Lumpy Idle

[synergy]

Hi Guys,

So I have had my '96 BA Astina (auto) for just under 5 months now and am still very much in love..... except for one slight hiccup (besides the rattly windows). When idling, it has a tendency to dip a little low in the revs, causing the car to shudder.... nothing too severe, just something I have noticed. Have had it checked out, but apparently nothing seems to be wrong. Have kind of figured that maybe there is a sensor somewhere that manages the revs that may be faulty or loose or something...... anyone got any ideas??

[ABC]

Hmmm...... the first thing I always go for in that type of situation is the spark plugs.

Take them out and make sure there is no oil on them or in the wells where the leads go in and that they are the right gap. If you haven't replaced them in a long time then I'd do that also.

Maybe even faulty spark plug leads?

Replaced the air filter lately? If not either replace or take it out and see if the idle is still lumpy.

Maybe dirty fuel filter?

check all hoses and stuff are all connected and don't have any cracks or splits in them.

Oh - welcome to the forums too! :D

Also, given that its an auto, it could be related to the slushbox/clutch somehow.

Alternatively the idle speed could be set a little low and it just needs to be wound up a touch. Does the lumpiness stop when you rest your foot on the accelerator real gently when stopped???

[Toyboy]

I have the same problem with mine and am yet to find out what it is :( Does any1 else here have the problem of everytime they start the car the idle drops right down to about 4/500rpm then it pick back up to where its meant to be :?
Dont know if its meant to be normal or not,ive learnt to live with it 8)

[Trav]

Yep - been there done that.

It was actually the HT Leads (spark plug leads for the laymen). Because they are Bakerlite they develop hairline cracks which cause the spark to jump out to the block instead of the plug whaere it is meant to go. This gives an intermittent missing problem which sounds/feels/looks like a rev drop.

Since you havn't hat the car long, i would replace your plugs first (they are only $10 and run some petrol treatment. If it still goes on, replace the HT Leads ($120). If it still does it, then you might be up for an ignition module ($2500).

Check and replace all the simple/cheap stuff first :)

[synergy]

hey guys - thanks for all that!

it isnt really a huge problem, just somehting that I have begun to notice over the past couple of months. It doesn't happen all the time, which makes it even harder to pinpoint... but, yeah, the revs just dip sllightly, the car gets a little rough, then it adjusts back up to where it is suppossed to be...... looks like I'll be checking the plugs and leads and all..... though I will have to wait till the weekend as she is currently being repaired after a mo-fo in an X-Trail ran a red light and hit me last week. :evil:

[KittyKatSmack]

Wow, talk about timing...

The same thing happened to me yesterday, for the first time!

Admittedly the motor was cold when it first happened, but I did pull over and foot on clutch and brake try to wait it out a bit.....

If things are abnormal, I tend not to push it... but listen look and watch first.......

It was definately lumpy and around the 400-500 rev range... I gave it eensy weensy bit of juice and eased off, same, did again and seemed normal... whew! I thought... but about 2k's down the road in Braddon it did it to me again.... I was pulling in to car spot anyway but it idled again at 400-500 and stalled out.

We got out anyway and did the car yard trip.

When I got back in, started it a bit gingerly.... and it was fine.
No sign whatsoever of low revs......
I was a bit gobsmacked but hasn't happened today that I know of, but Aaron had my pride and joy today.

It is due for service in September, don't know date, but figured it might not hurt booking it in slightly early.. ie/ in 2 weeks or so... if I actually have some cashies for a change.....

Hmmmmmm, now I will watch and wait... keeping in mind the things you guys have mentioned.

Anyone else have similar happen?

[ezin]

I would also look at cleaning the idle control speed valve! as they always get dirty! take the air intake tube off the inlet manifold and look for the holes that bypass the throttle buterfly! they are machined into the buterfly housing! turn the ign ON! (this opens the ISC valve) and then spray some brake cleaner or carby cleaner through the holes! U should see heaps of black crap come out! A small torch comes in handy! Then replace the tube and start it up! It may take a couple of cranks to ignite the cleaner but thats ok!

It should fix that problem! for the cost of $5 for a can of cleaner! :)

[dfvadr]

hi guys dont no weather this helps but a mates wrx was idling up an down but wen u drive is perfect just the idle played up it turned out to be the air ratio valve it the inlet manifold after the air cleaner aparently he got water in there an it was stuffed changed the valve an it hasn't missed a beat

[siffin]

Sorry old topic I know, but im having the same problem now I've got a 1996 Mazda 323 Astina BA V6 Hatch

and when I start it up in the mornings it tends to shake and jerk the car a bit, and sometimes looses revs and stalls.

