I Need Some Help Please. Car Pops Out Of Intake.

Discussion in 'Fox 5.0 Mustang Tech' started by erniet17, Sep 9, 2013.

  1. Hey everyone. I need some help with my car. I had a turbo 363 setup and I recently took it out to replace it with a 302 H/C/I. I had to replace the ECM harness cause the car would go crazy when I moved the harness around. The harness had been tapped into in a few places as well. I first took the turbo setup and left the 363 in it. The car ran great with no issues whatsoever. I pulled the engine and the car sat for about 6 months. I dropped in the 302 and it has never an correctly. The block is an old block that I had and ran good when I pulled it.

    Here's a quick run down of the parts it has:
    Edelbrock heads, which had a valve job prior to installing.
    TFS Stage 1 cam with 1.7 Rockers
    Edelbrock RPM 2 intake with an Accufab TB and Pro-M 80mm Mass Air calibrated for 24lb injectors
    24lb injectors
    Fuelab pump with -10 feed and -8 return with BBRC rails (I know it's overkill but it's what I had with the turbo)
    T5Z Transmission
    The distributor is a Motorcraft unit that was bought new and might have a few thousand miles on it
    All sensors have been replaced
    Timing is set at 14*
    Fuel pressure is at 38

    The issue I have is popping out of the intake while accelerating. It happens about 75% of the time. The car is down on power as well. I have swapped out mass airs and injectors with no luck.

    Also, if I disconnect the O2 sensors the car will really run bad. The sensors are new Motorcraft ones. When I had the car with the 363 it had no O2 sensors hooked up and it ran fine.

    I've been chasing my tail on this issue for about 6 months now and I'm about to call it quits. If anyone can suggest anything it will be greatly appreciated.
    #1 erniet17, Sep 9, 2013
    Last edited: Sep 9, 2013
  2. Backfiring out the intake is either a valve stuck open or a lean mixture or spark plug wire(s) connected to the wrong cylinder(s). Check compression on all cylinders and then look for vacuum hoses loose, cracked, or misconnected. Check the line for the vapor recirculation system – it is easy to knock loose and not see it when you connect the air pump plumbing. If the vacuum line for the EGR valve and the air pump are cross connected, some very strange things can happen. Check the mass air flow electrical connection and see that it is tight, the same goes for the fuel injection wiring harness connectors up on top of the manifold near the firewall.

    Sticking valves: If a intake valve is bent, has a bad spring or is misadjusted, the engine will sometimes backfire through the intake. Use a vacuum gauge connected to any convenient spot on the intake manifold. Run the engine at 1000 RPM & look for 18-21 inches of vacuum with a steady needle. A problem intake valve will make the vacuum gauge needle sweep 5-10 inches.

    Lean fuel mixture breaks out into several sub categories:
    A.). Vacuum leaks
    B.) Air entering the intake without passing through the MAF on Mass Air cars (89-95 models).
    C.) Failure of the MAF, BAP/MAP (Baro or Manifold Air Pressure, same sensor, different name), ACT (air charge temp), or ECT (engine coolant temp). These should set a code in the computer.
    D.) O2 sensor problems: one or both O2 sensors with low output or bad O2 sensor heater ground. This should set codes 41/91. The O2 sensor heater ground is an Orange wire in the engine mounted fuel injector harness. Ground it to the back of the head or intake manifold.
    E.) Leaking exhaust gases from EGR valve at WOT or EGR opening when it should not be open.
    F.) Poor fuel delivery due to bad fuel pump, clogged filter or bad fuel pump wiring. Look for low pressure or fluctuating pressure. Standard injector pressure is 39 PSI at idle, with the vacuum line disconnected from the regulator and capped.
    G.) Clogged fuel injectors.- see the cylinder balance test below
    H.) Fuel injector wiring problems causing injector not to deliver rated flow (dirty or stuck shut injectors).
    I.) Computer problems: (computer problems are not common like sensor problems)
    J.). ROM has bad data in fuel or timing table. This should also set a code in the computer.
    K.) Failure of one or more of the computer's driver transistors for the fuel injectors. No code set on this one. Use a noid test light to test the injector wiring & injector drivers,
    L.) MAF calibration off or mismatched to injectors.
    M.) ACT or ECT bad. Sometimes the sensors will be off calibration, but not bad enough to set a code. If they falsely read too high a temp, the engine will back off fuel delivery.

