| TheyCallMeBruce |
Okay, need some help please.
I indicated on another thread that I think the culprit to my stall problem is an evap purge valve that clicks rapidly and continuously on and off. This morning I took the cover off, and started the engine, no clicking. After about 3 minutes (after warmup) at idle, the rapid clicking resumed and did not stop until I shut off the engine 10 minutes later.
So, is this a normal functioning characteristic of the evap purge valve?
Can someone please help me see if your evap purge valve emits a rapid clicking sound once the engine is warmed up? The sound stops as soon as I disconnect the electrical harness, and restarts upon reconnect.
I would be eternally grateful if someone can confirm that my valve is going nuts before I either buy the part or try to talk the service manager into warranty-ing a non-emissions-extended-warranty part.
Thanks.
TheyCallMeBruce |
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| TheyCallMeBruce |
see above post; just takes 5 minutes. For all I've contributed . . .
:8: |
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| Robyjo |
Hey Bruce,
I listened tonight with the hood up but the cover on--if you want with the cover off, I can do so tomorrow afternoon.
With the cover on but hood up, I didn't hear the clicking you're talking about. I did hear a type of clicking from the serpentine, but that was soft and definitely not from the evap purge valve.
Let me know if you want me to check with the cover off,
Rob :31: |
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| TheyCallMeBruce |
quote:
Originally posted by Robyjo
Hey Bruce,
I listened tonight with the hood up but the cover on--if you want with the cover off, I can do so tomorrow afternoon.
With the cover on but hood up, I didn't hear the clicking you're talking about. I did hear a type of clicking from the serpentine, but that was soft and definitely not from the evap purge valve.
Let me know if you want me to check with the cover off,
Rob :31:
Mighty neighborly of you, Rob, . . .
but the only real way to check is to disconnect and reconnect the harness during idle (once the engine is fully warmed up) to see if there is a difference in sound. I didn't detect the clicking noise until I removed the cover, then it became very noticeable as I disconnected and reconnected a few times. I could also feel the clicking vibration of the valve as well.
There are 4-10mm bolts holding the cover in place.
I do appreciate your helping me out.
Thanks.
"Bruce" |
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| Robyjo |
I'm afraid I have some bad news for you bruce...I definitely had the same click, I believe, and I could also feel a tapping on the valve itself when I pulled the cover off. I had my ipaq with me after I pulled the cover off so I recorded a few seconds right next to the valve itself. It's a pretty bad recording because of the way I recorded it (long story), but I think it'll suffice.
Take a listen and let me know if it's what you hear.
Rob:31: |
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| TheyCallMeBruce |
I owe you one.
The news is a mixed blessing; while I didn't isolate the problem, I've saved myself from needlessly replacing a perfectly fine valve. Thanks.
Until I get an MIL code (malfunction indicator lamp) for a scanner to pickup, or until I have a better idea, I'll just kick up the idle to about 850.
The problem hasn't resurfaced yet, but it continues to be disconcerting to own a late model luxury vehicle and know that it could simply quit on you w/out warning at any time.
thanks again; since I can't buy you one, I'll have a cold one for you . . .:cool: |
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| DaleB |
Brue, this is probably not related but when I saw the picture of the intake manifold I was reminded of one forum member that removed the manifold cover (and gasket) (just above the yellow square in your picture) and cleaned up several passages inside that appeared to be carboned up.
It resolved a random rough idle had as well as a tendency to stall. For what it's worth.
At the time we had asked for some pictures and more detail but that never materialized. |
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| Robyjo |
No prob, Bruce--that's what we're here for in my opinion--to help each other out (especially against the nasty dealers). Hope the cold one was good! :2:
And a special thanks to my fairy point-godmother who gave me a nice present.
So you've found a definite correlation with your idle speed and the random shut-offs?
Rob:31: |
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| TheWorm |
Could a bad EGR valve cause this problem, too? Plenty of faulty EGRs (usually causing vibe or rough idle, tho) and IIRC none of them ever threw a code to the check engine lamp.
