Map Questions

moyer17901 · Feb 19, 2016

the code reader is on its way for $27, ill wait til it shows up next week with my new ecu and Bama tune chip, we will see if that gets me any closer

mikestang63 · Feb 19, 2016

moyer17901 said:
the code reader is on its way for $27, ill wait til it shows up next week with my new ecu and Bama tune chip, we will see if that gets me any closer

BAMA chip?

stykthyn · Feb 20, 2016

Am I the only one that thinks of Forrest Gump screaming Alabama every time they see those words?

moyer17901 · Feb 20, 2016

yeah well the local dyno shop uses SCT chips so I could either buy it from their shop for 350 or buy it online and save $100 and then have them tune it

Mustang5L5 · Feb 22, 2016

Thowing new parts at this won't necessarily fix anything until the cause of your troubles is identified. You probably do not need 24#ers, and running too much injector can be just as troublesome if you don't really need it.

Start with getting your ECU to dump codes first. For all we know, you have a bad ECT sensor or something simple like that.

moyer17901 · Feb 22, 2016

well thus far i have a bad egr, when i removed it so much rust and corrosion came out its not possible that it could read anything. second I had a pin hole on my vacuum line under my upper intake, third my lower intake where it seats to the heads was on it way out, with the upper intake off i used an adapter and vacuum pump and was mainly checking that the valves were seated but i found that the gasket was letting small amounts of air pass, i saw the oil i sprayed on it suck in. then i pulled the injectors and found two of the caps that were damaged and cracked so i rebuilt all of them, the kits are like $3 so i just did it. after i get it all back together i will see where i stand

Mustang5L5 · Feb 23, 2016

Failed EGR would cause some of the issues you saw

moyer17901 · Feb 23, 2016

also in the a/c vacuum line i found a pin hole where it rubbed another line, hopefully all of this will get me back in good running shape

moyer17901 · Mar 12, 2016

okay so after replacing the intake, all the vacuum lines the fuel pressure regulator, distributor and MAF I was going to check the timing but i cant get the car to stay running without holding it at about 1k it will just shut off checked the codes and all i get is 67 and 11 im losing my mind i checked and rechecked that i have the distributor on 10 degrees tdc, compression stroke. i have rechecked all the lines, the only thing that confused me is why during the maf install it has you cap the vacuum lines off to the map but it doesnt have you unplug it

jrichker · Mar 13, 2016

moyer17901 said:
okay so after replacing the intake, all the vacuum lines the fuel pressure regulator, distributor and MAF I was going to check the timing but i cant get the car to stay running without holding it at about 1k it will just shut off checked the codes and all i get is 67 and 11 im losing my mind i checked and rechecked that i have the distributor on 10 degrees tdc, compression stroke. i have rechecked all the lines, the only thing that confused me is why during the maf install it has you cap the vacuum lines off to the map but it doesnt have you unplug it

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.

moyer17901 · Mar 13, 2016

i have the car able to start, the timing is set but it wont stay running and has a miss but everything is set, new plugs and wires cap and rotor but its like im only running on a few cylinders ever since i shorted the other single wire over where the obd 1 connector is ive had this issue but the fuses are fine i dont get it

jrichker · Mar 13, 2016

Shorting the OBDI wiring to power damages the computer. Have you been able to dump codes according to my since your mishap?

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. http://www.stangnet.com/mustang-forums/threads/how-to-pull-codes-from-eec4.889006/

moyer17901 · Mar 13, 2016

yes i can, i replaced the computer because i thought i fried the other one but the car does the same with both computer, the codes are only the neutral switch, and the a/c switch because its been removed I dont know what else i could have killed, a sensor of some sort. wont idle, if i give it throttle it has a miss, and runs super rich

madspeed · Mar 13, 2016

did you fix the lower intake gasket issue?

moyer17901 · Mar 14, 2016

yes put a different intake on, all new gaskets and still having the issue im sure its a sensor issue

jrichker · Mar 14, 2016

You need to fix the code 67 - it isn't just an A/C code, it will tell if the A/C is on and prevent you from dumping the engine running codes. There are codes that do not show up unless the engine is running.

