[lextalionis]

Okay guys, I know there are plenty of threads about IAC valves, EGR valves, plugs, coils, power steering issues etc. but I do believe I'm beyond all of that at this point. Need a sanity check please:

Background:
2002 Honda Ody EX-L with 130K miles. Transmission rebuild at 89K. Upper,lower front and transmission mounts replaced at 89K. Starting last summer, when the weather reaches 100 here in central TX for a good number of days. When the van would reach normal op temps and then come to a complete stop (in drive, break depressed), the van would fluctuate from normal idle to very rough/erratic idle and even sometimes die (esp. after coming off a hot run on the freeway and stopping quickly at an off ramp light). But first 5-10 minutes of driving in the morning it would idle just fine when stopped in drive, not until hot would we experience this behavior. We lived with it last summer, didn't seem quite as bad as now. A week ago wife said the car died at a light. Then she got to work and 2 hours later came home and CEL came on. Only code pulled was P0505 (IAC). Well, I took the throttle body off and replaced it with an Echlin brand. No more codes but problem persists. Then I bring it to a local mechanic:

Hooking up a Snapon Modis computer he didn't find anything but a past misfire on cylinder #5. He also checked the P/S harness and wires while another tech watched the computer and no loose or bad connections there (there's a TSB about this but it includes an additional code to the P0505). He then pulled out cyc 5 plug and immediately said my plugs are past life (I put in NGK single platiniums at about 70K miles). Then he inspected the cylinder and found excessive carbon deposits and suspects the valves have pulled in some and need adjustment. His recommendations, change plugs (which probably won't solve the issue) and then perform a valve adjustment (4 hour labor job).

Also, last thing I checked just because it bothers me that the van idles fine before it gets to real operating temperature (i.e. first thing in morning and the first 3 miles with plenty of stop and go, she idles just fine), I checked the ECT (Engine Coolant Temperature Sensor (not sender, though my model may be both the sensor and sender, but I know for sure it was the sensor I checked). With the car off for several hours, still a little warm the resistance was 450 ohms and then after the car got to normal op temp the resistance was 250 ohm, which I believe to be a good operating thermister?

So, valve adjustment seem correct, thoughts?

Thanks

 

[otto888man]

Was anything done before this happened? When you get the rough idle is the idle as per specification i.e. 750 rpm or does it dip down or lower than specification? Have you tried to clean the air bypass circuit? Let me know.

 

[Our Odyssey]

You should start with some basics and changing the plugs and a valve lash adjustment is a good place to start. Have you checked the EGR port? If its clogged, that might cause some issues. What about a simple check like the air filter? You say you replaced the throttle body, but does that include the IAC valve etc as well? If the problem persists, I would be inclined to check your fuel too. Have you tried running some seafoam through the tank?

 

[lextalionis]

Thanks for the responses guys. More information:

Was anything done before this happened? When you get the rough idle is the idle as per specification i.e. 750 rpm or does it dip down or lower than specification? Have you tried to clean the air bypass circuit? Let me know.

Well, the transmission was rebuilt at 89K about 2.5 years ago. About 1.5 years ago I replaced the EGR and Throttle Position sensor (used a mechanic for help on back-probing the sensor to get the correct voltage, he has a Snapon Modis). Conditions in detail: Cold engine, start, drive, stop in drive car idles around 750RPM. After driving about 10 minutes, after stopping it idles at first fine but w/in about 5 seconds or less the tach dips to 500 then back up, very rough idle, shudder, etc.

Our Odyssey, I replaced and EGR valve and cleaned the EGR passages the best I could per a detailed post on this board about 1.5 years ago. I run a 1/3 pint of Sea Foam into the air intake where the break master cyclinder gets its vaccum, not sure if that's the best place to do it. I do it per instructions given on this board and other. Get car to normal op temps, slowly introduce 1/3 pint while keeping engine on, then shut engine off and let soak about 10 minutes and then drive car. Lots of smoke I do this about once a year and guess what? I just did it this morning I also run Lucas fuel cleaner anytime I take a long 100+ mile trip which is about 5 times a year.

Not sure about my fuel...where to start? Seems to me the mechanic would have found something there?

Thanks.

