|
|
Carb vacuum trouble
#670435
11/26/05 06:18 AM
|
Joined: Oct 2003
Posts: 183
OP
Wheeler
|
On my 85 2.6, I can't seem to gett the secondaries working. Can is good. Is there a secondary circuit within the carb that I am overlooking, as I don't seem to get any vacuum at the port at the base of the carb on that side.
Please enlighten me!
http://zywie.com Zywie's Law: If anything can go right, it will go right, and at the best possible time.
|
|
Re: Carb vacuum trouble
[Re: mag00]
#670436
11/26/05 06:28 AM
|
Joined: May 2000
Posts: 3,281
Roll Me Over
|
Secondary is operated by the "depression chamber" (Mitsu speak), the sort of flying saucer looking device at the back of the carb on the passenger side. It is operated by a short piece of vacuum hose that exits the carb close by. Usually the membrane inside the "depression chamber" breaks, and the device won't hold a vacuum, and won't actuate the secondary. Test it with a peice of clean vac hose by mouth. If you can keep pulling air through the depression chamber, it's toast. If it hold a vac, check the line that goes to it for leaks. Check my website (link in sig below) for the "Vacuum hose diagrams" pages, where all these parts are shown. Good luck!
Don `87 Mitsu 2dr, Rubicon survivor, GModified.
|
|
Re: Carb vacuum trouble
[Re: don]
#670437
11/26/05 06:41 AM
|
Joined: Oct 2003
Posts: 183
OP
Wheeler
|
Vacuum diaphram is good, Don't seem to have any vacuum at the tap at the carb. Is there a secondary circuit electrical or mechanical which activates this?
http://zywie.com Zywie's Law: If anything can go right, it will go right, and at the best possible time.
|
|
Re: Carb vacuum trouble
[Re: mag00]
#670438
11/26/05 07:19 AM
|
Joined: May 2000
Posts: 3,281
Roll Me Over
|
As far as I know the vacuum's all mechanical controlled. Check for leaks in the hoses, or a missing hose. Carb internals are not something I can help with, though. That short vac hose to the depression chamber should run direct off the vaccuum in the lower carb / upper intake manifold, based on it's location. Can you blow air into the carb from this line?
edit: When you checked the depression chamber membrane, you should have seen the secondary valve inside the carb moving as you applied suction. Did it move?
Last edited by don; 11/26/05 07:22 AM.
Don `87 Mitsu 2dr, Rubicon survivor, GModified.
|
|
Re: Carb vacuum trouble
[Re: don]
#670439
11/26/05 07:53 AM
|
Joined: Oct 2003
Posts: 183
OP
Wheeler
|
Ahh good idea, I will try blowing in it tomorrow. I'm also going to dig up one of my other carbs and take a look at them.
This has had this trouble since I owned it (almost 10 years). It's more of an annoyance as I know it should run better under accelration. Otherwise it runs great.
When it is cold and choke is on it does a little better on acceleration.
http://zywie.com Zywie's Law: If anything can go right, it will go right, and at the best possible time.
|
|
Re: Carb vacuum trouble
[Re: mag00]
#670440
11/26/05 07:59 AM
|
Joined: Oct 2003
Posts: 183
OP
Wheeler
|
Oh, I did hook the vacuum line from the other side to the diaphram and then the butterfly oppened up, but it didn't idle back down as the vacuum was still applied at idle.
Might be clogged passage, but when I rebuilt it I checked all passages and it still has the prob. I was wondering if the base gasket may be wrong, Hmm.
Also now that I think of it, I'm not sure what year the intake manifold is from. Might be off of an older car engine. Again I must check the parts in storage.
http://zywie.com Zywie's Law: If anything can go right, it will go right, and at the best possible time.
|
|
Re: Carb vacuum trouble
[Re: mag00]
#670441
11/28/05 07:36 AM
|
Joined: Dec 2002
Posts: 120
Wheeler
|
I've had exactly the same problem for a couple of years now. I can blow air through the port into the carb but very little vacuum is created at the port. My new depression chamber works fine with a vacuum pump and the linkage isn't binding. I've had the carb off twice and cleaned all of the passages. None of the "brains" on this site can come up with a solution to this problem. If you figure it out PLEASE post it, I'm leaving on a trip soon and will be towing a popup and sure could use that other barrel.
'97 Jeep Cherokee XJ, Country, Black/Gray Leather, 4.0L, 4WD Command-Track, AW-4 Auto, 3.55:1 Gears, PowerTrax No-Slip Locker, Hi Country Tow Brackets, Spectre Air Filter, 235X75R15 Goodyear Wranglers, 126K miles
|
|
Re: Carb vacuum trouble
[Re: weebur]
#670442
12/06/05 04:59 PM
|
Joined: Aug 2004
Posts: 644
Rock Warrior
|
The secondary throttle diaphram recieves its vacuum internaly from a tube in the carburetor that supplies venturi vacuum as the primary throttle is opened past a certain point. You should check for vacuum after three quarters throttle opening. Conner
Over the hill but still climbing. 88 Montero 2.6L auto, manual hubs, cooling fan conversion gps,recurved distributor,LSD Diff.
|
|
Re: Carb vacuum trouble
[Re: conner]
#670443
12/08/05 01:31 AM
|
Joined: Dec 2002
Posts: 120
Wheeler
|
Thanks for the tip Conner. I've checked the vacuum at all stages, including WOT (wide open throttle). I get a couple of inches of vacuum at WOT but apparently not enough to open the depression chamber. It looks like I need just a little bit more vacuum but can't get it. I've even tried Teeing into other ported vacuum lines with no luck.
'97 Jeep Cherokee XJ, Country, Black/Gray Leather, 4.0L, 4WD Command-Track, AW-4 Auto, 3.55:1 Gears, PowerTrax No-Slip Locker, Hi Country Tow Brackets, Spectre Air Filter, 235X75R15 Goodyear Wranglers, 126K miles
|
|
Re: Carb vacuum trouble
[Re: weebur]
#670444
12/09/05 01:07 AM
|
Joined: Oct 2003
Posts: 183
OP
Wheeler
|
Sorry for the lapse in time, been moving again, aargh.
I looked at one of my carb and I'm curious as to what the smaller 3 hole part that screws onto that side of the carb. Sorry I don't know what it is called.
http://zywie.com Zywie's Law: If anything can go right, it will go right, and at the best possible time.
|
|
|
|