When i'm at lights the revs seem to jump up and down and the car starts to shake.

[RedLineResident]

It may be the aircon.

Sometimes I notice in the old mans car that when the cars cold and the aircon on it drops in revs significantly. Shudders and any attempt at a bit of a take of stalls it.

So did any of you have the air on at the time?

[project.r.racing]

Sorry old topic I know, but im having the same problem now I've got a 1996 Mazda 323 Astina BA V6 Hatch

and when I start it up in the mornings it tends to shake and jerk the car a bit, and sometimes looses revs and stalls.

When i'm at lights the revs seem to jump up and down and the car starts to shake.that could be heaps of things. plugs, leads, dissy, blocked injector, air/fuel ratio/valve, very dirty air filter.

i'm currently running on 3.5 cylinders atm. after 3 days in the panel shop. my car was running weird the guys said. i said its just big exhaust. but when 1 was backing it out of spray booth at 7pm last night, it was violently shaking. checked leads in to dissy. ok. pushed leads between cams further into engine. engine gains 200rpm and stops shaking. so just 1 loose lead...

but still dropping a cylinder on the way home. sometimes 3, sometimes 4. altho the rotory sounds is tops. it'll fark some engine and exhaust parts real quick. gotta get out there today and find the problem.

Could be something like a simple throttle body/air control valve, see link below:-
http://carclub.freeforums.org/viewtopic.php?t=41

Ryan

[project.r.racing]

Update - mine was just water in the no.1 spark plug camber. Grrr for using high pressure cleaners after painting the car. Partners hair dryer and 5 minutes work and all fixed.

Ryan

[siffin]

Just picked it up from the mechanic took it kmart auto.......

Still not idling properly, its especially bad with the air con turned on.

last night whilst parked outside my house I had the aircon on full, whilst in drive and the engine seemed to be jerking back and forth like it was miss firing.

I think it might be something to do with the ECU, cos last time I had trouble with it idling was after my altenator was replaced, took it back to the auto electrician and he reset some error code and it idled fine.

Hopefully theres a mobile auto electrician somewhere who can help me out.

[bourbon]

check your intake pipe...turn your aircon to test this stuff out dude...aircon always plays with the revs...might be your IAC...and throttle body might need a clean out...check for air leaks after the air flow meter...

[siffin]

I think ive fixed, me and my work mate had a play around and we adjusted the idle.

And now its not vibrating, starts up perfectly, with the aircon off and on....I guess i'll find out how well it goes on the drive home.

When it comes to cars/engines I know nothing, always had friends who are mechanics etc...but I'm trying to learn new things.

[siffin]

Well I've just got home now, and it still seems to be shaking/jerking/vibrating at the lights, not as bad as before.

I'm just wondering if the problem maybe to do with the gearbox, what sort of problems can you get with a BA Automatic gearbox?

My mate who was in my car a week ago said it could be the torque convertor, is that similar to the post below?

for those who don't know flex plates is auto's fly wheel it's very thin and only transfers drive the outer of the converter and the engine so the starter can turn over the motor.

but I've had Flex plate go at 80,000k's on my old 626 what ourrs is it warps or gets out of blaance and you either notice it on start up or more common a noise hum or rattle and can tranfer a vibration to the car usually in areas of RPM not driven at often.

[bourbon]

bud get the error codes done...that way you narrow it down more...i say intake leak or something simular

[RedLineResident]

Auto gearboxes can play around with your idle when in gear and holding the break because they reduce the revs a significant amount. Try adjusting your idol again (slightly higher) and see how it goes.

And if that fails do what bourbon siad because it is pretty hard to pinpoint a problem when it isn't narrowed down.

[siffin]

What would smoke and water sputtering out of my exhaust mean??? Only just made this discovery :(

[Smikey]

When my car was spluttering, turned out that water had gotten into the spark plugs, simple way to eliminate one of the possibilities. First time was after a service engine bay wash and the second was engine bay spray during detailing.

By the way, cool avatar synergy, ba race car?

[Rupewrecht]

By the way, cool avatar synergy, ba race car?

http://www.astinagt.com/forums/showthread.php?t=2658

[siffin]

Car is fixed took it to a proper mechanic, he replaced 2 of the rear spark plugs, ignition leads, distribution cap and the rotor.

Its now running absolutely mint:D

It hasn't run this way since I first got the thing back in April, i'm so happy with it.

Cheers for all your guys help....

[OZY-323]

something so simple! well its usually the case