 

[otto888man]

Remove the idle air screw in this diagram. Its item #1. Remove it, be sure you count how many turns while turning. Spray some throttle body cleaner into the hole & let it soak for 15 mins. clean the idle screw if its gummed up or carbon up. Be careful not to damage the o-ring. Then place back everything. Let me know.

 

[OdyVanMan04]

bad gas??? fuel filter, fuel pump, fuel pressure regulator....I wouldn't say egr because it would still run....

 

[lextalionis]

Remove the idle air screw in this diagram. Its item #1. Remove it, be sure you count how many turns while turning. Spray some throttle body cleaner into the hole & let it soak for 15 mins. clean the idle screw if its gummed up or carbon up. Be careful not to damage the o-ring. Then place back everything. Let me know.

What diagram?

 

[sontakke]

Get code reader capable of giving you live data (you can now get these gizmos for under $30!) Look at the ECT aka engine coolant temperature and IAT (intake air temperature) to see if it is reporting correct temperature. Heck, you can even look athe fuel trim and O2 readings to see if they are working correctly.

Given that you are impressed with Snap On (> $5000 tool), picking up your own tool at less than $30 should definitely interest you.

I finally convinced my brother to pick one up after bugging him for years. Now he picks my brain any time his beloved Porsche STFT/LTFT moves even slightly! Where is that head slap icon??

 

[lextalionis]

ECT is good, 250 ohms at normal operating temperatures. I did get a code for the ECT but that was when I unplugged it while running. IAT pass when in the shop. That Modis is far better than the $30 reader you are suggesting. I cleaned the idle air screw and seat with throttle body cleaner, I will report back any changes after I drive the van this morning.

 

[lextalionis]

Remove the idle air screw in this diagram. Its item #1. Remove it, be sure you count how many turns while turning. Spray some throttle body cleaner into the hole & let it soak for 15 mins. clean the idle screw if its gummed up or carbon up. Be careful not to damage the o-ring. Then place back everything. Let me know.

No good Mr. Otto88man Thinking that valve adjustment job could be right around the corner? Need to find the procedure on this so I can order parts and have correct tools.

 

[otto888man]

No good Mr. Otto88man Thinking that valve adjustment job could be right around the corner? Need to find the procedure on this so I can order parts and have correct tools.

Sorry i forgot to post the link. Here it is item # 1. Part Detail Be sure you count the number of turns when removing the idle screw. You will need a can of throttle body cleaner & a slot screwdriver. Let me know.

 

[lextalionis]

Still no good. It sure seems to me that there is ECU trouble lurking...its has got to be some bunk info the ECU is receiving. Damn car starts and idles fine, idles in park or neutral fine, idles in drive fine for the first 5-10 minutes of driving and then every stop, 2 seconds later the tach drops from 750rpm to 600ish rpm and the car shakes like a tin rattle can and sometimes dies, rare, but does at times. I drop the damn thing into neutral and she mellows out like a young kitten. Yes, I've had a few beers tonight...got Friday off...starting the weekend early. So why the hell would I do a valve lashing check/adjust for my first first time on this van of 130K miles and expect the problem to go away? IDK, I'm not a mechanic, so beers or no beers, think I know what ain't so is probably my best guess.

- change my own oil every 3.5K
- drain 3.5qt of transmission fluid and top off every oil exchange (got a little spooked at 89K when my 2nd gear clutch pack disintegrated)
- changed the "accessible" transmission filter 3 times in its life...hate that job
- just changed the plugs with NGK Platinum singles...standard OEM
- changed all o2 sensors once in its life (denso, as bosch couldn't' keep the dame heartbeat to save its life)
- all engine mounts replaced at 89K though and number of the 3 main ones could be going bad or bad???
- replaced the EGR valve at 115K, cleaned the EGR ant farm, recirc passages
- replaced coolant twice in its life, just burped it the other day...seems good
- flushed the P/S fluid a few times in its life
- ran sea foam in the intake about 5 times in its life, including one just the other day
- replaced the IAC and cleaned the throttle body
- calibrated the TPI with computer and back-probing
- oh added a plate and fin atf cooler around 60K...that did a lot of good didn't it? it's still there
- oh I add lube guard to my atf fluid, per instructions
- added air bags to the rear springs and rear shocks
- I think she needs new struts
- 3 sets of tires...directional Michilen Hydro Edges kind of suck if you ask me
- 3 brake jobs
- checked the ECT sensor and it's good

Darn...I don't know what else to say???

