BoriTL

still having an idle issue. Have replaced all the mounts, PCV valve, coolant hoses, added an intake. Cleaned the manifold, EGR hole, EGR black thingy lol and the TB, the IACV replaced last year. Air bleed radiator and still having this stupid idle of up and down, seems to get stuck at 2k after doing the cleaning more than the up and down. whoever messed with the TB before had put the same gasket on both ends so one side of the spacer gasket was blocking a passage but both gaskets were replaced and cleaned well. The intake gasket felt a little crispy but wasn't broken or chipped not sure how it suppose to feel. what else haven't I looked at that could cause this issue???


oh forgot I also sprayed TB cleaner around the TB and any air hoses and no change in engine speed.

ErickUa5

Have you tried pinching the hoses attached to the intake one by one?
Check the throttle cable adjustment, there should be some slack on it.
If you have a scanner check for Throttle position it should be 9.4%

BoriTL

Gonna try and pinch some of the lines like you mentioned see if anything changes.

no scanner to do the TP, i did have to readjust as it was a little accelerated but still idle issue.

does the sensor that connects to the motor mounts affect anything??

fsttyms1

^ Its not a sensor, its a solenoid. It gets vacuum from the motor and it applies it to the motor mounts. If the hose isnt connected you would have a vacuum leak which could cause an idle issue.

If your idle is bouncing or high, you could have a couple issues.

1. Vacuum leak. (get a can of carb cleaner and with the motor running spray it on the vacuum lines, near the TB, around the intake and see if the engine speed changes)
2. IACV issue
3. TB cable is improperly adjusted

BoriTL

#1 I tried that but no luck no change.
#2 Not even a year old, but was thinking of changing it again but $100 is a little rough.
#3 They were a little tight initially but I loosened them


Does that solenoid ever mess up?? And does the brake booster line that connects to where the PCV effect anything, I was looking around and noticed it had a little bulge in the middle of it. Seems like my issue is somehow related to something with either the brakes or I dunno, cause when I have the idle issue I also get a jolt forward whenever coming to 0mpg. That's really the easiest way for me to know when I am having the idle issue cause it does that jolt every single time.


Almost as if the whole mounts hydra system worked with an on/off switch cause my shifts get a little rougher when the idle issue is happening as well as a bad shudder at exactly 45mph.

bnance63

Try pinching the hose to the PCV valve closed while it's idling bad. If pinching the hose closed smooths out the idle, replace the PCV valve.

ErickUa5

Check your idle screw it should be completely closed, its on the throttle body near the map sensor turn it clockwise until it stops.

3.2TLc

Hmmm, it appears as though ya did alot of work.
Try backtracking and recheck everything again. It could be something simple which ya overlooked ?

BoriTL

That's how I found that the brake booster line had a bulge in it, haven't changed it yet, but i had took advantage while I had everything off to look around and make sure no lines were disconnected or broken. Only thing I found was a negative cable they never put back when I rebuilt trans.

3.2TLc

Make sure that ya adjust the TPS according to the service manual's procedure.

Recheck the TB intake for leaks, throttle cable, vac lines, pcv, air filter, cooling fan's thermosensor, coolant level, etc. burp !!!

BoriTL

Seems to only start happening once car is warmed up.

ErickUa5

Tps are not adjustable unless an aftermarket one was added on most if not all hondas I believe. Have you checked the Idle screw? If open it creates a small vaccum leak.

BoriTL

Didn't even know that there was an idle screw.

BoriTL

Reading on another site a Honda tech had commented that on the v6 models Accord, odyssey, and TL's this part#50913-S87-A81 Electric Control Mounting Solenoid was a common failure for the 99 models. Wonder if it can be cleaned???

BoriTL

Would getting the genuine accord thermostat be the same thing as getting the genuine acura tl one, about a $10 difference locally??

ErickUa5

Nope on the valve that only provides vacuum to the engine mounts.
#50913-S87-A81
Not sure on the thermostat but they should fit. maybe someone else can chime in on this one.

BoriTL

So i've been replacing a ton of parts on the car lately, mainly two things: she's old some corrosion on sensors etc. & still having idle issue of bouncing up and down.

