Mass Air Sensor For A Tune Help

Discussion in 'Fox 5.0 Mustang Tech' started by Wicked50Chris, Jun 28, 2013.

  1. Some basic theory to clarify how things work is in order…

    EGR System theory and testing

    The EGR shuts off at Wide Open Throttle (WOT), so it has minimal effect on performance. The addition of exhaust gas drops combustion temperature, increases gas mileage and reduces the tendency of the engine to ping. It can also reduce HC emissions by reducing fuel consumption. The primary result of EGR usage is a reduction in NOx emissions. It does this by reducing the amount of air/fuel mixture that gets burned in the combustion process. This reduces combustion temperature, and the creation of NOx gases. The reduced combustion temp reduces the tendency to ping.

    The EGR system has a vacuum source (line from the intake manifold) that goes to the EVR, computer operated electronic vacuum regulator. The EVR is located on the back of the passenger side shock strut tower. The computer uses RPM, Load. and some other factors to tell the EVR to pass vacuum to open the EGR valve. The EGR valve and the passages in the heads and intake manifold route exhaust gas to the EGR spacer (throttle body spacer). The EGR sensor tells the computer how far the EGR valve is open. Then computer adjusts the signal sent to the EVR to hold, increase or decrease the vacuum. The computer adds spark advance to compensate for the recirculated gases and the slower rate they burn at.


    There should be no vacuum at the EGR valve when at idle. If there is, the EVR (electronic vacuum regulator) mounted on the backside of the passenger side wheelwell is suspect. Check the vacuum line plumbing to make sure the previous owner didn’t cross the vacuum lines.

    Diagram courtesy of Tmoss & Stang&2birds. (the diagram says 88 GT, but the EGR part is the same for 86-93 Mustangs)

    The EGR sensor is basically a variable resistor, like the volume control on a radio. One end is 5 volt VREF power from the computer (red/orange wire). One end is computer signal ground (black/white), and the middle wire (brown/lt green) is the signal output from the EGR sensor. It is designed to always have some small voltage output from it anytime the ignition switch is the Run position. That way the computer knows the sensor & the wiring is OK. No voltage on computer pin 27 (brown/lt green wire) and the computer thinks the sensor is bad or the wire is broken and sets code 31. The voltage output can range from approximately .6-.85 volt.

    The EVR regulates vacuum to the EGR valve to maintain the correct amount of vacuum. The solenoid coil should measure 20-70 Ohms resistance. The regulator has a vacuum feed on the bottom which draws from the intake manifold. The other vacuum line is regulated vacuum going to the EGR valve. One side of the EVR electrical circuit is +12 volts anytime the ignition switch is in the run position. The other side of the electrical circuit is the ground path and is controlled by the computer. The computer switches the ground on and off to control the regulator solenoid.

    EGR test procedure courtesy of cjones

    To check the EGR valve:
    Bring the engine to normal temp.

    Connect a vacuum pump to the EGR Valve or see the EGR test jig drawing below. Connnect the test jig or to directly to manifold vacuum.

    Do not connect the EGR test jig to the EVR (Electronic Vacuum Regulator).

    Apply 5in vacuum to the valve. Using the test jig, use your finger to vary the vacuum

    If the engine stumbled or died then EGR Valve and passage(there is a passageway through the heads and intake) are good.

    If the engine did NOT stumble or die then either the EGR Valve is bad and/or the passage is blocked.

    If the engine stumbled, connect EGR test jig to the hose coming off of the EGR Valve.
    Use your finger to cap the open port on the vacuum tee.
    Snap throttle to 2500 RPM (remember snap the throttle don't hold it there).
    Did the vacuum gauge show about 2-5 in vacuum?
    If not the EVR has failed

    EGR test jig

    To test the computer and wiring to the computer, you can use a test light across the EVR wiring connectors and dump the codes. When you dump the codes, the computer does a self test that toggles every relay/actuator/solenoid on and off. When this happens, the test light will flicker. If the test light remains on the computer or the wiring is suspect.

    To check the EVR to computer wiring, disconnect the EVR connector and connect one end of the Ohmmeter to the dark green wire EVR wiring. Remove the passenger side kick panel and use a 10 MM socket to remove the computer connector from the computer. Set the Ohmmeter to high range and connect the other ohmmeter lead to ground. You should see an infinite open circuit indication or a reading greater than 1 Meg Ohm. If you see less than 200 Ohms, the dark green wire has shorted to ground somewhere.

