Carter BBD Idle curb idle adjustment problem and other issues.

[Techlight]

Hey all

I searched the forums but couldn't come up with anything answering my question.

I live in California so no skipping emissions or OE vacuum etc. General info on jeep: 1984 jeep CJ7 crate motor just installed since PO blew it up after driving it when it was overheating. Actually drove it until it was so hot it was stalling. Anyway...Jeep sat for 5 years brought it home got it started verified blown motor (he wasn't sure).

New motor runs fine actually perfectly (minus the curb idle), when it's cold it idles fine until it steps down to curb idle then it promptly dies. Steps I followed below:

Set the timing according to
Sol-Vac

Set timing fine (9* at 1600) vacuum switch unplugged and distributor advance vacuum plugged.

Reconnected everything double checked timing. Set fast idle on second step (1700rpm but I might have been a tad under) with EGR vacuum plugged.

Reconnected EGR vacuum. Went on to the curb idle. Plugged sol vac vacuum and disconnected wire from harness. Blipped the throttle (not running) to disengage fast idle stepper (this wasn't in the instructions but I could see no way that the curb idle screw would reach the pivot to adjust because well it's the fast idle screw with the stepper, right?).

Either way: curb idle screw will get me to about 350-400 rpm before bottoming out on the pivot and of course will not turn anymore.

Had to stop here before next step. Did I do this correctly? Should I be concerned with the main idle mixture screws at the bottom of carb? The PO was a nice guy, but I really have no idea what he did to this thing...from the looks of the plugs before new motor it was running very rich but the thing was leaking everywhere so who knows really. From reading it seems that I should turn the idle mixture screws all the way in and then out 2-2 1/4 turns, but I would be unclear on how to go about adjusting carb after that. I'm also a littler weary because my Chilton yells at me about those screws (seriously in all CAPS tells me not to touch them. They get their torque values incorrect all the time so I'm unsure if I should listen to them, especially since they're yelling at me ).

I'm sure it could use a rebuild (just because everything else did), but was hoping to get it running somewhat for a few before I tear into that or take it to a mechanic for a few other emissions tests.

Sorry, long post. Am I doing something wrong with the curb idle? When I read the sticker on my emissions tag it says to set the curb idle first (after timing, but before fast idle) but from the looks of it, that curb idle screw is going to do nothing for me regardless of when I set it.

I tried snapping some photo's but they didn't come out so well in the dark. basically shows fast idle screw set and not sitting on stepper and curb idle screw bottomed out (which gains me a rough idle of about 400 rpm).

Thanks in advance for any help.

 

[Techlight]

Oh, I meant to add when I put the motor in I checked and rechecked each vacuum hose and replaced as needed. I'm fairly certain they are all correct and not leaking. Did not check the operation of anything else emission wise though.

 

[Techlight]

I went back out to look at the carb for a few minutes because I just knew I was missing something and curb idle screw was in contact with the post and it could be adjusted. It was not making contact when I was out there before...go figure.

I'll start over and figure it out tomorrow. I guess that's what I get for working on it too late into the evening. I'll either post here or start a new thread if I have a different issue and can't find an answer.

 

[Torxhead]

This guy has a pretty detailed layout of the very complex late model CJs emission system:Jeep Adventures Under the Hood

 

[Fastatv]

Hey all

I searched the forums but couldn't come up with anything answering my question.

I live in California so no skipping emissions or OE vacuum etc. General info on jeep: 1984 jeep CJ7 crate motor just installed since PO blew it up after driving it when it was overheating. Actually drove it until it was so hot it was stalling. Anyway...Jeep sat for 5 years brought it home got it started verified blown motor (he wasn't sure).

New motor runs fine actually perfectly (minus the curb idle), when it's cold it idles fine until it steps down to curb idle then it promptly dies. Steps I followed below:

Set the timing according to
Sol-Vac

Set timing fine (9* at 1600) vacuum switch unplugged and distributor advance vacuum plugged.

Reconnected everything double checked timing. Set fast idle on second step (1700rpm but I might have been a tad under) with EGR vacuum plugged.

Reconnected EGR vacuum. Went on to the curb idle. Plugged sol vac vacuum and disconnected wire from harness. Blipped the throttle (not running) to disengage fast idle stepper (this wasn't in the instructions but I could see no way that the curb idle screw would reach the pivot to adjust because well it's the fast idle screw with the stepper, right?).

