braking, RPMs dropping, stalling

[mycarhatesme]

i've read a billion responses on here so far, so forgive me if i'm repeating a question:

I have a 1989 Honda Accord LX (carb) automatic.

my car's routine goes as follows:
I pump the gas 4 times. Start it. Starts fine. at this start-up idle, the RPMs go to about 2500 or so for awhile (to warm up), then drops to 1000. THEN rhythmically goes between 1000 and daaaaangerously close to 0. When it gets near zero, it shakes violently and then the rpms go back up. sometimes it stalls when it's near 0.

I put it in drive (or reverse), and if i dont have it already coasting before I push the accelerator, it stalls. If i keep going, it goes fine.

While driving it runs fine. BUT when i brake (regardless of whether it's warmed up or not), it stalls. I've tried using my left foot to brake and keeping my foot on the gas a bit and that seems to work. but what a pain! i've also just been coasting thru stop signs, which seems to keep it going too.

When it stalls, the headlights dim and the dash lights dim first. It starts easily. but as soon as i put it back to drive......stall.

I've replaced the air filter, sprayed the heck outta the choke with carb cleaner, used pour-in carb cleaner in the fuel tank.

What's the prob? I've got myself a brand-spankin new repair manual and i'm not afraid to use it (although i really have no idea).

thanks!

[smufguy]

have you tried adjusting your throttle screw and idle stop screw?

How long has it been since u changed the primary and the secondary fuel filters?

Any Vaccum leaks in your car?

How long has it been since you gotten a tune up?

Check your Oxygen sensor.

[nswst8]

Sounds like Smufguy said, Check the idle settings first. See if they backed out from neglect, Then work from there vaccum leaks, fuel filters, ignition system. LOL
NSWST8

[mycarhatesme]

have you tried adjusting your throttle screw and idle stop screw?

nope. still trying to figure that procedure out. (anyone with the patience to _totally_ explain that to me, PM me.)

How long has it been since u changed the primary and the secondary fuel filters?

were changed in sept.

Any Vaccum leaks in your car?

not sure yet.

How long has it been since you gotten a tune up?

september

Check your Oxygen sensor.

will do.

[smufguy]

Also get a bottle of gas treatment and try using it. Its more likely ur idle is messed up due to the fault idle control. PM PosCarb or Andy (Phyduex) or post this question in Carb tech. Also do a search and u will find a lot of threads similar to yours.

To be honest bro, this is the reason i swaped to EFI. I boast about this all the time and i tell it to everyone, but you will be suprised how easy it is to find fault with the EFI than with the Carb.

[mycarhatesme]

thanks so far for the help.

believe me, i'm an avid user of gas treatment. the poor car lives on it.

I've been reading around in the carb section about adjusting the carb. I'm not terribly confident in removing my air filter housing (took off the bolts, went to unhook the hoses from the housing and such......got pretty overwhelmed and just put the bolts back on).

I read that you can just reach around the air filter housing to adjust the Idle Screw (the one that's plastic and ribbed). will that help?

more questions about the idle screw:
Will it be doing any good to adjust the idle while in park? Wont I only be adjusting the idle speed in park? the RPMs seem to drop when I put it in Drive or tap the gas to disengage the fast idle warm up.
Can I make the idle too dangerously high by doing so?
What can I mess up by doing this?

ugh, so many questions. sorry. but thanks for the help so far. this place is fantastic!

[sporkHSP]

...is there rust around your gas tank inlet piping...
i know thats the first thing i had to replace when i got my 87 LX... mine was doing the same thing, and the auto repair chains wanted to relpace the carb, but one of the honda dealers hooked me up with new piping UNDER WARRENTY.
****if you havent replaced the rusted piping, and any other people who are reading this that have rusted piping, the rust is getting into the gas, and clogging the filters and the carb. at idle there is not enough gas getting through, so it stalls. when you are on the accelerator, ur forcing gas through...
Summery: if you have rusted gas tank piping (u see it when you put gas in the car), replace it, its clogging EVERYTHING. your car will be better.
you can clean your fliters and carb all you want, any you will clean them forever.

