edogmb

I just bought a 92 accord lx with 81,000 miles on it. (my first honda) It appears to have been sitting for quite a while (couple years). It had a fast idle when I bought it and needed some work... The main issue is that after I started taking things off to inspect and clean I noticed alot of "tree material" such as pieces of acorns and twigs in the FITV top and were even blocking the port in front of the IACV screen!!! Somehow this junk got into the intake! The rest of the engine appears to be in suprisingly good shape. Inside the valve cover and intake plenum were very clean. Anyway, after I vacuumed out all of that debris I could find, cleaned the TB, did some basic maintenence, changed all of the fluids and put it all back together... the idle shot up from high to higher (from ~1000 in gear to ~1400rpms). It also started to rev up and down in a surging manner from ~2000 to ~1300rpms in park or neutral. So now I have an idle surge from 1300 to 2000 out of gear and 1300 or so in gear.
I replaced the FITV and IACV with no change. I am pretty sure there are no vacuum leaks unless a possible huge intake manifold leak. My coolant has been topped off and bled a dozen times or so now...and Im running out of ideas. I have an intake gasket ordered for next week. I figure it's a cheap job so why not give it a shot, right? Other than that...I'm thinking maybe my TPS, idle screw, or throttle body. I tried to turn my idle screw down while my IAC was disconnected and I can't get it lower than 1300 or so in park! ...and my idle does drop when my IACV is disconnected, but it begins surging at around 1200-1500 instead of the usual 1300-2000. I've also head a couple stories of the idle screw being obstructed not allowing it to be tightened properly??? But I could be grasping at straws now...lol. Any help would be greatly appreciated. So far i've replaced:
-valve cover gasket
-alternator
-power steering belt
-ECTS
-master cylinder
-IACV (used)
-FITV
-air/fuel filters
-spark plugs
-wires
-dist cap and rotor
I also cleaned the TB, checked all the hoses I could find, and changed all fluids, etc.
Also....I noticed that when I disconnected my cruise control actuator when changing my alternator, that a hose leading down into the front driver's side fender came right out of its housing??? It is a 3/4" or so rubber hose from the bottom of the actuator into the fender/wheel well. Could this be a broken vacuum line? The cruise control worked fine the last time i tried it but its been since I first got the car. I couldn't find any helpful info on that even in my chilton manual...???
Thanx again to all for any input....my first post

nus_dogg

Have you try spraying Brake/Carb cleaner around the IM and vacuum hoses to see if the idle changes?? There might be something that you might not see easily.

edogmb

i have tried that. i also tried it with propane and had no effect that i could tell. i have never had any luck with that test personally... i also wonder if the fact that the idle already surges heavily would hide any effect that test would otherwise have? i have never tried spraying directly into the housing that the "broken" (?) cruise control hose disappears into though, maybe i should try that...

nus_dogg

Hmm..

You should try to take apart that new FITV you bought and tighten down that white wax ball inside and put it back on the TB and see if that idle would settle.

edogmb

that has also been done...sorry, forgot to mention that one. I put the new FITV on the car and then noticed that the plastic doughnut wasn't screwed down all the way. I tightened it yesterday and managed to get it about 5 turns tighter!!! it was either very loose from the factory or it loosened up while driving. I've had it installed on the car for about a week now. In any event...tightening the FITV as loose as it was, and then resetting the ECU...had no noticable effect.

poorman212

The disconnected hose you mentioned on the cruise. Have you plugged it or checked to see if you have vac when the car is running.

edogmb

i did try to plug the part of the hose that i could get to coming off of the actuator. I did not notice any vacuum there. I also tried to block the hole inside the wheel well where the hose disappears into and I felt nothing there either. I did't really expect anything on the latter because i figured even if vacuum was getting through there, simply blocking the hole that perhaps leads to the other end of that broken hose probably wouldn't plug it enough to make any impact on idle....however, if that hose was the vacuum problem I suppose i wouldn't have sniffed out the hiss being that its down inside the body of the weel well AND its underneath my alternator/PS belts....
Im about to take off the TB and re-check all of the vacuum ports and idle screw. I just got my TB fel-pro gasket, so that will go on too.

