She's running rough....Help me tune..... - JeepForum.com
 20Likes
Reply
 
LinkBack Thread Tools
post #1 of 47 Old 06-19-2020, 09:20 AM Thread Starter
ccoyle71
Registered User
1986 CJ7 
 
Join Date: Sep 2017
Location: Franklin, TN
Posts: 152
She's running rough....Help me tune.....

I feel like I have so much floating around in my head:


Vac leak?
I know my carb is undersized - I've almost pulled the trigger on a weber 38 from redline, but now I'm wondering if that's the 1st step?? It used to run much better than it does now....and I feel something has changed.

Mixture screws way out of wack? I did 'attempt' to make a few adjustments....

Timing off??
Ignition problems?? It's original I believe

Spark plugs are a year or two old, but obviously show some issues. Covered in soot.


With my timing light, I did check each wire and they all appear to be firing / flashing.
It's hard for me to really see the mark on the harmonic balancer to check the timining - I can see the degrees (4, 8, 12, 16).....but I can't really tell exactly where it's set.
The jeep will start - every time, and hasn't stranded me yet.....but it seems to be getting worse / and choppier. I find my self sometimes feathering the gas a stop lights
A few months ago....it started missing really badly one day when it was hot and had run for a while. I suspected maybe a coil, so picked one up - and didn't notice it again until last week - it did the same thing - sounded like it was running on 1 or two cyliners.
All that is to say, I'm ready to start tackling this. Even though it gets me around the neighbored and small town trips, it needs some attention. So where to start - you guys have helped me with other projects over the years.....so I trust your guidance.



I've attached pictures of the plugs - they all look about the same to me - which is terrible. And I attached a video that I hope works and helps. Is this the correct way to post a video?? Just copy the link?? It shows a low vacuum, and you can hear the rough idle. Things smooth out some when the rpms get up to 1500 or so. But that said, it seems to smoke more now - and definitely not tuned correctly. Thanks a ton!




Attached Images
         
ccoyle71 is offline  
Sponsored Links
Advertisement
 
post #2 of 47 Old 06-19-2020, 09:31 AM Thread Starter
ccoyle71
Registered User
1986 CJ7 
 
Join Date: Sep 2017
Location: Franklin, TN
Posts: 152
Sorry - for got to attach the pic of the last plug, but it looks the same.
ccoyle71 is offline  
post #3 of 47 Old 06-19-2020, 10:16 AM
JoonHoss
Registered User
 
JoonHoss's Avatar
2011 JK Wrangler 
 
Join Date: Mar 2005
Location: Washington State
Posts: 9,308
Definitely looks to be running a little rich, and/ or firing a little weak (or a combination of both, each making the other a bit worse)

Hoss

Good judgement comes from experience; experience comes from bad judgement
JoonHoss is online now  
 
post #4 of 47 Old 06-19-2020, 11:29 AM
Matt1981CJ7
Web Wheeler
 
Matt1981CJ7's Avatar
1981 CJ7 
 
Join Date: May 2011
Location: Elbert
Posts: 22,629
First, your idle RPM is way too low, which is likely contributing to the excessive carbon fouling on the plugs It should be 650-700 RPM at idle, not 450.

What carb do you have?

What vacuum source are you using for the vacuum advance?

Matt
pedal2themetai likes this.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Matt1981CJ7 is offline  
post #5 of 47 Old 06-19-2020, 02:24 PM Thread Starter
ccoyle71
Registered User
1986 CJ7 
 
Join Date: Sep 2017
Location: Franklin, TN
Posts: 152
Yes, idle rpm are too low I know. I had tried adjusting idle speed screw, but havenít had much luck. Carb is a 32/36 which I know is NOT ideal..... but itís gotten worse lately. Used to idle ok, but has always run a little rich. So Iím wondering if I have another / other new issues. Vac advance comes from manifold - not ported source. Doubt it would even idle with it disconnected. Would it be a Terri or idea to just advance the timing a degree or two?


Sent from my iPhone using Tapatalk
ccoyle71 is offline  
post #6 of 47 Old 06-19-2020, 02:36 PM
Matt1981CJ7
Web Wheeler
 
Matt1981CJ7's Avatar
1981 CJ7 
 
Join Date: May 2011
Location: Elbert
Posts: 22,629
You won't gain the RPM you need with just timing.

When you say you didn't have "much luck" adjusting the idle speed screw, does that mean it had no affect on idle speed? Or....?

Where are your idle mixture screws set at (how many turns out from lightly seated)?

