(Help) Car Wont Run : Mass Air Conversion 1986 Mustang Issues

gotcat85

New Member
Nov 28, 2018
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Bardstown
Hello,
Just installed the mass air conversion on my 1986 mustang GT so that I could run a bigger cam. It is a 5 speed car no cruise control. After installing the mass air conversion the car will just start and die. You can feather the throttle to keep it running but barely. The car dose have a new factory fuel pump. Its hard to check the running fuel pressure due to the fact it wont run but it will hold 38 psi by just turning the key. After reading several comment from other people it could be a variety of issues. I have read a few post about dumping the codes? Dose any one have a video on this. Can you dump the codes if it wont run? Am I even looking in the right direction?

Engine set up: 24lbs injector's, Gt 40 heads ,75 mm TB, BBK Cold Air intake, 1992-1993 A9L ECM , LMR mass air conversion harness, 232/242 duration cam, and a edelbrock plenum and intake.
 
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Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
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Do you have a mass air calibrated for the 24s?

Although prob not your issue, if you notice the car stalking out when you come to a stop, you'll want to add the VSS and run two wires to the ECU.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
33,596
9,881
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Massachusetts
Vehicle Speed Sensor. It's located on the speedo cable where it plugs into the trans. It's not present on 86-88 cars without cruise control and 86-87 cars lack the wiring completely.

You just need to run two wires from trans area to ECU. All mass air instructions will tell you the two pins to connect them too. You will need a VsS and a speedo cable for cars equipped with it.

This however is not the cause of your issue. Car should still start with the VsS not hooked up.
 

jrichker

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Mar 10, 2000
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lowendmac.com
Dump codes sticky

Look at the top of the 5.0 Tech forum where the sticky threads are posted. One of them is how to dump the computer codes. Codes may be present even if the CEL (Check Engine Light) isn’t on. You don’t need a code reader or scanner – all you need is a paper clip, or if your lady friend has a hair pin, that will do the job.
I highly suggest that you read it and follow the instructions to dump the codes. http://www.stangnet.com/mustang-forums/threads/how-to-pull-codes-from-eec4.889006/
 

Blown88GT

Founding Member
Nov 13, 1999
2,132
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Palm Beach Gardens, FL
Hello,
Just installed the mass air conversion on my 1986 mustang GT so that I could run a bigger cam. It is a 5 speed car no cruise control. After installing the mass air conversion the car will just start and die. You can feather the throttle to keep it running but barely. The car dose have a new factory fuel pump. Its hard to check the running fuel pressure due to the fact it wont run but it will hold 38 psi by just turning the key. After reading several comment from other people it could be a variety of issues. I have read a few post about dumping the codes? Dose any one have a video on this. Can you dump the codes if it wont run? Am I even looking in the right direction?

Engine set up: 24lbs injector's, Gt 40 heads ,75 mm TB, BBK Cold Air intake, 1992-1993 A9L ECM , LMR mass air conversion harness, 232/242 duration cam, and a edelbrock plenum and intake.
Probably messed up the timing with the cam install.