    Late Model Restoration may still have the Ford Racing M-12071-N302 kit with the EGR valve & sensor along with the ACT & ECT sensors for $45. See;item?item_no=M12071N302 1&comp=LRS for more details

    Thermactor Air System
    Some review of how it works...

    Revised 17-Sept-2011 to add testing procedure.

    The Thermactor air pump (smog pump) supplies air to the heads or catalytic converters. This air helps break down the excess HC (hydrocarbons) and CO (carbon monoxide). The air supplied to the catalytic converters helps create the catalytic reaction that changes the HC & CO into CO2 and water vapor. Catalytic converters on 5.0 Mustangs are designed to use the extra air provided by the smog pump. Without the extra air, the catalytic converters will clog and fail.

    The Thermactor air pump draws air from an inlet filter in the front of the pump. The smog pump puts air into the heads when the engine is cold and then into the catalytic converters when it is warm. The Thermactor control valves serve to direct the flow. The first valve, TAB (Thermactor Air Bypass) or AM1 valve) either dumps air to the atmosphere or passes it on to the second valve. The second valve, TAD (Thermactor Air Diverter valve or AM2 valve) directs it to the heads or the catalytic converters. Check valves located after the TAB & TAD solenoids prevent hot exhaust gases from damaging the control valves or pump in case of a backfire. The air serves to help consume any unburned hydrocarbons by supplying extra oxygen to the catalytic process. The computer tells the Thermactor Air System to open the Bypass valve at WOT (wide open throttle) minimizing engine drag. This dumps the pump's output to the atmosphere, and reduces the parasitic drag caused by the smog pump to about 2-4 HP at WOT. The Bypass valve also opens during deceleration to reduce or prevent backfires.

    Code 44 RH side air not functioning.
    Code 94 LH side air not functioning.

    The computer uses the change in the O2 sensor readings to detect operation of the Thermactor control valves. When the dump valve opens, it reduces the O2 readings in the exhaust system. Then it closes the dump valve and the O2 readings increase. By toggling the dump valve (TAB), the computer tests for the 44/94 codes.

    Failure mode is usually due to a clogged air crossover tube, where one or both sides of the tube clog with carbon. The air crossover tube mounts on the back of the cylinder heads and supplies air to each of the Thermactor air passages cast into the cylinder heads. When the heads do not get the proper air delivery, they set codes 44 & 94, depending on which passage is clogged. It is possible to get both 44 & 94, which would suggest that the air pump or control valves are not working correctly, or the crossover tube is full of carbon or missing.


    Computer operation & control for the Thermactor Air System
    Automobile computers use current sink technology. They do not source power to any relay, solenoid or actuator like the IAC, fuel pump relay, or fuel injectors. Instead the computer provides a ground path for the positive battery voltage to get back to the battery negative terminal. That flow of power from positive to negative is what provides the energy to make the IAC, fuel pump relay, or fuel injectors work. No ground provided by the computer, then the actuators and relays don't operate.

    One side of the any relay/actuator/solenoid in the engine compartment will be connected to a red wire that has 12-14 volts anytime the ignition switch is in the run position. The other side will have 12-14 volts when the relay/actuator/solenoid isn't turned on. Once the computer turns on the clamp side, the voltage on the computer side of the wire will drop down to 1 volt or less.

    In order to test the TAD/TAB solenoids, you need to ground the white/red wire on the TAB solenoid or the light green/black wire on the TAD solenoid.

    For 94-95 cars: the colors are different. The White/Red wire (TAB control) is White/Orange (Pin 31 on the PCM). The Green/Black wire (TAD control) should be Brown (pin 34 at the PCM). Thanks to HISSIN50 for this tip.

    Testing the system:

    To test the computer, you can use a test light across the TAB or TAD wiring connectors and dump the codes. When you dump the codes, the computer does a self test that toggles every relay/actuator/solenoid on and off. When this happens, the test light will flicker.

    Disconnect the big hose from smog pump: with the engine running you should feel air output. Reconnect the smog pump hose & apply vacuum to the first vacuum controlled valve: Its purpose is to either dump the pump's output to the atmosphere or pass it to the next valve.