Matt


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Matt1981CJ7 is offline  
post #7 of 47 Old 06-20-2020, 09:30 AM Thread Starter
ccoyle71
Registered User
1986 CJ7 
 
Join Date: Sep 2017
Location: Franklin, TN
Posts: 152
Checking will report


Sent from my iPhone using Tapatalk
ccoyle71 is offline  
post #8 of 47 Old 06-20-2020, 10:47 AM Thread Starter
ccoyle71
Registered User
1986 CJ7 
 
Join Date: Sep 2017
Location: Franklin, TN
Posts: 152
Idle speed screw is almost bottomed out. Mixture screw is between 1/2 and 3/4....but doesnít seem to change much when I rotate. Below is a pic of the diagram Iím working off of - and a video of the idle circuit pulling in fuel. Seems like a LOT to me....but this is my first rodeo with carb adjustment.




Sent from my iPhone using Tapatalk
ccoyle71 is offline  
post #9 of 47 Old 06-22-2020, 11:30 AM Thread Starter
ccoyle71
Registered User
1986 CJ7 
 
Join Date: Sep 2017
Location: Franklin, TN
Posts: 152
Not sure if anyone can see in the video - but does that seems like an excessive amount of fuel? You can also hear it. I have the idle mixture screw barely backed out from being lightly seated - probably no more than 1/2 turn....
ccoyle71 is offline  
post #10 of 47 Old 06-22-2020, 12:18 PM
JoonHoss
Registered User
 
JoonHoss's Avatar
2011 JK Wrangler 
 
Join Date: Mar 2005
Location: Washington State
Posts: 9,308
Do you run a fuel pressure regulator? If so, what is it set at?

Hoss

Good judgement comes from experience; experience comes from bad judgement
JoonHoss is online now  
post #11 of 47 Old 06-23-2020, 03:24 PM Thread Starter
ccoyle71
Registered User
1986 CJ7 
 
Join Date: Sep 2017
Location: Franklin, TN
Posts: 152
Quote:
Originally Posted by JoonHoss View Post
Do you run a fuel pressure regulator? If so, what is it set at?Hoss

I don't - never have had one since I bought the jeep several years ago. I've read that some people say it's not necessary, and others do. I'd be glad to take any advice if that's a place to start.
ccoyle71 is offline  
post #12 of 47 Old 06-23-2020, 03:33 PM
turbogus
Registered User
1978 CJ5 
 
Join Date: Jun 2005
Location: Albany~town, Oregon
Posts: 2,544
Garage
Once the plugs are fuel fouled you'll need to either clean them up with a mini sandblaster or replace the plugs, as the condition they're in, won't function properly.
I had the same situation on my bike years ago and until I figured it out I invested in a little sandblaster kit to keep my 'working' plugs clean until I found the culprit.
Shawn Watson likes this.

The parts shop that stocks part for Skylab II will not have parts for our year/model of Jeep
We cannot accurately judge the trajectory of a speeding critter (cat, dog, sasquatch)
Record heat waves and floods only occur when we visit that area
turbogus is offline  
post #13 of 47 Old 06-23-2020, 03:38 PM
JoonHoss
Registered User
 
JoonHoss's Avatar
2011 JK Wrangler 
 
Join Date: Mar 2005
Location: Washington State
Posts: 9,308
I found a FPR made a huge difference in my '83 cj7 when came to dealing with an overly rich tuning issue.

I don't know if it's the same in your case, but just offering that up as an option.

Hoss

Good judgement comes from experience; experience comes from bad judgement
JoonHoss is online now  
post #14 of 47 Old 06-23-2020, 04:28 PM
pedal2themetai
Registered User
1956 CJ5 
 
Join Date: Apr 2015
Location: Boise
Posts: 1,600
HI, ?? Maybe your mixing up the screws...

The idle speed screw (would be located where the linkage hooks to the carb ) It should increase the rpm when screwed in. not having much luck with that you say makes NO since..

The fuel mixture screw (the one with a spring warped around it) should be 1 to 1 1/2 Out from lightly seated.

First With the idle speed screw You have to get your rpm up to 650 your way to low and it well cause flooding and black plugs...

Then you adjust the mixture screw to best smoothest idle.. then readjust the idle speed screw so it at 650 rpm's.

The 32/36 is fine for the stock motor your already to rich and idling to slow. going to a 38 would open up a new can of worms..

good luck
tim
pedal2themetai is offline  
post #15 of 47 Old 06-23-2020, 05:22 PM Thread Starter
ccoyle71
Registered User
1986 CJ7 
 
Join Date: Sep 2017
Location: Franklin, TN
Posts: 152
This is the diagram Iím working off of Ė Iím assuming itís correct.


When I mention I am ďnot having any luckďÖ I mean that the idle speed screw is turned almost all the way in. Perhaps with a longer screw, I could raise the RPMsÖ But the screw thatís in there isnít long enough to do anything. - it doesnít move the linkage enough to raise the idle RPMs. I donít think this is my only problemÖ But maybe my throttle linkage has just worn out over time? Is it common to need to continue adjusting the throttle linkage to maintain a healthy idle?


Sent from my iPhone using Tapatalk
ccoyle71 is offline  
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.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may 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
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome