Automotive Forums .com - the leading automotive community online! Automotive Forums .com - the leading automotive community online!
Automotive Forums .com - the leading automotive community online! 
-
Latest | 0 Rplys
Go Back   Automotive Forums .com Car Chat > Honda > Accord/TSX/Accord Hybrid
Reply Show Printable Version Show Printable Version | Email this Page Email this Page | Subscription Subscribe to this Thread
 
Thread Tools
Old 10-10-2009, 05:51 PM   #1
Pawl
AF Regular
 
Join Date: Mar 2008
Location: cypress, California
Posts: 164
Thanks: 3
Thanked 1 Time in 1 Post
93 accord losing all vacuum to EGR valve during acceleration

1993 accord LX- Thought I had the problem solved by taking the 6 small port plugs out of the emissions system and cleaning up all the buildup plus opening the ports back up that were plugged. When I put a vacuum gauge on the black rubber hose going from the control box to the EGR valve there is an initial buildup of vacuum upon acceleration but within seconds it drops off to zero. I switched control boxes and used one my brother had from his 91 accord he parted out and still had the same result. Mpumas has been giving me a lot of help but no luck. My daughter is going to apply for assistance with the state and see what happens.Any other suggestions would be appreciated.
Pawl is offline   Reply With Quote
Old 10-12-2009, 12:14 AM   #2
mpumas
AF Enthusiast
 
Join Date: Sep 2004
Location: los altos, California
Posts: 1,249
Thanks: 0
Thanked 1 Time in 1 Post
Re: 93 accord losing all vacuum to EGR valve during acceleration

As explained earlier, the EGR valve only opens under certain conditions. It is not open at idle but starts to open about 1500 RPM, I think, and only when the car is in motion as determined by the VSS sensor and then closes at a certain higher RPM. The opening is controlled by the ECU. So unless you have the front wheels on a treadmill, you are not going to be able to simulate the open and closing of the EGR. What you experienced is probably normal under your conditions and indicates that the ECU is commanding the solenoid to open as evidenced by vacuum at the EGR. I think you need to pull a vacuum on the EGR with the engine at idle and see if the engine stalls. It should if the ports are clear.
mpumas is offline   Reply With Quote
Old 05-10-2012, 08:53 AM   #3
wiseguy01
AF Enthusiast
 
wiseguy01's Avatar
 
Join Date: Dec 2004
Location: beaumont, California
Posts: 588
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

Hey i don't mean to revive a dead thread but I have a 93 accord and didn't want so start new thread so
Here it goes I have a 93 accord rough idle and low gas mileage so I drilled and replaced egr
Runners in the intake and cleaned out and checked egr vacuum solenoid for voltage and applied
Voltage for it to open the reason is because I have a code 12 which is egr system so my problem is
When I drive the car feels like its gonna stall really bogs down so I have determined that the egr vacuum solenoid applies vacuum to the egr to activate it and I already did the egr test I push up on diaphram and car stalls instantly so my problem now is still code 12 and when the egr vacuum solenoid puts
Vacuum on the egr it does not release so the diaphram stays up and stalls car so when it does this I pull the vacuum line off the egr and the engine recovers right away so my question is the egr solenoid still faulty because its not releasing the vacuum causing the car to stall I'm confused also when I did the egr port cleaning not only was all four ports plugged but the car ran ten times better when I was done with it but the egr is the main issue right now because my car doesn't overheat but everytime I turn the car off it turns the cooling fan on to cool the motor down I know its programmed to do that but since I had the car for ten years it has just begun turning on the fan after I park it so that leaves me to beloved that the motor is getting hot and egr malfunctioning is making it hot because egr system is designed to reduce heat make better gas mileage and reduce emmisions so if anyone with real good knowledge about this or has had this problem please help me out I love my cb7 and wouldn't trade it for anything but i hate that its nickel and dimeing me when I'm living on a real tight budget
wiseguy01 is offline   Reply With Quote
Old 05-10-2012, 05:48 PM   #4
somick
AF Enthusiast
 
somick's Avatar
 
Join Date: Dec 2005
Location: Oceanside, Alaska
Posts: 1,596
Thanks: 6
Thanked 26 Times in 26 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

One of the causes of EGR problems mentioned in my Haynes book is faulty ECU. That sounds right, since all of the sudden it started turning the fan on.