    The next vacuum controlled valve directs the air to either the cylinder heads when the engine is cold or to the catalytic converter when the engine is warm. Disconnect the big hoses from the back side of the vacuum controlled valve and start the engine. Apply vacuum to the valve and see if the airflow changes from one hose to the next.

    The two electrical controlled vacuum valves mounted on the rear of the passenger side wheel well turn the vacuum on & off under computer control. Check to see that both valves have +12 volts on the red wire. Then ground the white/red wire and the first solenoid should open and pass vacuum. Do the same thing to the light green/black wire on the second solenoid and it should open and pass vacuum.

    Remember that the computer does not source power for any actuator or relay, but provides the ground necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side will go to ground or below 1 volt as the computer switches on that circuit.

    The computer provides the ground to complete the circuit to power the solenoid valve that turns the
    vacuum on or off. The computer is located under the passenger side kick panel. Remove the kick panel & the cover over the computer wiring connector pins. Check Pin 38 Solenoid valve #1 that provides vacuum to the first Thermactor control valve for a switch from 12-14 volts to 1 volt or less. Do the same with pin 32 solenoid valve #2 that provides vacuum to the second Thermactor control valve. Starting the engine with the computer jumpered to self test mode will cause all the actuators to toggle on and off. If after doing this and you see no switching of the voltage on and off, you can start testing the wiring for shorts to ground and broken wiring. An Ohm check to ground with the computer connector disconnected & the solenoid valves disconnected should show open circuit between the pin 32 and ground and again on pin 38 and ground. In like manner, there should be less than 1 ohm between pin 32 and solenoid valve #2 and pin 38 & Solenoid valve #1.

    If after checking the resistance of the wiring & you are sure that there are no wiring faults, start looking at the solenoid valves. If you disconnect them, you can jumper power & ground to them to verify operation. Power & ground supplied should turn on the vacuum flow, remove either one and the vacuum should stop flowing.

    Typical resistance of the solenoid valves is in the range of 20-70 Ohms.

    Theory of operation:
    Catalytic converters consist of two different types of catalysts: Reduction and Oxidation.
    The Reduction catalyst is the first converter in a 5.0 Mustang, and the Oxidation converter is the second converter. The Oxidation converter uses the extra air from the smog pump to burn the excess HC. Aftermarket converters that use the smog pump often combine both types of catalysts in one housing. Since all catalytic reactions depend on heat to happen, catalytic converters do not work as efficiently with long tube headers. The extra length of the long tubes reduces the heat available to operate the O2 sensors and the catalytic converters. That will cause emissions problems, and reduce the chances of passing an actual smog test.

    Now for the Chemistry...
    "The reduction catalyst is the first stage of the catalytic converter. It uses platinum and rhodium to help reduce the NOx emissions. When an NO or NO2 molecule contacts the catalyst, the catalyst rips the nitrogen atom out of the molecule and holds on to it, freeing the oxygen in the form of O2. The nitrogen atoms bond with other nitrogen atoms that are also stuck to the catalyst, forming N2. For example:

    2NO => N2 + O2 or 2NO2 => N2 + 2O2

    The oxidation catalyst is the second stage of the catalytic converter. It reduces the unburned hydrocarbons and carbon monoxide by burning (oxidizing) them over a platinum and palladium catalyst. This catalyst aids the reaction of the CO and hydrocarbons with the remaining oxygen in the exhaust gas. For example:

    2CO + O2 => 2CO2

    There are two main types of structures used in catalytic converters -- honeycomb and ceramic beads. Most cars today use a honeycomb structure." Quote courtesy of How Stuff Works (HowStuffWorks "Catalysts")

    What happens when there is no extra air from the smog pump...
    As engines age, the quality of tune decreases and wear causes them to burn oil. We have all seem cars that go down the road puffing blue or black smoke from the tailpipe. Oil consumption and poor tune increase the amount of HC the oxidation catalyst has to deal with. The excess HC that the converters cannot oxidize due to lack of extra air becomes a crusty coating inside the honeycomb structure. This effectively reduces the size of the honeycomb passageways and builds up thicker over time and mileage. Continuous usage under such conditions will cause the converter to fail and clog. The extra air provided by the Thermactor Air System (smog pump) is essential for the oxidation process. It oxidizes the added HC from oil consumption and poor tune and keeps the HC levels within acceptable limits.