The next thing you need to do is to dump the engine running codes and do a cylinder balance test.

Code 67 –
Revised 2 Nov 2012 to add definition of the NSS functions for both 5 speed and auto transmissions

Cause of problem:
clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On Engine On tests.

External evidence from other sources claims that a code 67 can cause an idle surge condition. Do try to find and fix any issues with the switch and wiring if you get a code 67.

What the NSS (Neutral Safety Switch) does:
5 speed transmission: It has no connection with the starter, and the engine can be cranked without it being connected.
Auto transmission: It is the safety interlock that prevents the starter from cranking the engine with the transmission in gear.
What it does for both 5 speed and auto transmission cars:
The computer wants to make sure the A/C is off due to the added load on the engine for the engine running computer diagnostic tests. It also checks to see that the transmission is in Neutral (5 speed and auto transmission) and the clutch depressed (T5, T56, Tremec 3550 & TKO)). This prevents the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven.

The following is for 5 speed cars only.
The NSS code 67 can be bypassed for testing. You will need to temporarily ground computer pin 30 to the chassis. Computer pin 30 uses a Lt blue/yellow wire. Remove the passenger side kick panel and then remove the plastic cover from the computer wiring connector. Use a safety pin to probe the connector from the rear. Jumper the safety pin to the ground near the computer.
Be sure to remove the jumper BEFORE attempting to drive the car!!!

Cylinder balance test: use this to find dead or weak cylinders:

Revised 19-Dec-2015 to update RPM ranges and include a more complete description of the engine running tests that are done prior to the cylinder balance test. Added YouTube video to show the process.

The computer has a cylinder balance test that helps locate cylinders with low power output. You’ll need to dump the codes out of the computer and make sure that you have the A/C off, clutch depressed to the floor and the transmission in neutral. Fail to do this and you can’t do the engine running dump codes test that allows you to do the cylinder balance test.

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.

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

Here's how 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.

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 the 86-88's except possibly the Cali Mass Air cars.

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.

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

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 the wiring 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 and drivability 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, clutch depressed 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

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® 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 (3145It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $22-$36.

Cylinder balance test

If you have idle or IAC/IAB problems and the engine will not idle on its own without mechanically adjusting the base idle speed above 625-750 RPM, this test will fail with random cylinders pointed out every time it runs. The IAC/IAB must be capable of controlling the engine speed to run in the 1300-1500 RPM range. Playing with the base idle speed by adjusting it upwards will not work, the computer has to be able to control the engine speed using the IAC/IAB.

Warm the car's engine up to normal operating temperature. With the test jumper in test position, start the engine and let it stabilize. It should flash a 10 and then a 4 and maybe an 11. If no 11, then there are other codes that will be dumped.
One of the first tests it does is to open the EGR all the way, this will cause the engine to stumble and almost die. If the engine dies here then you have EGR problems.
To start the cylinder balance test, briefly floor the accelerator past 2500 RPM and let off the accelerator. The engine will stabilize at about 1300-1450 RPM and the cut off the fuel injectors one at a time. The engine speed will drop briefly and the computer will turn the fuel injector for the cylinder under test back on. Then it starts the process for the next cylinder. When it has sequenced through all 8 injectors, it will flash 9 for everything OK, or the number of the failing cylinder such as 2 for cylinder #2. Quickly pressing the throttle again up to 2500 RPM’s will cause the test to re-run with smaller qualifying figures.
Do it a third time, and if the same cylinder shows up, the cylinder is weak and isn’t putting out power like it should. See the Chilton’s Shop manual for the complete test procedure

See View: https://www.youtube.com/watch?v=HDXrkKS4jTE
for a visual tour through the process. There is no voice narration so you have to listen carefully for the engine sounds.