There is also a long testing procedure for EGR control box in chapter 6, section 6. Have you tried it? In one of the steps you need to apply 8 in-Hg of vacuum to the EGR and it suppose to stall the motor. Try it.

My Haynes is for 1994 - 1997. Yours might be different.

Good luck,
Sam
__________________
Quote:
Originally Posted by RIP
Please post back when you fix it so we all will learn something

somick is offline   Reply With Quote
Old 05-10-2012, 07:08 PM   #5
wiseguy01
AF Enthusiast
 
wiseguy01's Avatar
 
Join Date: Dec 2004
Location: beaumont, California
Posts: 588
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

Initialy when I applied the vacuum it did not stall but now after I clean the egr runner ports it stalls with 5-8 lbs of vacuum but I think I have either a faulty egr solenoid because one side of egr solenoid has vacuum and the side that is switched doesn't have any vacuum even when holding idle stable but when I pulled solenoid and manually switched it by applying voltage it opens and allows air through so that's what I'm stuck with right now but it does stall and the egr valve was taken off and cleaned a lot so its not sticking
wiseguy01 is offline   Reply With Quote
Old 05-10-2012, 09:08 PM   #6
jeffcoslacker
Lactose the Intolerant
 
jeffcoslacker's Avatar
 
Join Date: Aug 2004
Location: Nowhere, Missouri
Posts: 6,410
Thanks: 4
Thanked 52 Times in 51 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

Congratulations for creating the longest sentence in the history of written words.

I'd really love to help, but have a headache trying to figure out where your ideas stop and start.

I'm not normally a grammar nazi, but dude, that's impossible to read.
__________________
You made three mistakes. First, you took the job. Second, you came light. A four man crew for me? F**king insulting. But the worst mistake you made...

...empty gun rack.
jeffcoslacker is offline   Reply With Quote
Old 05-10-2012, 10:20 PM   #7
wiseguy01
AF Enthusiast
 
wiseguy01's Avatar
 
Join Date: Dec 2004
Location: beaumont, California
Posts: 588
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

Ok yea grammer is bad but put plain the egr vacuum solenoid applies vacuum to egr but does
Not release so the car runs like its mis firing . When the car runs like this I open hood and disconnect egr hose and idle comes right back to normal . Things I have tried pulled up on egr diaphram stalls car checked for voltage on both the egr lift sensor and the egr vacuum solenoid. I have cleaned the egr ports had to drill and plug with plugs purchased from Honda . Check engine light comes up code 12
Car is a 93 accord lx automatic. Also used vacuum pump applied vacuum before I cleaned egr ports the car would not stall but now after I cleaned ports the egr stalls the car as soon as I apply 5 on the vacuum pump. Hope this helps and thanks for your help
wiseguy01 is offline   Reply With Quote
Old 05-11-2012, 12:21 AM   #8
jeffcoslacker
Lactose the Intolerant
 
jeffcoslacker's Avatar
 
Join Date: Aug 2004
Location: Nowhere, Missouri
Posts: 6,410
Thanks: 4
Thanked 52 Times in 51 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

OK thank you, not trying to bust yer balls but without some periods I have trouble following the ideas.

So would you say that it's definitely that vacuum is being applied to the valve inappropriately, not that the valve itself is getting stuck in its bore and hanging up, right?

Now i haven't had to work on many EGR problems on Hondas, and haven't worked on one that old in a long time, so I have no clear picture in my head of how it works, exactly....but I'm wondering rather than disconnecting the vac hose to get it to return to normal idle, have you tried giving the solenoid a smack to make sure it's not hanging up and causing the problem...if that's even possible in this arrangement, like I said I can't picture it.

But it sounds possible. Solenoids like to do that when they get old and dirty inside. Sometimes it takes them a while to snap closed once the voltage is off....giving them a sharp smack with something like a wrench or a screwdriver blade will usually make them drop closed if hung....
__________________
You made three mistakes. First, you took the job. Second, you came light. A four man crew for me? F**king insulting. But the worst mistake you made...

