Go Back   Ford Mustang Forums > Mustang > Classic Mustang > Classic Tech

Welcome to our Mustang forums where Mustangers come together to hang out, discuss and enjoy their favorite Mustang hobby with fellow Mustang enthusiasts. We invite everyone to read, post, and enjoy our Mustang forum as well as the many other sections of our site.

You are currently viewing our forums as a guest. By joining our community you gain access to post topics, communicate with members, upload your photos and access many other special features. Registration is fast, simple and free so why wait, join our Mustang community today! If you have any problems with registration or your account login, please contact support.

Classic Mustangs Tech Forum

Technical discussions specific to 1964-1967, 1968-1970, and 1971-1973 Classic Mustang. Discuss all tech related to in-line six cylinder and V8 powered Vintage Mustangs here.

Classic Forums | Classic Talk | Classic Tech | Classic Pictures | Introductions | Mustang Tech | Mustang Lounge 


Reply   Post New Thread
Unread 08-04-2009   #1 (permalink)
jb36jb is offline Apprentice

Classic Member


Joined: Nov 2006
Posts: 87 Threads: 34
 jb36jb's Country Flag
San Diego   California
jb36jb is on a distinguished road
Default 1968 Mustang 302 trouble shooting surging and stalling.

So I have been slowly and progressively illiminated many possible problems but still end up with the same symptom. I have a recently rebuilt 302, with a 570cfm holley street avenger, stock heads, weiand intake, mild comp cam, and stock ignition system. My problems started when the engine started surging, only noticeable when the car was in neutral and i reved the engine, to about 2,000 rpm. Later the car started stalling and i had to play with the gas to get it to run, now the car wont stay on unless i have my foot on the pedal. Ive done the following things but still havent found the solution:

1. changed the inline and internal fuel filters

2. set the timming to 6 and then advanced it to 8 since the cam is a mild one

3. changed the distributor cap and rotor

4. checked for vacumm leaks around the carb base, and intake, and hoses

5. replaced the PCV valve and hose

6. set the mixture screws to the highest vacumm reading using the full vacumm port

7. Checked the float level on the side holes, and it was were its suppose to be

So now I have removed the carb. and Im debating over rebuilding it, or just buying a new one, of another brand. But I noticed something while I was removing it, and was wondering if its nothing or its a sign that could lead me to whats wrong, I saw that there was some type of brown residue, like when oil gets burned on hot metal, but not actual oil. The attached pictures are that of what I saw.

Ive also been told that a sticking float could be causing this problem, so Ill get back when I tear into the carb. But any other ideas or solutions would be greatly appreciated.
Attached Thumbnails
1968 Mustang 302 trouble shooting surging and stalling.-dsc03886.jpg  1968 Mustang 302 trouble shooting surging and stalling.-dsc03887.jpg  1968 Mustang 302 trouble shooting surging and stalling.-dsc03888.jpg  1968 Mustang 302 trouble shooting surging and stalling.-dsc03885.jpg  
jb36jb is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Sponsored Links
Advertisement
 
Unread 08-04-2009   #2 (permalink)
SharonAnne is offline Rookie


Joined: Jul 2009
Posts: 7 Threads: 0
 SharonAnne's Country Flag
Phoenix, AZ   Arizona
SharonAnne is on a distinguished road
Default

before you sell the carburetor why not take it to a carb shop and have them trouble shoot it ON the car. Might save you some $
SharonAnne is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 08-04-2009   #3 (permalink)
shagadoodle is offline Made Member

Classic Member


Joined: Nov 2007
Posts: 394 Threads: 57
 shagadoodle's Country Flag  View shagadoodle's 7 photos
Knoxville   Tennessee
shagadoodle is on a distinguished road
Default

ok just to say i had problems like this very similar b4 and it was all carb problems. good motor, dirty carb. If you want to peice it apart to clean it good and rebuild it (not that hard) go right ahead. if you'd rather try some other stuff to the carb b4 peicing it apart i'd tell you to remove the idle mixture screws one at a time and take a can of carb cleaner and spray down that hole. you may use copressed air also. oddly enough if these are clogged it can give you hell....when i took my carb off and peiced it apart to put a new accelerator pump in it the thing was looking nice but when i put it on the idle was crazy...and that wasn't even my original problem. peiced it apart and cleaned it again....and still then i sprayed just a bit down the mixture screw holes and purr'd like a kitten. but lol thats a little off subject but try that b4 peicing the thing apart.
shagadoodle is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 08-05-2009   #4 (permalink)
jb36jb is offline Apprentice

Classic Member


Joined: Nov 2006
Posts: 87 Threads: 34
 jb36jb's Country Flag
San Diego   California
jb36jb is on a distinguished road
Default

Ill give that a try, I took off the carb. and will be working on it this weekend, hopefully I find out what the problem is.
jb36jb is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 08-06-2009   #5 (permalink)
The Greek is offline MACH I Member

Classic Member
5.0L Member


Joined: Nov 2006
Posts: 3,177 Threads: 1
 The Greek's Country Flag
Jacksonville   Florida
The Greek is on a distinguished road
Default

While you're inside of the carb, check the diaphram on, or replace the power valve. Make sure that it isn't sticking or loose and its gasket is sealing. Holleys have a problem with the idle and main circuit air restrictor orifices (Bleeds) often getting clogged. These are the two small openings just above each venturi. (8 in total) The ones for the primary venturies are inside of the choke horn. These can be the problem. A main jet that has worked loose is another.

You could have a fuel pressure or delivery problem, (A kinked fuel line, a clogged screen on the fuel pickup in the tank or an internally collapsed hose can affect delivery and volume). There may be water in your fuel. Did you start getting the problem a short time after buying fuel?

As for the brown discoloration on the carb and manifold. Looks to me to be from oil vapors that have entered the carb from the PCV valve.
The Greek is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Sponsored Links
Advertisement
 
Reply   Post New Thread



Thread Tools



Mustang Photos
Mustang Links    Top Sites    RSS    Link To Us    Add to Favorites    Archive    Terms of Use    Site Rules    Privacy    Contact    Sponsors    Advertise   
AllFordMustangs is not affiliated with or endorsed by Ford Motor Company. ©Copyright 2002-2011 All Auto Enthusiasts Network

Search Engine Friendly URLs by vBSEO 3.5.2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172