Electrical Hey Guys.what Is This ?

Real time recon

Mustang Master
Aug 21, 2016
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90 Mustang GT 302.
This 2 wire plug is not plugged in. Its on the passengers side firewall.What is it & what does it do ?
Thanks much..........
007.JPG
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Stuff for your emission/air pump and related stuff. Should be plgged in.
Egr vacuum regulator
TAB solenoid near fender apron
TAD solenoid
This is on a 89 but yours should be the same, I think, maybe, probably,
 
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Mustang5L5

i'm familiar with penetration
Mod Dude
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Ontrols on of the solenoids directing airflow from the air pump to either the upstream or downstream cat converters.

If those are still on the car, plug it back in
 
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Real time recon

Mustang Master
Aug 21, 2016
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Thanks . Car has no cats.Should they be plugged in ? With a car, w/o cat. converters ?
 
Last edited:

mikestang63

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Aug 27, 2012
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your car is running rich because you have no cats
plug the lines back in.
Do you still have the smog pump, hoses, and vacuum lines all hooked up?
Are just the cats removed? If so I would put on a set of high flow aftermarket cats
that will solve the gas smell and the car will run cleaner
 

Real time recon

Mustang Master
Aug 21, 2016
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Cats & smog pump are removed.
Plugged the plug back in,went for a ride.Seems to idle better/smoother.And running a little less rich.Probably as good as its going to be w/o cats. I Also have, cleaned the MAF sensor.Cleaned the Throttle body.Installed 2 new O2 sensors.And installed new plugs.Thanks
 

Mustang5L5

i'm familiar with penetration
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That's all you need to dump codes in a 1990.

Paper clip to ground the test plug and the check engine light blinks the codes.


There's also a $20 code reader
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Here you go, thanks to jrichker
Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.

Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.

Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. On a manual transmission car, be sure to press the clutch to the floor.
Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.

underhoodpictures007-01-jpg.560548.jpg


underhoodpictures010-jpg.560549.jpg


If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the86-88's except possibly the Cali Mass Air cars.

attachment-php-attachmentid-58312-stc-1-d-1242744354-20-gif.560550.gif
The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.[/B]

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

attachment-php-attachmentid-57945-stc-1-d-1240584741-gif.549675.gif


The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that thewiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy anddriveablity problems

Some codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

Your 86-88 5.0 won't have a working Check Engine Light, so you'll need a test light.
See AutoZone Part Number: 25886 , $10
4-jpg.549676.jpg




Alternate methods:
For those who are intimidated by all the wires & connections, seeActron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see www.midwayautosupply.com/Equus-Digital-Ford-Code-Reader/dp/B000EW0KHW Equus - Digital Ford Code Reader 3145.
It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $22-$36.
41p3gqvdshl-_ss270_-jpg.549671.jpg
 

imp

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Jul 13, 2017
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your car is running rich because you have no cats
plug the lines back in.
Do you still have the smog pump, hoses, and vacuum lines all hooked up?
Are just the cats removed? If so I would put on a set of high flow aftermarket cats
that will solve the gas smell and the car will run cleaner
When I put a Mustang '92 5.0L HO engine with it's AOD in my '79 Ranchero, I used no cats, 2 HO2S near the exh. manifolds, which were the SS tube headers from Ford. The big, heavy vehicle, with 3.50 gears delivered > 25mpg on the highway. It ran remarkably well, better than expected. Emissions test in Phoenix read Carbon Monoxide 0.0%, which of course has nothing to do with cats. I did have operating Smog Pump. Used Cardone rebuilt PCM as called out for year & model.

So, I wonder about your statement above. imp
 

mikestang63

SN Certified Technician
Aug 27, 2012
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When I put a Mustang '92 5.0L HO engine with it's AOD in my '79 Ranchero, I used no cats, 2 HO2S near the exh. manifolds, which were the SS tube headers from Ford. The big, heavy vehicle, with 3.50 gears delivered > 25mpg on the highway. It ran remarkably well, better than expected. Emissions test in Phoenix read Carbon Monoxide 0.0%, which of course has nothing to do with cats. I did have operating Smog Pump. Used Cardone rebuilt PCM as called out for year & model.

So, I wonder about your statement above. imp
glad to hear you have it covered
 

imp

Mustang Master
Jul 13, 2017
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glad to hear you have it covered
@mikestang63
I wonder what you mean by your reply? I agree that if O2 sensing is done both BEFORE and AFTER the cat, fuel/air mixture will be affected by removing the cat. However, in the case of OBD-I, using one O2, presence of the cat makes no difference to the fuel/air mix. imp
 

Noobz347

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@mikestang63
I wonder what you mean by your reply? I agree that if O2 sensing is done both BEFORE and AFTER the cat, fuel/air mixture will be affected by removing the cat. However, in the case of OBD-I, using one O2, presence of the cat makes no difference to the fuel/air mix. imp
Cars do not produce power at stoich AFR. Air/Fuel is enriched as power production increases. The job of the catalytic converter is to capture ad combine the excess emissions.

Without the cats, that mixture is released "rich" in reactive materials and produces that unspent fuel smell.

If the exhaust mixture is catalyzed, then much of that mixture is combined with particles from the converter to make it inert (or as close to as we can manage).

You can minimize the smell to a certain degree through tuning but I don't know of many cat-less cars that don't have that "smell".
 
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