edogmb

ok...so after yet another entire day of troubleshooting I am left with a little more than a hint of optimism..
I started out by yanking my throttle body to further inspect/clean. I removed the idle screw for cleaning and the old gasket (They both looked like they needed it). I also checked ALL of my vacuum hoses visually...and then went as far as removing them to check for blockage and wear. I removed and cleaned my EGR and put new fel-pro gaskets on both.
****(EGR removal was a PAIN due to its location and the fact that the EGRs body protrudes just over the nut and prevents you from getting a good seat with a 12mm socket...i broke a 3/8" drive socket trying to loosen the nut closest to the distributor and then stripped it trying to get it loose with a wrench. I ended up having to remove the coil also to get a vice grip in there! the other one was no prob. I tried to find a wobbler extension at the local hardware store, but no dice)****
Anyway, after cleaning the TB and EGR and putting new gaskets on I turned the idle screw all the way down. (as far clockwise as it would go) Then I topped off the radiator with the bleed screw near the EGR open until a steady flow of coolant came out of the bleeder screw. I start up the engine and it goes up to 1700rpms right away. Little by little the rpms creep up to 2000 and after a minute or so the idle surge starts again. So there's no change...
While the car was idling I went to the front and noticed the coolant pouring out of the top of the radiator! I know that the level rises a bit as it heats up, but it was coming out a bit more than I liked. So when the fans kicked on and the thermostat opened up the coolant level dropped. I let this happen 3 times and then topped off the rad when the t-stat opened. It came right up and out of the top again. I tried topping off the overflow tank and the coolant ended up all over my driveway! The overflow tank wouldn't hold anything past the low mark. After yanking it I saw there was a 2 inch gash in it's side just above the "low" level!!! I always thought my symptoms sounded alot like the thermo valve not getting coolant scenario, so I can't help but to get my hopes up...but I've been down this road before...lol
I tried fusing (melting ) the plastic back together the best I could until I can find a new one...it shouldn't take more than a day or 2...PLLEEEEEAAASSE!!!

h22apwrcb7

I'm having the same problem with my car, only it has a H22A. Seems like we have been trying the same fixes. My idle goes up to about 2K and drops back to 900.

Bwill9886

Have you checked the idle and WOT voltage on the TPS and made sure it's in spec yet?

It may not fix where your idle is at, but could resolve it's hunting behavior. Also, the sensor itself could be bad.

edogmb

i didn't check the voltage to the TPS yet...i ran out of sunlight again and i'm not familliar with the procedure, so that will have to wait till tomm. The bad part with that is that in order to fix a bad TPS you have to replace the entire throttle body assembly! ...bad design! I've read threads about making grooves in the screws holding it on, but then what???...anyway, if that's the case that it is in fact bad, I'm just going to lood for a used assembly since mine has some corrosion in it and could use being replaced anyhow.

phootbag

Pinch the PCV hose. A stuck open PCV valve can cause a high idle and a surge.

edogmb

upon further inspection it appears that the hose is not connected to anything inside the wheel well. I tried to probe it with a long screwdriver and it seems to just end. Im starting to think that it may be some kind of condenser line or something????

h22apwrcb7

once you make grooves in the screw heads you can unscrew it with a flathead screw driver and just replace them with 10mm bolts

edogmb

ok, but don't you then have to find a replacement TPS? Would anyone make this stand-alone part if it's not intended for replacement without the throttle body? hmmmm

edogmb

First off...thanx everyone for your insights. I appreciate you guys taking the time to help. My coolant overflow tank staying relatively full made no difference in idle after a day of driving...
I was doing some homework on the subject, and after the intake manifold gasket replacement, and lets say my TPS tests within spec.... (pouring all day today, so looks like tomm or wed the earliest) I would start to suspect my air boost valve or finally my ECU!!! When I pull the hose from the boost valve there is no change ... although I AM already idling above 2000rpms on a surge. When I plug the hose I still get a surge at idle, but it increases the RPMS even more! I'm not sure how to take that...also, I plugged hose #21 in my chilton manual (the 2 upper hoses on the TB...the one closest to the throttle cable) and it stalled out! This hose leads from the TB to the emission control box and without pulling it I can't see exactly where it goes. I cannot find any useful info on the control box either.
So...more questions...
-is there any definitive way to tell if my ECU is bad???
-does the fact that I have no codes coming up point toward any diagnosis in particular?
(the CEL does work)
-any idea where the hose in question goes to in the control box?
-is it telling me something being that the engine stalls out when that hose is restricted?
-any tips on the idle boost valve (the valve to the far right of the intake plenum)?
Thanx again in advance

dragon_lowrider

The hose you pinched off that killed the car goes the the map sensor in the emissions box and it's doing it's job if it dies from that

phootbag

You never mentioned if you pinched off the PCV.