- The Point Fairy :) |
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| DaleB |
Here is the info regarding the intake manifold assembly...
"Check engine light enlightenment
I have an '01 MDX with about 85K miles, when the check enginge light came on followed by the DTM-4 light after driving about 1-2 miles . I took it upon myself to try to diagnose the problem. I first started with a new air filter even though it only had a few thousand miles on it. Secondly, I took off the intake manifold cover and found that the air channels on the cover and gasket were plugged with alot of carbon (probably from EGR ). I carefully cleaned the channels with carburator cleaner, and various sized screwdrivers, being especially careful on the gasket. The damn car now runs like a top, and my fuel mileage went from about 20 to 23.5. I don't know if this is relevant to your problem, but the inspection is simple and free if you do it yourself. Good luck."
I consider this quite interesting, as this is a high-mileage vehicle and maybe this needs to be a preventative maintenance step. |
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| Robyjo |
Thanks Worm-O! Though I prefer to think of you not as a fairy, but maybe..."The Point Godfather"?
Interesting point (ahem), Dale, and it certainly makes sense that this could possibly lead to random stalls (and certainly take a hit on mileage). OTOH, if this is truly a systemic issue, wouldn't we be seeing alot more of this as many of us get into the higher mileage range?
In any case, can't hurt to pop off the cover and take a look...
:D |
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| frostyra |
quote:
Originally posted by TheWorm
Could a bad EGR valve cause this problem, too? Plenty of faulty EGRs (usually causing vibe or rough idle, tho) and IIRC none of them ever threw a code to the check engine lamp.
I got the check engine lamp AND the VTM-4 lamp when my EGR valve failed [~26K or so miles] after about three weeks of slightly-rough running -- just enough to be noticeable. Dealer said that lamp combo was the clue that it was either the EGR valve or the idle air control -- and the computer threw out the EGR code. BTW, replacing the valve cured the rough running, but not the tendency to stall now and then during a stop within a half-mile of first starting out in the morning. |
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| RipRocK |
quote:
Originally posted by frostyra
I got the check engine lamp AND the VTM-4 lamp when my EGR valve failed [~26K or so miles] after about three weeks of slightly-rough running -- just enough to be noticeable. Dealer said that lamp combo was the clue that it was either the EGR valve or the idle air control -- and the computer threw out the EGR code. BTW, replacing the valve cured the rough running, but not the tendency to stall now and then during a stop within a half-mile of first starting out in the morning.
When you say "slightly-rough running -- just enough to be noticeable", was that during idle only or while you were driving as well? Particularly, when you had the gas pressed just slightly, with the RPM between about 1500-2000RPM and at the lower range speed of the 4th or the 5th gear?
My car seems to vibrate, not violently though, just slightly but enough to be noticed, once in a while when it's being driven under those conditions I have just described. I've heard other MDX and Pilot owers who've had their EGR valve problems with similar stories, but I can't seem to duplicate the vibration all the time, which is a problem since all of the dealers in town (all three) have a policy of not taking a car into the shop to diagnose a problem unless they can duplicate the symptoms themselves.
At first I thought it was one of the tires causing this vibration or shaking, so I took my car to a Goodyear shop and had all of them inspected, but there was nothing wrong at all with them. And this has happened while I was on freshly repaired roads, so, I don't think it's the pavement either.
Thanks. |
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| frostyra |
quote:
Originally posted by RipRocK
When you say "slightly-rough running -- just enough to be noticeable", was that during idle only or while you were driving as well? Particularly, when you had the gas pressed just slightly, with the RPM between about 1500-2000RPM and at the lower range speed of the 4th or the 5th gear?
Definitely while driving, and just as you described. I could feel it between about 40 and 65 mph in D5 -- it sometimes felt like an engine miss, and sometimes felt like the transmission was popping in and out of "lockup" (but it never showed up on the tachometer). It did that for 3, maybe 4, weeks before the Check Engine light came on, followed 30-60 seconds later by the VTM-4 light. Each time you'd start the car after that, the Check Engine light would come on and stay on, and then, less than a minute later, the VTM-4 light. After a new EGR valve and resetting the computer, no more problems. |
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| RipRocK |
frostyra, thanks very much for your reply. Sounds like I have a faulty EGR valve as well, but seeing as how all three of the dealers in town have a strict "can't duplicate it, won't touch it" policy, I'll just have to wait and hope like crazy that the VTM-4 and the CE light comes on before my warranty expires. Arrrrrgh!!