    Newer catalytic converters do not use the Thermactor Air System (smog pump) because they are designed to work with an improved computer system that runs leaner and cleaner
    They add an extra set of O2 sensors after the catalytic converters to monitor the oxygen and HC levels. Using this additional information, the improved computer system adjusts the air/fuel mixture for cleaner combustion and reduced emissions. If the computer cannot compensate for the added load of emissions due to wear and poor tune, the catalytic converters will eventually fail and clog. The periodic checks (smog inspections) are supposed to help owners keep track of problems and get them repaired. Use them on an 86-95 Mustang and you will slowly kill them with the pollutants that they are not designed to deal with.
  2. Here is an update. Today i had some time to finally mess with my baby, lol. First off i decided to try the Hz test on the MAP sensor again. I am not sure if my meter is showing the Hz right, but i wasn't getting ANYTHING when i put the Fluke meter to Hz. But yesterday i picked up a new MAP sensor. I figured if it didn't help, then I could just return it. Well when i hooked it up, i used my meter again to see if my meter worked fine and the old MAP was dead. Well i still think my meter doesn't show Hz reading correctly for whatever reason, but i did get a result. On the new MAP, the meter has a big number that hows Hz, but it always stays at 0. But under the 0 there is a long line of dots, maybe 20 of them. Its part of the range setting. When its set on Auto, those dots moved from left to right at a continuous rate. Then when i put my finger over the Vac hole, the series of dots went a lot slower rate. So to make a really long story shorter, I came up with the conclusion the MAP sensor was junk. Car ran better when it finally warmed up. And for the FIRST time ever, the check engine light didn't come on when running. WOOOHOOO. But after i went for a ride, it came back on. Which was expected. I ran out of time and couldn't spend 5mins to get the running codes. I will try again tomorrow, hopefully.

    Also, off topic, my starter is not working good right now. Had to turn the key a bunch of times. Gotta check the cable. When i bought the car, guy said he just replaced the starter. It looked brand new, so hopefully its just the cable.

    Before i took the car for a ride, i did check on the ECT sensor. I got 24.4KOhm resistance, and 2.84v before i even started the engine. It was a really hot day of 90s, so my guess the sensor was about 75-80 degrees F. From what i can see the sensor is just fine. If anyone can confirm that for me i would appreciate it.

    I still don't know what i should do with my EGR codes tho.... I REALLY appreciate all the theory/testing you posted about the EGR but it doesn't really help me for my setup. PREVIOUS owner removed smog pump, capped off exhaust going to the non existent cats, capped off the exhaust holes in the heads, TAB and TAD are gone, and the other vac solenoid that i cant remember the name of, sorry. All that's left of the emissions stuff is the EGR valve that's right near the throttle body. That's the ONLY thing plugged in. The other plugs are just sitting there connected to nothing. Is there anything i could do to help out my situation? Or is my only option, besides getting all the emissions stuff and hooking it up, is to get a chip to program out that stuff???

    Car still runs crappy when cold, but runs a lot better when warm. The idle still jumps from 1000-1400 rps. Once in a while it will steady out at 1k for a couple seconds, then go back to the surge.

    Any help is appreciated as usual. Thanks in advance guys.
  3. I poked around a little more today. The MAP code is still there even after i replaced the old one. But i have a new idea. When i check resistance from the black/white and go to ground on the battery, the meter says 5-6 ohms. When i check resistance from sensor to sensor on the black/white wire, its always less than 1 ohm, which is perfect. When i check resistance from a sensor to the disconnected salt and pepper shaker(sensor side), i get a resistance less than 1, which again is perfect. But when i try the center pin on the salt and pepper shaker (disconnected) to ground (computer side), 5 ohms shows up. I also checked the resistance from a sensor to the pin on the computer plug, it comes up less than 1, which tells me the wires are perfect. I also tried disconnecting every sensor that uses the black/white while the meter was connected between ground and the black/white on one sensor, and the resistance did NOT change.