...empty gun rack.
jeffcoslacker is offline   Reply With Quote
Old 05-11-2012, 05:47 PM   #9
wiseguy01
AF Enthusiast
 
wiseguy01's Avatar
 
Join Date: Dec 2004
Location: beaumont, California
Posts: 588
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

Well that's what I'm assuming because as soon as I pull the vacuum hose off of the egr valve the idle will even out. So that should mean that the egr valve isn't getting Hung up right not only that when i manually push diaphragm and let go it snaps back closed real quick . And as far as hitting the solenoid I'm not to quick to go hitting a solenoid that costs 230 dollars to replace if I hit it too hard plus its located inside the black Honda control box on the firewall and has alot more sensors in it. It's snowy like the egr solenoid engages but the check valve that releases the vacuum after the car no longer needs the egr to be open is not releasing because as soon as I pull vacuum hose off the idle returns to normal and the egr valve closes quick like 1 second quick. Is there a check valve that releases the vacuum that is applied to the egr if so where and how to test it
wiseguy01 is offline   Reply With Quote
Old 05-12-2012, 05:45 PM   #10
wiseguy01
AF Enthusiast
 
wiseguy01's Avatar
 
Join Date: Dec 2004
Location: beaumont, California
Posts: 588
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

Ok the problem was the hose 16 which comes from egr valve was hooked up to
The switched side of egr vacuum solenoid. Switched hoses and now egr opens and closes
But the c e l still comes code 12 so I need to rent vacuum pump to check the amount of vacuum being applied maybe its not enough has more balls now should i expect mpg to go up since it will lower my emissions Idk I'm still not happy with it c e l coming on
wiseguy01 is offline   Reply With Quote
Old 05-13-2012, 05:32 PM   #11
wiseguy01
AF Enthusiast
 
wiseguy01's Avatar
 
Join Date: Dec 2004
Location: beaumont, California
Posts: 588
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

New problem the c e l is still on for code 12 I reset it and it still comes back on and overall the
Car runs better when the egr is disconnected idles smoother and everything what can be causing this?
Could it be that the code 12 says the egr lift isnt high enough because I have verified there is vacuum at egr now ?
wiseguy01 is offline   Reply With Quote
Old 05-13-2012, 07:13 PM   #12
jeffcoslacker
Lactose the Intolerant
 
jeffcoslacker's Avatar
 
Join Date: Aug 2004
Location: Nowhere, Missouri
Posts: 6,410
Thanks: 4
Thanked 52 Times in 51 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

There should be no EGR opening at idle. Any EGR lift is going to act like a vacuum leak at idle, which makes it rough, and the computer has to tell the injection to add more fuel to compensate, which eats into your fuel mileage if you do a lot of idling at lights, etc.

If it idles well with it disconnected, at least you know the valve itself is not failing to seat properly. If that were the issue it would be the same whether connected or not. So it's still in the plumbing I suspect. Make sure any vac lines involved are in good shape, not cracked or swelled or loose all the way to their source.

EGR is only there to deal with NOx emissions under throttle application. When you step down hard on the gas, the initial change in combustion temps is good for causing NOx to form. The EGR recirculates some spent (oxygen depleted in theory) exhaust gases into the combustion chamber, which actually cools the combustion (extra air would make it lean and increase temps, but the inert exhaust gases cool and slow combustion)...so it also tends to reduce tendency to detonate and cause pinging during hard acceleration too, but this is a secondary effect.

Directly or indirectly, the EGR system "knows" when to open by manifold vacuum level. At idle, the throttle plate is closed and vacuum levels behind it inside the intake are very high. When you step down on the throttle, vacuum levels drop to near zero, as the plate is now open but the engine has not build up speed yet to pull any vacuum through the now open throttle plate. This is the condition when NOx likes to form in the combustion chambers, as described above.....

So generally, EGR opening is keyed to manifold vacuum levels....when you smash down on the gas hard, the drop in vac level is used to make the EGR open wide....as vacuum level recovers, as the engine comes up to speed, the EGR starts to close and will remain nearly closed under cruise conditions, matching the vacuum level at cruise, which is not as high as at idle, or as low as under hard throttle, but someplace in between.