So far replaced.

water pump
timing belt w/ all components
IACV
PCV & Grommet
radiator w/ cap
thermostat (honda OEM)
all the coolant hoses & heater hoses (removed airbox rad)
added an intake in case stock intake was torn
TB & IM gaskets
all 3 Motor mounts
EGR port cleaned
EGR valve cleaned & new gasket
bypass valve gasket
all of the temperature sensor/senders

But i'm still having the stupid idle issue, which starts a tranny issue as well. The car runs great but once warmed up the idle is noticeably higher a little above 1 at stops and if in park or nuetral does the bouncing up and down as if the IACV is bad/dirty but it was replaced last year and i cleaned it last week again just to be sure. I recently changed the radiator and burped the system and was weird cause for some reason the idle issue didnt show up till almost at work today which is 25 mins slow traffic and usually once i'm out of the neighborhood it starts doing it. Once the idle issue shows up it starts messing with my shifts as well, i can feel the points it shifts, and exactly 45mph decelerating the engine will literally start to shake violently until it hits 40mph and than stops. When the idle issue isn't happening the tranny shifts perfect and the 45mph thing disappears. Is there anything i'm missing that i haven't replaced or haven't cleaned or looked at?? anything with the PCM that could cause any of this???

Skirmich

DAMN! That's a lot of parts from what it seems to be a faulty IACV...
Are you damn sure you can disregard the IACV? is it an OEM replacement or aftermarket?.. Do you have any codes?

3.2TLc

Some things to recheck...... the IAC valve first, then the coolant system should be pressure checked and try burping it again.

Does the motor's idle seem normal when first started up cold ? .......or only when it's up to operating temp ? Were ya experiencing this bouncy idle prior to all the repairs which ya have recently done ?

BoriTL

IACV a year old, cleaned last week even though it was still very clean from being new. I'll try the burping again tonight.

If i turn the car on, on a fresh morning it will idle perfect, does the rev thing and goes down after a sec or two right below 1k, until the moment i put the car in reverse and actually warm up the engine more than the idle is very apparent. i can tell because right away when it does what it does the idle goes above the 1k. Before the tranny was rebuilt the idle issue didnt exist but when i got the car back from being rebuilt he mentioned the shudder it does now, which i know my motor mounts were all shot but replaced those and still idle issue. i started disconnecting sensors to see if anything changes and the only one that it affected it was the MAP sensor, soon as i pulled it off the idle flattened to a little above 1k.

Issue has me stumped, does the PCM control anything to do with idle??

On the brightside those hoodlifts do wonders after using a broomstick for 2 yrs, i'm so used to the stick i still have my hand on the hood as if its gonna fall. Also noticed the idiot that had my car before apparently tried to be slick and put a piece of paper holding the temp gauge in place so gotta open up the cluster and hopefully it still works.

Skirmich

What about your TPS?
Try this: rev while idling first thing in the morning just rev a little over 3K and remove immediately your foot from gas, What the rev does?

3.2TLc

The PCM will read the various sensor's input attempting to monitor and control the motor's running. Things like the IACV and sensors can be fooled by varying coolant temps. Therefore if the coolant level is low or has trapped air within it, the ECT sensors may get faked out.

BoriTL

So in a sense the PCM gets readings from the sensors and adjust the engine accordingly but if the temp are off or fans not turning on when its suppose to than the PCM would be sending incorrect info, am i getting that right??

the other thing i brought up in another topic was ground, since the tranny was just rebuilt, would that effect anything if they didn't connect or if the wires are rusted from age, also where would be the best place to throw my own grounds particularly for the TB sensors side.

I reconnected one ground recently that ran on the drivers side body was just hanging there just took out a bolt of the tranny and bolted it down.

fsttyms1

Still sounds like a vacuum leak or IACV issue. With the engine running with the idle issue, what happens when you disconnect the IACV

ErickUa5

BoriTL If I remember right, You mentioned something about a gasket on the throttle body spacer missing ?

BoriTL

The IACV is actually the only other one i forgot to unplug since its on the bottom, but i'll try it during break see what happens.

The gasket issue was actually that whoever had it before put two of the TB gaskets instead of the spacer one as well.

BoriTL

So this morning before taking the niece to school i took off cap, put heater on and let sit for about 10 mins while we both got ready. Came back outside and thermostat still didn't open as bottom hose was mildly warm, so waited till i saw the coolant flowing but still fan didn't come on. Held Revs at 3k and the minute i let off the pedal starts doing the up and down. Unplugged the IACV and hung at a little above 1k, plugged back in and started again.