    So i came to the conclusion that the black/white wires that go between all the sensors, to the salt and pepper shaker plug, are not the problem. I'm pretty sure the problem is between the salt and pepper shaker to the computer. I hope you guys understand what i mean. I am stumped because if there was an issue with the wires, i would have gotten a crappy reading from when i tested from the black/white wire to the plug on the computer, which gave me like .1 ohms. Confused. Hopefully you guys know what the problem is.
  4. Clear the MAF code 66 from the computer's memory: You will have to disconnect the battery for 5 minutes or so.
    Or you can dump the codes, and when they start to dump, disconnect the test jumper used to start the dump process.

    Be sure to take reistance readings with the battery negative cable disconnected.. Even with the ignition switch off, there is still a small amount of current flowing through the main ground path. It may be just enough to upset your readings.
  5. Ok just had some more fun again today. I disconnected the bat like you said, and nothing changed in my resistance readings. But i decided to do some poking around. I wanted to check the clutch switch, because i just had a feeling. And i was right. There are 2 plugs for the clutch switch. One of the plugs has 2 red/lt blue wires on one side, and 1 red/lt blue on the other. Its called the Clutch pedal position switch in my book. The other plug is, black/white and lt blue/yellow. Book calls this Clutch sense switch. The guy before me had ALL of these wires connected together. Which i can tell is a big no no. The red/lt blue is 12v pos, and the black/white is negative and is the common wire that goes to most of the sensors, egr, throttle pos, ect, map..... I just found the clutch switch in a box of parts the guy gave me with the car. So this was putting 12v into the black/white signal return line. uh ohhhh.

    Before i continue, i forgot to mention, that the car has the 140 cluster in it with a check engine light in it. And when i did the jumper to get the codes, the light actually functioned. The guy before me must have done something to get it to work. BUT, and i mean BUT, when i disconnected the jumper on all those wires that goes to the clutch switch, the check engine light no longer functions. I also tried to get the codes using my meter, and it wont spit the codes out. Something fishy here. So the only way for me to get the codes once again was to jump all those wires together. I even tried just jumping each plug, like the switch would do normally, and it wont spit the codes out. So i had to jump both plugs together, thus adding 12v to the black/white line. UGH... Hopefully someone can explain why, or knows what the problem is.

    When i separated both clutch switches, and started it, OMG the car ran BEAUTIFUL. The stang always had a nasty bouncing idle. I have never heard the car run so PERFECT. Took it for a ride this way and she felt great. But i had to put the damn jumper back so i could get the codes again. I got all the codes again, to see whats up.

    First set was, 81,82,85,84
    continuous (2nd set) 22,35,51,53,54
    engine running 41,91,32

    If you notice, ALL the continous codes are all the sensors that use the black/white wire. So i am pretty sure that most of those codes are because of that stupid jumper on the clutch switches, putting 12v on the black/white wire which would throw every sensor reading off. I am pretty sure this is whats going on. The only place i found the red/lt blue wire is at the TFI module on the distributor.

    After i removed the jumper i also checked the resistance on the black/white wire on the ect sensor to ground, and i got a lot of resistance, over 1k.

    Well i know this is a lot of info, and i hope someone knows whats going on.
  6. 12 volts applied to black/white wire on pin 46 usually fries the signal ground trace inside the computer...

    Computer will not go into diagnostic mode on 86-90 model 5.0 Mustangs

    Disconnect the battery positive terminal before making any resistance checks.
    The voltage drop in the ground cable will cause incorrect resistance readings.

    How it is supposed to work:
    The black/white wire (pin 46) is signal ground for the computer. It provides a dedicated ground for the EGR, Baro, ACT, ECT, & TPS sensors as well as the ground to put the computer into self test mode. If this ground is bad, none of the sensors mentioned will work properly. That will severely affect the car's performance. You will have hard starting, low power and drivability problems. Since it is a dedicated ground, it passes through the computer on its way to the computer main power ground that terminates at the battery pigtail ground. It should read less than 1.5 ohms when measured from anyplace on the engine harness with the battery pigtail ground as the other reference point for the ohmmeter probe.

    What sometimes happens is that the test connector black/white wire gets jumpered to power which either burns up the wiring or burns the trace off the pc board inside the computer. That trace connects pins 46 to pins 40 & 60.

