Engine Smog Delete

FrankenStang88

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Feb 2, 2016
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Ok so before you guys call me a "dumb ass redneck", I just want to let you know that the previous owner deleted all the emmisions parts off my 88 gt. I put a new engine in it recently and now the cel is on and its running in limp mode. I havent run the code yet but im 95% sure its the smog bypass. Ive looked on other threads and all it is other owners calling the guy that needs help stupid... so im just looking for some actual help
 
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jrichker

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The emissions equipment does not normally set the computer into limp mode. Do you have Mass Air conversion? You may have other problems like MAF, MAP/Baro or O2 sensors.

Simple things like using the wrong type gasket sealer can poison the O2 sensors. I found that out after putting a rebuilt engine in my previous 89 Mustang GT. Ouch...that was another extra $90 or so after having spent $2300 for a long block with a 3 year warranty....

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. I highly suggest that you read it and follow the instructions to dump the codes.
 

Noobz347

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Ive looked on other threads and all it is other owners calling the guy that needs help stupid... so im just looking for some actual help


The majority of that stems from the fact the the Original Posters of such threads, generally think that eliminating emissions equates to horse power for some reason or that the EGR system is the difference between a 14 second and 12 second car.

Your circumstances are a bit different. You are trying to mitigate the carnage of the previous owner.

Follow JRs instructions. He not only understands the emissions systems but also how it effects associated systems.
 

FoxMustangLvr

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Welcome to Stangnet. Looks like you have already got some solid advice to get you started with your problem solving. Good luck!
 

FrankenStang88

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You need to run codes and find what exactly is the problem.
Ok so i ran the cel test and it came up as 85 twice and then a bunch of random ones i couldnt seem to find a correlation with. I looked online and code 85 deals with the charcoal canister purge failure, i dont have one. I put a vented gas cap on and it and the cel is still on. Will i have to actually put back on all the stuff the previous owner took off?
 

FrankenStang88

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Feb 2, 2016
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The emissions equipment does not normally set the computer into limp mode. Do you have Mass Air conversion? You may have other problems like MAF, MAP/Baro or O2 sensors.

Simple things like using the wrong type gasket sealer can poison the O2 sensors. I found that out after putting a rebuilt engine in my previous 89 Mustang GT. Ouch...that was another extra $90 or so after having spent $2300 for a long block with a 3 year warranty....

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. I highly suggest that you read it and follow the instructions to dump the codes.
Yes the car was converted to MAF by previous owner, hopefully it was done correctly. Theres three empty screw holes on the side of the bracket were it connects the intake. Is soethimg missing off of it? And i just ordered new O2 sensors as stupid me used the old ones with the new engine i put in
 

jrichker

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Ok so i ran the cel test and it came up as 85 twice and then a bunch of random ones i couldnt seem to find a correlation with. I looked online and code 85 deals with the charcoal canister purge failure, i dont have one. I put a vented gas cap on and it and the cel is still on. Will i have to actually put back on all the stuff the previous owner took off?
There is no need to reinstall the emissions equipment if it is already removed. The codes tell what is wrong and that the computer has bypassed trying to operate these systems. The computer will try to talk to the sensors and actuators of the emissions systems like the carbon canister. When it doesn't get the reply signal it expects, then it sets the code for that sensor or actuator.

If the previous owner didn't cut, rip and tear the wiring, there shouldn't be any problems that you can't fix.

Post your list of codes and I will post the 5.0 Fox Mustang specific definitions and fixes.
 

FrankenStang88

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jrichker

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One of the things I saw right away was the air filter in the engine compartment. That has been known to cause idle and surge problems.It sucks up hot engine air from the radiator and the turbulence from the fan causes uneven airflow. The stock airbox and flat panel filter is miles better that what you have.
I suggest that you put the air filter and airbox back like it was from the factory. The original setup is in fact a cold air intake since it pulls air in from the fenderwell.
 
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Mustang5L5

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Only a handful of the codes actually set the CEL off. I don't think code 85 is one of them. What are the other codes you are getting?


Also, the car has carbed valve covers on it and the vac line to the TB is blocked off.
 

Mustang5L5

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I put a vented gas cap on and it and the cel is still on. Will i have to actually put back on all the stuff the previous owner took off?

The canister is still there. Unsure why the owner decided to cut the lines to it. One line goes to the intake manifold, and the other connects to a hard line running to the gas tank. If ou reconnect these, and plug the wiring harness back in that plugs into the charcoal canister, the code 85 should go away. The vented gas cap won't work on an EFI car.


Your EGR system looks intact. At least from what I can see. It looks like the original owner removed the smog pump and lines, and cut the lines to the charcoal canister but never took it off for some reason
 

Mustang5L5

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Yes the car was converted to MAF by previous owner, hopefully it was done correctly. Theres three empty screw holes on the side of the bracket were it connects the intake. Is soethimg missing off of it? And i just ordered new O2 sensors as stupid me used the old ones with the new engine i put in

I'f never seen a stock MAF with two sets of mounting bosses on it.

