Nuttered 87 YJ bucking and losing power in gear - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > Nuttered 87 YJ bucking and losing power in gear

50" LED CREE Light Bar Pair With Wiring KitFLASH SALE! Open thread to reveil the Newest Sale @ ROCKRIFS: Jeep Fog Light LED Bulbs! Several Brightness Options!

Reply
Unread 04-16-2015, 08:23 PM   #1
ob1korobi
Junior Member
 
ob1korobi's Avatar
1987 YJ Wrangler 
 
Join Date: Aug 2013
Location: Sonoma, CA
Posts: 88
Nuttered 87 YJ bucking and losing power in gear

I know there are other subjects in here with similar problems but I'm coming up short with my particular Heep. My nuttered 87 6 cylinder 4.2 with MC2100 has suddenly started losing power once in gear after being warmed up. If I start her up and just go after a minute, no problem. problem . Once I get around the corner I start sputtering and losing power and when I give it gas in 1st and 2nd I get a lot of bucking as the fuel that is dumping seems to combust. When I pull over and put her in neutral I can rev away. It gets worse and worse and is undrivable. The only way I can get it back home is clutching and raving and basically dripping the clutch to get high rpms and get up to speed. The first few inches on the accelerator I can rev but once the load kicks in it just dies. The reason I am posting this similar problem is because I do not have a TPS and most remedies I am reading it to either tune the tps or replace it. Am I having cat converter issues? Fuel pump? Choke? Throttle body. I will add I have the electric choke hooked up but I also tested this without it hooked up. My pcv valve is also just venting into the engine bay. Not hooked up to the carb like Gronk suggests. I'm kind of at the point where I am pretty lost and not sure what to do. The day before I drove her over 100 miles and was getting around 200 Miles on my tank. Next day, this. Any help is appreciated.

ob1korobi is offline   Reply With Quote Quick reply to this message
Unread 04-17-2015, 04:13 AM   #2
Mike Romain
Registered User
1986 CJ7 
 
Join Date: Nov 2007
Location: Off the Grid in Chester Grant, Nova Scotia, Canada
Posts: 15,504
If it tested the same with the choke not hooked up, you have a choke issue. The choke needs power to open. Unhooked or no power and it stays closed. Have you checked the fuses? Back up light uses same fuse as choke.
__________________
Mike
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00, 'New' frame,wires and plumbing in '09. Carter BBD Carbed 4.0 HO in '10.
89 YJ Renegade. BBD Carbed 4.0 HO. Locked front and rear with 33x9.5 BFG AT's
Some Canadian Bush Jeep Runs and Build Photos: http://mikeromainjeeptrips.shutterfly.com (10 new albums added Sept 16/10)
Mike Romain is offline   Reply With Quote Quick reply to this message
Unread 04-17-2015, 04:01 PM   #3
dancytron
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: st. louis
Posts: 1,513
Not really on point, but your pvc isn't venting into the engine bay. It is just sitting there closed not venting at all. You will have different problems down the line unless you fix that.

Possibly on point, when did you last do a regular tune up (cap, rotor, plugs and wires)?
dancytron is online now   Reply With Quote Quick reply to this message
Unread 04-17-2015, 08:59 PM   #4
ob1korobi
Junior Member
 
ob1korobi's Avatar
1987 YJ Wrangler 
 
Join Date: Aug 2013
Location: Sonoma, CA
Posts: 88
I just replaced the cap and rotor, plugs wires. Had the timing and carb tuned at a shop. The electric choke was hooked up during that time. Before I just has the adjustment screw set to keep it at enough of an open position that it wasn't really doing anything it seemed. I'll plug it back it and check the fuses and reverse light.