    The STI (Self Test Input ) is jumpered to ground to put the computer into test mode. Jumpering it to power can produce unknown results, including damage to the computer. The ohm test simply verifies that there are no breaks in the wiring between the test connector and the computer input.

    How to test the wiring :
    With the power off, measure the resistance between the computer test ground (black/white wire) on the self test connector and battery ground. You should see less than 1.5 ohms.


    If that check fails, remove the passenger side kick panel and disconnect the computer connector. There is a 10 MM bolt that holds it in place. Measure the resistance between the black/white wire and pin 46 on the computer wiring connector: it should be less than 1.5 ohms. More that 1.5 ohms is a wiring problem. If it reads 1.5 ohms or less, then the computer is suspect. On the computer, measure the resistance between pin 46 and pins 40 & 60: it should be less than 1.5 ohms. More that that and the computer’s internal ground has failed, and the computer needs to be repaired or replaced.

    See for Joel5.0’s fix for the computer internal signal ground.

    If the first ground check was good, there are other wires to check. Measure the resistance between the STI computer self test connector (red/white wire) and pin 48 on the computer main connector: it should be less than 1.5 ohms. More that 1.5 ohms is a wiring problem

    The following is a view from the computer side of the computer wiring connector: it is for an A9L, A9P computer.


    Diagram courtesy of Tmoss & Stang&2birds

    Check out the diagram and notice all the places the black/white wire goes. Almost every sensor on the engine except the MAF is connected to it.


    See the following website for some help from Tmoss (diagram designer) & Stang&2Birds
    (website host) for help on 88-95 wiring

    See the graphic for the 10 pin connector circuit layout.
  7. Now all my issues are coming to perspective. I did as you told me to do and found the trace on the computer burnt. The soldering iron is heating up as i type this. And the other good thing, is i know for sure why its fried. Its all because the MORON hooked all the clutch switch wires on the petal all together. The red wire was pos and the black wire is the negative pin 46 to the computer. So now i know whats going on with the car.

    The only other thing that's bugging me a little is my o2 harness at the 8pin connector. There is NO loop at the plug, so my guess its still the speed density o2 harness. I know it wont put 12v to the ground, because there is NO jumper there. I am just not sure if that harness is ok to use with mass air. I did read hours of info on it last night, but never came across my setup. 89 mass air harness 5 speed with a9p, and using the speed density o2 harness. I saw many posts by you JR, but nothing that applied to my setup.

    Fixing the computer now, and will install and try it out. I'm so excited that i found the issue! Thanks again.
  8. Fixed the issue with the check engine light not working. Thanks. Just went for a ride and she felt great. Only issue is now shes running rich. My air/fuel gauge was at 10 when i got on it. I'm sure that's because of the huge injectors. But the check engine light didn't come on when driving. sweeeeeet. Im going to get all the codes in a couple mins. Other thing i noticed is it has a hanging idle. It sits at 1500 for 2 seconds before it goes back to idle at 1000-1100. Defiantly going in the right direction. I thank you again. I will post the engine codes soon
  9. Ok here is the newest set of codes.....
    KOEO 81,82,84,85
    Continuous 41,91
    Running 91,33,13,41

    From my understanding, all the KOEO codes are for missing emission stuff
    The 2 cont codes of 41,91 are for the O2. But they aren't to old at all. Maybe its because of my O2 harness??????? Because i have the older one for speed density with NO jumper at the 8pin plug.
    I think the running codes are ok to, 13 is idle which is ok, 33 egr which is expected, 91 i THINK is because of my 42lb injectors, and maybe 41 is because of the wrong o2 harness???

    That is what im thinking. Do you know if i need to add a jumper, or repin my o2 harness??? Like i said i looked for hours last night and couldnt find the right info. Maybe you can help??? I saw some of your posts already.

    Like usual, ANY help is appreciated. And i think WE are going in the right direction. Thanks buddy
  10. Wait i lied. The o2 harness at the 8 pin connector DOES have the purple wire looped between pi 5 and 6. From my readings that is an automatic o2 harness. I thought it didnt have the jumper, but it did. Now i need to see if this is the right one that i need for my setup with a 5 speed tranny, A9P computer, and the auto o2 harness. Doing some more reading.
  11. Still have not found if my O2 harness is correct or not. I read A LOT of stuff in the past 24hrs. Anybody know if my O2 harness is ok with my setup? Or do i need to move a couple wires around? Thanks
  12. I finally just found it! Here is a pic of the connectors on the body side, so now i can just match it up to what i have and see if everything is ok. This also shows you the pins that you need to know for the jumper wire on the o2 harness. You can have a 5speed O2 harness and repin it for an auto. If you have an A9P you you pin it for Auto, A9L you pin it for 5speed. I think this is a GREAT pic to have. Glad i just found it.