[mycarhatesme]

I'll definitely check the gas pipe rusting, but i'm not certain that piece was recalled for 1989s

so i figured i'd see if it was a more simple problem to diagnose first.

in addition to my idle screw questions, does anyone think it could be a gummed pcv valve?

[smufguy]

I'll definitely check the gas pipe rusting, but i'm not certain that piece was recalled for 1989s

so i figured i'd see if it was a more simple problem to diagnose first.

in addition to my idle screw questions, does anyone think it could be a gummed pcv valve?

Take out the Pcv valve and shake it. If u hear the rattle sound. THen the valve is fine. The pcv valve is basically a one way valve with a ballbearing kinda stuff inside. it could be that too. people have had bad problems with a leaky Pcv valve holder, where the pcv valve plugs into. That one gets cracked cause its just regular plastic.

[mycarhatesme]

still trying to diagnose

went to NAPA to talk to them about an oxygen sensor

why do i think it's the oxygen sensor:
I've used lots of fuel treatment before, that could have probably effed it up. seems that lots of low idle problems similar to mine on this board come from the o2 sensor.

see, but then i told the dude at NAPA that when i first start it, a burst of white smoke comes out of the exhaust.

he said it's most likely not the 02 sensor then.

who's right here?

from what i read on this board, a fuel air mixture that's too rich (caused by the 02 sensor not doing its job) _will_ cause a white smoke burst at startup and all this idle fluctuation and stalling bullshit.

and so for now, i gave a Seafoam treatment a try (because i was frustrated and needed to _Something_ before i lost my mind) . the seafoam didn't do much just yet.

and for no good reason, i took out my air control diaphragm to take a look. (but COULDNOT get the hose off of it) it's nasty and scummy, even rusted a bit. is this a cause of the problem too?

[accordlxi2.0]

i have a 89 lxi and had that rust shit happen to me.
but one don't pump the gas 4x's. my brother pump's his lx once.
it start's up.
the idle stop screw is the black knob-like thing in tha back.
take a flay head screwdriver and have tha screw turning torward's the pass side to raise tha idle.
that should work.
as for tha idle flunctuation's
his car did tha same unless u adjust the air/fuel mix or the idle stop screw, but it seem's 2 b doing it's job.

[gmech]

Some great ideas posted here already, but thought I'd give it my two cents since I have considerable experience in this area.

I'll try to address each of your questions so bare with me:

While driving it runs fine. BUT when i brake (regardless of whether it's warmed up or not), it stalls.

Seen this erratic idle behavior b4 and it definitely sounds to me like a vacuum leak. This would also explain why depressing your brake is killing the engine since the brake booster is consuming the remainder of what little vacuum you may have. If you don't have a vacuum guage, remove the top of the air cleaner cover and listen for a hissing sound; the louder the hiss, the greater the vacuum leak. If there is a loud hissing sound, first check the plastic hose that runs alone side the air cleaner to valve cover hose. The plastic hose connects to a plastic reservoir located directly in front of and to the right of the air cleaner via a 3/4" rubber hose about 3" long. A small leak anywhere in this area would be sufficient to cause this. If this checks out, you'll need to remove the cleaner to verify all visible vacuum lines are connected. If this checks out, I would then check the EGR valve for a possible vacuum leak.

i've also just been coasting thru stop signs, which seems to keep it going too.

Not only is this a dangerous habit, but it could prove costly, plus - what if someone with a similar problem is heading your way -- Yikes! watch out bro! j/k

When it stalls, the headlights dim and the dash lights dim first. It starts easily. but as soon as i put it back to drive......stall.

This is typical behavior due to incorrect idle speed. The alternator isn't spinning fast enuf to maintain the vehicle's minimal current draw.

I read that you can just reach around the air filter housing to adjust the Idle Screw (the one that's plastic and ribbed). will that help?

The screw is located under the air cleaner so you may have a difficult time reaching it without first removing the air cleaner. Plus, adjusting the idle speed to offset other inherent problems, i.e., vacuum leaks, etc. is not a good idea. Doing so may result in poor fuel economy and other problems.

more questions about the idle screw:
Will it be doing any good to adjust the idle while in park? Wont I only be adjusting the idle speed in park?

