Hi All,

I recently did an engine swap on 89 accord LX automatic carb, finally got everything going where, once warmed up, the car runs great and pretty much flawless. Now the issue I am looking at is to try to get cold idle working.

The problem I am having is that in order to get moving after starting one has to wait 4-5 minutes with the pedal pressed down to get everything warmed up before it will shift into drive without stalling. Idle is good, possibly a little high, when everything is warmed up.

I had to fix the choke heater when I swapped the engine. The choke heater cable was only giving about 3V so I spliced into the ign coils to get 12V and now after a few minutes the choke stands up correctly, so I don't think that is the issue. Also actually cranking and starting is ok but if you let off the gas right after starting it will stall out. I tried to check all vac lines with carb cleaner but it is a little hard to tell because the idle seems to fluctuate a bit by itself. I was not able to find any major idle changes with carb cleaner yet. Is there anything I can look into to get a good high idle when cold that slows down when hot? It is this part of the process that seems to be failing.

Thanks for reading. I never would have gotten this far without you guys!

 

It sounds like the carb/choke steps aren't doing their job. Put another way, when you go to start the engine (when it's cold), the choke linkages should drop a couple of notches, then when you start you'll have a high idle. After a few minutes, you step on the pedal again, and it should drop a step (slight drop off of idle speed), then once the choke is fully open, another step on the pedal should drop the linkage down to "hot idle" speed (should be at least a couple 100 rpm below what "high idle" speed when cold is). This might be more of a case of a link that is frozen (rusted) in place, or something that really just needs to be lubricated (or could be in a bind). I'd check those first, before getting too far along. Also, if your hot idle speed is too high, the step downs for the choke might not be coming into play.
Note; I'm not sure how Honda does the above, but Gm, holley, Edlebrock, weber and other carb makers do it similarily to like I explained above.
I hope this helps.

 

Hi ToeCutter,

That sounds like a simple check. Go crazy with the carb cleaner around all of the moving parts.

Let me step back a minute and just check the simple things: this is the first carb car I have owned and it did not come with the manual. Also after checking extensively I can not find the manual online. Can you explain the proper process of how you are actually supposed to start and drive the car if it is working correctly? Usually I step the pedal to the floor twice and then crank with the pedal pressed slightly. Suppose there are no mechanical problems and everything is working as it should. After starting I should get a high idle are you supposed to manually drop the idle down before shifting to drive or you should drive until the temperature is higher with the high idle still engaged?

I know it sounds really noobish. If you have a few scans of those pages of the manual maybe it would help!

Thank you!!

 

Sorry, I don't have a manual for your car. All 3 of my Hondas are injected.
But from my days of owning and driving carb cars, yes step on the gas twice to set the choke, take foot off the pedal and start the car. After it warms up a minute or 2, then tap the pedal to see if the choke steps down a notch. If it does, you should be able to drive off. If it doesn't, you should still be able to drive off, although you might have to feather the throttle a little at first. Once you've got some heat into the engine, the choke should be wide open, and the idle lowered to "hot idle" speed (about 750 to 850 rpms +-50 rpms). I'm kind of guessing as some cars are set higher, and some lower. The emissions decal on the hood should tell you what to set it to though. Some of those stickers also have the vacuum hose routing on them. Just something to keep in mind.

 

I can't find a good picture, but here goes...

Before staring, you pump the pedal at least once, and the accelerator pump squirts a bit of fuel down into the manifold. This also allows a thermostat-spring to close the choke.

At the same time, when the choke closes, there's a linkage that goes down to the neighborhood of the throttle shaft. This linkage moves a kind of stepped-wedge that will hold the throttle a bit open - this is the fast-idle cam. There is probably a little screw that can be adjusted to hold the throttle a bit more open for higher cold-RPM.

As it begins to warm up, the choke begins to open. But the fast-idle cam is kinda stuck under the throttle adjustment and the RPM gets higher & higher. If you just barely tap the gas pedal, the fast-idle cam will move out from under that adjustment screw & allow the RPM to drop. Eventually, the fast-idle cam will move completely out of the way as the choke goes completely open.

