95 3.8L Mustang Electrical problems

Discussion in 'SN95 V6 Mustang Tech' started by tommyhilfing, Mar 14, 2010.


  1. tommyhilfing

    tommyhilfing New Member

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    This will be my 1st post.
    I am having problems with idle, rpm, and lack of power to begin with. At idle it sounds fine maybe a little rough but when I give it gas in park it hesitates then it revs fine after hesitation. While driving it seems sluggish and when i get to 80kms the rpm drops to 1000 and runs rough. I have a po340 code which is cam shaft positioning sensor which could be a number of things. So i was wondering if I could someones shed some advice or input about what they think it could be.
    2. I have about 2 inches of play in my steering wheel.
    3. When i get to 70kms my passenger side front tire seems to wobble.
    4. My power locks don't work the key fob doesn't work neither (probably needs to be reprogrammed but cant because you need the door lock buttons to work to set the code.) My interior light or map lights don't work either but the dash lights work fine. Also my heater works fine except on all settings it comes out of my defrost port.
    Thank you for reading and responding.

    Tom D.
  2. MustangLX-5.0

    MustangLX-5.0 Founding Member

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    Hi , and welcome to SN :)

    To answer you first question... The Cam sensor is faulty. the 0340 code is "Camshaft Position Sensor circuit fault" .I see this problem often on the 3.8's. First, the crank sensor is what is used instead of a distributor , to notify what position the crank is in at all times. This gives you your ignition timing. The Cam sensor is used to fine tune the timing by reading the position of the camshaft. Right now, your cam sensor has an internal fault which is causing it to mis-read the cam position thus making your engine run like crap. What I suggest you do at the moment is unplug the cam sensor until you can get it replaced. Don't worry, the engine will run fine without it, just that you will have a very slight hesitation on throttle. And it wont be as bad as if the sensor were plugged in. I don't suggest you leave it like that though. get it replaced if you have emissions testing where you live. FYI - the cam sensor is located directly behind the water pump , between the thermostat housing (water neck) and the ignition coil pack. Careful unplugging it as the tabs on the sides tend to break easily.

    2. " I have about 2 inches of play in my steering wheel " - If you are referring to free spin play, then it could be a couple of things. First, if the free play is so bad, I would suspect a loose steering shaft to steering rack pinch bolt. This is where the steering shaft fits directly into the steering rack itself. There is a bolt on the end of the shaft that is tightened to lock the shaft onto the rack. If the bolt is loose, the steering wheel could have as much as a couple inches of free play turning. I would suspect the rack pinch bolt only if the free play is like ( You're able to easily spin the steering wheel with your index finger alone). If this is not the case, then look at my response to your number 3 question.

    3. " When I get to 70kms my passenger side front tire seems to wobble. " - KM/H I assume you meant. First, check to make sure your lugnuts are secure. The most obvious culprit of this is a bad inner, or outer tie rod end. Tie rods are like ball joints , in which they have a metal ball end pressed into a socket. The tie rods secure the steering rack to the spindle. The spindle is where your struts mount and is also where your wheel is attached. When a tie rod starts wearing out, the wheel is allowed to move too easily on it's own. This can result in wobble , numerous vibrations and clunking noises, not to mention very poor ride control. Does your steering tend to wander off left and right at higher speeds?

    And as for you last questions.. Power locks and lights not working, first check the fuses. Both under the dash and the power dist box under the hood. I'm sure that's all the problem is. Same goes for remote. does the panic button on the remote work? Does anything else not work (that you are aware of) ?

    Fan only blowing out of defroster vents.. probably a disconnected vacuum line for the vent door air diverter. Open the hood and look at the very top of the firewall, just behind the engine. Along the very top is a skinny plastic vacuum line going straight across from left to right side. Follow it and make sure it hasn't come unplugged from it's other half (usually in the very middle where its plugged in). If it's still plugged in, check along the entire line and make sure there aren't any cracks in it. If there aren't any, it may be disconnected where it plugs into the vent control knob.
  3. Aeroman

    Aeroman New Member

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    PO340 is the code for faulty CMP sensor which is what the engine control looks at for fuel injector timing with sequential fuel injection. It tells the engine specifically when the #1 cylinder is on the power stroke. Otherwise the injection could be 360* out of phase with the spark & valve timing. You may have a damaged CMP sensor or the synchroniser assembly could be damaged. Do you hear a squeaking noise sometimes? if so then that is an indication that the syncho vane is bent (if yours has the hall effect unit), which will ultimately break the magnet from the CMP sensor. The other problem you could have is an malfunction in the electrical circuit which feeds the sensor. Either way symptoms of p0340 could be ranging from poor acceleration to hesitation or sometimes no noticable effect at all!
    However I would fix it for sure. It will likely have a marked affect on fuel consumption.
  4. tommyhilfing

