Mazda 323 BJ Rough Idle

[grayeagle]

Ah have the BJ model but ever so often i get ah rough idle. Ive cleaned the injectors, changed plugs, service and use treatments but still get the rough idle. Sometimes while in traffic or if the car just idling for too long it will go like if it want to cut off. Need some help...................

[klyman]

hmm.... that sound like the trottle body solenoid given trouble. Try raising the idle screw a bit an see what happens.

[damieG82]

^^ DO NOT DO THAT.... at least not as a permanent fix. You'll end up burning a lot more gas, and probably destroy your engine mounts.

3 things to might be the problem

1) damaged intake tubing. A split will cause a vacuum leak, and heat will cause it to expand, thus producing the rough idle.
2) the air flow sensor. A malfunctioning one will give you the occasional rough idle, and possibly have the engine dying out too.
3) worn ignition module in the distributor. This causes one or more plugs not to fire sometimes, and can also lead to the engine cutting out

[Strugglerzinc]

The EGR valve is a known culprit in a problem like this. Tends to stick at times. Wouldn't hurt to service it.

MAF as above is also a possibility. The BJ ZL/ZM engine doesn't have a distributor.

[Groovemaster]

I don't recommend to adjust the idle air screw!! You said u serviced it what really, what mileage? Anyways u can clean the throttle body, EGR and PCV with some cyclo throttle body cleaner. Don't 'dig up' with the sensors and disconnect your battery terminal while cleaning.

[cinco]

there is no idle screw to adjust AFAIK
remove the throttle body and there is a little hole in there the egr flows through clean your EGR the Throttle body and that little hole

[damieG82]

cinco there should be a recessed idle screw right at the tippy top of the throttle body, facing the front of the car, and above the throttle cable connection.... but its set at the factory and mere rotation can cause problems... there are 2 connections points in the diagnostic port that need to be bridged before adjusting that screw

but grayeagle, like I said b4, DO NOT MESS WITH IT.... idle speed doesn't appear to be the problem, so no need to adjust it. Check the other things that have been cited

[dredman1]

Leave the idle screw alone - use it as a last resort desperation attempt to keep the car idling. From experience with my BJ, try these 2 things:

(1) check your MAF sensor (easier of the 2 to check). It may be dirty. If you have a K&N filter, the oil vapours from the element get onto the tiny resistors and yellow bulb like thing on the sensor. Carefully take out the sensor and look inside the tube and you should see 2 tiny white resistors. If you can't see them, that means it's covered in gunk. If you can't see the yellow colour if the bulb, then it's dirty also. Clean them both by spraying it out with electrical contact cleaner. Make sure you do not touch them as they are very fragile, and let it dry properly before reinstalling.

(2) One of your two ignition coil packs (located on top the spark plugs) is defective. When they start to go bad, they work intermittently - sometimes they fire fine, other times they don't. When they don't only 2 cylinders are firing, leading to the poor rough idle. Easiest way to check this is to either borrow one from a parnder's BJ and replace it with one of yours. If you still get the same problem, put back in the one you took out change out the other and test again. Also try putting yours in a pardner's car one at a time. You can identify the defective one when his car starts to idle bad. Since it's an intermittent problem, you have to be lucky to get it to malfunction at the time you're troubleshooting. The other way to troubleshoot it is this: when next you get the bad idle, pop the bonnet and follow the plug wires from one of the coilpacks, and pull the plug wire. If the car shuts off, that coilpack is the good one. Restart the car and when the bad idle happens again, follow the wires off the other coilpack and pull that plug wire off. If its malfunctioning, there should be no change in your poor idle, since that plug wasn't firing in the first place due to the malfunctioning coilpack.

If this is the case, replace the coilpack and you should be good to go.

Let us know how it goes.

[grayeagle]

I made the mistake an adjusted the idle screw and burning alot more gas. However, adjusted it back but found that the intake tubing that runs from the air filter 2 the trottle body is cracked. I tried getting a new one but no luck yet.

Does anyone know where i can get the intake tube????????????????

[cinco]

never noticed that idle screw is it a zm?
those cars are all distributorless ignition so i never even though about messing with anything like that

[mazdamig]

grayeagle, adjusted the idle screw so the car will idle at 800rpm

[grayeagle]

More problems. Dont just need an intake tube but also need a coil pack. Does anyone have the coil pack for the 323 BJ model.

[PPR Electronics]

just wanna say dreadman1 sound like he know his sheit thumbs up because ur advice is helpful

[nuffkuff]

hear this ,i have a bj and i have the same problem got a diagnostic done and it revealed the tps was the culprit,don't adjust any thing see if u can get it replaced,i looking 4, 1 now and is pressure,so if u find one let me know, how is ur fuel consumption,when u rev out do u get black smoke? if so check ur maf sensor also.peace!

[jacquesman]

My BJ doing the same rough idle problem but after i serviced it. I changed MAF sensor, and coil packs but still getting that rough idle. But the car was working fine b4 i service it so i tried putting back the old plugs and same thing. When i looked at the new plugs that i took back out they were fouled. Right now I don't know what to do again.