    Gotta give credit to them, the website for the pic is!-Mass-air-conversion

  13. Today i turned my fuel pressure regulator up a couple psi and it solved my lean problem. Its set at 40 with the vac attached at idle, and 48ish with the vac disconnected and plugged with my finger. When i got on it hard, my air/fuel gauge was around 13 which is pretty much perfect from what i have read. These little tweeks, keep making this car run better and better. From what i could see, my O2 harness is perfect, but just to make absolutely sure, i will take a reading at the computer at both pins to make sure the o2 signal is getting to the ecu properly. JR thanks again for your patience at helping me with my issues.

    I will get all my codes again tomorrow to see if the O2 codes go away, or to see if anything else pops up. I know i have been talking to myself the last couple days, sorry.
  14. Now to get BACK to the Mass Air meter stuff. I was looking at some slot style mass air meters, to replace my C&L. Lets just say i buy a ProM slot style mass air meter. Now for me to use it, i have to get a tune adjusted for it first before i actually use it right? Don't i need to tell the chip that i am using this with 42lb injectors right? With the 42s installed already, i cant just put this in and use it? I'm going to say, no i cant.

    When i am on eBay and see the slot mass air meters, some of them say, '30 point transfer function sheet". What exactly is that? Whats it for? I know its something to do with tuning, but i'm not to sure.

    Also how would i go about installing it, besides the wiring. Do i need to buy a housing for it to? Or can i just cut a hole in the intake and insert it???

    I did a good amount of reading on this topic, but i couldn't find the info i needed.

    Thanks guys
  15. The slot style mass air sensor can be used with a tune. The 30 point transfer is how the computer communicates with the sensor. It's called a Maf transfer table in the tune. It will get the car close to running right but most likely the points will be adjusted a little bit because every setup is different. I have heard of people just cutting a hole in a tube and mounting them but I would recommend something like this

    You can use a stock maf sensor from a 05+ mustang.. Cheap on eBay. Mine wasn't from a mustang. But worked fine
    Here is a link, hopefully this gives you some additional info
  16. Thanks a lot for all that info. It was helpful to me. I didnt realize a cheap slot meter was ok to use. But you showed me a couple options to mount it, and a cheap priced meter. Will a meter like that be good for lets say 500hp? Im not near that yet, but eventually going turbo. Will this work without the turbo, and with the turbo setup? As long as i tune it right? Thanks bro for the help.
  17. No, not 500 hp. You will need a hi flow meter for that. They are about 200$. I bought a hpx sensor for my turbo setup. If your gonna go turbo just buy the high flow sensor now. Otherwise you will need to change the maf transfer later. The hpx comes with an excel spreadsheet to give you the 30 point transfer. Because the transfer will change depending on what size pipe you put it in. That sensor I think is good for close to 1,000 hp I think if you put it in a 3.5 inch tube. For you, a 3 inch pipe will prob be what you want. You want to keep the pipe as small as possible because the sensor is more accurate in a smaller tube.
  18. I will look into it. Thanks bro
  19. If you are shooting for 500 HP, you will need an aftermarket block with thicker webs to support the crankshaft and a block with 4 bolt mains. The stock blocks start to split when subjected to enough boost to make 450- 500 HP. The block spit starts in the lifter valley and travels down into the crankshaft webs. Do a search on split blocks here in 5.0 Tech.
  20. Oh i know that stock blocks are good till 400. Going over that is not a good idea, and will lead I was only planning on getting a turbo next, boosting to about 7psi to get me somewhere near 400. Then when i want more, i was planing on getting a good bottom end with really good pistons for a turbo setup. Just trying to buy a new maf that will work for 500, because that's what i am shooting for eventually. I am always looking for a sweet bottom end. One should come up for sale near me someday. Thx jr