So anything that interferes with the system sensing the intake vacuum level correctly could be a cause. Bad hose or line, misrouted, even a major vacuum leak someplace else but which shares a common vacuum source with the EGR system....it's all gotta be considered. But you should show a zero vacuum reading at the EGR diaphragm at idle.

I just thought maybe if you knew a bit more about what it actually does and how it works, it may make it easier to find your way to your problem...good luck with it. Let me know if I can help more...
__________________
You made three mistakes. First, you took the job. Second, you came light. A four man crew for me? F**king insulting. But the worst mistake you made...

...empty gun rack.
jeffcoslacker is offline   Reply With Quote
Old 05-13-2012, 07:23 PM   #13
jeffcoslacker
Lactose the Intolerant
 
jeffcoslacker's Avatar
 
Join Date: Aug 2004
Location: Nowhere, Missouri
Posts: 6,410
Thanks: 4
Thanked 52 Times in 51 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

PS...a good vacuum gauge costs about $25 and is one of the best diagnostic tools you can have....most people just don't understand what it tells you and aren't familiar with its use.

I've found it to be indispensable. Aside from helping you to figure out issues like this, you can tell with a quick reading if an engine is healthy, or has bad rings/valves, or if valve timing has slipped, exhaust plugged up, etc.

The gauge comes with a handy guide that explains the readings. Read it and know it, it's not difficult to understand if you think of it in terms of what the motor is actually doing internally.

Make sure you get one that is a dedicated vacuum gauge. Sometimes they'll try to sell you a low pressure gauge that reads pressure to 15 psi or so (for use with carburetor fuel pumps, etc) and has a very small portion of the gauge reading for vacuum. That type is useless. You want one that has the whole sweep devoted to vac level, and perhaps a small portion for pressure.
__________________
You made three mistakes. First, you took the job. Second, you came light. A four man crew for me? F**king insulting. But the worst mistake you made...

...empty gun rack.
jeffcoslacker is offline   Reply With Quote
Old 05-13-2012, 08:52 PM   #14
wiseguy01
AF Enthusiast
 
wiseguy01's Avatar
 
Join Date: Dec 2004
Location: beaumont, California
Posts: 588
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

What would explain it running better with egr vacuum hose disconnected than with the hose connected?
I looked up a lift sensor test says it should be between 1.2-4.1 1.2 being closed and 4.1 being fully opened the egr that is all I know is my mileage used to be 350-375 miles full tank to e now im lucky if i hit 260. Also I need a better tecnique in locating vacuum leaks cause i really don't want to use carb cleaner too risky i have seen one guy set a car on fire using that stuff also melted all the hoses on vacuum not on my car though lol
wiseguy01 is offline   Reply With Quote
Old 05-13-2012, 09:57 PM   #15
jeffcoslacker
Lactose the Intolerant
 
jeffcoslacker's Avatar
 
Join Date: Aug 2004
Location: Nowhere, Missouri
Posts: 6,410
Thanks: 4
Thanked 52 Times in 51 Posts
Re: 93 accord losing all vacuum to EGR valve during acceleration

When you say running better you mean at idle or when driving?

You can also use water in a sprayer to find vacuum leaks....only thing is it won't cling as well as other things with a petro base. So if you have a leak on the underside of something water may not crawl all the way around and find it. You have to really soak it or spray directly at it.

Other things that work are WD-40, starting fluid, etc....starting fluid obviously is volatile, but low residue and needs pretty hot ignition temp to burn....and if it does you'll get a momentary flare and gone....doesn't leave residue to burn for any length of time like other things.

I can't see any way an EGR issue could cause the kind of fuel economy drop you are seeing...like somick said the PCM might be bad and causing other problems, the EGR issue could be a red herring but indicative of a larger problem.

I'm kind of at a loss to tell you where to proceed from here.
__________________
You made three mistakes. First, you took the job. Second, you came light. A four man crew for me? F**king insulting. But the worst mistake you made...

...empty gun rack.
jeffcoslacker is offline   Reply With Quote
 
Reply

POST REPLY TO THIS THREAD

Go Back   Automotive Forums .com Car Chat > Honda > Accord/TSX/Accord Hybrid

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 04:20 PM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts