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Loud bang, and now car is LOUD!

Discussion in '1994-2004 V6 Mustang Tech' started by jessipanda, Sep 18, 2017.

  1. jessipanda

    jessipanda New Member

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    Hi everyone! I joined this forum hoping to get some help diagnosing an issue with my boyfriends 2004 Mustang. I'm not extremely experienced with working on vehicles, but I'm a pro compared to him...

    So a bit of backstory. We've been having some issues with this car. For about 2 years, we would have to mess with the battery terminals to get the car to start. Never thought much of it, it would always start. Figured it was caused by loose terminals. Replacing them didn't fix it. Replacing the battery didn't fix it. So we just dealt with it. Then, it decided it was just going to stall out while it was being driven down the road. It did this several times over a 2 day span. That day (Friday) we took it to a shop, explained what's been going on, and they couldn't figure out the problem. So we scheduled an appointment with the Ford dealership for that Monday. Dropped it off, explained the situation, and they had the car until Friday. In those 5 days, they never could quite figure out the true issue, but they did replace the water pump (never had any issues with it over heating and we live in FL), as well as an ignition wire. A grand later and the car is running great, and was even performing much better (accelerating like you would expect a Mustang to, when before it seemed to drag a$$ when trying to accelerate). So even though I had questions, they seemed to have fixed the problem. That was exactly a month ago today.

    Today, my boyfriend was driving home from work and claims the car backfired (sounds more like it had an after fire from the way he describes it) when he accelerated quickly. Following the gunshot sound, his car now sounds as though he has a straight pipe with no cat or muffler. It's also lost a bit of power, but it still feels better than it did prior to being in the shop.

    To me, it sounds (and smells) as though the exhaust is escaping at the connection to the cat. If I'm right, would that also explain the minor loss of power while accelerating? It doesn't affect it much, and the car hasn't "backfired" since even though I've attempted to recreate it.

    I know another issue could be the fuel-to-air ratio being off one way or the other, but I feel the car would have a significant difference in power from that and would most likely backfire again.

    If you have any suggestions for me, additional issues that could cause this, or would like more info, please let me know. I appreciate any input on the matter.

    Thank you!
     
  2. douglass

    douglass Active Member

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    Probably the best way to start is to jack car up, put on jack stands, and look for broken exhaust connection/parts. You could also start the car, and have someone under the car while it's running to check for exhaust leaks. If you have having an raw exhaust smell now, I would suspect an issue around or before the cats.

    Douglass
     
  3. Serpent

    Serpent Member

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    mods to the car?
     
  4. jessipanda

    jessipanda New Member

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    Thanks Douglass, I can't axtually see any leaks, but can feel air escaping at the cat connection from the engine.

    Serpent, no mods at all. Completely stock.

    He has noticed it's going through nearly twice as much gas and the "service engine soon" light came on this evening. Having him take it up to the parts store to get the code for me. I checked all the fluids and such the day this happened, and forgot to mention that the radiator overflow tank was nearly empty. Filled it with the coolant we had left, but having him grab more while he's at the parts store today. Everything else appears to be fine though.

    Thanks for the input. =)
     
  5. Serpent

    Serpent Member

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    see what the cel says. sounds like a sensor has failed and the cpu is getting erroneous information causing the car to run rich and possibly throw the timing maps off.
     
    Last edited: Sep 20, 2017
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  6. jessipanda

    jessipanda New Member

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    Thanks Serpent. I will get back with that once he returns. =)
     
  7. jessipanda

    jessipanda New Member

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    Got 2 codes. One for the O2 sensor, the other saying cylinder bank 1 in running to lean. Hopefully replacing the O2 sensor takes care of the air/fuel ratio issue. However, I have a feeling the issue with the exhaust would also need to be fixed to ensure the air/fuel ratio is good. Am I correct with this thought? Anything I'm missing or any other suggests/tips/input?

    Thanks for all the help thus far.
     
  8. Serpent

    Serpent Member

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    yes, on both counts. get the leak fixed at the same time someone replaces the O2 sensor. see what you have then.
     
  9. jessipanda

    jessipanda New Member

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    Called to see when we can get it in. Due to the hurricane, they have no openings until Oct. 2
    Can we continue to drive it until then or do we risk causing further damage by driving it? Don't want to make things worse
     
  10. Serpent

    Serpent Member

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    lean condition while also smelling gas....first, lean conditions can cause damage if too lean. gas dumping into the cat can ruin the cat which is expensive. the lean condition could be the cpu dumping more fuel to make up for it, or you may have a leak somewhere. smelling gas may be indicative of another issue. hard to say about the driving especially since no other code and may not have another code until the lean condition is fixed first.

    as far as having to wait...where are you? all you need is a competent muffler shop. they can take care of the leak and replace the O2 sensor if you are unable to do that yourself. if you do replace the sensor yourself, I would wait until you are going to take the car for the leak so as not to damage the sensor. ain't cheap.

    I can only say what I would do if my car. this is not advice, it is what I would do. I would limit the use of the car as much as possible until fixed.
     
  11. jessipanda

    jessipanda New Member

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    Thank you, Serpent. =)
     
  12. Serpent

    Serpent Member

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  13. Serpent

    Serpent Member

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