edogmb

ok...some more updates...
I pulled my control box and all of my hoses are connected/good. I will confirm that hose #21 is indeed to the map sensor. When I pulled it completely off this time...the car seemed to idle down to almost normal. It was idling rough until the fan kicked on, then the engine cut out on me. I assume this is typical behavior with my idle being so high.
I checked the voltage on my TPS and saw that it was .5V closed and 4.45 WOT with a steady climb and decent with throttle movement. I checked my PCV valve by pulling it and blocking the bottom with my finger at idle with no difference. I am doing my intake manifold gasket this weekend with hopes this will help as I am running thin on ideas.
I tried pulling the connector for a few sensors such as my TPS, IACV, and a couple others to see if my CEL would come on. It did. With the codes stored I jumped the connector and saw that my ECU was in fact giving me the correct codes. I don't know how sure-fire this method is, but I took that as my ECU is working as it should.
A couple more things that should be noted is that my repair manual states that there should be no vacuum to the air boost valve with the A/C off. There WAS vacuum at the hose that goes from the air boost valve to the snorkel just before the throttle body. I took the connector off of the solenoid at the firewall as the manual suggested to see if vacuum remained at the air boost valve. Vacuum was still there. If Im correct, this points either to a faulty air boost valve, or a faulty solenoid. My manual is not completely clear as to which. I found an air boost valve for around 100 bucks, but can't seem to find that little solenoid anywhere!?!?! Any thoughts?
Also...my transmission seems to be acting up now. I'm under the impression it's probably the solenoids just need cleaning or replacing...but it's intermittent, and has me wondering. I suppose it could also be caused by my high idle...but sometimes, when at a light, I will let off the brakes and the car won't fully go into gear until my foot is comp off the brake pedal. You can feel it "kick in" as you start to roll. Also, whenever I feel this happening it's always accompanied by the car not wanting to go into 3rd gear easily. It revs up to about 3300rpms before it goes into 3rd gear...everything else seems normal.

phootbag

What is your MAP sensor voltage at idle?

edogmb

I don't have a vacuum gauge, and I'm not sure how to do that. It looks like it's simply a matter of having a multi-meter read some values at the terminals...but what terminals??? Is it at the connectors outside of the emissions control box?
I don't know if it has any affect on idle...but I noticed my tach seemed "off" today while driving on the highway. Usually, the rpms are around 3000 at 70mph. Today, it was approaching 3000 just above 60mph...and when I let off the gas, the rpms quickly dove by approx 500rpms or so. It also seemed that while cruising around 60mph, if I gave it a decent amount of gas, it would accellerate smoothly enough...but it looked like the rpms were barely moving up. It just seems to not be very stable like I am used to seeing...It doesn't seem completely accurate...almost sparadic.

Bwill9886

It is. Find the wire (through process of elimination or do a google search) sending a signal to the ECU and give us the reading.

edogmb

ok...its been a long road so far...but here's some info. I did the intake manifold and plenum gaskets which seem to be holding up great. It took my idle down ~150rpms. (i noticed a trace where the plenum gasket was leaking a little) After a little more looking around I figured I would try blocking off my air boost valve, which stopped my idle surge when disconnecting the IACV. With the boost valve blocked, the idle screw tightened all the way, new gaskets all around, and the IACV unplugged I can get the rpm's down to around to a relatively steady 1000rpms...and a few hundred less in gear. That being said:

I tried to check out the MAP readings today on a whim the best I could with just a multimeter. I found the following...
+The white/blue wire at the MAP sensor connector is the "MAP sensor signal" and was 4.85V at the connector terminal to the ecu
+The "MAP sensor signal" probed at the sensor side while running was 1.03 and dropped to ~.093 when warm
+The red wire at the MAP sensor connector is the "MAP sensor VREF" and was close to 5V at both the connector wire to the ecu and at the sensor connector probed, at idle, cold and warm.
+Then after a few seconds the surging from 1500-1300 or so and the "MAP sensor signal" surges from ~.09V to ~1.9V in relation to the surge. If my memory serves me right the MAP sensor VREF stays around 5V more or less...until....
+I tried disconnecting the IACV and checking the readings to get the RPMs down and eliminate the surge. The MAP sensor VREF signal (red wire at MAP sensor) was jumping sporadically from ~5V ALL OVER THE PLACE!!! I thought it might be a bad reading, so I repositioned the probe and tried again, but again the same... It would stay at 5V, then drop to ~2V, then up to 5, then down to 0.2, then up to 3.....etc...
What should I make of this??? bad MAP? My manual says the "signal" reading should be .8-.9v at warm idle...which seemed almost right, a little lower than my readings. I should also be getting 4.9-5.1v on the "VREF" reading, which seems to be right, until the idle goes down to where it should be, then it jumps??? I'm seriously considering trying to buy a new MAP at this point.....

edogmb

I found out that the hose going from the cruise controll actuator into the body of the car is just the actuator vent hose.

h22apwrcb7

so let me this get right:
You changed the gaskets in the intake manifold and that lowered your idle but it still surges but with the IACV unplugged its fine
and the MAP VREF varies with the surge
and still no CEL...

I have the original MAP sensor in that Black box connected right now, I will switch to the MAP on the TB (prelude) and I will let you know what that does.. Hopefully that is our problem