Either way: curb idle screw will get me to about 350-400 rpm before bottoming out on the pivot and of course will not turn anymore.

Had to stop here before next step. Did I do this correctly? Should I be concerned with the main idle mixture screws at the bottom of carb? The PO was a nice guy, but I really have no idea what he did to this thing...from the looks of the plugs before new motor it was running very rich but the thing was leaking everywhere so who knows really. From reading it seems that I should turn the idle mixture screws all the way in and then out 2-2 1/4 turns, but I would be unclear on how to go about adjusting carb after that. I'm also a littler weary because my Chilton yells at me about those screws (seriously in all CAPS tells me not to touch them. They get their torque values incorrect all the time so I'm unsure if I should listen to them, especially since they're yelling at me ).

I'm sure it could use a rebuild (just because everything else did), but was hoping to get it running somewhat for a few before I tear into that or take it to a mechanic for a few other emissions tests.

Sorry, long post. Am I doing something wrong with the curb idle? When I read the sticker on my emissions tag it says to set the curb idle first (after timing, but before fast idle) but from the looks of it, that curb idle screw is going to do nothing for me regardless of when I set it.

I tried snapping some photo's but they didn't come out so well in the dark. basically shows fast idle screw set and not sitting on stepper and curb idle screw bottomed out (which gains me a rough idle of about 400 rpm).

Thanks in advance for any help.

By reading your posts, looks to me like you are doing things correctly.
- Have a good read on what Torxhead has provided.
- A possibility would be a sticking/malfunctioning EGR valve. Some can be
removed and cleaned to a degree. Worth a shot.
- Verify again that you have no vacuum leaks. Since it wont idle, you could
try while choke is on fast idle. Spray WD, or carb or brake cleaner, listen for
change in idle.
- Check your PCV system, is it all connected and tight
- You could advance your distributor a bit..to see if it will curb idle
- You could bring the A/F screws out to 3.5 to 4.0 turns out from seat
- You may simply have a dirty carb...the idle passages.
Good luck and keep us up to date. Most of us like to learn the "fixes" others experience. Rick

 

[mtnwhlr]

From reading it seems that I should turn the idle mixture screws all the way in and then out 2-2 1/4 turns, but I would be unclear on how to go about adjusting carb after that. I'm also a littler weary because my Chilton yells at me about those screws (seriously in all CAPS tells me not to touch them. They get their torque values incorrect all the time so I'm unsure if I should listen to them, especially since they're yelling at me ).

This is where I would start, you could even start with them out to 3 turns just to make sure it won't idle because it's to lean. Then set your idle at 750 RPM and turn each back in untill it starts to stumble and then back it back out untill it smooths back out.

 

[Hedgehog]

Seems like a lot of work where a 1/2 turn or so on the idle speed screw is probably all you need.

 

[Techlight]

Hey all ...thanks for the replies. I actually got those timing instructions I was following from the link up above. They're different from my smog sticker and my service manuals but I figured he's been right about everything else I'd start there. Been reading that site like a bible for 3 weeks lol, there's a lot of vacuum hoses on that thing. I live in CA if that's any indication why I'm working hard to keep it all.

I went out in the morning to look things over. Jeep will start right up and fast idle with no problems. It's after it warms up that it won't idle. I'm sure it was just late and I wasn't paying attention properly. I noticed the carb was leaking gas in a few spots as well which needs to be fixed, so I didn't try to tune it after that. The more I thought about it I've done so much work on this jeep that I just decided to grab a rebuild kit and fix it correctly before I start digging much deeper. Can't have gasoline leaking all over my pretty new motor

The new motor with the RV cam feels pretty good and I'm half way through replacing all the bushings. Put a 1" body lift on it today...This weekend is suspension/sway bushings and carb. I should have just done a frame off since I have a local guy that has a jeep yard with good prices. But I'm itching too badly to be back in a jeep and my 6 year old wouldn't be happy if it was garaged for a year or two. He's as bad as I am.