    The HO firing order is 1-3-7-2-6-5-4-8.
    Non HO firing order is 1-5-4-2-6-3-7-8


    Cylinder balance test:
    See the procedure below to dump the codes and place the computer into diagnostic mode.

    Warm the car's engine up to normal operating temperature. Use a jumper wire or paper clip to put the computer into test mode. Start the engine and let it go through the normal diagnostic tests, then quickly press the throttle to the floor. The engine RPM should exceed 2500 RPM's for a brief second. The engine RPM's will increase to about 1450-1600 RPM and hold steady. The engine will shut off power to each injector, one at a time. 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

    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.



    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 driveablity 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.

    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 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 $30.
  3. I dumped the codes with my scanner. Am I supposed to keep the clutch down during the whole test? That's the only way it will work.
  4. These are the KOEO codes I got: 67,81,82,85,84,87
    I haven't had smog equipment in about 6 years.

    The KOER codes were: 12,33,44
  5. And I have the EGR eliminated by one of those simulators.
  6. Do you have a open breather on the valve cover? If so take it off

    Sent from my XT907 using Tapatalk 2
  7. No, I don't have a breather on. I have it setup like factory from the valve cover to the throttle body.
    #7 erniet17, Sep 10, 2013
    Last edited by a moderator: Sep 10, 2013
  8. Code 67----did you have clutch pressed down the entire time?

    Code 81 + 82 ---referring to smog pump equipment. Not critical

    Code 85 --Charcoal canister. You prob yanked it. Hopefully you are venting the fumes somewhere safe

    Code 84--- EGR circuit failure. Usually causes a code 33

    Code 87 -- Primary Fuel Pump Circuit Failure. Is this a Mass air converted 87-88 Mustang??

    Code 12 - Idle speec control out of range. Search for the "Idle reset procedure" here and perform it. This code usually happens when someone adjusts idle by the set screw and doesnt reset the computer to relearn idle strategy.

    Code 33 -- EGR not opening

    Code 44 - Related to smog pump valves not opening.

    Remove it.

    You are tricking the car into thinking the EGR is functioning when it's not. So the car pulls fuel and timing and goes lean. Remove the simulator and let the EEC see the EGR is faulted and disable that function. The CEL will be lit up until you get a custom tune.

    I hate to say this, and I say it often...but yanking smog equipment is sometimes more trouble than it's worth. It robs zero HP, but i've seen it time and time again where sometimes cars have issues due to the removal of smog/EGR stuff.
  9. Yes, I had the clutch down the whole time.

    The car came without most of the smog equipment and with my aftermarket tank the vent goes back in the fill neck. I've had the EGR simulator on the car with the old 302 and with the 363 and never had an issue.

    The car is a 93 and the thing that gets me is that the car ran perfectly until I swapped the engine out. The only thing I am not using is the 42lb injectors and mass air. I changed the harness out too. Other than that it is all the same. I have even swapped out computers, distributors, etc...
  10. Fix the code 12 and the code 67 and run the cylinder balance test.

    Code 12 -Idle Air Bypass motor not controlling idle properly (generally idle too low) - IAB dirty or not working. Clean the electrical contacts with non flammable brake parts cleaner at the same time.
    IAC doesn't work: look for +12 volts at the IAC red wire. Then check for continuity between the white/lt blue wire and pin 21 on the computer. The IAC connector contacts will sometimes corrode and make the IAC not work. The red wire on the IAC is always hot with the engine in run mode. The computer provides a ground for the current for the IAC. It switches the ground on and off, making a square wave with a varying duty cycle. A normal square wave would be on for 50% of the time and off for 50% of the time. When the idle speed is low, the duty cycle increases more than 50% to open the IAC more. When the engine speed is high, it decreases the duty cycle to less than 50% to close the IAC. An old-fashioned dwell meter can be used to check the change: I haven’t tried it personally, but it should work. In theory, it should read ½ scale of whatever range you set it on with a 50% duty cycle. An Oscilloscope is even better if you can find someone who has one and will help.


