still cant shake this idle problem

[Yorb]

things my ka24de s13 has had in the past couple weeks:- new timing chain kit- new clutch- new spark plugs- new plug wires- new O2 sensor- new fuel filter- new MAFS

what's left? fuel pump? air filter?

the symptoms are: slight sputtering during idle; RPMs drop and climb randomly, sometimes low enough to stall; when stalling does occur, it's usually as i put the clutch and brake in to approach a stop light; slight bogging/sluggishness at lower rpms, once it hits 3000 or 4000 it picks up dramatically.

another little tidbit: when it first came back from the shop with a new timing chain, it was doing this horrible jerky bogging during acceleration. he told me it was my MAFS, so i got another. didnt fix it. i took it back to the mechanic, he said it WAS the mafs, but the ecu needed to be reset...no more bogging now. was it really the mafs that the ecu needed to be reset for, or was it the timing chain? oh well, maybe unrelated.

thanks.

[frapjap]

Mine has that VERY same problem. Recently its been idleing at about 600rpm, then will drop off and stall. Only when I just start it and don't go anywhere, or when I am at the street light braking. A quick temporary fix for it that I have found is that Fuel injector system cleaner crap. (sounds like a gimmick, but hey) It steadied my idle a lot and it isn't stalling anymore. Occasionally I get a fluxation in rpms still, but other than that the problem seems to have subsided. I think I am going to opt for new fuel injectors next. The last owner put only one in..who the hell does that? Anyway, sorry to hear that you had to shell out for a maf. If anyone has any imput on the idle thing, I'd love to know too.

[Yorb]

its okay i got the mafs used for $50 off a dude on here =)

good to hear someone else has this problem though... whats this fuel injector cleaner? i totally want to try it now. =P

[(TDS)Apocalypse]

mine has been doin that off and on for awhile but yesterday it got real bad, it would stall 9 out of 10 times when i went back to neutral on my way back from work. the first fix was that there was an open hole in my intake line (for a resonator or something) that i plugged, and that fixed it for awhile, then when it came back i did the injector cleaner too, now its back with a vengence and im scared to drive my car anywhere cause i might stall at the wrong time and get run into. it seems to be the worst when i come off the highway. i replaced the fuel filter and the fuel pump less than a month ago, so i'm at a loss as well as to what it could be.

[Stuntman240]

try the lucas ****. their stuff works for some reason. i just cant explain it.

[240_Keyy]

ok the things that I can think of off of the top of my head that would cause this are

1- timing2- vacuum leak3- mafs4- AACV or AIV thing

#1 Set the motor to TDC on the compression stroke of #1 cylinder and then take out the distributor, line up the little mark thing and put it back in the motor. If that doesn't fix it move to step 2

#2 Go to a parts store and buy a cheap vacuum gauge thingy and hook it up, you should be pulling about 16 to 20 mm/hg at idle (assume about 900rpm) On the KA, there is a rats nest of vacuum hoses at the back of the engine that have a tendency to heat up and crack, totally fuxoring your idle. Check all those hoses and if that doesn't fix it, move to step 3

#3 Unplug the mafs, clean it with some carb cleaner, let it dry, clean the connections on the plugs with a toothbrush and some electrical parts cleaner and plug it back in. If that doesn't fix it move to step 4

#4 the air idle controller- It is the kinda big hose that connects to the plastic intake thingie right before the throttle body. in thory if you close that at idle, the car *should* die. if it makes no difference, then you have found the problem, if not, move to step 5

#5 Give me the car, cuz it is broken

I put them in order of probablility since to me it really seems like a timing or vacuum issue since it sucks and bogs at idle, but runs really well at higher RPM's I kinda don't think it is a MAFS problem because typically the exact opposite will occur. It will run perfectly fine at idle, but totally crap out at about 3 to 4k rpm I have dealt with MAFS problems on both SR and KA motors for a while now and I haven't seen any of them cause the car to be sluggish down low and fine up high, that just isn't how they "work" when they break.

Let us know how it goes, good luck to you.

[Stuntman240]

my car has been dieing at idle lately aswell but if the car sits at idle for like 5-10 mins. but before it dies it usuasly starts hunting. so last week i started my car and it was hunting immediately. i pop the hood , check everything still shaking and hunting. so i smacked th mafs, problem solved. hope that helps.

[Yorb]

i put in a bottle of that greased lightning stuff today. only stalled once all day. improvement for sure, but obviously still not a complete fix.

what's hunting? is that when it drops and climbs randomly?

the vacuum leak thing sounds possible. like i said before the forum took a crap, i doubt its timing since it was happening before my mechanic put in the new timing chain and everything. they obviously had to re-align that stuff and what possible chance is there that they screwed it up with the exact same problem as before? =/

what its been doing today is that it usually runs fine, occasional wobble during idle, like it stumbles. but then when i pull up to a stop light, either with the clutch in or in neutral, the rpm drops to about 400, then 200, then 0 (or slightly below) on my tach and stays there for 10 seconds or so, sometimes stalling. then itll climb back to normalish and i'll be okay. during acceleration, its like some gremlin is controlling the accelerator and im just suggesting to him what to do. i push the pedal in and hold it at a certain point and itll accelerate slowly (as if i had the brake on or something) then do some slight lurches and then by the time i shift to 2nd, its picking up the pace pretty rapidly.

i would check the aac but i cant get to the harness :< i wanna check the vacuum thing but i dont have a gauge... advance auto parts didnt really have any. dunno where to look.

