Surging during warm up

[hdpayne]

Hello all, I just picked up a very clean '88 LXi from the original owner for my daughter's first car and she and I both love it. During warm up from a cold start it will idle smoothly at about 1700 rpm for a couple minutes, then hunt between about 1200-1700 for a couple more minutes before settling into a smooth idle at about 1100. Is this hunting normal? Thank you.

[2geeSEi]

Is it carb or FI?

[Karynne]

My '87 Lxi had the same issue originally and a lot of people recommended checking for vacuum leaks. The hunting idle seems to be a very common issue with older Hondas in general so you're definitely not alone. If you search the forum for "hunting idle" or "idle surge" there are a lot of threads that can give you an idea of what worked for other people who encountered the same issue. As far as I can tell there isn't just one issue that causes this, the hunting idle can be a symptom of a lot of different problems. Checking for vacuum leaks is easy and free to do if you already have carb cleaner or a vacuum pressure gauge so I'd start there for now.

Welcome, and congrats to your daughter for getting such an awesome first car! When you get a chance you should definitely post some pics. :)

[derolph]

Hello all, I just picked up a very clean '88 LXi from the original owner for my daughter's first car and she and I both love it. During warm up from a cold start it will idle smoothly at about 1700 rpm for a couple minutes, then hunt between about 1200-1700 for a couple more minutes before settling into a smooth idle at about 1100. Is this hunting normal? Thank you.Flushing the cooling system might help. The reason is that cruddy coolant and some corrosion in the cooling system might interfere with proper temperature sensing, which could cause the "hunting", or fluctuating, idle speed. Also, opening the little cooling system bleeder valve on the engine to release any air pockets in the cooling system might help.

[2geeSEi]

We still haven't heard whether its carb of FI. It makes a difference on what to check. If it's FI, it is mos likely poor coolant circulation to the fast idle thermal valve.

[Karynne]

He said it's an LXi so it's fuel injected.

[2geeSEi]

He said it's an LXi so it's fuel injected.
I guess I should have paid more attention to that! It was late the first time I read it, and I never went back and read the first post again. That being said, I would check the coolant flow to the fast idle thermal valve first. It seems like it is not closing fast enough, but is eventually closing.

[Karynne]

I guess I should have paid more attention to that! It was late the first time I read it, and I never went back and read the first post again. That being said, I would check the coolant flow to the fast idle thermal valve first. It seems like it is not closing fast enough, but is eventually closing.

Happens to the best of us :)

[Karynne]

Here's a *video* (http://www.youtube.com/watch?v=L788jKEVblY) addressing some of the most common things that cause the hunting idle in Hondas. Most of them have already been suggested here but the video has some good info to help you narrow it down. Best of luck!

[ghettogeddy]

ya make sure you bleed the coolant system. i had the same issue and i just made sure it had enough coolant and then used the bleeder valve and the idle went back to normal

[2geeSEi]

Once you have verified that the coolant is full and bled, if you still have the problem, you should check the fast idle valve where the two very small coolant hoses attach. These are very prone to clogging. One thing I don't agree with in the video is that you don't want to take that little cover off and thread down the plastic seat until you have verified that coolant is flowing through the reservoir on the bottom of it. If you do that, and coolant is not flowing, it will solve the surging problem, but will also take away your cold start fast idle, which can be a real problem if you live in a cold area. The easiest way to check this is to run the car for about 2 min from cold, then touch the reservoir on the bottom of the fast idle valve and it should be getting very hot, if not, you will need to take the hoses and try to clean it with wires or whatever. Once you have verified coolant flow through it, then take the little cover off when it is just warming up and put your finger over where the plunger is and verify that no air is flowing past. If there is, then proceed to thread the plastic seat down like he shows in the video. I don't think you have a vacuum leak other than this, since the surging goes away after the car is fully warmed up.