    tommyhilfing New Member

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    Thanks for your replies.
    I checked the vacuum hose for the heater vent and it was broken off so i jimmy rigged it for now and all work fine now.
    I will be getting a new cps this weekend and have unplugged the sensor for now. (will I notice any difference with it unplugged?)
    I checked the ball joint on the outer tire rod and moving the steering wheel just enought to not turn the tires I see some play in the tie rod so I'll be changing that this weekend also.
    As for checking the fuses that was the 1st thing I checked. Heres the thing on this issue I looked at the wires in the door loom well as much as I could see since the boot was hard to get off enough to see. After playing with the wires the door lock button locked the passenger side door but not the drivers side. I tried to unlock and nothing. Now it dosn't even lock any more but when I push the door lock button the radio and clock light go out.
  5. tommyhilfing

    tommyhilfing New Member

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    Ok I put the new cps in and now the rough running in drive is better but still present. When I come to a stop now it vibrates. What else could it be? Maybe it needs a tune up?
  6. Aeroman

    Aeroman New Member

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    Is your engine misfiring? when did you last change plugs & wires, air filter, fuel filter etc. Assuming all these are fine, I would suspect your Idle speed controller (IAC). Pull the plug from this & see if the engine behaves differently. On a normal engine your rpms will drop when you pull the plug. Otherwise your MAF sensor could also do this. Cleaning the MAF sensor requires finesse, spray clean only with electrical contact cleaner or MAF cleaner. DONT touch the wire, it will break really easily.
    Also that CMP syncroniser has to be timed pretty accurately otherwise you will get a CEL.
    Aeroman.
  7. wmburns

    wmburns SN Certified Technician

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    Check small vacuum lines for leaks/disconnection

    Check the small grey vacuum line from the engine bay through the firewall. This vacuum line provides the vacuum needed to activate the damper servos. Without vacuum, the servos can not change position. This could also be a source for a vacuum leak that will cause issues.

    Note, the default position is in the defrost mode.

    If the vacuum line is OK, it will be necessary to diagnose the heater/AC controls. Look for leaks or disconnected vacuum lines under the dash. Esp if recent radio install.

    Regarding the CMP, if you did not use the special tool to install it, it is wrong. Use the correct tool for the type of CMP on your car as there are differences.

    Good luck.
  8. tommyhilfing

    tommyhilfing New Member

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    OK so I fixed the vent problem nice to have heat on my face again.
    I changed the cam shaft positioning sensor, that cleared the engine light.
    Now my MAIN problem is still my idle and acceleration. It is worst now then ever I changed my fuel and air filter my spark plugs (NGK) but not the wires yet. I don't think they are the problem I will be changing them anyways to NGK's. Also my car now vibrates at idle so mush i can see my fingers shaking when I touch the steering wheel. It has a loud vibrating humming sound when at high speeds or climbing hills and it seems to lag going up the hill. :shrug:
  9. MustangLX-5.0

    MustangLX-5.0 Founding Member

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    You changed the cam sensor? Did you have it re-synchronized? If not, then thats probably what your problem is. Any new cam sensor must be sychronized otherwise it wil be off timing and cause very rough running conditions. Unplug the new cam sensor and see if it runs better. If it does, thats your problem.
  10. Aeroman

    Aeroman New Member

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    Do the plug wires first, then we can rule out a spark loss problem. No flashing CEL? you should get a misfire code or a flashing CEL with a bad misfire. Are your engine mounts loose or broken?

    Loud vibrating humming sound, is this from the engine or driveline ? Does it vary with engine speed/ load or road speed? First we need to establish exactly where it is coming from. Bearings tend to whine, gears tend to hum, does this occur in any specific gear? or is it engine rev related (does it in any gear?)
  11. tommyhilfing

    tommyhilfing New Member

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    The Haynes book says you don't have to sync if just changing the sensor. I tried unplugging it anyways no difference. New wires no difference. No misfire codes. I was thinking it could be the mounts I'll have to look at them. There are 2 noises. Definitely 1 from engine and 1 from front left wheel. The one from the front left wheel almost sounds like an airplane engine now so loud. The vibration sound is coming from the engine when I hit 80km/h the rpm drops and the engine vibrates. While at idle I see the engine kinda bounce with the hood open. Thats what makes me think it could be an engine mount. Im taking it to a mechanic this week I'm no mechanic just thought Id get some input to see if I could save money by doing it my self but now I'm just annoyed with it. :nonono:
  12. mrv8outboard

    mrv8outboard Member

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    Wheel bearing is bad. Do a compression test, or better yet do a leak down test. It sounds like you have a bad hole.
  13. tommyhilfing

    tommyhilfing New Member

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    What is a leak down test?
  14. Aeroman

    Aeroman New Member

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    Wheel bearing on front sounds pretty definate.

    The vibration at 80 KMH could be drive shaft related, can you feel it through the floor of the vehicle?

    Leak down test is a way of determining where you may have an engine compression problem. Basically by pressurising the combustion chamber, you are able to listen at various passages, intake, exhaust valve cover area etc. Thus able to "hear " the hiss of the leaking component.
  15. VunderBar09

    VunderBar09 New Member

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    hey did you try cleaning your mass air flow sensor it is a thin sensor made of wire when i cleaned my sensor it woke it up. no lack of power

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