ticks over @ 1500rpm

jimbob · Post by **jimbob** » Wed Aug 25, 2004 10:06 pm

only sometimes, but quite often when my car is ticking over it revs @1500rpm if im right it should just be below 900rpm has this problem occured with anyone else if so how have you overcome the problem

Car - polo gt

Thanks. JimBob

metz · Post by **metz** » Wed Aug 25, 2004 10:41 pm

mine ticks over at just over 900rpm bit more when first started in the morning

hardhitter · Post by **hardhitter** » Wed Aug 25, 2004 10:56 pm

Idle stabilisation valve isnt working properly, quite common as the tend to stick. Either try a second hand one which is a gamble, or get a new one which will be cheaper from a bosch dealer.

LogIK · Post by **LogIK** » Thu Aug 26, 2004 12:49 am

Or try clenaing it out first. If it is sticking (which it sounds like it is) it may just need a good flush out with carb cleaner and a smidge of WD40.

deadcat · Post by **deadcat** » Thu Aug 26, 2004 9:09 am

ISV's are a pain in the bottom.
I fixed mine by running a new earth lead from the battery to the lambda probe earthing point. No trouble with the ISV after that.

BTW anyone got any figures as to what speed I'm supposed to be doing in what gear at what revs?
I think my rev counter is a bit off.

hardhitter · Post by **hardhitter** » Thu Aug 26, 2004 7:01 pm

Cleaning the isv usually doesn't work. I have done it many times on different ones and it hasnt made it better. My advice is to swap it.

Tahrey1043 · Post by **Tahrey1043** » Fri Aug 27, 2004 12:36 am

well what flavour of CL is it deadcat...... gareth gt hatch proffered up a nice slab of numerology on that subject recently that i'm soon going to integrate with my gearboxy spreadsheet

for example if yours is a 1.3 CL 5-speed, then it's likely an 8P gearbox... ratios (roughly, from mem*) 3.45, 1.96, 1.25, 0.89, 0.74, and 4.06 final drive. speeds per 1000rpm and at the 6500 limiter (i think you can figure out the rest) in each gear on standard 145/80 R13 tyres being

1st - 4.74 ...... 30.8mph
2nd - 8.35....... 54.3
3rd - 13.07 ..... 85.0
4th - 18.38 ...... 119.5
5th - 22.11 ...... 143.7 (hm, as if)
(or 5th with a vanilla GT box - 0.851 / 4.0625 = 19.25/1000 and 125mph maxed - or 131 with a GT rev limit... all other ratios from 2nd to 4th also being altered)

um.... ish

(when you get down to that 4th significant figure, the amount of treadwear starts affecting the result..)
* from memory but then quickly adjusted using windows calculator to match the annoying result below - see the teenytext. (damn, i'd meant this to be short as well!)

its likely both your speedo and revolomometer are a bit fast 'n' loose with the real information - they're not too precise from the factory and may have been affected if you've swapped em in from another car. i'm planning on getting mine properly calibrated somehow, sometime soon. if it comes down to having a very "intimate" run on a rolling road..... so be it.

but im hoping a microphone, a laptop, and a known length of straight flat road late at night will do the job well enough.

playing thru the above calculations, just to be sure.... ((note: originally stated as 4th being 17.6, and the other figures adjusted to compensate for such after the following surprise))

rolling circumference of 145/80 R13s assumed to be -
tyre profile = 145mm x 1.6 = 232 + say 2x5mm of tread = 242mm
plus 13 inch rim = 242 + 330 = 572mm diameter (22.5 inch)
circumference = diameter x pi = 572 x 3.14etc = 1798mm
call it 1.8 metres for the hell of it. temperature differential on the internal air pressure will have that much effect!
2000rpm at crank, in 4th = 2000 divided by (4.0625 x 0.891) at wheel
= 2000 / 3.620 = 552.5rpm = 33152 turns per hour
33152 x 1.8m = 59674m per hour = 59.67km/h
59.67km/h over 2 = 29.84km/h per 1000 = 18.54??!mph per 1000........ if i haven't just made an almighty cock up.

just to test - removing the tread from the equation gives... 18.22... hm.
(half 'n' half - 18.38)

ooooookay, i can see where gaz was coming from on the "numbers are all wrong" front now (tho he could have made it a bit less vague!).... the guy from whom i got the other numbers has some 'splainin to do... my own rev counter/speedo dont seem so far out any more. still out, but not by as much, and probably not by any recalibratable degree.

or alternatively, adds weight to the idea that my GB has a 4.267 differential in it. because otherwise, that still doesnt explain the figures i get on the speedo when holding it at the revlimiter - unless the thing really *is* set at 6300rpm as the vw manual vaguely suggests it is ("for all petrol engines" - including the GT and G40 as well as my 1-litre??), rather than the 6500 the haynes manual states for both SPi's?!

i swear blind i've worked this out before and the result was different, so i invite anyone who wants a go to come and pick a hole in the above calculations

for the hell of it, 155/70s or 135/80s = 21.7 inch = 17.87mph/1000... crapola.....
so at 90 im actually turning 4900 on regulars or 5000 on 155s, worse even than what i thought (5100)?? balls..

