There are two idle problems. A) Fast idle: The engine will not idle below 1K RPM even after it has reached operating temperature; adjusting the idle control screw has no effect. Although no codes are displayed on the computer, disconnecting the electrical connection @ the EACV causes the engine speed to decline to normal (and illuminates the check engine light). B) Surging: However, the engine immediately begins to surge regularly @ 2 second intervals from 500 to 800 RPM.
Background: engine was completely rebuilt and all coolant and vacuum hoses were replaced with Honda parts. EACV gasket was replaced but the valve is original. I suspect a problem with the EACV but the electrical circuit tests suggested by the shop manual indicate it is functioning normally.

What do you suggest I do? 1) Replace the EACV together with a new gasket in the hope that is the cause of the high idle? 2) But how can I cure the surging? I have been told that surging often indicates an intake air leak but all the vacuum lines that enter the intake manifold are new as are all of the intake manifold and head gaskets and all are Honda parts. Can anyone suggest a strategy of identifying the source of the intake air leak?
Dennis Waller

 

i had a similar problem... turned out i hadn't installed a TB gasket and it was causing a TINY vacuum leak which would raise the idle.

 

remove the fast idle thermo valve from the bottom of the throttle body. remove the cap from the end of it and check the large white screw to see if it is loose. if it is loose tighten it with a flat head screw driver and reinstall it. this is most likely your problem.

 

The 1.5L DX engine with throttle body FI does not have a fast idle thermo valve. That is only installed on the 1.6L EX engine which has port FI.
Dennis Waller

 

is there one of those on the d16a6 engine with the multi port? Cause i have the same problem

 

hey guys,

seems like all threads die here...I am trying to figure out a hunting(idle) problem on my 1990 Si hatch. I also need a place to start to figure out why my tach is not working. Any suggestions? My ecu threw a igniter output signal code(code 15) . I cleared the ecu memory and so far no reoccurring code but the tach still not operative. I have voltage at the blue wire coming out of the dist. and into the harness.

Thanks

 

sounds like you need to start your own thread...!!!

 

???.......It appears you have an issue with my remarks. I, like several people here, am simply asking for some help with a couple problems. Obviously you do not have the answers so why the sarcastic reply? Why write anything?

O.K.

I will continue to try and solve my idle/tach problem. I do not appreciate your child like comment. I know you do not represent the majority of people on this forum so I will leave it at that and not give you a second thought.

Thanks for nothing.

 

calm down chicken man...the problem aint that you need advise about your own problem, it lies with the fact that you need to start your own thread and not thread jack someone elses thread to post your own problem...obviously it seems to me that either your lazy or a idiot to not use the search function stickied above the ef thread section to try to resolve your own problems

 

why the hell would you clear the code if you didn't fix the problem? and are you checking to see if you blue wire is "outputting voltage" with a test light? if so then you really should stop working on your car before you do damage to it, this is NOT how you test this properly.

 

You ignorant? Thats not really a question...

I searched and guess what...this is where I ended up. No, not lazy/stupid-just an unlucky MF to get connected to an idiot like you who can't help anyone.

 

that come back was more idiotic than your screen name...first its a question about a answer to your problem and now its not a question...i guess im just wasting my time responding to a moron but then again i got free time

 

here is your imaginary question...you are one dumb SOB

 

Clipsed,

Used a digital Fluke(multi-meter). Also, the code reset question you asked...??? I cleaned all dist/ignitor connectors with electronic contact cleaner per the maintenance manual and reset the ecu per the same manual.What should I have done different?

 

alright in that case, you need to adjust your dynamic timing by tweaking your dizzy and your idle screw. In some instances this will rid the problem, but very rare.

 

Dennis, are you working with the benefit of the factory Helm manual?

 

I had this issue with my crx and replacing the IACV did not seem to help; I just put a double layer of duct tape over the holes on the Intake manifold, trimmed it to size and reinstalled the IACV. I then adjusted my idle via the idle screw normally.

 

Anybody on the board suspect a malfunctioning or port-clogged "tandem control solenoid valve"?

 

Clipsed and anyone else interested,

Tweaking the dizzy timing seems a little amateurish-maybe?I would think its better to have the timing set to factory spec's, still have to get car smoged and all. I currently have the cluster out of the dash, wondering if anyone has diagram or info to troubleshoot the tach on the bench? I do have 12v at the harness connector on the blue wire.

