TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC 6 Cylinder Engine Repair and Modifications
  New Posts New Posts RSS Feed - Carter BBD issues
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

Carter BBD issues

 Post Reply Post Reply Page  123 11>
Author
Message
Tarnish View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Sep/28/2016
Location: Missouri
Status: Offline
Points: 33
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tarnish Quote  Post ReplyReply Direct Link To This Post Topic: Carter BBD issues
    Posted: Sep/28/2016 at 10:30am
So my engine has been slowly dying for the longest time. When I got it, it had a knock on one of the cylinders, which the previous owner told me was a lean condition. Figured it was something I could fix later, but now I'm thinking I should have probably done so earlier.

Lately, the carburetor in the car has been... Sneezing(?) every time I punch the accelerator. It sounds like it's sneezing, because I can hear air being sucked into the barrels. Loudly. The car accelerates after a bit of hesitation, but it lacks power, and sometimes the car will just up and die when you try to slow it down.

What with the sucking and the power loss, I obviously assumed it was likely a vacuum issue.

I fingered this as a bad gasket somewhere in the carburetor, so I rebuilt it. The carburetor no longer seemed to be sneezing after mounting, and the accelerator gave immediate power to the engine. Eureka! It worked!

For about five seconds. Me and the missus went out to eat after the test drive, and something seems to have gone wrong in the thirty minutes it was in the parking lot, because now it's exhibiting the same problems as before. I don't think I did anything wrong in the rebuild (save for putting a few links on weird and correcting it later), but with the fact that it worked for a short while, I don't know whether or not to search different areas for a cause. Most likely the intake manifold would be next on the list to check.

Can anyone help? I don't think this matters, but it's an AMC inline-6-258 engine with stock... Basically everything. Even has the original shift linkage assembly from Chrysler.

I'd like as munch brainstorming as possible. Thanks for reading, and thanks for any help you can provide.
Back to Top
uncljohn View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/03/2013
Location: Peoria AZ
Status: Offline
Points: 5394
Post Options Post Options   Thanks (0) Thanks(0)   Quote uncljohn Quote  Post ReplyReply Direct Link To This Post Posted: Sep/28/2016 at 11:41am
Knowing the year and the model would certainly help along with whether you have servicing information for the vehicle or not
While the carburetor takes the most blame it is largely unjustified. Granted the carburetor for a simple application is quite complex and while rebuilding it one must be careful to make adjustments correctly when correct it is bot reliable and efficient.
The biggest single problem is the complexity of the smog configuration and the many many feet of vacuum lines which after all the years since manufactured, are usually both incorrectly configured and the rubber is some what shot causing leaks.
As the configuration changed both from year to year, but it also depended on whether the car was a 49 state car, California, or high altitude configured. This information is in part available on the white sticker on the passenger side of the engine compartment on the firewall.
Additionally it is important as to automatic and standard transmission and if an Eagle a few other variables. And then the Service manual will give connection configuration based on that information.
The ability to use a vacuum gauge while tuning the engine does help but knowing how to use a vacuum gauge helps too.
That said!
The odds are you have vacuum lines leaking and/or hooked up wrong.
I would start by looking to see if there is a vacuum leak in or around the carburetor mounting and the intake manifold.
This is done by spraying something like WD40 or a carburetor cleaner at potential areas with the engine running, a change in the way the engine runs indicates a leak and what ever was sprayed is getting sucked in and affecting the way the engine runs.
Thus the source of a vacuum leak is located.

70 390 5spd Donohue
74 Hornet In restoration
76 Hornet, 5.7L Mercury Marine Power
80 Fuel Injected I6 Spirit
74 232 I-6, 4bbl, 270HL Isky Cam
Back to Top
amcfool1 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jun/18/2011
Location: roanoke va
Status: Offline
Points: 1071
Post Options Post Options   Thanks (0) Thanks(0)   Quote amcfool1 Quote  Post ReplyReply Direct Link To This Post Posted: Sep/28/2016 at 11:42am
hi, what car/year do you have? feedback or non feedback BBD? gz
george z
Back to Top
Tarnish View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Sep/28/2016
Location: Missouri
Status: Offline
Points: 33
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tarnish Quote  Post ReplyReply Direct Link To This Post Posted: Sep/28/2016 at 1:40pm
Apologies, I forgot about the specific vacuum diagrams for specific vehicles.

