Surging troubles......

[Papabug]

Hi GuyZ,

I own a 1991 FI, 5 spd Festiva.
It has always (since I have owned it about 2 years) had a definite on/off the gas thing where it seemed that you could not hold a steady speed (not so noticeable in the higher gears but still there). It was like when you backed off the gas the engine would shut off or go to compression until you stepped on the accelerator again. No in between.

As I drove it over time the engine idle speed increased significantly or it was like the fast idle circuit doesn't shut off.

Then about 6 months ago I noticed that when I applied the brakes there was a notice able drop in RPM as long as the brakes were in use. Later it started to surge (go from fast idle down to almost normal idle and back) when the brakes were applied. It has gotten progressively worse until now it surges all the time, with or without the brakes being applied, although there is still a slight difference when the brakes are in use.

It is not safe to drive as it actually will vary enough that I have to apply the brakes to hold it back or shift to a lower gear to stay at the speed limit.

Surge probably isn't the right word to describe the problem since the idle is high it actually drops back to near normal idle and then resumes it's fast idle then back. It's an up and down cycle or to be more precise down and up cycle.

I have replaced the air filter cleaned the VAP replaced the TPS, cleaned re-gapped plugs, cleaned the distributor cap and rotor read a bunch of posted advice here and learned a lot of things that, I know will come in handy in the Festiva world.

I really love this little beast and would appreciate any help/ideas you all may have.

Great forum BTW
Thanks in advance

[Mike McKown]

A really easy thing to check is to pinch off the vacuum hose to the brake booster and see what that does to your idle speed. The booster may be leaking.

[Papabug]

Brake Booster

A really easy thing to check is to pinch off the vacuum hose to the brake booster and see what that does to your idle speed. The booster may be leaking.

Removed this hose to test. When the hose is removed at idle the idle goes down to the point that the car just barely continues to run and sometimes stalls.
If I put my thumb over the connection on the intake,the hose is not connected at the booster, the surging returns as if the hose was still connected. This hose as you probably know contains a one way valve. I haven't left the hose on the intake and plugged the connection at the booster because of this valve. Should the connection at the booster be blocked also or would that make any difference? Thanks for your assistance.

[Mike McKown]

Whether you pulled the hose at the engine or at the booster, as long as you blocked vacuum flow to the booster and plugged engine vacuum, you've eliminated the brake booster as a problem.

I believe I'd look around very closely for a vacuum leak, somewhere.

[Papabug]

Ok, I went out and twisted this and rapped on that plus a little jiggling. Sprayed carburetor choke cleaner in the small vacuum lines on the plenum and into the PVC(?) valve. Didn't help. I unplugged the O2 sensor that didn't make any difference, that seems odd to me but what do I know? I have uploaded a video to u-tube so you all might be able to hear the problem. The sound quality isn't very good but you can get the idea. The link is here -----> http://www.youtube.com/watch?v=kkutmYIavWE
if that doesn't work copy/past this: http://www.youtube.com/watch?v=kkutmYIavWE
I am thinking I might replace the O2 sensor just for fun and see what happens. Don't think they are too expensive.
Thanks again for your advice I need all I can get.

Papabug

[mechanicaldj]

check the Idle Air Controller

behind the distributor, bolted to the intake

may have to clean it out with Gum Cutter

[Papabug]

Idle Air Controller

check the Idle Air Controller

behind the distributor, bolted to the intake

may have to clean it out with Gum Cutter

I have ordered a repair manual but I would like to get the Beast back on the road. I went out and looked for something behind distributor bolted to the intake. This is what I found (see pic) I don't think this is the Idle Air Controller or is it? If it's not what is it? And if possible could someone upload a pic of the IAC so I know what to remove? I don't see how you would clean this with de-greaser.

Thanks to both of you for your help and suggestions.



Pic here:

http://www.flickr.com/photos/papabug/sets/72157622525419590/

[FestYboy]

that sir is the IAC, the long large tube feeds filtered air into the inlet and the stepper motor regulates a valve to create a controlled vaccum leak (idle control).

[Papabug]

that sir is the IAC, the long large tube feeds filtered air into the inlet and the stepper motor regulates a valve to create a controlled vaccum leak (idle control).

Would it damage it if I let it soak in a parts washer overnight and use compressed air to blow it out? I did blow through it by mouth and it seemed to be open.

It's been along time since n-e one called me "sir", kinda like it. .

Thanks for the info.

"Sir" Papabug

[Papabug]

Grrrrrrrr

Would it damage it if I let it soak in a parts washer overnight and use compressed air to blow it out? I did blow through it by mouth and it seemed to be open.

It's been along time since n-e one called me "sir", kinda like it. .

Thanks for the info.

"Sir" Papabug

Ok I decided not to put it in the parts washer cuz of the electrical connection. I did use some carburetor/choke cleaner on it. I sprayed into all connections, it came out about as clean as it went in. I then blew it out with compressed air. Reassembled it and same thing absolutely no difference.

Does this car have a EGR valve if so where is it located? Maybe I should go get a new Oxygen sensor. I don't have a code reader and the check engine light has never come on. The battery has been disconnected since yesterday so that should have cleared all the codes any way right?

I am about to take it to a shop. I don't want to do that unless I have exhausted all my options. HELP PLEASE

Sorry 4 buggin ya all,
Papabug

[FestYboy]

no EGR on the efi festys. the IAC should be open (pass air) all the time, just depends on how much. i would recomend try finding a new IAC (from junkyard) and swapping it out. if the stepper motor in yours has failed, then the ECU will use the injector pulsewidth to regulate the idle (hence the surging).

[Papabug]

no EGR on the efi festys. the IAC should be open (pass air) all the time, just depends on how much. i would recomend try finding a new IAC (from junkyard) and swapping it out. if the stepper motor in yours has failed, then the ECU will use the injector pulsewidth to regulate the idle (hence the surging).

I am having trouble trying to locate this thing at a junkyard. I noticed that there is a allen screw located on top is this for adjustment or can you disassemble the unit and clean it out by removing this screw?

Also, if possible I would like to know what other makes and models have this part in common. I pretty sure that one from a FI 323 will work but are there others that will inter-change?

Thanks for all your help it IS appreciated
Papabug

[MONSOON]

Nope it wont. Its shaped slightly different than Festivas. As far as cleaning it. I believe a few here have cleaned theirs but they did so after removing. Theres only 2 bolts that hold it. And I dont think Id mess with that set screw on top. Dont ask me why but I dont think Id mess with it myself.

[Papabug]

Idle Air Controller

Nope it wont. Its shaped slightly different than Festivas. As far as cleaning it. I believe a few here have cleaned theirs but they did so after removing. Theres only 2 bolts that hold it. And I dont think Id mess with that set screw on top. Dont ask me why but I dont think Id mess with it myself.

Thanks for the advice. I did have it out when I cleaned it. I think there is a link to a pic in one of my older posts.

Seems that you cannot get this part new anymore, not around here n-e way.

60$ to have it run on diagnostics. I'm gonna pull the O2 sensor and replace just for fun I guess maybe it will change something been spraying it penetrating oil for a couple of days now. We'll see.

Again I do appreciate all who have helped
Papabug

[doylerl]

well, if it is the motor in the IAC, you may be able to buy a new one. I am not sure if it is available in your area, but check this link:

http://www.autozone.com/autozone/catalog/accessories/accessoriesShelf/detailsFromStoreSelection.jsp?

Don't know if it is what you need or not, but a simple search pulled it up on autozone.com.