Technical Idle problems...HELP!!!!!

[F R O S T Y]

Ok i seem to have a really annoying problem with my UTs idle behaviour. No matter how many times i re-adjust the idle speed back down to 1000rpm this problem keeps coming back again.

Basicly it idles too high like 2000rpm or if i lower the idle speed back down then i sometimes get a problem with the revs going too low like 700rpm which makes the car cut out. Therefore to avoid the car cutting out i've left it with a higher idle speed as it cuts out when i brake or come to a stop if the idles too low unless i manage to get my foot on the accelerator which is tricky lol.
I've changed the coolant sensor before and i have also replaced the supplementary air valve which made no difference. Could my AFM be fooked??? As this is the only thing i can think of now? Also i can hear a slight hiss from somewhere in the engine bay but havent found out where exactly just yet? Could it be a air leak causing this problem somewhere? I've looked at obvious things such as throttle cable getting stuck etc which is fine. Also the Dump valve isnt as loud as it should be either. Any ideas???

F R O $ T Y

 

[Jai]

Could my AFM be fooked???

is it the same as a mk1 afm? i have a couple can try a swap test at the ace tonight?

 

[oldskoolmk1unoturbo]

sounds like a vacumm leak somewhere, when i got my red uno it idle'd too high and i had to wind the screw all the way and it was still a bit too high, i changed the airflow meter and it idle'd properly so maybe you have the same problem with yours

 

[antsuno2]

Hi mate ive replaced loads of airflow meters at work and my old cars (peugeot 309 gti (3) 205 (2) 6 meters on ,and most of them made a hissing sound when they died, good if you have a spare to swap bits, and that little switch on the top of the inlet manifold that i sometimes tweek, its a good idea to have a poke at your spade connectors, wire ends, then soak the bay in weasle **** (wd40 duck oil ) cos the cold is a coming Ant!

 

[Biz]

My old MK2 had the same problem frosty

It used to cut out after the throttle had been touched, but only when on the move, never at idle (i think it did, it was about 3 years ago tho!!)

It turned out to be an air leak where the T-peice was for a dump valve (between intercooler and thottle body)

 

[the mk1 kid]

Hey Frosty,

Spray some wd40 on the inlet manifold where it meets the head. If there is a leak there the revs will change for a few seconds as the liquid seals the gap. I've seen this simple test work loads of times, it does require a liberal spraying of the stuff but its such an easy way tro find the leak if thats what it is.

Tom

 

[Dragyth]

DV hoses. Worth a check.

Bit of a simple thing to ask, but yours is a twin pishhhton, right??

 

[F R O S T Y]

Sorted Sorted Sorted!!! Turns out it was a combination of a few things, one kinked/melted vacume pipe, vacume pipe on dump valve wasnt on properly and one other vacume pipe wasnt pressed in fully either. Its amazing such small things can cause so much lack of power i mean i was struggling to pull away from a 106 gti the other day lol oh well... she runs like a beast once again woohoo!!!!!! Cheers lads, just gotta sort out the bloody heater matrix now as its began to leak into the car today looks like a proper bitch of a job to do i seriously cant be bothered, any volunteers wana help me out with this one? lol

F R O $ T Y

 

[antsuno2]

great you sorted your problem!, mine seams to have a slight flatspot only when first started, put some michael shumacher petrol in it and she runs miles better, i think my afm needs a tweek, someone else is doing a matrix at the mo on here, there not hard a good sunday morn will sort, you'l need that heat soon, thanks for the help on collective cheers ant!

 

[Dragyth]

glad to hear that you sorted it mate
I was sorta right with DV hoses, shame my post came a little late.


Hey i've done heater matrix stuff before, or switched em round... absolute bitch.

Centre console, stereo, hoses, drain water, wiring, wiring.
...and even more wiring if you have a Mk2, which you do. =)

 

[Dragyth]

Ain't 106 GTIs 120bhp & 21kg more than a mk2 UT?
I think they're 7.6 to 60. I'd only be able to match that at .9BAR in my UT, which was where I was happy with my boost, I reckon.

I think 7.6 to 60 is right. Seems about .2 of a second enthusiastic to me.

I gotta say, I do like the spirit/handling/idea of the 106 GTIs... a little bit Unoish with some of their looks, their general size, handling, the lack of choice of rims, and power:weight ratio. But far far less tuneable =).

 

[alexGS]

I've always had the slight issue with the engine idling, pretty much exactly what F R O S T Y said, where if the engine speed drops rapidly (e.g. slowing for an intersection, then foot on clutch) the engine will often cut out.

It's mainly a problem when the engine is only partly warm:
1. Start up, idle speed about 1200RPM, idle speed slowly drops as engine starts to warm after a couple of minutes running
2. Drive off and at the first stop, engine dies, restart, idle speed now about 800RPM
3. Engine fully warmed up, idle speed 900RPM. Press and release accelerator, and tachometer needle bounces off the bottom stop (!) as the engine almost churns to a halt before returning to a steady 900RPM. It would be nice to solve this problem.

I found some improvement from adjusting the throttle plate opening. Haynes say that this should be adjusted to give 700RPM, then the idle speed screw (bypass) should be adjusted for the final 100RPM increase. I find that it seems to work better with the throttle plate opening adjusted to 800RPM and the idle speed screw not used at all, though this doesn't seem right. If the throttle plate opening is fully-closed, the engine seems to die more readily when the throttle is closed sharply, i.e. the problem gets worse.

I have, of course, looked for vacuum leaks... I can't hear any hissing and the engine idling seems even enough. Any great ideas? I've even adjusted all the valve clearances and tried tweaking the mixture screw on the AFM, which didn't help. I replaced the dump-valve which made a difference (the idle speed can be turned down lower now) but this doesn't change the problem really. And of course all the pipework came off for cleaning/inspection during my gearbox removal.

I'm used to driving with this now, so the engine doesn't cut out, but of course when anyone else gets in, the engine dies every time...

By the way F R O S T Y, the heater matrix is a simple job really - well worth the effort - even if you have to drop the heater box for access, that's only the four nuts on the bulkhead and the screw in the top of the dash. The matrix is stuck-in with foam tape, but with some jimmying it should come free. They don't fail very often on the Uno - it's usually the tap that won't turn on or off...

-Alex

 

[oldskoolmk1unoturbo]

Dragyth have you ever actually raced a 106 gti/saxo vts? i wouldnt go comparing standard stats and weights etc because your wasting your time,

an old friend of my has a saxo VTS, with 4-2-1 manifold, full stainless exhaust system, chipped with raised rev limiter, Kent Cams and K&N induction kit, it was r/r with 150bhp

I raced him a lot of times in my red mk1 Uno Turbo running 14psi but holding 12psi and i could beat him every time. I raced him off the lights once and he jumped on yellow and i was about 2 car lengths behind but by 4th gear i was going past him.