Engine 1990 mustang GT no signal to fuel pump and not pulsing injectors

[brandyn200]

The color of those wires are 91-93 colors not 88-91. 1990 is one year specific and there are two plugs down by the brake booster for the dash harness connections, one gray and one black. 91-93 have one plug in this spot and its a weird brown color. Wondering if at some point either a 91 harness was forced into the car or if the MAP plug was replaced with an 91-93 plug and wires and its spliced down in the harness under the loom.

Can you run the VIN on the car and see if it was an original 5.0 or maybe a 2.3 swap car?

The harness is all labeled and everything and a bunch of the retaining clips are broken so I guess anything is possible also it is a regular gt body but there is a lot of cobra parts swapped onto it for example valve covers, wheels, badges ect. All done before my father got the car i will run the vin and see what I get

 

[AeroCoupe]

What got me going on that was the EEC pinout that 89ripper has in Post #18 is for 88-91 cars and the colors do not match up to what you have. This diagram is for 91-93 cars and you can see the wire colors are different and are what you have. Being your car is a 90 I would think the colors would be like what 89ripper posed and not this one.

 

[brandyn200]

What got me going on that was the EEC pinout that 89ripper has in Post #18 is for 88-91 cars and the colors do not match up to what you have. This diagram is for 91-93 cars and you can see the wire colors are different and are what you have. Being your car is a 90 I would think the colors would be like what 89ripper posed and not this one.

Either way what I'm getting is that the wiring in my car isn't the original wiring and somebody swapped it. Is there another map sensor wiring test that would work for my wiring so I could figure out what is wrong with my map?

 

[brandyn200]

Looked up the vin and the car was originally a 5.0 so the harness must've been swapped at some point or maybe the whole engine? Who knows but I still need a different test for my wiring so I can get the right results

 

[AeroCoupe]

It may be the correct harness and someone just wired up a 91-93 MAP pigtail and did it incorrectly or poorly i.e. a back connection.

You will have to go point to point on the harness to verify the MAP sensor wiring. The first thing I would do is check continuity from on the green / black wire from the sensor connector to PIN 45 on the ECU, from the brown / white wire to PIN 26, from the gray / red wire to PIN 46 on the ECU, from PIN 30 on the ECU via the light blue / yellow wire to the clutch pedal switch, and lastly from the clutch pedal switch via the gray / red wire to the sensor connector. Once you have verified the continuity on those wire and fixed them if broken then its either the MAP sensor that is bad, the 91-93 MAP sensor pigtail is not original and wired incorrectly to the 90 harness, or the ECU has an issue.

If it is a 90 harness then the colors at the ECU would be as follows:

PIN 26 - Orange / White
PIN 30 - Not sure what color this on is on the 90 as the diagram does not show it. I Google searched and saw on a couple diagrams that it is still light blue / yellow but do some research here.
PIN 45 - Light Green / Black
PIN 46 - Black / White

 

[brandyn200]

It may be the correct harness and someone just wired up a 91-93 MAP pigtail and did it incorrectly or poorly i.e. a back connection.

You will have to go point to point on the harness to verify the MAP sensor wiring. The first thing I would do is check continuity from on the green / black wire from the sensor connector to PIN 45 on the ECU, from the brown / white wire to PIN 26, from the gray / red wire to PIN 46 on the ECU, from PIN 30 on the ECU via the light blue / yellow wire to the clutch pedal switch, and lastly from the clutch pedal switch via the gray / red wire to the sensor connector. Once you have verified the continuity on those wire and fixed them if broken then its either the MAP sensor that is bad, the 91-93 MAP sensor pigtail is not original and wired incorrectly to the 90 harness, or the ECU has an issue.

If it is a 90 harness then the colors at the ECU would be as follows:

PIN 26 - Orange / White
PIN 30 - Not sure what color this on is on the 90 as the diagram does not show it. I Google searched and saw on a couple diagrams that it is still light blue / yellow but do some research here.
PIN 45 - Light Green / Black
PIN 46 - Black / White

I don't have a brown/white I have

Grey/red
Green/ black
Black/white

Would it still work the same or would the black/ white wire make it different

 

[brandyn200]

If it is a 90 harness then the colors at the ECU would be as follows:

PIN 26 - Orange / White
PIN 30 - Not sure what color this on is on the 90 as the diagram does not show it. I Google searched and saw on a couple diagrams that it is still light blue / yellow but do some research here.
PIN 45 - Light Green / Black
PIN 46 - Black / White

My 26 black/white and there is continuity between black/white at map plug and pin 26

30 looks like a purple/yellow

45 is LT green/black and there is continuity between green/black at map and pin 45

My pin 46 is grey/red and there is continuity between grey/red at map and pin 46

I can't make any sense of this because all of the other sensors are working off of the same wiring so why not the map?

The sensor itself is new could it be defective from the factory?

 

[AeroCoupe]

At least you know the wires are good. Definitely could be bad out of the box. Happens more than you would think.

 

[brandyn200]

At least you know the wires are good. Definitely could be bad out of the box. Happens more than you would think.

But is my plug pined right? It's not like you described and it's different from the diagram 89ripper posted is it just a whole different harness?

 

[AeroCoupe]

This is how my 93 is supposed to be pinned at the MAP sensor and the wire colors are the same as yours.

 

[brandyn200]

Ok so I have a 91-93 harness does that mean I need a 91-93 eec? Or are there cross compatible?

 

[AeroCoupe]

I have a 93 and run an A9L so doesn’t matter.

Is the MAP connector pinned correctly?

 

[brandyn200]

Ok so I guess I'll get another new map and see if it works or not I'm hoping it's that simple but I'm thinking there's something else I'm not seeing.

 

[brandyn200]

Ok this is kind of in another direction but how would I be able to tell if it's the factory engine or not since mines got cobra parts on it. Would the casting number say if it's a cobra engine or not? If so where would I find the casting number

 

[brandyn200]

I have a 93 and run an A9L so doesn’t matter.

Is the MAP connector pinned correctly?

I can't find a good picture online could you possibly take a picture of your plug so I can compare?
Hard to tell the orientation of the plug in that diagram

 

[AeroCoupe]

Best I can do.

Not sure I can unplug it unless I remove it and I don’t want to get that started this evening.

There should be a partial VIN on the block behind lower intake next to PVC.

 

[brandyn200]

Mine looks the same besides that the brown is black

 

[AeroCoupe]

let me look some more.

 

[AeroCoupe]

It appears the plug is pinned correctly. Of the colors at the plug are correct at the ECU and the wires are in good shape then you are good there.

Another possibility is that the connector is not making a good connection with the sensor.

I would be curious if someone else can check their 1990 car and see if the wire colors on the MAP sensor connector are the same as yours. 90 is a one year only harness so Ford may have changed colors for that one year.

 

[brandyn200]

The wires all look good I'm not going to tear the whole loom apart to look at every inch of them but the look good