I'm having another beer. Good night folks!

 

[otto888man]

That's a lot of stuff you did on the vehicle. Try this when its idling low. Adjust the idle screw see if it stabilizes the idle. Increase it to spec. to 750 rpm. Let me know.

 

[lextalionis]

Okay update, the VERY rough idle after the car is hot at a stop in drive has improved. It's still there, esp. say after running 65mph for 10+ minutes and then exiting and stopping at a light, the idle does dip from 750 to about 600 and is rough but it's more steady whereas before it would pulse more wildly and sometimes cause the car to die.

So after replacing the IAC (since I got a P0505 code) and cleaning TB really good = very little to no improvement.

After running 1/3 pint of seafoam into the intake = very little improvement...a little more responsive in acceleration.

After changing plugs = noticeable difference, still poor to slightly rough idle after car gets hot and comes to a stop in drive.

After cleaning the idle air screw and jacking with the position (I feel a little odd about doing that and hope I didn't create more issues) = maybe a smidgen better that the last step. BUT! now it seems to take more turn-over to start the car, could be my imagination but I think so...it's not terrible though.

So now after the car warms up good and I do normal driving, in park at a stop the idle is better but it's still there, just not as bad. I am almost wondering now if a good valve lash job will finally make it right? The key is hot engine, in drive, still poor idle. If we were to fast forward to max outdoor temps of 70 the issue would be much less noticeable.

Oh and I forgot to mention in my list of work that the timing belt, accessory belts, main seals and A/C pulley tension-er was replaced at 90K

Thanks.

 

[otto888man]

Do you still have the old IAC valve? Did you had this problem before installing the new valve? I would suggest if you do still have the old valve install it. See what happens. If its still the same. I will suggest something else to try. Let me know.

 

[lextalionis]

The problem existed before the IAC replacement.

 

[otto888man]

I see. Try this, find a tin can or similar material that will not burn off when heated. Then use this material to block the port on the EGR & drive it around to see if you do get the same symptom. Let me know.

 

[lextalionis]

Okay, been some time for me to work on the car. So I have the gasket kit, 10mm jam nut wrench and go-no-go offset feeler gauges for the intake and exhaust. BUT! Let's have a look close at my ERG valve. See the pictures...one is of the seating surface with the flange gasket (obviously very bad looking and maybe even leaking some...see that crack? Then the other picture is the under side of the actual valve w/o the gasket. So, ottoman, what do you mean by blocking with a can/etc.? Which how do I block...both?

Can I get a new gasket or can I make one or just as a temporary test I do have permatex gasket compound, the kind that gets hard.

Thanks,
Roy

 

[lextalionis]

Update: ottoman, I do believe you just meant to "blank" off the EGR, so that's what I did...actually had 1/8" AL stock plate that I cut to match a litter larger than the gasket. I also bought a new gasket, so I cleaned the surface and put new gasket on, then the blank plate, then the EGR valve and bolted it back on. I also plugged the connector back into the EGR valve.

I drove it around to get to normal operating temps and still once car is hot and I come to a stop in drive, foot on the brake, the car idles fine at about 800rpm, then every 10 to 15 seconds the idle dips to about 600 and then back up...lights dim and the idle is rough...does this a couple of times and then may go 30 seconds until it does the same thing a few times again. Frequency of the rough idle seems worse if the outside air temp is 100+ degrees, but even tonight at 87 and 90% humidity it still rears its ugly head.

So it's killing me that I'm about to tear into the valve covers to to a valve lashing check/adjust....I just can't see that a valve adjustment could rectify this issue? It sure seems to me that there's some malform signal going back to the ECU causing this. Can a valve issue cause this behavior? Again, no other codes registered, new IACV, Snapon Modus computer checked the car fine. What could a Honda shop do any different?

Dang, just so frustrated!

-Roy

 

[OdyVanMan04]

did you get gas where you normally wouldnt? also check the coils , a dead or dying coil can create your issue as well, unplug and then plug them one at a time while the van runs andsee which one doesn't change the idle.....I still say it isn't egr...