idle not staying still and backfiring (4k)

[scope]

hello

my idle moves from 700rpm to 900rpm, it won't stay still. what is the reason for this? it kind of sounds like it's doing little backfires also if i stand by the exhaust

and that brings me to the second question. when i'm slowing down using the gears, the car will backfire really loud and alot of times. also happens when i'm going down hills. i've heard before that this is just because of a 4k and having an exhaust (2") but just wanted to make sure

thanks

[Fraud]

Could be missing by the sound of it. Have you had the car long, and has it done this for awhile?
While its idling, pop the bonnet and have a look at the motor. Does it move around when it chugs?

[mad_te71]

check your points in the dizzy and check the spark plug gaps or it could be sumtin to do with the carb.

[Ae92typeX]

as above check those things. You could get those problems from running very lean in the carb.
check that, plugs, timing and exhaust for leaks.

[Go_the_mini]

i also get this in mi 4k, and the engine shakes so much somtimes i feel like im guna fall out the window, mine is a mixture of timming being out causing it to misfire and the car running to rich which i think has somthing to do the fact that the carb has an auto chock and the car is manual.

[scope]

Could be missing by the sound of it. Have you had the car long, and has it done this for awhile?
While its idling, pop the bonnet and have a look at the motor. Does it move around when it chugs?

yeah it moves. the whole car shakes

what about the backfiring?

[vhpacer]

Is the engine stock standard just with the exhaust?

If it is try turning the mixture screw anti-clockwise half a turn.

[fatgtr]

check your ignition timing, also check for fouled plugs

[Loudtoy]

inlet manifold may be leaking after the carb as well, had same problem on my one sorted with a new manifold, you may be able to hear it leaking if it's bad enough. Otherise it will be a combination of timing and mixture, but nothing to worry about unless it is running lean which can be checked by seeing what colout your sparkplugs are

[ATOYOTA]

also check replace the condencor
its a smal component that looks like say half a battry
its bolted to the distributer

[gothegravel]

How far advanced is your timing. It is possible to run the 4k well advanced depending on your mods. come back to me.

[Dell'Orto]

Intake/exhaust manifold leak

[vvega]

Intake/exhaust manifold leak

for teh win

[scope]

How far advanced is your timing. It is possible to run the 4k well advanced depending on your mods. come back to me.

it's not advanced at all that i know of

Intake/exhaust manifold leak

will check for this, thanks. does this account for the backfiring also?

inlet manifold may be leaking after the carb as well, had same problem on my one sorted with a new manifold, you may be able to hear it leaking if it's bad enough. Otherise it will be a combination of timing and mixture, but nothing to worry about unless it is running lean which can be checked by seeing what colout your sparkplugs are

what colour would they be?

[mad_te71]

if their black its running rich if its greyish white its leaning out

[Dell'Orto]

Intake/exhaust manifold leak

will check for this, thanks. does this account for the backfiring also?

Yup, most definately.

[scope]

what's an easy way to find the leak? can i put some liquid shit on it like dish washing liquid or something and see where it bubbles? heh

[gothegravel]

your on to it....what inlet manifold re you running?

[scope]

just a standard one

[Dell'Orto]

You havent fixed this yet? Gasket is like $10 from Repco, and it'll take all of half an hour to do