    Recommended procedure for cleaning the IAC/IAB:
    Conventional cleaning methods like throttle body cleaner aren’t very effective. The best method is a soak type cleaner used for carburetors. If you are into fixing motorcycles, jet skis, snowmobiles or anything else with a small carburetor, you probably have used the one gallon soak cleaners like Gunk or Berryman. One of the two should be available at your local auto parts store for $22-$29. Take the solenoid off the body and set it aside: the carb cleaner will damage some types of plastic parts. Soak the metal body in the carb cleaner overnight. There is a basket to set the parts in while they are soaking. When you finish soaking overnight, twist the stem of the IAB/IAC that sticks out while the blocker valve is seated. This removes any leftover deposits from the blocker valve seat. Rinse the part off with water and blow it dry with compressed air. The IAC/IAB should seal up nicely now. Once it has dried, try blowing through the bottom hole and it should block the air flow. Reassemble and reinstall to check it out.

    Gunk Dip type carb & parts soaker:

    Setting the base idle speed:
    First of all, the idle needs to be adjusted to where the speed is at or below 600 RPM with the IAC disconnected. If you have a wild cam, you may have to raise this figure 100-150 RPM or so. Then the electrical signal through the IAC can vary the airflow through it under computer control. Remember that the IAC can only add air to increase the base idle speed set by the mechanical adjustment. The 600 RPM base idle speed is what you have after the mechanical adjustment. The IAC increases that speed by supplying more air under computer control to raise the RPM’s to 650-725 RPM’s. This figure will increase if you have a wild cam, and may end up between 800-950 RPM

    Remember that changing the mechanical idle speed adjustment changes the TPS setting too.

    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!!!

  11. Thanks, I hope to get to it on Thursday and post the results.
  12. Regarding the code 67...I jumped the clutch switch in the past by inserting a spade fuse and it didn't help and I replaced the switch while I was in there too.
  13. Doesn't seem like the weather is going to cooperate today.

    What can be causing the car to run worse when the o2 sensors are disconnected?
  14. The computer goes into limp mode when it detects a missing or malfunctioning major sensor like the O2 sensors. Limp mode means reduced power and fuel economy.
  15. I've had them disconnected in the past but not with this setup. I know lots of people disconnect them as well. Maybe the computer has an issue???
  16. Chasing rabbits and throwing parts at a problem will only leave you poorer and frustrated.

    Computers seldom fail, usually it is a sensor or wiring problem. I can point you to resources written by OEM Ford engineers and top Ford Tuners that tell you exactly what's in the computer and how it works. However, that is not necessary at this time.

    Go back to my first post, start at the top and work your way down to the bottom. Then dump the codes and do a cylinder balance test. Your success at fixing this depends a great deal on your wiliness to Test, Observe and then Diagnose. Once you have a good diagnosis, then repair or replace what you diagnosed as the problem.
  17. Code 87 -- Primary Fuel Pump Circuit Failure. Is this a Mass air converted 87-88 Mustang??

    That's probably what's leading to his lean popping.
  18. No, it is a 93. The pump aftermarket pump has bee on there for a few years now and have never had an issue. I don't have an inertia switch.

  19. I only got around to cleaning the IAC and I sprayed the O2 harness contacts with cleaner and put dielectric grease on them. No change there.

    I did remove the EGR simulator and that seems to have helped a bit but it still pops under acceleration sometimes. Just not as severe.
  20. What I want to know is why get rid of the turbo 363 set up? I bet that was a mean SOB.