What are the part numbers of that MAF?
 

KissMyAssphalt

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I'f never seen a stock MAF with two sets of mounting bosses on it.

What are the part numbers of that MAF?[/
Only a handful of the codes actually set the CEL off. I don't think code 85 is one of them. What are the other codes you are getting?


Also, the car has carbed valve covers on it and the vac line to the TB is blocked off.


just wondering what TB stands for. I am sure it is something simple. I am trying to get this car going also. Runs good just have some rough idle issues and its getting a little hot also. Have new water pump with new 195 thermostat. keeps running around 210 to 220 under normal conditions (normal for AZ anyways) 100+ degrees.
 

FrankenStang88

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So appearently the car is one of the few california cars with both MAF and MAP. Im not certain but the MAF sensor and housing must be the stock one that came with the car. Does this change anything or help any? We got the new O2 sensors in and car seems to be running "cleaner" in a sense. We also noticed a vacuum line from the MAP sensor was not even blocked off so we put it back into the manifold like it should be.
 

jrichker

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Wrong idea.... MAF and MAP do not work on any Ford product, MAF and Baro do work together.

On a Speed Density car, the MAP/BARO sensor is connected to the intake manifold and acts to sense the manifold pressure. Lower vacuum inside the intake manifold when combined with more throttle opening measured by the TPS means more airflow through the engine. As airflow increases, fuel flow through the injectors needs to increase to keep the air/fuel ratio where it needs to be. When manifold vacuum increases, the engine is either decelerating or idling, and it needs to reduce the fuel flow through the injectors.

On a Mass Air car, the MAP/BARO sensor vents to open air and actually senses the barometric pressure due to changes in weather and altitude. Its purpose is to set a baseline for the computer to know the barometric pressure. As barometric pressure decreases, it leans out the fuel flow to compensate for less oxygen in the air. When the barometric pressure rises, it increases to add fuel since there is more oxygen in the air. The fuel requirements decrease as altitude increases, since the atmospheric pressure decreases.

Disconnecting the MAP or BARO sensor will set code 22.

Misconnecting the BARO sensor to vacuum on a Mass Air car will cause the computer to lean out the fuel mixture.

Code 22 or 126 MAP (vacuum) or BARO signal out of range. The MAP or BARO sensor is pretty much the same sensor for both Mass Air & Speed Density cars. The main difference is where it is connected. Mass Air cars vent it to the atmosphere, while Speed Density cars connect it to the intake manifold vacuum. Its purpose is to help set a baseline for the air/fuel mixture by sensing changes in barometric pressure. The MAP or BAP sensor puts out a 5 volt square wave that changes frequency with variations in atmospheric pressure. The base is 154 HZ at 29.92" of mercury - dry sunny day at sea level, about 68-72 degrees. You need an oscilloscope or frequency meter to measure it. There a very few DVM’s with a price tag under $40 that will measure frequency, but there are some out there.

Map sensor wiring:
black/white - ground
orange/white or +5 volts power
white/red signal out.

Measure the +5 volt supply using the orange/white and black/white wires
Measure the signal using the black/white and white/red wires.

The MAP/BARO sensor is mounted on the firewall behind the upper manifold on 86-93 Mustangs.

Baro or MAP test using a real frequency meter - run the test key on, engine off. The noise from the ignition system will likely upset the frequency meter. I used a 10 x oscilloscope probe connected from the frequency meter to the MAP/BAP to reduce the jitter in the meter's readout. And oscilloscope is very useful if you have access to one or know of someone who does. With an oscilloscope, you can see the waveform and amplitude.

If it is defective, your air/fuel ratio will be off and the car’s performance & emissions will suffer

Some basic checks you can make to be sure that the sensor is getting power & ground:
Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.
Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1 ohm. Next check the resistance between the black/white wire and the negative battery cable. It should be less than 1.5 ohm.

The following power on check requires you to turn the ignition switch to the Run position.
Use a DVM to check for 5 volts on the orange/white wire. If it is missing, look for +5 volts at the orange/white wire on the TPS or EGR sensors. Use the black/white wire for the ground for the DVM.

a9x-series-computer-connector-wire-side-view-gif.71316.gif


eec-iv-computer-connector-for-5-0-mustang-gif.88243.gif



Diagrams courtesy of Tmoss & Stang&2birds

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
88-91_5.0_EEC_Wiring_Diagram.gif


Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
91-93_5.0_EEC_Wiring_Diagram.gif


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

O2 sensor wiring harness
http://www.veryuseful.com/mustang/tech/engine/images/mustangO2Harness.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pin out
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

87-92 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang87-92 PowerWindowWiring.gif

93 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang93PowerWindows.gif

T5 Cutaway showing T5 internal parts
http://www.veryuseful.com/mustang/tech/engine/images/5_Speed_Cutaway_Illustrated.jpg

Visual comparison of the Ford Fuel Injectors, picture by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/Ford_Injector_Guide.jpg