Hi,

I am fresh in the forum!

I have an old Honda Civic 1994 1.5 LX AT. Whenever I start it on, everything goes well while the engine is cold - and it keep accelerated at about 1500 RPM.

The problem is when the engine gets warmed up, so it begin to loop by itself as if I would stepping and releasing the throttle repeatedly (RPM get nuts going back and forth between 500 and 1500). It makes almost impossible to drive the car!

I have noticed that if I unplug a part that stays behind the block (I think its name is IAC, IAS, IEYS or something like that), the engine stops to loop and stabilize but in an extremely low idle RPM and unless I put my foot in the throttle to keep it accelerated, it will stall.

There is anybody that can give me a clue about what is going on and how to fix it?

PS: I live in Brasil and it is NOT easy to find replacement parts for this car here, so I would be glad if there would a simple and cheap way to fix it. If the problem is a defective IAC (or whatever), it would be great if I could simply bypass it (although I would have to know a way to increase engine idle)...

Thanks!

 

They will do that if the cooling system has a bubble of air in it. With engine cold, take the radiator cap off and make sure the radiator is full to the top.

The IACV could be sticky from the black gunk that typically accumulates inside them. Unbolt it and spray carburetor cleaner (or throttle body cleaner) into its air passages to clean it out.

 

Hey hey Mk378!

Thank you very much for the advice. I will check the radiator. I had sprayed a lot of WD-40 into the IACV some time ago, but it didn't solve the problem, but I will get a can of throttle body cleaner and will do it again.

I will let you know if it solve the issue.

Question: should I check for the radiator water with the engine on or off? I am asking it because my other car (a VW Fox) always look like to have more water than it really has when the engine is stopped. Thanks!

 

well the civic that i have in my shop right now has the same issue i found it was MAF mass aif flow sensor . i tryed to clean it but didnt make to much of a difference so i just replaced it and its fine now.

 

MAF on a Civic??

 

1994 Civic does not have a MAF. It's a MAP controlled system.

Check radiator with the engine off and cold. If it is low, fill up then start engine with radiator cap off and add more as needed. Car should be parked on level ground or slightly uphill so the radiator is the highest part.

 

Do later model year Civics have MAF?

 

Thanks for clarification, mk378!

I will make the test the sooner I can!

I just noticed that the Civic battery has discharged completely (regardless the fact I had the contacts unplugged to avoid it to be drained by the alarm and the clock)...

To complete the disgrace, my Fox was arrested this weekend by police tow truck so I am by foot until tomorrow when I'll be able to release it! Yikes!

Anyway, tomorrow a friend of mine will pick me up in home to go the police station to get my car, so I will bring the battery together and leave it in a shop to get a charge in the meantime. Therefore, I hope to have some news until the next weekend!

Thanks a lot! I will let you know!

 

and yes i am damn sure its the MAF then its the sensor like that unless my civic has a newer motor

 

I couldn't check the radiator of my car YET, but I have found this video at YouTube that shows EXACTLY what is happening to it (just in case it can help anyone else to explain the problem). The guy has an 94 Civic too that is suffering of the very same erratic idle issue...

http://www.youtube.com/watch?v=sEiTi5GAcrQ

PS: I have found that this is a very recurrent problem in these cars? I thought that it was only mine, but there is a bunch of people talking about the same thing.