Is this system an autosyn system?

 

I also understand that idle can be adjusted by bending the tab on the dashpot diaphragm linkage up or down (to or fro?)

 

Yes, I have the factory shop manual

 

Thanks to everyone who replied. The problem was an overly tight accelerator cable which prevented the throttle from closing completely. I had checked the cable but failed to notice that as the adjusting nut was tightened it shortened the cable causing the problem I described. The lesson from this experience is check and double check the simple, obvious solutions before assuming the problem is complex. A clear application of Occam's Razor to Honda repair.
Dennis Waller

 

Update.....Idle/Tachometer problems

Idle problem(surging/hunting idle)solved. My issues were tied to my electrical system, specifically the alternator. When measuring my charging systems output voltage I noted it was all over the place- ranging from 13 to 15 volts and jumping around in between these values indicating a bad voltage regulator.Also had instrument panel lights flickering during this episode.

As soon as the cooling fan or a/c condenser fan actuated resulting in an electrical load placed on the alternator, the measured voltage would settle down to 14.1 volts and the idle would smooth out(the instrument lights also stopped flickering) until the electrical load was removed and then the slight surging/hunting/voltage fluctuation would continue until again the fans kicked in.

Removed alternator and had it tested-it failed as suspected it would. Replaced alternator and now have a very smooth idle.

Also, as reported earlier-my tach was inop. I removed the cluster and disassembled it removing the tach to see if there was anything obvious, there was not. I did rotate the indicating needle to appx 3000 rpm with my finger to see if it was binding and it was! It seemed to not want to fall back to 0 after I moved it and I thought maybe I broke an internal part? So, I put the cluster back together and re-installed it. I started the car and the tach did not move-not immediately anyway-but then the needle jumped up to the first radial line below 1000 rpm and she's been working normally ever since.

***Note***

It has been my expierience that Honda's are extremely sensitive where their electrical system is concerned. I had all sorts of symptoms that pointed to bad sensors and even a few ecu codes that would lead one to believe other issues were causing my problems. The alternator does send an electrical signal to the ecu and mine was all over the place which I believe scrammbled its brain somewhat causing problems in the idle circuit.

I still have an idle issue which I think will be resolved after I remove and clean the IACV and the TB. The idle at normal operating temp is 750-800rpm - normal according to spec. However, when I rev the engine and upon returning to idle, the idle drops down to appx. 500rpm and then slowly recovers and returns to normal idle rpm - smooth with no surging/hunting.

I hope some of you will be able to resolve similar issues as a result of my problems described here. If anyone has any other ideas with regard to my above mentioned remaining issue, please chime in-I would greatly apprciate your input.

Thanks

 

hello!
I know this issue has already been covered and repaired but I thought I might add an additional tip on repairing the idling issue.

I had the same issues with my crx dx 1.5l.
I was able to source the problem to the Dashpot located on the throttle body. The diaphragm inside the DashPot had gone bad and was causing 1- a vacuum leak out of the diaphragm itself 2- lack of pressure to the diaphram from that vacuum leak causing it not to "inhale and exhale" correctly via the throttle. Since this device circumvents your idling, it created high idles that would stick for moments at a time.

I havent found a replacment at a junkyard yet and they are hard to find and/or overly expensive to replace ( 70-100$$) @ HondaPartsNow.com, I just disconnected the DashPot peice off of the throttle but left the vacumm hose still connected in order to keep somewhat of a vacumm pressure still intact on whatever line it was connected to on the other end.

Since it was removed, idle issues have subsided. The only negative that removing the DashPot would create is:
a slight jerk of the car when the foot is removed on the gas due to the dashpot not able to fluctuate your idle ( it adjusts your throttle when you let off the gas allowing for a more fluid decrease in rpms)

I hope this long and boring Post might help somebody.
Thanks for your Time!!

 

Kind-of helped me. I am going to examine some of this and see if it in any way relates to the problem I am having, which is that I get a CEL when I maintain speed on a decline, with the throttle almost completely closed. What happens is that the mixture goes into idle mode, and not rich-lean mode, and if it stays like this for over 10 seconds, it throws a Code 1 oxygen content code.

...But I will start a new thread, lest I offend anyone.