put 351 in 5.0 need tech help - Forums at Modded Mustangs
 
LinkBack Thread Tools
post #1 of 10 Old June 5th, 2007, 10:52 PM Thread Starter
Newbie
 
Join Date: Jun 2007
Posts: 4
 
iTrader: 0 reviews
put 351 in 5.0 need tech help

i had a 351 put in my 88 5.0 GT but the computer wont compensate for the bigger engine and i had to disconnect the O2 sensor to keep it running, any ideas where i went wrong?
DreFromTheBay is offline  
Sponsored Links
Advertisement
 
post #2 of 10 Old June 5th, 2007, 10:54 PM
Administrator
 
BWAL's Avatar
 
Join Date: Nov 2006
Location: Clothes Hamper
Posts: 32,898
Blog Entries: 2
                     
iTrader: 4 reviews
i think you need a new computer

'65 Fastback
'89 LX 5.0
'90 LX 5.0
'92 LX 5.0
'92 LX 5.0
'97 Cobra


BWAL is offline  
post #3 of 10 Old June 5th, 2007, 11:05 PM Thread Starter
Newbie
 
Join Date: Jun 2007
Posts: 4
 
iTrader: 0 reviews
well i think that might be a problem, because i dont know all the specs on this engine yet, it runs good but i'm gonna have to deal with a smog check soon
DreFromTheBay is offline  
Sponsored Links
Advertisement
 
post #4 of 10 Old June 6th, 2007, 08:53 AM
Enthusiast
 
Join Date: Apr 2006
Posts: 638
 
iTrader: 0 reviews
+1

Quote:
Originally Posted by BWAL09
i think you need a new computer
+1 for new computer

"Those who forget the past are condemned to repeat it" Rev. Jim Jones
OTreborO is offline  
post #5 of 10 Old June 6th, 2007, 12:55 PM
MM Fanatic
 
ryans88gt's Avatar
 
Join Date: May 2007
Location: Bloomington, IL
Posts: 4,781
     
iTrader: 0 reviews
88 is a speed density computer, you need to upgrade to mass air or you'll blow it up from running too lean.

88 GT CHI headed 351w 10.8 @ 125 - still figuring it out.
03 Cobra 2.3 whipple 10.7 @ 129 - sold it
04 Mach 1 12.7 @ 109 mostly stock - sold it
89 LX procharged 302 515 hp 497 ftlbs 10.7 @130 mph - sold it

ryans88gt is offline  
post #6 of 10 Old June 7th, 2007, 03:37 AM Thread Starter
Newbie
 
Join Date: Jun 2007
Posts: 4
 
iTrader: 0 reviews
do they have a section here on how to do that?
DreFromTheBay is offline  
post #7 of 10 Old June 7th, 2007, 09:36 AM
MM Fanatic
 
ryans88gt's Avatar
 
Join Date: May 2007
Location: Bloomington, IL
Posts: 4,781
     
iTrader: 0 reviews
Buy a mass air conversion kit....instructions will come with it. Basically you replace the computer and add a mass air sensor in the intake plumbing. It isn't a hard install, if you are mildly competent at following directions it shouldn't be a problem.

They run around $500 for the cobra kit from ford racing for a recalibrated computer, mass air meter, and they used to come with 24 lb injectors too, not sure if that is still the case.

That should fix your problem, in the mean time don't drive you car like that or you'll blow it up.

88 GT CHI headed 351w 10.8 @ 125 - still figuring it out.
03 Cobra 2.3 whipple 10.7 @ 129 - sold it
04 Mach 1 12.7 @ 109 mostly stock - sold it
89 LX procharged 302 515 hp 497 ftlbs 10.7 @130 mph - sold it

ryans88gt is offline  
post #8 of 10 Old June 8th, 2007, 10:13 AM Thread Starter
Newbie
 
Join Date: Jun 2007
Posts: 4
 
iTrader: 0 reviews
ok the guy who helped me gave me a little more info, my 88 mustang has MAF already but he he doesnt think that the engine is a 351 because it has a different firing order, since the engine is more powerful do you think the problem is the small MAF sensor, because with the O2 sensor unplugged it runs good, i'm lost
DreFromTheBay is offline  
post #9 of 10 Old June 8th, 2007, 10:18 AM
MM Fanatic
 
JBIGBOOTSY's Avatar
 
Join Date: Aug 2006
Location: Hobart Indiana
Posts: 4,424
         
iTrader: 0 reviews
pull codes


Bolt-on Abraham Lincoln Log motor. With extra wiring.
JBIGBOOTSY is offline  
post #10 of 10 Old June 9th, 2007, 03:47 PM
Regular
 
Join Date: Feb 2007
Location: persian gulf
Posts: 253
 
iTrader: 0 reviews
Send a message via AIM to zero
Quote:
Originally Posted by DreFromTheBay
ok the guy who helped me gave me a little more info, my 88 mustang has MAF already but he he doesnt think that the engine is a 351 because it has a different firing order, since the engine is more powerful do you think the problem is the small MAF sensor, because with the O2 sensor unplugged it runs good, i'm lost
ford made two different firing orders for the 351W.
one is for the m code motor which was the 4bbl version in early years
1-3-7-2-6-5-4-8
one is for the h code motor which was the 2bbl version.
1-5-4-2-6-3-7-8

it could still be a 351, just a different one than you thuought. easy way to tell, measure. there are two different deck heights for the 351 though... i think one is 8.2 and one is 9.5 but im sure im wrong about the 8.2. if you want to be thorough in your identification, take off your heads and measure your piston width. as for your other problem, a new maf and a computer will clear things up. a 351 eats more gas than a 302.. so naturally the 302 computer is going to starve it.

92 lx
351W w/ 60 overbore
holley 600cfm carb
weiand stealth dual plane intake
240/[email protected] cam
bbk long tube headders
msd coil

5 lug axle conversion
3.55 gears
mach1 style 17" rims
zero is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Forums at Modded Mustangs 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 email address for yourself.

Email Address:
OR

Log-in










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 On
Pingbacks are On
Refbacks are On

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