Do a compression test on all the cylinders.
Take special note of any cylinder that shows up as weak in the cylinder balance test. Low compression on one of these cylinders rules out the injectors as being the most likely cause of the problem. Look at cylinders that fail the cylinder balance test but have good compression. These cylinders either have a bad injector, bad spark plug or spark plug wire. Move the wire and then the spark plug to another cylinder and run the cylinder balance test again. If it follows the moved wire or spark plug, you have found the problem. If the same cylinder fails the test again, the injector is bad. If different cylinders fail the cylinder balance test, you have ignition problems or wiring problems in the 10 pin black & white electrical connectors located by the EGR.

How to do a compression test:
Only use a compression tester with a screw in adapter for the spark plug hole. The other type leaks too much to get an accurate reading. Your local auto parts store may have a compression tester to rent/loan. If you do mechanic work on your own car on a regular basis, it would be a good tool to add to your collection.

With the engine warmed up, remove all spark plugs and prop the throttle wide open with a plastic screwdriver handle between the throttle butterfly and the throttle housing. Crank the engine until it the gage reading stops increasing. On a cold engine, it will be hard to tell what's good & what's not. Some of the recent posts have numbers ranging from 140-170 PSI. If the compression is low, squirt some oil in the cylinder and do it again – if it comes up, the rings are worn. There should be no more than 10% difference between cylinders. Use a blow down leak test (puts compressed air inside cylinders) on cylinders that have more than 10% difference.

I generally use a big screwdriver handle stuck in the TB between the butterfly and the TB to prop the throttle open. The plastic is soft enough that it won't damage anything and won't get sucked down the intake either.

A battery charger (not the trickle type) is a good thing to have if you haven't driven the car lately or if you have any doubts about the battery's health. Connect it up while you are cranking the engine and it will help keep the starter cranking at a consistent speed from the first cylinder tested to the last cylinder.

Mustang5L5 · Mar 14, 2016

moyer17901 said:
yes put a different intake on, all new gaskets and still having the issue im sure its a sensor issue

Did it start after swapping out the intake?

moyer17901 · Mar 14, 2016

well the ac compressor is gone, so it the receiver drier so i could just make a jumper wire for that pressure switch. This all started when i went to get the codes manually before i bought a code reader, i shorted the black single wire near the gray single wire. fuses, relays, fusable links are all good. so my thought is it caused a sensor to burn out, i know the tps is good. its just a matter of figuring out which one it is, and replacing it

jrichker · Mar 14, 2016

moyer17901 said:
well the ac compressor is gone, so it the receiver drier so i could just make a jumper wire for that pressure switch. This all started when i went to get the codes manually before i bought a code reader, i shorted the black single wire near the gray single wire. fuses, relays, fusable links are all good. so my thought is it caused a sensor to burn out, i know the tps is good. its just a matter of figuring out which one it is, and replacing it

You don't need to do anything with the A/C except make sure it is off when you dump the codes. Jumpering the A/C cutout pressure switch will just make things more difficult. See the diagram below.

I highly suggest that you go back and read the code 67 definition that I posted. Until you do what is necessary to fix the code 67 you can't dump the engine running codes or do a cylinder balance test.

Fox 5.0 Mustangs use the same computer and wiring harness in cars with A/C and cars without A/C. The fact that you A/C is missing parts does not affect the dumping of codes. When the A/C is on and has a full charge of refrigerant, there is 12 volts present on pin 10 of the computer pink/lt blue wire. This disables the engine running diagnostics and sets code 67 when the computer is put into diagnostic mode

Diagrams courtesy of Tmoss & Stang&2birds

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs

The A/C sense wiring is the same on 87-93 5.0 Mustangs

moyer17901 · Mar 19, 2016

okay i now have the car able idle, it surges and dies idling after like 3 or so min. codes are 67, 82, 10, 11 i have the entire ac system unplugged, 67 is just me being lazy and not keeping my foot on the clutch. 82 says its the air diverter is that the purge valve for the charcoal can or is that the EGR. I'm getting closer and i thank you all for your input. it truly has been a big help. I just want to get it to drivable again

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