Check that system out like this. When it's cold, go under the hood & take off the air cleaner & any other stuff that gets in the way of watching the linkages on the carburetor.. Open the throttle just a bit, so the choke springs shut. Hold the throttle open just a bit, and push the choke butterfly open & closed as you watch the linkage. That's the best way I know for you to visualize how that fast-idle cam is supposed to work.

 

There is about 20~30 pages in the service manual that cover the choke on these....trust me I go crazy every time I read them and I've read them more than any one person should in their life.

The fun with these is there is vac lines that are used to "unload" the choke....so it is not a purely controlled by the choke heater.....BTW, a quick look and I could not find the proper voltage for the choke heater.......so at this time I can't say if 12v is right or wrong.

I won't get into the vac lines that "drive" the fast idle unloader.......which will pull down the cold/fast idle without touching the gas pedal. Trust me I've owned enough of these 3rd gen carb'd cars to know .

You need to watch what is going on. As stated, when cold and before starting the car, one push of the gas pedal to the floor.....not sure if you still have the little "screen" over the top of the carb that can be removed once to top of the air cleaner is off. Anyway, set the choke and start the car - should NOT have to press the gas pedal to start it. Watch the choke "plate" at the top of the carb.

The car should start with a fast idle and then as the coolant warms "slowly" drop on it's own....and when I say fast, these things will jump to ~2500 rpm when cold.

 

Edit...add.....Send me a PM with your address, then give me a few days and that to burn the one I have to a CD.....find something to put it in to mail it and then go to the post office and actually mail it.

Not the best manual, bookmarks don't work very well but it is usable. Pic's of the fast idle unloader attached.....the PVS (ported vac switch)/thermo valve for the unloader is on the back side of the engine block on the drivers side.....not saying this is your issue, just giving an example.

 

Hey Poorman,

I have the service manual, which is available online, just not the 'owners manual' which I presume would outline the correct starting procedure. I will still shoot you a Pm though.

When you mentioned "should have to press the gas pedal to start it" I assume you mean after the first pump, while cranking you should also press the pedal?

I will try to get a video of the whole thing, but the problem is that right now when cold it will not actually idle it will just die so I cant really get out and watch it. I could try to ask a friend to hold down the pedal while I look/film if that would also provide good information. One other consideration that I have noticed, which makes debugging more difficult, is that the car seems to idle quite differently when the air cleaner and vac hoses attached to it are disconnected, so it is hard to both watch things and get the same idle I would otherwise.

Thanks for the tips. I don't give up easily and I love to see old machines work again!

 

My bad....once you press the gas pedal to the floor whne the car/key is off...should "not" have to press it to start the car.

Service manual vs owners manual? Owners manual gives very basic info on the car. A Service manual will give info like the pic's I posted....what vac line number goes from point a to point b....what ~ temp the ported vac switch opens from cold to point b, then the temp it opens from point b to point c.

A simple owners manual can be had from American Honda (not sure about an 89) but just signing up with them

 

Hey Well, it seems these threads keep going off topic. If you ever get too annoyed with me just stop replying: I understand .

Anyway yesterday I was replacing the WP/Alt belt because it had started squealing. While I was there I also decided to try more carb cleaner around all of the moving parts of the carb. After this I was going to try to take the aforementioned video. I pumped twice and started. engine started and stopped as it had done before. (wont stay on without holding pedal when cold) Started again and held at 3k rpm for a while until temp went up and it idled at 1.5k, this was normal. I then got out to look at how things were going and do a walk around, and about 30 seconds later rpms slowly dropped off and it died. This had never happened before. Now went to start it again and very hard to start, and in addition there was a lot of grey smoke coming from out of the top of the carb (cool to touch). Ended up turning the idle screw all the way up, and holding pedal all the way down and it started to go, with rpms rising really slowly (with pedal all the way to floor) until it hit about 3krpm then throttle started responding normal again. However if I let foot off gas, after about 3 seconds RPM start to plummet and engine dies. Tapping gas starts the cycle over again.

I am sure at this point that more then one thing is broken in the fuel control system but I am interested in fixing what is required for a relatively stable idle. It could be a shot in the dark but the hard start and slow rising rpm could be a flooding condition? Is there any specific fix I can try to address this?

This car has a mind of its own

Hope you all have a great day!