This particular car is a 1983 AMC Concord, A904 trans (no vacuum), and all information forthwith consistent. The carburetor, as I understand it, is a non-feedback carburetor. At the very least, it has no wires or hookups leading from it, save for the vacuum lines and the... Actuator, I believe?

I've already plugged up all the lines from the carburetor save for the delivery lines (gas, air, etc) and it didn't help in the least. I had assumed this meant it was from the carburetor down, but I'm not sure. Despite this, I went around doing clamp tests to various accessories, and nothing changed the idle.

The vacuum system itself doesn't seem to have been correctly connected since the Concord left the showroom floor in '83. My guess would be because no one could find the "p/air chck vlvs" in the engine compartment. God knows I've looked around for them enough, and it's a mystery to me.

Despite this, the car functioned fine until it started steadily losing power within the past few months, when the Carburetor started "sneezing." So while the car is hooked up wrong according to the factory, it seems as though it should function fine with the current setup.

However, I have already mapped out the project, and if you think it would help, I can give a list of where everything is hooked up.

Thanks once again.
Back to Top
tomj View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/27/2010
Location: earth
Status: Offline
Points: 7522
Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Sep/28/2016 at 2:33pm
Factory Technical Service Manual. 

the Malaise Era cars, 75 through 80s, certainly have a lot of hoses and weird nonsense. its tempting to just pull it all off, and while you can set an engine back to "1972", it's a lot more complex than just yanking hoses.

i successfully got a 1975 California-smog V8 Gremlin to run just great, with all that crap in, and while it was a PITA, it ran great and had decent power. finding the right parts was half the hassle, and deciphering and debuggng the smog stuff even with the TSM was some effort. without the TSM, this will not be possible. 

usually a bunch of systems are out of whack all at once, which makes it hard to find because it's all "open loop" kludges. but if you methodically check each one, eg. correct EGR operation, probably needs a new one (NEW, not used, mine was $100, back in 2002 or so), then the various valves that switch vacuum on and off, it will run fine.

shotgunning the hoses probably isnt a bad idea. even when they stay flexible they often bell at the ends and don't seal well. sometimes chopping off the last inch is enough.

the "sneeze" could be spark timing for example. get a TSM if you dont have one, and start with something like EGR, or the process to set the idle mixture and speed, and one-thing-at-a-time...

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

Back to Top
uncljohn View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/03/2013
Location: Peoria AZ
Status: Offline
Points: 5394
Post Options Post Options   Thanks (0) Thanks(0)   Quote uncljohn Quote  Post ReplyReply Direct Link To This Post Posted: Sep/29/2016 at 11:24am
The 1983 Concord I-6 engine was equipped with a feedback carburetor. The indications that it no longer has one is the first clue to what ever the vacuum hoses are connected to, they were not that way when they came out of the factory.
Tom therefor covered the problem of correctness quite thoroughly. The original source or application of your carburetor is a non-issue as long as there is nothing wrong with it. It could be from something in the middle 70's or an Eagle application with California smog equipment where the eagle was classified as a truck, thus had "truck" not car, smog certification. They came standard with a non-feedback BBD.
Also as Tom indicated, yanking hoses is not the proper method to convert back to convert back to 1972.
I have had two 1980 AMC engines restored back to 1980 OEM smog configuration, one modified under the appearance of correct and the other full factory stock. Both ran well and passed smog. It can be done, but fast forward to today, so much of the installation is no longer available as individual parts any more.


The documents should (with some study) reflect what under the hood needs to look like depending in part on what you have left to hook up and need.
The top one reflects the use of ported and manifold vacuum to run things and on engines using the Carter YF carburetor manifold vacuum came from an adapter that sat between the carburetor and the manifold. Other applications either used a port on the carburetor or a tap into the intake manifold. Up to the owner to figure out what configuration suits your needs.


Edited by uncljohn - Sep/29/2016 at 11:27am
70 390 5spd Donohue
74 Hornet In restoration
76 Hornet, 5.7L Mercury Marine Power
80 Fuel Injected I6 Spirit
74 232 I-6, 4bbl, 270HL Isky Cam
Back to Top
Tarnish View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Sep/28/2016
Location: Missouri
Status: Offline
Points: 33
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tarnish Quote  Post ReplyReply Direct Link To This Post Posted: Sep/30/2016 at 12:33pm
Would these change if I had a six-tube vacuum switch on the side of the manifold? Not to mention this adapter that keeps showing up in the diagrams which my carburetor simply does not have.

