New to me 88 foxbody

KAWMAN2

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Aug 9, 2022
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I just bought a 88 foxbody, 331 stroker bbk intake bbk long tube headers coil overs , moser rear end upgraded maf wiring and system , appears to have a big cam 12 inches vacuum.
run real good but when cold it surges on the idle between 500 and 1500 rpm and wants to die warmed up it idles at 900 nice
 
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With the car injected and converted to mass air did they do the mass air conversion properly? These are the instructions for the Pro-M mass air conversion:

Pro-M_Mass_Air_Conversion_Instructions.jpg


What is missing from the instructions above is as follows:

In 1986-88 vehicles, you may need to connect other wires to avoid EEC error codes. These are:

Pin 19 is the fuel pump monitor. A wire with a pin is provided to put in pin 19, and it must run to the got wire on the fuel pump. Pink under driver seat Pk/Blk. This wire is only necessary if you do not want a diagnostic code. Omitting this wire will not help performance.

Pins 3 and 6 are vehicle speed sensor lines, and will affect some closed throttle operation of your car. Pin 6 is the Orange (-) wire and should be spliced/soldered to the O/Y (-) wire of the speed sensor. Pin 3 is the Green (+) wire and should be spliced/soldered to the DG/W (+) wire of the speed sensor. These wires are found in the driver side kick panel or at the tail shaft of the transmission where the speedo cable connects to the VSS sensor in the transmission.

First thing is check for any codes then double check the mass air conversion. From there probably a base idle reset and possibly a tune up (plugs, wires, cap, rotor, etc.). Simple free stuff first.
 
With the car injected and converted to mass air did they do the mass air conversion properly? These are the instructions for the Pro-M mass air conversion:

Pro-M_Mass_Air_Conversion_Instructions.jpg


What is missing from the instructions above is as follows:

In 1986-88 vehicles, you may need to connect other wires to avoid EEC error codes. These are:

Pin 19 is the fuel pump monitor. A wire with a pin is provided to put in pin 19, and it must run to the got wire on the fuel pump. Pink under driver seat Pk/Blk. This wire is only necessary if you do not want a diagnostic code. Omitting this wire will not help performance.

Pins 3 and 6 are vehicle speed sensor lines, and will affect some closed throttle operation of your car. Pin 6 is the Orange (-) wire and should be spliced/soldered to the O/Y (-) wire of the speed sensor. Pin 3 is the Green (+) wire and should be spliced/soldered to the DG/W (+) wire of the speed sensor. These wires are found in the driver side kick panel or at the tail shaft of the transmission where the speedo cable connects to the VSS sensor in the transmission.

First thing is check for any codes then double check the mass air conversion. From there probably a base idle reset and possibly a tune up (plugs, wires, cap, rotor, etc.). Simple free stuff first.
Thanks I just realized who did the conversion used a new harness but I,m going the double check everthing , I guess the big cam is"nt the problem
 
So is the injection stock Ford or aftermarket? Only asking as BBK does not make an ECU for injection. They make throttle bodies, EGR spacers, cold air intakes, and fuel system stuff but not anything with regards of the control of the engine controls system.

You need to post up what all the car has if you need additional help.
 
So is the injection stock Ford or aftermarket? Only asking as BBK does not make an ECU for injection. They make throttle bodies, EGR spacers, cold air intakes, and fuel system stuff but not anything with regards of the control of the engine controls system.

You need to post up what all the car has if you need additional help.
all ecu parts appear to be stock.
 
With the car injected and converted to mass air did they do the mass air conversion properly? These are the instructions for the Pro-M mass air conversion:

Pro-M_Mass_Air_Conversion_Instructions.jpg


What is missing from the instructions above is as follows:

In 1986-88 vehicles, you may need to connect other wires to avoid EEC error codes. These are:

Pin 19 is the fuel pump monitor. A wire with a pin is provided to put in pin 19, and it must run to the got wire on the fuel pump. Pink under driver seat Pk/Blk. This wire is only necessary if you do not want a diagnostic code. Omitting this wire will not help performance.

Pins 3 and 6 are vehicle speed sensor lines, and will affect some closed throttle operation of your car. Pin 6 is the Orange (-) wire and should be spliced/soldered to the O/Y (-) wire of the speed sensor. Pin 3 is the Green (+) wire and should be spliced/soldered to the DG/W (+) wire of the speed sensor. These wires are found in the driver side kick panel or at the tail shaft of the transmission where the speedo cable connects to the VSS sensor in the transmission.

First thing is check for any codes then double check the mass air conversion. From there probably a base idle reset and possibly a tune up (plugs, wires, cap, rotor, etc.). Simple free stuff first.
 
I think you need to confirm the ECU harness that is in the car. Biggest thing to look at is the connectors on it over by the brake booster where it connects to the dash harness. On the 87-90 cars there should be a round gray connector and a round black connector. If the ECU harness was changed to a OEM harness that already had mass air it would have to be from an '89 5.0 car. No other year harness will work due to the the 90 and up cars having air bags and the wires for this are integrated into the harness and affects the pinout on connectors and the 87-88 cars were speed density with the exception of the 88 California cars which got mass air a year earlier than the rest of the country.

The easiest thing would have been to get a mass air conversion harness like the Pro-M one and just lay that into the existing harness.

You need to confirm that the wiring is correct and if anything is not correct then fix it. Once this has been confirmed or fixed then you can move on to more traditional trouble shooting like pulling codes, base idle reset, etc.
 
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I think you need to confirm the ECU harness that is in the car. Biggest thing to look at is the connectors on it over by the brake booster where it connects to the dash harness. On the 87-90 cars there should be a round gray connector and a round black connector. If the ECU harness was changed to a OEM harness that already had mass air it would have to be from an '89 5.0 car. No other year harness will work due to the the 90 and up cars having air bags and the wires for this are integrated into the harness and affects the pinout on connectors and the 87-88 cars were speed density with the exception of the 88 California cars which got mass air a year earlier than the rest of the country.

The easiest thing would have been to get a mass air conversion harness like the Pro-M one and just lay that into the existing harness.

You need to confirm that the wiring is correct and if anything is not correct then fix it. Once this has been confirmed or fixed then you can move on to more traditional trouble shooting like pulling codes, base idle reset, etc.
 
Okay, “salt and pepper shakers” aka the injection harness connectors are behind the upper intake and they are black and white.

I have to ask, is this your first Fox Mustang as you don’t seem to know much about them. Not being an ass here just wanting to know the level of detail you may or may not be needing.
 
Okay, “salt and pepper shakers” aka the injection harness connectors are behind the upper intake and they are black and white.

I have to ask, is this your first Fox Mustang as you don’t seem to know much about them. Not being an ass here just wanting to know the level of detail you may or may not be needing.
 

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Sorry guys . not realiy good at using the forum , a little background, spent 10 years building a ffr scca car, ford racing motor, cobra injection absolutly picked up on eec, the fox body is converted Din't think its wired correct, seems like I don't have time like I did when I was working ,I thanks for the help,
 

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Sorry guys . not realiy good at using the forum , a little background, spent 10 years building a ffr scca car, ford racing motor, cobra injection absolutly picked up on eec, the fox body is converted Din't think its wired correct, seems like I don't have time like I did when I was working ,I thanks for the help,
 
You guys educated me on the fact that it was converted from speed density to maf i,m on track now as sone as I finish the VSS I,m going to take a hard look at the wiring the harness doesn"t seem original !
 
I have a missing speedometer gear coming for my ess , apparently the clip that retains the speedo cable is not avalible without the vss is there a ford part# or someplace where I can buy a clip?