Engine breaking up Problem help request. - Ford Mustang Forums : Corral.net Mustang Forum
LinkBack Thread Tools Display Modes
post #1 of 5 Old 07-20-2011, 07:54 PM Thread Starter
Registered User
Trader Feedback: (0)
Join Date: May 2011
Location: Rochester, N.Y.
Posts: 9
Engine breaking up Problem help request.

I have a 1993 Mustang LX that we recently finished installing a 306 cuin ford racing engine into. The engine is running but we have a problem with it breaking up under heavy throttle. This is Fuel Injected and we have a new MSD Distributor and coil on it. What's happening is the tach is erratic during the times the engine is mis-firing and we can watch it drop off and bounce around as the engine mis-fires. Some times it runs fine for a brief period of time and then it runs badly again. I haven't gotten too deep into the diagnostic process yet, but I was wondering if this may be a common problem and someone can point me toward a place to begin looking for a bad connection or areas to do voltage checks. Any help would be appreciated, Thanks!


Hreagle is offline  
Sponsored Links
post #2 of 5 Old 08-21-2011, 12:00 AM
Registered User
Trader Feedback: (0)
Join Date: Dec 2000
Location: Washington,WV
Posts: 131
What kind of alternator is on it and have you checked the battery voltage and made sure it is fully charged?. MSD systems require a good charging system...battery and alternator. Most 3G alternators use overloads in the circuit . Make sure it's not tripped if installed.

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

87gt,3200# a4 306 w/ported canfields,AFM b4 blower cam, welded & ported GT-40 w/Downs upper,mac long tubes, vortech t-trim 17-19# boost.
60 ft 1.39
best 1/4 mi 9.75 @ 143
best 1/8 mi 6.25 @ 113
AJ is offline  
post #3 of 5 Old 08-22-2011, 03:05 PM
Registered User
91BlueGT's Avatar
Trader Feedback: (2)
Join Date: Jan 2002
Location: Oklahoma City, Ok
Posts: 521
you've got a lot of searching to do. i wouldn't just narrow it down to electrical

mech engineer - OKLAHOMA STATE
88 gt hb - 347 all forged, canfield 195cc's, xr282, holley 750, vic jr

89 gt hb - 306, windsor jr's, 70mm turbo, FAST efi, 10pt, vic 5.0, 60lb inj, front wheels off the ground
91BlueGT is offline  
Sponsored Links
post #4 of 5 Old 08-28-2011, 12:43 AM
Registered User
Trader Feedback: (0)
Join Date: Jan 2008
Location: Goose creek sc
Posts: 14
A bad pip in the distributor would do that
drexelsteve is offline  
post #5 of 5 Old 09-23-2011, 02:23 AM
Registered User
Trader Feedback: (2)
Join Date: Nov 2009
Location: Northern California
Posts: 91
Bingo!! You are most likely loosing a crank signal to the PCM.
93 Twintrbo is offline  
Sponsored Links


Quick Reply

Register Now

In order to be able to post messages on the Ford Mustang Forums : Corral.net Mustang Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Similar Threads
Thread Thread Starter Forum Replies Last Post
Check engine light with 3inch exhaust bwd1973 General Mustang Tech 4 03-27-2011 11:15 PM
Engine will not go into fast idle when started cold, causes? FormerlyBlue88Notch 5.0/5.8 Engine Tech 5 03-10-2011 09:27 AM
Broken Engine Problem found out! quick89gt 5.0/5.8 Engine Tech 4 01-03-2002 05:21 AM
Official Mod Motor 2vna rules Dave King GT & SOHC 37 12-21-2001 01:27 PM
Proposed Modular Shootout Renegade rules (very long!) Modular Performance GT & SOHC 30 12-19-2001 07:30 PM

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 On
Pingbacks are On
Refbacks are On

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