Unless these diagrams are just being used as a learning tool? In which case, I'll probably just end up plugging up three of the six switch holes and hook it up with this setup with new tubes and see if that fixes it. With that little base, it should give me a good idea of where the problem lies even if it doesn't fix it.

Thank you.
Back to Top
uncljohn View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/03/2013
Location: Peoria AZ
Status: Offline
Points: 5394
Post Options Post Options   Thanks (0) Thanks(0)   Quote uncljohn Quote  Post ReplyReply Direct Link To This Post Posted: Sep/30/2016 at 4:01pm
The Adapter shows up on some applications simply because a manifold vacuum tap is not available on some carburetors, specifically the Carter YF but I am sure others. It is a source for manifold vacuum. The point is you need a source for manifold vacuum for the distributor vacuum can and maybe other things. If you do not have an adapter the solution is simple. You do not use it. You find a manifold vacuum tap some where else! Either on the carburetor you are using or a tap on the manifold itself. That is one of the reasons it is called a manifold vacuum. It is the value measured at the manifold no matter where it is found.
As to the 6 tube vacuum switch on the side of the manifold, more needs to be known about it as the verbal description of 6 tubes is lacking in explanation as to what it is.
I (and others) might be able to answer your question with further information starting with in your opinion is it OEM that is did it originally come with the engine and it's manifold. What year is the engine? Thus the manifold and is your car an automatic transmission or standard transmission, If you look on the white tag on the passenger side of the firewall does it say anything about how it is smogged such as is it, 49 state, California, High Altitude or Denver or even Canadian. And might you post a picture.
Just plugging and using things with out having a clue what it is or how it works rarely solves anything but generally adds to the problems.
70 390 5spd Donohue
74 Hornet In restoration
76 Hornet, 5.7L Mercury Marine Power
80 Fuel Injected I6 Spirit
74 232 I-6, 4bbl, 270HL Isky Cam
Back to Top
amcfool1 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jun/18/2011
Location: roanoke va
Status: Offline
Points: 1071
Post Options Post Options   Thanks (0) Thanks(0)   Quote amcfool1 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/01/2016 at 12:14am
hi, don't despair! take a deep breath and start at the beginning. a vac diagram should be on the cowl, if you don't have a TSM. I strongly suggest you get one, they are pretty cheap on ebay. the 82 will work, you don't really need an 83. If your Concord is stock, you have a feedback carb. It is controlled by the ECM (computer), which is located behind the pass. kick panel. BTW, still available as a reman. from Rockauto, etc. about $120. Also, btw, the "six" port switch is really a 5 port with one port unused. If you have a connector that fits this, you need one, if you don't, then you don't.You have to understand what it does, and when. Basically it sends vacuum to different places depending on the temp of the motor. The "adapter" you are speaking of is a vac. tap from the carb insulator, and you are correct, the BBD does not have a vac. tap there., but it  DOES have a phenolic insulator. Manifold vac. on the late 258 is accessed from a brass fitting directly below the carb on the intake, or at the rear of the intake. Again, we can't really diagnose this over the computer, but some pictures would really help. The late AMC engine controls can be a bear to decipher, but not impossible. There are six to eight sensors telling the computer what to tell the carb. and dist. Been there, done that! Best way to start, is to hook everything back up. NOT to pull stuff off in a Hail Mary. Also, the idle tubes in these carbs are known to clog up. Easy fix, pull idle tubes out, CAREFULLY, and drill tips out to .032". Will need a wire gauge drill bit for this, and do by HAND, or a dremel at lowest speed. If it's the original carb in there, could probably use a rebuild kit anyway. good luck, gz btw, that 5 port PVS is still available, BWD EC958
george z
Back to Top
amcfool1 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jun/18/2011
Location: roanoke va
Status: Offline
Points: 1071
Post Options Post Options   Thanks (0) Thanks(0)   Quote amcfool1 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/01/2016 at 12:29am
um, sorry, PVS= Ported Vacuum Switch, fyi :)
george z
Back to Top
 Post Reply Post Reply Page  123 11>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.125 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or