[240_Keyy]

man that really still sounds like timing or a vacuum leak. Timing and vacuum leaks wil do some straaaaaaange stuff on cars. You can visibly check those hoses and feel them with your hands. Typically the break right at the bottom of those two actuator dealies at the back of the motor.

[Yorb]

what am i feeling for? should i like take the hoses off one by one and plug one end and blow in it or something? its not like you could see a pinhole. =/

i really appreciate your help by the way. i am dying to figure this thing out. =)

as for the timing... i dunno what TDC or whatever means but isnt it kind of a pain to get the distributor out? dont you have to take out the fan and stuff?

EDIT: by the way... are there any rubber hoses that are going to like blow the engine up if i take them off while its running? just to check seals and stuff. or would it be better to take them off while its off.

[180fan]

Yorb, do you have any other auto parts stores in your area or a Sears? They do have vac gauges there. Run a tee off your fpr and when you start it up, let us know your vac readings. If you can run new vac hoses that should at least eliminate the vac hoses themselves. If those aren't it, then get some carb cleaner and hose down the parts between the intake manifold's collector to the runners, and the runners to the head. When you see the idle jump stable for a second, you've found your leak. Let us know what you find.

Also try wiggling the maf wires and also check for continuity across the mafs wires. A buggy mafs can do some strange things.

[Yorb]

yeah i have autozone. and sears.

http://www.sears.com/sr/javasr...79000

is that what i want?

oh and whats an fpr?

[180fan]

Yep that'd be it. Just tee the vacuum line off the fuel pressure regulator's vacuum line. Then start up your car and let us know the readings

[Yorb]

k, pressure gauge in hand. im gonna browse through the fsm and find where this fuel pressure regulator is, but if someone feels like telling me real quick first, that'd be cool too ;D

[Newcastle82]

Ok guys, listen up.

If it's an idle problem and you've fixed just about every damn thing you can to try and correct it, what ELSE could be the problem? Has anyone thought about the idea of a faulty and/or totally dead TPS?

I'm talking about your throttle positioning sensor. It's a little black electrical box attached to the front of your intake with a wire coming off of it.

It's bolted to the side of your ECCS (for 89-90 models), and just to the side of your polished intake buttefly valve for 91-98. Your TPS regulates how much fuel to add to a rich/lean mixture and works directly with your MAF to produce what the ECU says is perfect, programmed idle speed.

CHECK IT!

[Yorb]

okay i think i may have found at least part of my problem. remember that hissing noise? yeah, turns out one of the hoses that attaches to the intake line was completely disconnected. just hanging there. i couldnt see it because its the one on the bottom, hidden by all the other hoses. i just decided to get to the bottom of the hissing, so i starting moving things and there it was.

i just took it for a brief test drive. the bogging on acceleration is pretty much gone as far as i can tell. the idle was smooth, but theres no telling how itll be tomorrow.

i feel pretty stupid. =/

EDIT: by the way, i found this when i was looking for the TPS that you mentioned newcastle. black box on the side of my intake? do you mean the wire coming from the MAFS? because i've checked that. im pretty much an engine newbie so you have to tell me where stuff is in relation to big things like the airbox, valve cover, battery, etc. ;D

[240sxJay]

Don't feel stupid, feel relieved, I'm going to have to buy that kit from sears, did you but it Yorb? If u took it to a mechanic how much did they charge to test for it? Anyways I read TONS of forum post (took 6 hours to completely read them all) about idle problems. Seems like our little 240's are notorious for that problem, a lot of people still havent' gotten it fixed. My quest is to do everything i've read on the post So far...

Changed Spark Plugs (however might switch from ngk plat, to ngk iridium )changed cap and rotorchanged mafchanged fuel filterchanged air filter (new intake)greased practically everything that needed to be/cleaned

now I have to check for those vaccum hosespossibly fuel pump?

[Yorb]

i did buy it from sears... havent used it though. =P the fuel pressure regulator is nestled in there pretty tight, plus i didnt know which was the vacuum hose and which was the fuel line. didnt wanna disconnect one and have fuel go everywhere ;D

ive never taken my car to a mechanic for idle problems. not exactly a life-threatening problem so i dont think its worth paying money.

[240_Keyy]

YAY I was RIGHT!!!

Good job on troubleshooting your own problem man!!! Mad props on fixing it :thumbup:

[niznos]

If you guys are not subject to emissions tests, take the AIV (PAIR)out completely. They don't do much and once they go bad, they put exhaust in the intake.