Oh, the cruel irony. I'm hoping for something to be wrong with my car so the warning lights would come on. With the waterpump and the timing belt recall, I would cross my fingers hoping that my car would be in the VIN range. But no such luck. Anyway, thanks again. |
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| RipRocK |
quote:
Originally posted by TheWorm
Could a bad EGR valve cause this problem, too? Plenty of faulty EGRs (usually causing vibe or rough idle, tho) and IIRC none of them ever threw a code to the check engine lamp.
- The Point Fairy :)
Yeah, that's true. I've read many posts in which the owners say they never had a CE or a VTM-4 light come on but took it to the dealer and was diagnosed as being faulty EGR valves.
What's perplexing is, when I asked to have my EGR valves checked, all of the service advisors I spoke with told me that you can't determine if there's something wrong with an EGR valve until the ECU gives you a code saying so. One of them told me that you can't tell visually nor are there any diagnostic tools you can use to determine if the EGR valves are faulty. He told me that if there's something wrong with them, the lights surely will come on.
But then how did all the MDX and Pilot owners get their EGR valves replaced even though none of them ever threw a code nor had the lights come on? I'm more inclined to believe that the dealers I visited and called just aren't willing to open up my hood for whatever reason unless they're almost guaranteed a warranty work. Double Arrrrrrgh!!! |
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| TheyCallMeBruce |
quote:
Originally posted by DaleB
Here is the info regarding the intake manifold assembly...
"Check engine light enlightenment
I have an '01 MDX with about 85K miles, when the check enginge light came on followed by the DTM-4 light after driving about 1-2 miles . I took it upon myself to try to diagnose the problem. I first started with a new air filter even though it only had a few thousand miles on it. Secondly, I took off the intake manifold cover and found that the air channels on the cover and gasket were plugged with alot of carbon (probably from EGR ). I carefully cleaned the channels with carburator cleaner, and various sized screwdrivers, being especially careful on the gasket. The damn car now runs like a top, and my fuel mileage went from about 20 to 23.5. I don't know if this is relevant to your problem, but the inspection is simple and free if you do it yourself. Good luck."
I consider this quite interesting, as this is a high-mileage vehicle and maybe this needs to be a preventative maintenance step.
No check engine light, and the EGR gas passages have a thin film of oiled-up carbon, as expected, but its not like it should significantly block the gasses from circulating. I can't imagine there's more than a 5% blockage, but I'm thinking its worth the effort to pull the entire intake manifold and hot-tank it at a machine shop. The gaskets are sheet metal, so I can probably just scrub them down w/ carb cleaner and a pad.
Now the for stupid question. I can't locate the EGR. There's no location diagram in the manual, only a functional diagram, and while I know what an EGR looks like, what I see behind the forward cylinder head which kinda looks like an EGR does'nt have any pipes or hoses attached to it. Maybe the passages to the intake manifold are internal, but it sure stumps me. Maybe I'll check with the dealer parts computer diagram when I stop by in a few days.
DaleB, thanks for the info on the gas passages, though I don't know if that would be my particular problem. I turned up the idle needle half a turn (no measurable increase in RPM) and went ahead and reset the PCM, hoping that it will re-learn the engine and driving parameters, and adjust for differences in the engine system after 51K of driving. Need to find the time to dissassemble the intake and see if hot-chemical cleaning will take car of it as indicated by bblume.
I appreciate everyone's input, and I would think that if the cause is from a systemic buildup of carbon, or iminent failure of EGRs, a high number of MDX owners in the next 2 or 3 years will become very interested in the information we are able to put together now.
Here's what I found today: |
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| TheyCallMeBruce |
| Close of the EGR gas passages in the intake cover: |
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