The PO treated the Jeep like garbage and it was at 180k when I picked it up and it was covered in about 1/2 an inch of oil across the entire undercarriage. It was a mess but hey, it kept the frame protected from rust, lol. And it sat for five years so I'm sure the carb could use a rebuild. Won't hurt....everything else is new or low mileage replacement haha.

I'll post back up in a few.

 

[Lumpy Grits]

Where are the idle mix screws set at, and are they BOTH set the same?
Check this out..
Idle Problems

Been play'n the smog game here for 29 years-Its a major PITA!

You REALLY must get a copy of the REAL, factory FSM, MR252.
Haynes and the like, don't cut it at all.
LG

 

[Techlight]

Funny cause I do have that manual...it basically says the same thing as my smog sticker and the sight that you linked to.

I have checked that site out on the clogged tubes. Both screws weren't set the same...the one on the stepper (the fast idle one) was out farther than the curb idle.

I didn't mess with it after the morning since it was leaking fuel. No way it's gonna get set up right while it's leaking gas, since I assume that means vacuum leak too.

I ended up with a rebuilt carb. I know a guy in Rosamond who strips Jeeps for a hobby. I was out grabbing some seat belt parts and I off handedly asked him for some return springs and he asked me what I was working on. I said carb rebuild and he came back with a rebuilt carb with only 200 miles on it. Said he got it from a guy who put it on tuned it, and then decided he wanted a fuel injection kit instead. Works for me...AMC 150 bucks and it's got a new stepper motor too. Beats a 5 hour rebuild and two hours of tuning haha.

I shouldn't be allowed out there lol...I always come back with more than I went for. Nice thing about it is he's a Crown dealer too so he has new odds and ends like pedal covers clutch springs and various other seals etc. He's made this whole build really easy. Let me know if you need any parts local. He has everything for most any year quite literally.

 

[Hedgehog]

I've got a local guy like yours. A good one can literally be a light in the darkness when it comes to working on old Jeeps. Lots of people think all Jeeps are he same, well hey are NOT. Some parts look the same and probably can be made to work, but the same they are not.

 

[Lumpy Grits]

I'm talk'n about the idle mix screws at the base of the carb, in the front.
They MUST be set the same!!
LG

 

[Techlight]

I'm with you Hedge...it was nice to find him in my area. He always knows what part fits what and what Jeep I can get it off of if not off a CJ. He even had a brand new crown air intake induction hose which even my local auto parts store doesn't carry.

LG...ah, that makes more sense now. I didn't mess with those at all. But was getting ready to before I noticed the gas leaks. I'm gonna bolt the new one on and make believe like I bought it tuned. I'm not sure why those main adjustments intimidate me, but they do all the same. If I can get the new carb to idle and run properly I'd like to avoid those. I'll post here when the dust settles...

The carb was supposed to be bolted on yesterday and today was supposed to be suspension but it never quite works that way. It's always, I might as well retorque my intake/exhaust, oh that hose looks cracked better change that...Now I'm off to a kid birthday party with my son so it will have to wait till this afternoon...along with the power steering pump that needs to go in and a million other things

 

[Lumpy Grits]

Quartz Hill Auto Parts on 50th West is a good place to try.
So is the NAPA warehouse on 12th West buy the 14 Fwy.
Gas leaks sez to me you may have a 'sunk' float in the fuel bowel or a bad needle and seat.
Whoz this 'local guy' you speak of?
LG

 

[Techlight]

I've never been to the NAPA warehouse...will have to remember that one. I'm always told stuff is a day out. I like the guy on 50th...and he's right around the corner. I think his name is Tom or something...he just never has the part I need in stock. He's better on knowledge then the auto zone people though.

The local guy is Tommy out in Rosamond. I think he said he's parted out about 200 jeeps. Which kind of makes me sad haha...would rather see them on the road, but we all need parts too. Either way, he buys them and takes them apart and then puts the parts in 40ft bins. Has about 20 jeeps currently in different states of dismantled. Think small jeep parts yard and it's about accurate. He has just about everything and he's a good guy. Doesn't mind walking around ticking of the list. He keeps a want list for guys too...so if a part comes in you want he'll call you. Keeps an eye out for nicer parts, that sort of thing.

