat nav!! :hugegrin:

Screw Satnav - they're on the A30 between Hartley Wintney and Hook. Booking essential at new place. http://www.thephirm.co.uk/Pages/Article ... me=history


Serial Rocco-ist.........