No - however all idle speed adjustments should be performed in Neutral with the parking brake engaged and wheels blocked. Remember to set your idle speed while in neutral to offset the drop in RPMs once the engine is engaged. As a rule of thumb, set it to approximately 300-400 RPMs higher than where you want the idle once your car is in Drive.
Here's some good carb adjustment pics for the G3.

the RPMs seem to drop when I put it in Drive or tap the gas to disengage the fast idle warm up.

This is normal behavior.

Can I make the idle too dangerously high by doing so?
What can I mess up by doing this?

Setting the idle speed too high will result in hard transmission engagement when shifting out of Park or Neutral, which is not only bad for the tranny and motor mounts, but may result in inadvertently movement of the vehicle without the use of the accelerator pedal - something you want to avoid!

in addition to my idle screw questions, does anyone think it could be a gummed pcv valve?

No - a stuck PCV valve might cause excessive oil burning, gasket leakage or blowby, but very unlikely to cause idle problems unless the PCV valve was leaking externally.

Other possible causes include:
- Clogged air filter
- Faulty fuel pump or clogged fuel line
- Leaking Head Gasket
- Excessive Timing Belt/Pulley Wear
- Excessive Camshaft lobe wear

Once you have the problem resolved, let me know if you need further assistance adjusting the idle, fast idle and A/C idle adjustments. I have considerable experience performing these adjustments on the Carb models.

good luck bro! l8rz

[mycarhatesme]

ya know what gmech, that was the most comprehensive and complete answer to the questions i've seen _yet_. thanks so much for your help!

but, according to my 3rd Gen-obsessed friend, here is my problem:

once i had a spark plug that had been cross threaded.

so someone put a friggin HELI COIL in my #3

my friend says he's never seen a Heli Coil used successfully in a Honda.

and now my compression is messed up. (no, i've not had it compression tested yet, but you can _hear_ the effed up compression)

damnit, what a pain in the ass to replace that head it's going to be (especially since i'm gonna have to get someone to do it....that shite is way beyond my capabilities)

anyone else have any probs with this heli coil? or do they have any solutions besides head replacement?

sidenote: seafoam is fun stuff. seems to clean stuff up nicely.

[Blkblurr]

One thing you can look at that I have not seen mentioned is the idle boost solenoid and diaphram. The purpose of this is to keep your engine rpms stable during idle when you shift into gear and when you turn your air conditioner on. It is controlled by vacuum so if you have a vacuum leak, it will cause the idle speed to vary or if the solenoid is not working it can cause the same symptoms. Let me know if you need a diagram to find this on your carb.

Hope this helps

[mycarhatesme]

hmm....so many reasons for so many things wrong

yes blkblrr, that would be fantastic if you could provide a diagram of this, and what one does to fix those problems.

thanks

[x3r0]

i have a 89 lxi and had that rust shit happen to me.
but one don't pump the gas 4x's. my brother pump's his lx once.
it start's up.
the idle stop screw is the black knob-like thing in tha back.
take a flay head screwdriver and have tha screw turning torward's the pass side to raise tha idle.
that should work.
as for tha idle flunctuation's
his car did tha same unless u adjust the air/fuel mix or the idle stop screw, but it seem's 2 b doing it's job.

idle stop screw is not the black knob in teh back.. thats actualy the idle mixture screw :-) the idle stop screw is on the passengerside of the carb where the throttle linkage is.

[nswst8]

Hey good luck, sounds like you don't feel you have the skills to do this. Well if you have the desire you have the skill, One thing that I did when I did my first head was label everything, I even used my kids finger paints to color code the hoses and connectors but after a few weekends under the hood you start to see this stuff with your eyes closed. You can do this you have a book and you have this sight. LOL
NSWST8

[Coroncho80]

.........................................

[Florin]

i had the same problem and i tried what everybody said so far untill i started disconecting stuff. for whatever reason when i unplugged the blue connector thing underneeth the relay on the left (passanger) side of the engine compartment the problem dissapeared. my car never ran better.

[88_accord_dx]

where is this blue connector thing