What should the pcv valve be going to?
ob1korobi is offline   Reply With Quote Quick reply to this message
Unread 04-17-2015, 09:20 PM   #5
dancytron
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: st. louis
Posts: 1,513
Quote:
Originally Posted by ob1korobi View Post

What should the pcv valve be going to?
Manifold vacuum at the base of the carb.

http://home.sprynet.com/~dale02/vac-pcv.htm
dancytron is online now   Reply With Quote Quick reply to this message
Unread 04-18-2015, 07:20 PM   #6
ob1korobi
Junior Member
 
ob1korobi's Avatar
1987 YJ Wrangler 
 
Join Date: Aug 2013
Location: Sonoma, CA
Posts: 88
Quote:
Originally Posted by dancytron View Post
Manifold vacuum at the base of the carb.

http://home.sprynet.com/~dale02/vac-pcv.htm
Thanks Dancytron. It was not hooked up before and ran alright but it is for sure best to have it hooked up. I appreciate the help.
__________________
Don't Tread On Me
ob1korobi is offline   Reply With Quote Quick reply to this message
Unread 04-26-2015, 05:25 PM   #7
ob1korobi
Junior Member
 
ob1korobi's Avatar
1987 YJ Wrangler 
 
Join Date: Aug 2013
Location: Sonoma, CA
Posts: 88
Had free time this weekend. Checked electric choke wiring, and reverse lights. Everything working. Electric choke is moving. I connected the pcv valve too. Too her for a ride and still the same problems. I recently changed the ignition cap, rotors, wires and plugs and it was running really well. Maybe something is out of whack there? I also replaced fuel filter at this time and hoses are new. Maybe fuel pump? Pinched line. I'm seriously stumped. A mechanic is my next step. Hope not though.
__________________
Don't Tread On Me
ob1korobi is offline   Reply With Quote Quick reply to this message
Unread 04-26-2015, 05:40 PM   #8
paultek6
Registered User
1988 YJ Wrangler 
 
Join Date: Aug 2009
Location: Levittown, Pennsylvania
Posts: 16
I hope you followed completely thru with the nutter and also adjusted your timing to 8 degrees BTDC as the instructions tell you
paultek6 is offline   Reply With Quote Quick reply to this message
Unread 04-27-2015, 06:42 AM   #9
Mike Romain
Registered User
1986 CJ7 
 
Join Date: Nov 2007
Location: Off the Grid in Chester Grant, Nova Scotia, Canada
Posts: 15,504
Quote:
Originally Posted by ob1korobi View Post
Had free time this weekend. Checked electric choke wiring, and reverse lights. Everything working. Electric choke is moving. I connected the pcv valve too. Too her for a ride and still the same problems. I recently changed the ignition cap, rotors, wires and plugs and it was running really well. Maybe something is out of whack there? I also replaced fuel filter at this time and hoses are new. Maybe fuel pump? Pinched line. I'm seriously stumped. A mechanic is my next step. Hope not though.
It was running well before or after you changed the wires?
When it messes up, you should open the air filter to verify the choke is straight up open.
__________________
Mike
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00, 'New' frame,wires and plumbing in '09. Carter BBD Carbed 4.0 HO in '10.
89 YJ Renegade. BBD Carbed 4.0 HO. Locked front and rear with 33x9.5 BFG AT's
Some Canadian Bush Jeep Runs and Build Photos: http://mikeromainjeeptrips.shutterfly.com (10 new albums added Sept 16/10)
Mike Romain is offline   Reply With Quote Quick reply to this message
Unread 04-27-2015, 08:21 AM   #10
ob1korobi
Junior Member
 
ob1korobi's Avatar
1987 YJ Wrangler 
 
Join Date: Aug 2013
Location: Sonoma, CA
Posts: 88
Quote:
Originally Posted by Mike Romain View Post
It was running well before or after you changed the wires?
When it messes up, you should open the air filter to verify the choke is straight up open.
When it is warmed up the choke is straight up. Verified.

For sure I followed the nutter instructions thoroughly. The timing I had to have a mechanic do because I lacked the tools for it. It was adjusted to what made the vehicle run smoothest. It was running fine with that timing. I can't understand how that might come undone somehow or change while running.
__________________
Don't Tread On Me
ob1korobi is offline   Reply With Quote Quick reply to this message
Unread 04-27-2015, 09:07 AM   #11
paultek6
Registered User
1988 YJ Wrangler 
 
Join Date: Aug 2009
Location: Levittown, Pennsylvania
Posts: 16
You stated timing adjusted at shop .If they used the factory specs it will run like crap. If you did the nutter it should be at 8BTDC
Bad load of gas ?
Fuel filters?
Compression test ?
paultek6 is offline   Reply With Quote Quick reply to this message
Unread 04-27-2015, 09:15 AM   #12
Mike Romain
Registered User
1986 CJ7 
 
Join Date: Nov 2007
Location: Off the Grid in Chester Grant, Nova Scotia, Canada
Posts: 15,504
Quote:
Originally Posted by ob1korobi View Post

When it is warmed up the choke is straight up. Verified.

