1988 Honda Accord Automatic Idle Issue (Suspect Vacuum)

[DanJDT]

Hows it going everyone? I flipped through almost 40 pages of this forum last night to find the information I was looking for. Since I hadn't registered yet I couldn't use the search feature. So I am on my way to the 5 posts i need to upload a pictured.

I have a 1988 Honda Accord "Special Edition" (Not Sure about the SE part... looks legit but also looks suspicious. haha) Right now the main issue is the idle. It starts out fine at idle (1200 for warm up) and after that it will go up. I sprayed intake cleaner around trying to find a leak with no luck. Along the intake seems to be sealed well enough that it didnt change the idle. I let the engine warm up and pulled the Air Cleaner and checked the choke butterfly valve. I started it up and ran it a bit and it seemed to be in the proper open position. However, since I had removed the air cleaner the idle seemed to go to a normal idle. (800 rpm) and stayed there. I got in and put it in drive and it shuddered and shook. So obviously something is still wrong.

I put the air cleaner back on and got it snug. I started putting lines back on one at a time. I got to 2 vacuum lines that seemed to spike the idle. I pulled up the diagram for it and came up with Vacuum Line #33 and #8. I am missing the intake diaphram thing (No idea what its called.) thats on the intake side that looks similar to an EGR. It feeds into line #8.

Now. Question is. Is it easier to remove all the Emissions/Vacuum lines and do the "stage 4 delete" or should I just attempt to repair it as stock. I am not a fan of how it is now. I rather do the delete.


Thanks for the input and I am going to bring my post count to 5 so I can get some pictures attached.

[DanJDT]

So I looked it up finally and I found this thread
( https://www.3geez.com/forum/how/11067-running-keihin-2bbl-carburetor-without-emissions-electronic-contorls.html#post470501 )

Only problem I have is I want to do as much of a delete as I can but I want to keep my Cruise Control. Can I run a line off and still maintain that luxury? Or does it have a specific amount of pressure it needs to function properly?

[DanJDT]

Looks like I will lose a lot of things I would rather keep. Cruise Control, A/C Idle boost. Things I would rather keep. Guess I am going to be doing some research into the diagram to see what I can keep and what I can toss.

[DanJDT]

Test post

[DanJDT]

Okay, So I unplug number 33 and 8 and it seems to idle at the ideal RPM. I will post a picture of the part I am missing.

[DanJDT]

Well I cant locate the part but on the diagram its where #8 starts at the intake where it goes from metal to plastic

[Dr_Snooz]

1988 "Special Edition" LOL.

I'm not sure what the question is here, but it sounds like you got the idle issue narrowed down to a vacuum leak?

[DanJDT]

No, Still havent narrowed it down very much. I am going to tear into it again 1 more time. I was wondering if anyone knew what vacuum line #8 and #33 went to.

[Dr_Snooz]

Your problem is in the Keihin carb. Somewhere. God help you.

Here's the deal on the Keihin. It is a wonky carb that Honda tacked 4 billion little electric actuators, vacuum pots and assorted doo-dads to make it perform like a fuel-injection system. It worked remarkably well, giving the cars peppy performance and preternatural mileage. Alas, 30+ years on, the whole mess comes unraveled. If you're ambitious, you can download the manual (https://www.dropbox.com/s/vzcxevmh7x4c5r4/1989%20Accord%20Service%20Manual.pdf?dl=0) and spend some quality time in ch. 11 learning about all the multitudinous controls fighting for supremacy. If you're lucky, you'll find a bolt-on piece that's gone bad, readily available at a junkyard near you. If not, well, you'll learn why the Keihins are so feared.

[Rendon LX-i]

put a weber on it problem solved

[DanJDT]

I am not apposed to putting a new weber on it. Question is can i keep the cruise control, and the AC idle boost? Not to worried about the AC boost. Really want to keep cruise control.

[DanJDT]

Cold start it runs rough almost like blown head gasket (On 3 Cyls) after its warm it runs okay. After its warm I can shut it off for a few hours and it will start up and run mint.

It does have bad gas I am trying to run through. it. Once i get a few gallons through it I think I will have a better idea of what I am working with . It runs great but with a higher idle (it seems to come and go at will)

Good news is it sat for a few weeks and started right up


Yay free cars.

[DanJDT]

I am now looking into "Carb Icing" for one of my issues.

[DanJDT]

Lets bring this one back up. Something weird happened. (Maybe not to some of you season professionals. )

I found my diverter valve for the pre heat that comes off the exhaust manifold in a weird location (It looked legit where it was sitting) I installed it back into its location and when I started it back up the idle was a little low but it was good. I removed the air box and bumped up the idle a little. When i started it back up the idle was 3 -4 k. So i brought the idle screw back down until it seems like its out of the bracket. Still have a 3k idle. What issues can I look at to get it fixed up? I removed the battery to clean the terminals and a few grounds that I thought suspect for the dim head light issue.

Help would be appreciated. Thermovalve B I hear is something to look at.

[DanJDT]

Who has a weber for sale? lol

Idle is back up and the idle adjustment screw is back all the way off. I am just confused as to why the damn idle fixed itself for a couple minutes when I put the diverter valve back in place. I really want to just splurge and get the weber for it but I am holding out hope that I can get it all figured out without much fuss.

[DanJDT]

Hopefully someone will reply to this one. I am getting tired of talking to myself.

Any rebuild with pictures of the stock carb? I am going to try to keep cost to min and not buy gaskets but i cant make them if I have to.

[Dr_Snooz]

Find your vacuum leak first then see where that puts you. After that, run some injector cleaner through a tankful of gas. If the car has been sitting for a long time, or otherwise abused and neglected, then settle in for a long work out period. Drive the car every day and work on the worst problem at a time. In a year, the problems you have fixed will have fixed themselves. Download the manual and read through the chapter on the carb. There are a million vacuum operated contraptions and electric doodads that control the carb. They fail and cause problems. Test them all to make sure they work. If you're lucky, you'll be able to swap one out and avoid a rebuild. If none of that works, come back and we'll continue from there.

[Dr_Snooz]

Also, they sell aftermarket cruise control kits at hot rod shops like summitracing.com. So you can go that route too.