thou engine design vary greatly there are two common things for all petrol engine, vacuum and idle, if a engine has 4 pistons no matter the cc its supposed to idle at the same rpm (600-650) and produce the same ammount of vacuum (17-22')

by design i've noticed euro cars idle is slightly higher (700-800 rpm) and japanese car lower (500-600) i know that pistons that travel more produce lower rpm and piston that travel less produce higher rpm so i can understand this desing diference.

my Feli seems to idle nice @ 750-800 rpm and a little shaky @ 650-700 rpm but two things are off

if i go below 750 rpm the alternator will not generate enough power and the light in the console will dim (if driving at night) i have 80/100W light bulbs (and still i find that they are not bright enough wile driving at night) and if i use anything that uses electricity (rear window heater, air blower, headlights, etc..) rpm will go down and if i use for example the blower and the lights i can dip to 560 rpm where engine tick over is rough...

posible cullprit for me are;

Battery, it starts the car ok, but doent have enough amps so the alternator is always on to compensate... sounds strange since i can start the engine without hesitation all the time

Wiring something is robbing me of current, highly doubt it since battery doesnt get depleted over night or after not using the car for a day or two.

Engine. it could be a tell sign off low torque and problem with the combustion eficiency. no mind you i've service the car, check for air leakes tuned valve, ignition, and carburator and spark plug are reading perfectly (mild chocolate on base porcelain with slight color and ground strap with color change in he apex)

so to rule out some posibilities i want to ask you guys....

What is your normal tick over (fully warm engine, no accesories on) rpm

i set it to 900 rpm

what is your cold start rpm

mine is 1500 rpm

what your warm (not full) rpm

mine is 1000 rpm

what is you idle with blower

mine is 800 rpm

what is you idle with lights and blower

mine drops to 650-700 rpm

i would like to compair, so i can figure out whats wrong and have a good idea of what i should tune my car to when i take it to the dyno

I'd help but my rev counter doesn't work

I'd help but my rev counter doesn't work

what kind of ignition do you have ?, does it have a canister coil, or a coil pack ? rpm counters are very simple to get working (if you know what wire goes where, since its only one)

Its a 1.3 spi (so injection with the bosch system and just a coil pack i think with a dizzy.

from what i can work out the wire for the rev counter comes from the ECU. I have tried bypassing the wire straight to the back of the dash but no luck. Have had a completely new dash pod and rev counter (fixing another unrelated problem) but the rev counter still doesnt work!

Sorry to hijack your thread!

Phil

In Germany we have to do the "Abgasuntersuchung" every 2nd year. There they test the exhaust values (CO, Lambda, Idle etc.) and the idle for succeed this has to be between 750 - 850. This is given by Skoda.

At my car Idles are:

Cold: 1250 rpm

Very Cold 1300 rpm

warm: 753 rpm (depends on valve clearence)

In Germany we have to do the "Abgasuntersuchung" every 2nd year. There they test the exhaust values (CO, Lambda, Idle etc.) and the idle for succeed this has to be between 750 - 850. This is given by Skoda.

At my car Idles are:

Cold: 1250 rpm

Very Cold 1300 rpm

warm: 753 rpm (depends on valve clearence)

thanks dude, but since i got my Autodata CD (muahahahaha) i looked it up there, it gave me everything i needed,

i still have to tune it a little, but i set it to 800, after tweaking a little with the vacuum gauge (the cheap dyno) i got it to do ok, i'm still gona go to the dyno next weekend to test the emisions of CO HC NOx

found out that the car's battery is getting old, it just barely make the amps needed... that's why when i turn on accesories the rpms go down

on a side note, i think i'm gona get a little better FE after i replace the battery (since the alternator wont be working so hard all the time)

Its a 1.3 spi (so injection with the bosch system and just a coil pack i think with a dizzy.

from what i can work out the wire for the rev counter comes from the ECU. I have tried bypassing the wire straight to the back of the dash but no luck. Have had a completely new dash pod and rev counter (fixing another unrelated problem) but the rev counter still doesnt work!

Sorry to hijack your thread!

Phil

that's ok dude, as the thread says. "its a question of idle" not mine in particular...

get a mate to lend you a after market tak, and with it try to tap in the original cable at the sorce, see if you can get a reading,

also go to a web site of those after market taks, they usualy have instalations instruction and can give you al alternate option on setting the original

google "skoda felicia" select images and select high quality or highest quality, you'll find a wiring diagram for the felicia and you can follow it to hook the cables correctly

i also have the dashboard panel's wiring diagram might help you (got it from the internet too)

if you have the ODB-II connector, see if you can get the cable, with a friend that has the scangauge II you can check if the computer is sending the data ok..

i'm just throwing ideas at you mate... see if whe can get you'r tak working again

best of luck

what says autodata about valve clearance?

what says autodata about valve clearance?

intake = 0.20mm

exhaust = 0.20mm

note.

aluminium = 0.25mm

so is like you have them (but i think is the intake valves that have aluminium pushrods)