For sure I followed the nutter instructions thoroughly. The timing I had to have a mechanic do because I lacked the tools for it. It was adjusted to what made the vehicle run smoothest. It was running fine with that timing. I can't understand how that might come undone somehow or change while running.
Is your gas tank vent hooked up? If that messes up, it can starve it for fuel. Quick test is to drive with the gas cap loose or loosen the cap when trouble starts.
__________________
Mike
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00, 'New' frame,wires and plumbing in '09. Carter BBD Carbed 4.0 HO in '10.
89 YJ Renegade. BBD Carbed 4.0 HO. Locked front and rear with 33x9.5 BFG AT's
Some Canadian Bush Jeep Runs and Build Photos: http://mikeromainjeeptrips.shutterfly.com (10 new albums added Sept 16/10)
Mike Romain is offline   Reply With Quote Quick reply to this message
Unread 04-27-2015, 04:00 PM   #13
dancytron
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: st. louis
Posts: 1,513
Quote:
Originally Posted by paultek6 View Post
You stated timing adjusted at shop .If they used the factory specs it will run like crap. If you did the nutter it should be at 8BTDC
Bad load of gas ?
Fuel filters?
Compression test ?
This might be it. Did your mechanic set the timing at idle? For the Nutter, you set the timing at idle, vacuum advance unhooked and plugged, to 8 degrees. Like a 1980 CJ7. The instructions for stock are different and would give you the wrong setting.
dancytron is online now   Reply With Quote Quick reply to this message
Unread 04-28-2015, 10:39 AM   #14
ob1korobi
Junior Member
 
ob1korobi's Avatar
1987 YJ Wrangler 
 
Join Date: Aug 2013
Location: Sonoma, CA
Posts: 88
Quote:
Originally Posted by paultek6 View Post
You stated timing adjusted at shop .If they used the factory specs it will run like crap. If you did the nutter it should be at 8BTDC
Bad load of gas ?
Fuel filters?
Compression test ?
Good question. Would it all of the sudden start running like crap though after a month of driving it this way? Fuel filter is new, it did start after a new tank of gas though. I have a test kit. I'll definitely be hooking it up.

Quote:
Originally Posted by Mike Romain View Post
Is your gas tank vent hooked up? If that messes up, it can starve it for fuel. Quick test is to drive with the gas cap loose or loosen the cap when trouble starts.
This was one of the first things I tried because I figured it was after the fresh tank of gas. I don't know if I drove it around enough though. Maybe the lines are old and collapsing and not giving it adequate fuel?

Quote:
Originally Posted by dancytron View Post
This might be it. Did your mechanic set the timing at idle? For the Nutter, you set the timing at idle, vacuum advance unhooked and plugged, to 8 degrees. Like a 1980 CJ7. The instructions for stock are different and would give you the wrong setting.
Still not sure exactly on what they set it to but why after a month of driving it this way would it all of the sudden become picky about it?
__________________
Don't Tread On Me
ob1korobi is offline   Reply With Quote Quick reply to this message
Unread 04-28-2015, 12:13 PM   #15
Mike Romain
Registered User
1986 CJ7 
 
Join Date: Nov 2007
Location: Off the Grid in Chester Grant, Nova Scotia, Canada
Posts: 15,504
The stock gas lines are not ethanol proof, they rot and crack. It seems only FI lines are safe, the carb ones go bad.
You might have an air leak on the suction line between the pump and tank. It won't leak much, but air gets in.
__________________
Mike
86/00 CJ7 Laredo, 33x9.5 BFG AT's, 'glass nose to tail in '00, 'New' frame,wires and plumbing in '09. Carter BBD Carbed 4.0 HO in '10.
89 YJ Renegade. BBD Carbed 4.0 HO. Locked front and rear with 33x9.5 BFG AT's
Some Canadian Bush Jeep Runs and Build Photos: http://mikeromainjeeptrips.shutterfly.com (10 new albums added Sept 16/10)
Mike Romain is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.