Engine 95 5.0 Still Running Like S#@!, Many New Parts Installed, Stumped?????

Discussion in '1994 - 1995 Specific Tech' started by israela, Feb 15, 2014.


  1. israela

    israela New Member

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    Hello fellow stang brothers, haven't posted here in a while but due to my current situation I figured I come on here and ask for some help. I recently purchased a 95 gt 5.0, two weeks into my ownership my block split at the crankshaft :( so I found a used 5.0 HO from another 95 and replaced all possible gaskets, freeze plugs, water pump, hoses, rear and front seals before dropping it in. Timing chain checked out good when measured for slack so I left that alone. Engine is now installed and the following parts were purchased new, motorcraft plugs, msd cap n rotor, new wires, new maf, new intake air temp sensor, new coolant temp sensor, new air filter, new pvc valve, new fuel filter, new thermostat,new radiator cap, fluidyne radiator. Well the engine started on the first try and idled okay but when I tried to take off it had low power and sputtered but still somewhat driveable. Fast forward two days later now I can't even get her to stay on, it idles very rough, seems like a couple of cylinders aren't even firing and a very strong of cruede gas enough to make your eyes watery. The only way to keep her on is if I unplug the maf, iac, tps and intake air temp sensor and when I do this I get slight black smoke from the pipes. Tried pulling codes but the dash mode isn't working for me, don't know if am doing wrong or what...... Any help would be appreciated, thanks guys
     
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  2. davis3

    davis3 Active Member

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    Dash mode?
    Do you mean counting the flashes of the check engine light?

    I would buy a code reader from walmart or orileys.
    They are around $40 and much easier then counting flashes.

    Get the codes and report back.
     
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  3. israela

    israela New Member

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    So nobody around here seems to carry OBD1 scanners anymore, I had to order one online but it won't get here for a couple of days. Aside from that I made some progress, seems like my problems might be timing related.

    I wanted to try my other distributor from the previous engine because I knew it was working prior to the block giving out so I stabbed the new distributor in using the following steps:
    - Remove the #1 Spark Plug
    - Ensure the car is in Neutral
    - Get a 15/16" Socket and Ratchet
    - Put Ratchet on Crank and being to turn over the engine while holding thumb over the #1 spark plug hole, eventually when you come around to the compression stroke, the air in the cylinder will start to push your thumb off the spark plug hole
    - STOP, look down at your balance, note where the timing pointer is on the harmonic balancer, it should be coming around - Continue to slowly crank the engine over passing -0- TDC, and stopping on 10* BTDC.
    -Identify where the #1 Spark Plug Wire is or will be, and using a marker run a line down the side of the cap so with the cap off you will know where the #1 contact would be.
    -Remove the cap, and see where the rotor is pointed. It needs to be dead center on this line you drew, this would mean that the timing is at 10* BTDC (approx. only way to do it 100% is with a light, but this will get you well within reason).

    So as soon as I did this this she started right up and felt a little better but when I tried to use my timing light I couldn't even get it anywhere close to 10-14 degree marks. Advancing all the way would only get me to the TDC mark and even this was just enough to keep her on anything opposite (retarding) would just shut her down. So I went back to turn the crank to the 10* mark and open my distributor and noticed that the rotor was nowhere near the #1 contact!!!! I did this with two different distributors and the same thing kept happening. Also I know am still misfiring because at times I couldn't even get a pulse from the #1 plug.
     
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  4. jozsefsz

    jozsefsz Active Member

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    Did you remove the spout connector when attempting to set timing?
     
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  5. israela

    israela New Member

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    Yes I did, made that mistake too many times before lol.
     
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  6. jozsefsz

    jozsefsz Active Member

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    The only other thing I can think to check if your timing light doesn't seem to match what's happening in the distributor is the condition of the harmonic balancer. Those have been known to come apart / shift (check for any protruding rubber behind it). You mentioned the timing chain is solid so I wouldn't think you jumped a tooth or two but it might not hurt to crank it over with the distributor cap removed so you can see if the rotor is moving smoothly and consistently around the circle. Then of course you could have a PIP/TFI problem as well or just general engine ground issue.

    Aside from a timing issue, you could also be running rich for some other reason, but probably important to get the timing sorted first. Then it's on to codes. Did you move the injectors over from your old engine as well?
     
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  7. jrichker

    jrichker StangNet's favorite TOOL
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    Computer will not go into diagnostic mode on 91-95 model 5.0 Mustangs

    How it is supposed to work:
    The grey/red 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 grey/red 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. Only an experienced electronics technician can open the computer up & repair the trace if it burns up and creates an open circuit.

    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 (grey/red wire) on the self test connector and battery ground. You should see less than 1.5 ohms.

    [​IMG]

    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 grey/red 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 replaced.

    See http://www.stangnet.com/mustang-forums/749974-computer-issue.html#post7490537 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.
    [​IMG]

    [​IMG]

    Diagram courtesy of Tmoss & Stang&2birds

    Check out the diagram and notice all the places the grey/red wire goes. Almost every sensor on the engine except the MAF is connected to it.
    [​IMG]

    Complete computer, actuator & sensor wiring diagram for 94-95 Mass Air Mustangs
    [​IMG]

    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

    See the graphic for the 10 pin connector circuit layout.
    [​IMG]
     
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  8. israela

    israela New Member

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    @jrichker I think you might be right about the ecm on this one. After reading your post I began to search around and found a post over at allfordmustangs where this guy describes all my symptoms like my cooling fan coming on at start up, whining fuel pump, rough idle, not being able to pull codes and a new ecm fixed all the issues after he bought all new parts. Sounds familiar???
     
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  9. israela

    israela New Member

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    @jozsefsz Do I need to turn the crank over twice for the rotor to complete a full turn??? Sorry for my lack of knowledge on 5.0 distributors lol, am used to coil packs
     
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  10. jrichker

    jrichker StangNet's favorite TOOL
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    Not being able to pull codes is definitely a sign of trouble. See my previous post in order to correctly diagnose the problem.
     
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  11. jozsefsz

    jozsefsz Active Member

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    Yes you're correct, twice around the crank gives you once around the distributor. I'm siding with you both on the potential for computer problems, though agreed with jrichker I'd go through the whole procedure before making that guess (unless you had a spare computer laying around already).
     
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  12. toyman

    SN Certified Technician

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