deadcat · Post by **deadcat** » Fri Aug 27, 2004 9:22 am

Tahrey1043 wrote:well what flavour of CL is it deadcat......

rolling circumference of 145/80 R13s assumed to be -
tyre profile = 145mm x 1.6 = 232 + say 2x5mm of tread = 242mm
plus 13 inch rim = 242 + 330 = 572mm diameter (22.5 inch)
circumference = diameter x pi = 572 x 3.14etc = 1798mm
call it 1.8 metres for the hell of it. temperature differential on the internal air pressure will have that much effect!
2000rpm at crank, in 4th = 2000 divided by (4.0625 x 0.891) at wheel
= 2000 / 3.620 = 552.5rpm = 33152 turns per hour
33152 x 1.8m = 59674m per hour = 59.67km/h
59.67km/h over 2 = 29.84km/h per 1000 = 18.54??!mph per 1000........ if i haven't just made an almighty cock up.....

GAH! maths!!!

It's a 5 speed CL, and from the maths, that sounds slightly weird. I'm sure there is something wrong there, I just can't spot it.

anybody know what revs the little red marks on the speedo are at?

metz · Post by **metz** » Fri Aug 27, 2004 9:47 am

well mines a 1ltr 5spd and at 80mph its doing 4000rpm

Tahrey1043 · Post by **Tahrey1043** » Fri Aug 27, 2004 2:35 pm

ok metz... what i want you to do now.... is go off and have your guages professionally calibrated, on standard rims & rubber....

then if it still matches, come back and sell me your gearbox. 20mph/1000 i'd still be very happy with... i'm sure i can find you a nice GT box to give your ride a more sporty edge

that's wildly different from any other actual box i've seen, but matches the supposed "rare" one which is like an 8P but with a lower geared diff... perhaps it's rarity is because it was only offered on saloons (more likely to be used as cruisers)??
get your code off the housing while you're at it... if it's AYZ, CMC or CEE then you're laughing (as well).

well?
what are you waiting for? (points gun) muhahahahahaaaaaaaaa...... *dies*
(hehehe no, dont bother... but if you can get your code at some point when you're already under the car and maybe get a rough idea of rpms per thou in 3rd and 4th too in an idle moment of riding about, that'd be handy)

the little speedo marks, as far as i'm aware and have worked out before, are somewhere around 5000 - 5250 rpm. They're WELL inside of the redline. Hell you barely hit max power, let alone make any real use of it, if you change at those points.

And I know it sounds wierd - it's gone radically different to anything I worked out before, and I can just hope that i've cocked up this one time rather than the hundred or so other times i've figured it.

Running theme with me working things out though - i have to double check it about twenty times over until i finally go down a different path and find the mistake...

either that or it's the higher geared of the GT ones, and so you're looking at around 19.3mph/1000 with a slight miscalibration (all of, what, 3mph at an indicated 80?)

Gareth_GT_Hatch · Post by **Gareth_GT_Hatch** » Sun Aug 29, 2004 10:57 am

All those gearboxes in mk3 haynes that begin with the letter "C" are just a variation of another gearbox in the list. For example 8P has the same ratios as CEG. The only difference is something to do with the differential (or the casing around there) apparently the ones that begin with C can accept an LSD whereas the other types cant but im not 100% on this. I only know about this because this guy off pittstop called mark humter needed to find a CEH gearbox (uber-rare GT box) so he could fit his LSD

So maybe its the AYZ box hes got then. Which you never know tahrey could be the one ur after. It does sound like its the right one anyway.

Gareth_GT_Hatch · Post by **Gareth_GT_Hatch** » Sun Aug 29, 2004 11:06 am

A quick look on etka and it looks like were on to a winner tahrey! the cog used for 5th gear is on the 8P; AYZ and a few others.

Now all u gotta do is find one!

Tahrey1043 · Post by **Tahrey1043** » Sun Aug 29, 2004 1:24 pm

i dont know if my brain can take it any more though

and i bet anything the scappies wont be able to give me a decent match neither... just have to wait for someone with a 1-L saloon to come GT-box hunting.
(you have an ETKA? why are we doing all this blithering when you've got the figures right in front of you?

hehe)
but yes - AYZ, CEE and CMC, so far as i can tell (or 8P, AEB and CEG for the higher ratio)

nice heads-up on the LSD thing tho... next task - figure out exactly where in all those diagrams and things it shows the reverse gear or even it's idler (can't find that anywhere - most puzzling), and whether the 15-tooth pinion of the 4.27 diff could work with the 65-tooth ring of the 4.06... making a 4.33

(after all there's supposedly a 66/16, why not a 65/15)

anyway.. hey deadcat.... what i meant was... 1050cc or 1272..? (1.0 or 1.3??)

Gareth_GT_Hatch · Post by **Gareth_GT_Hatch** » Sun Aug 29, 2004 4:00 pm

Ive always had etka. Ive never need it for gearboxes. All the info ive needed has been in haynes or on mark hunters spreadsheet (which he will have got the info for from etka). Its just that one gearbox that hasnt been covered. Now lets not say any more about it.

LogIK · Post by **LogIK** » Sun Aug 29, 2004 4:37 pm