Let me know if you want his number...beware though, I always go out there and end up bringing home more than I went for

Speaking of which I got that carb bolted on today...little bit of tuning and the CJ is now running. A little rough around the edges but good enough for me to take to my mechanic so I pass smog with flying colors and can send that paper work in for the warranty on the new motor. I just need to change the suspension bushings and the power steering pump and she's good to go.

I'm hoping to have this done by the end of the week but we'll see...things never go as planned. I was suppose to get it all done this weekend. Spent more time parts hunting on the carb than I expected on saturday, but that's always the case.

 

[Lumpy Grits]

Who's your wrench?
Do all of my own. Always have.
Good luck on the smog deal. Real PITA!!
Please PM me the details on the 'bone-yard'. Lived here for 22+ years and never heard about it
Let me know if you want any help with the Carter. I know'em well.
LG

 

[Techlight]

Thanks for the offer on the help...I may yet take you up on that.

Yeah...I always think it's kind of funny. I'll do a full motor swap and just about anything else like suspension but I'm won't tune a carb...kind of silly really. It's all the smog stuff and if my papers show it running lean or rich I'll void my warranty on the new motor, so I'm kinda intimidated by it. A part of me wants someone else to look at it too so if I did anything out of sorts it can get caught before it's too late haha. I have never swapped a motor before. I know it's not all that complicated, but would still like someone to tune it. The other thing is if I get it wrong and try to smog it I could easily end up as a gross polluter...don't want that headache so I'd rather have the peace of mind really.

I don't really have a mechanic...usually do all my own stuff unless it's major engine work. Well, I have a Honda mechanic but that might not work out. I had plans to take it to Curt's Automotive on the corner of 50th and M...He owns a 90's cherokee and a late 80's wrangler...and he has old jeeps in there all the time from what I can see driving by. I hear they have a "jeep guy" so seemed like a good place to take it. He said he go through all my smog stuff and tune the carb for 100 bucks so that's not so bad.

I'll PM you that info...

 

[Colorado Yeti]

Have the exact same problem with my newly acquired 1986 CJ7 . Piss poor idle, dies all of the time, runs fine otherwise. Every single 1980's 6-cylinder CJ I jave owned have had this problem. (That's one reason I prefer the V-8 models from the 70's)

I have been told that one potential problem with idle quality is wear in the throttle bore shafts in the base plate. The aluminum that Carter used to make these carburetors was very poor quality and over several thousand of miles, the repeated rotation of the throttle shaft can wear out the shaft bores in the base plate. When that happens, the carb develops a small vacuum leak that is almost undetectable. When the electronic engine controls detect a lean mixture (due to the vacuum leak), it sends a signal to the carb to richen the idle mixture. This causes the engine to surge in RPM then it sucks more vacuum and the cycle perpetuates itself. The result is a unsteady idle that surges and dies in a cyclical manner.

You may want to check for play in your throttle shaft bores. If you have significant play, I belive that there are carb rebuild companies in SoCal that can redrill the throttle cores in the base plate and install bushings which eliminates the play and therefore the vacuum leak. Just something to consider. Good luck and let us know how you solve it.

 

[Techlight]

Just figured I'd post an update...not that "my fix" is going to help anyone. Although I guess bolting on a new carb does solve a lot of problems . Finally finished the suspension and took it to the mechanic. It sat on jack stands for a week waiting for parts on the front, and then another week waiting for a simple shackle. As mentioned I ended up throwing a very slightly used carb on it. Hopefully it has no issues.

It ran kinda ok when I took it in today but I had to start it like 15 times and keep it revved up or it would stall out haha...I could tell the timing was off and was thinking I was going to get it a little closer, but then just decided to drive it down there since I was going to pay him to tune it anyway...Hopefully it will come out tomorrow ready to smog and I can get it tagged.

I did notice it was a little squirrely like the suspension needed some tweaking, or the slight body lift is messing with my steering...hopefully who ever test drives it pays attention ...they did say they had a "Jeep Guy" so they better let him drive it haha. It feels like the springs are just old, but hard to tell over only a few blocks. It's possible my shackles aren't tight enough...will have to mess with it when I get it back. I'll have to start saving my pennies now for the old man emu yj conversion and 2.5 lift.

 

[Lumpy Grits]

That sounds like the choke's fast idle cam isn't set 'rite'.
Make sure your tire psi is correct or the CJ will be a road snake......
LG