Had to go so capped it off and went on my way, heard the fan on at a stop sign so its working, plus just changed radiator sensor.

ErickUa5

Starting to think you may have a bad throttle body assembly.
Seen on other forums about worn throttle body plate with a few other cars,
Did you ever check the throttle position on a scanner ? it should be near 9.4%

BoriTL

Can the scanner they use at Autopart stores read that??

ErickUa5

Yes most of them do, unless its the ones with a really small screen that only give a 5digit code and no live data.
If in doubt first ask if the scanner is capable of showing TPS percentage.

BoriTL

i'll try and get that done ASAP. Want this crap resolved, tried of slowing down and feeling that stupid kick at 45mph.

BoriTL

Going to Advance after work to get TPS reading, friend works there. Also doing my usual research came up on the idle speed screw, that if its messed with would cause to much air in TB and cause same up and down fluctuation. Guess what i closed that screw out completely thinking it might have been leaking, but when i tightened it, nothing changed as far as engine idle or change in rpm's. How can i go about adjusting this back to where its suppose to be??

Skirmich

^ You will need a OBD scanner with live data to know the EXACT RPM.. But I will advice you to first sort out the original problem or you might end up with an un-even transition between IACV and physical idle, That adjust screw is just in "case of IACV failure" its not like older cars where it had a big role.. If you end up with a higher idle at the screw your IACV will go loco..


Back it all up (This will physically close the butterfly) and unplug the IACV = Should shut down the engine
Adjust until engine remains barely ON even without the IACV = Below IACV threshold of course (Something like 700rpm).

BoriTL

Did that and didn't seem to due anything, what i did notice is the intake gets louder the more i unscrew it and quiets down as i tighten it. I did burp the radiator again, did have some bubbles in it which came out shaking the TB bypass hose but hopefully all out now.

Skirmich

You mean you backed it out the idle screw and unplugged the IACV and the engine didn't shut off??

BoriTL

Exactly did nothing. On the 99 is there suppose to be a negative split off from the wire harness for all the sensors, was looking up the oem wire harness and when I went to look for the wire on mine don't see any individual wire branching off.

BoriTL

This weekend i'm going to start tearing down the TB side, mainly to start looking at tranny stuff see if anything is loose or disconnected. And to see if i can locate the ground thats suppose to be on that side. Have to get this idle issue resolved, has been bugging me for a while now. Going to grab the meter and start testing sensors as well.

From reading up on the idle speed, theres a part where it mentions that if its off the PCM will get a signal as if your foot was on the pedal when its really not, causing the tranny to do some kind of lockup which would explain the kicking decelerating from 45 to 40mph and only at that speed exactly, now is the screw suppose to change RPM or something whenever moved, cause mines really does nothing closed all the way and the more i open the louder the intake gets but still no change in RPM or anything like that.

3.2TLc

How did the TPS check out ? Maybe a communication error to the PCM ?

BoriTL

Ok haven't done the TPS check yet, haven't really had time between moving and being in two different houses its hell. but anyway notice the other day coolant smell, so I happen to squeeze the top radiator hose and I hear air let out. So I bought new ones and just replaced them. Also replaced the plenum gasket and the other three gaskets that go to the IM.


So bleed the car, is the fan suppose to come on before the thermostat opens? seems like mines taking a while to turn on and I recently replaced the radiator switch and guage sensor so should be working up to par, but for some reason takes forever for it to come on. Both come on when a/c is on, just took more than 20 mins for the fan to kick in when I was bleeding. And really I'm stumped at this point, I've literally replaced everything in this BITCH and I'm still having stupid up and down idle. I'll check the TPS next but really would that affect it?? I also disconnected the throttle cables make sure I wasn't getting to much yank from them still had the constant revving. So...... Please help I'm really at the point where I'm going to take it to the mechanic and than sell the POS cause I'm tired of dealing with this shit!!!

3.2TLc

A pinhole leak in the cooling system could cause the coolant level to run low.....and in turn not be properly read by the sensors. This could possibly be the reason for a fluctuating idle.

Have the cooling system pressure checked for leaks. The motor must be up to and above normal operating temp at idle before the cooling fan will activate.

Leave the rad cap off, let the motor run with the heat and blower on high, once the rad boils over without any air bubbles.....rev the rpms up a bit and make sure that the fan comes on, turn motor off and let cool, top off rad and overflow tank, replace rad cap and then monitor the situation.