Question regarding raw fuel smell

Discussion in 'The Garage' started by Yon, Jun 30, 2015.

  1. Yon

    Yon New Member

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    So my build list is extensive, I had a total top half rebuild back in November.

    94 cobra 5.0L

    B303cam
    AFR 165 heads
    bbk headers
    CAI with 70mm throttle body
    MAC exhaust

    are the items worth noting.

    I asked my mechanic to put BBK hi flo cats on because I wanted her to be emissions legal. After about a day I took her out for a drive and I was in bumper to bumper traffic on the highway when i started to smell burning plastic and smoke coming out of my emergency brake well. I thought my car was on fire so i pulled immediately over and checked underneath. The cats were I sht you not, glowing blue. After I let them cool off a bit, i drove her back to the shop immediately. He told me that he never puts cats on any of his builds, and the cats were causing too much backpressure from the motor and overheating. So we cut them off.

    This fixed everything, except now everytime I drive her, I absolutely reek of fuel, he told me with the B303 he doesnt want the car to run lean, and not too long ago I went back because he said he double checked the tune he put on her and saw he left an emissions switch on so he turned it off, he failed to mention to me that he increased the timing on her. When we started her back up, she stalled immediately, I had to spend 2 hours resetting the idle with him. And shortly after fixing the idle we noticed blue smoke coming out of the tailpipe

    My question for you guys is, I assume the blue smoke is from him increasing the timing. the car hardly has 44k miles on it, i doubt the piston rings are spent that quickly and she wasnt pouring out blue smoke before (or at least i never noticed). and #2 is it that normal to reek of raw fuel with no cats? is there a way to change the tune where i can put catalytic converters on it without them overheating?

    alot of questions here I know... but i literally have to shower everytime I drive this thing. He told me thats just the way it is, and I have a hotrod now, its no longer a cruiser. Which i understand, except the drivability of this thing really went out the window.

    thanks for reading
     
  2. slow90coupe

    slow90coupe Well-Known Member

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    It's a 5.0 without cats, it's going to reek of fuel. If you have dumps, you will definitely smell like fuel 24/7, but if you have tailpipes it shouldn't be too bad.
     
  3. Yon

    Yon New Member

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    yea i have straightpipes right into the MAC mufflers/tailpipes

    is there any way to put cats on it without them overheating?
     
  4. Michael Plummer

    Michael Plummer Active Member

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    Honestly, find a new mechanic or performance shop for the following reasons below.

    * 2 hours resetting your idle: This isn't rocket science.

    * Blue smoke out of the tailpipes: Mechanic doesn't tell you that oil is usually the culprit or even checks out why.

    * High flo cats causing to much back pressure and overheating the engine: Is he serious?

    * Increased total timing will not cause blue smoke unless the timing is advanced to high. Either it detonated and oil is leaking into the combustion chamber or when the camshaft was installed he messed up when setting up your valve train.

    * And the lack of cats causing raw fuel smell: Check the following for your raw fuel smell: Injector leak, fuel tank leak, fuel line leak, charcoal canister needs replacing or missing or faulty gas cap.

    Good luck
    Michael Plummer
     
  5. Yon

    Yon New Member

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    not overheating the engine, the cats themselves were overheating, and melting the plastic interior console.

    He did tell me that the blue smoke was from burning oil, but he said it was because of the age of the car, not the milage.. suggested that all piston rings on a 94 mustang are worn at this point.

    And as far as the fuel lines, he replaced the fuel pump, he put on 42lb injectors because I told him that a supercharger was in my future plan. People were saying that thats too high for N/A but he said that by adjusting the tune it would be fine. I had a ton of work done all at once, almost everything was replaced/upgraded

    Anyone know any good tuners in the Philly area?
     
  6. Michael Plummer

    Michael Plummer Active Member

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    Q) not overheating the engine, the cats themselves were overheating, and melting the plastic interior console.
    A) Ok, I mis-understood.

    Q) He did tell me that the blue smoke was from burning oil, but he said it was because of the age of the car, not the milage.. suggested that all piston rings on a 94 mustang are worn at this point.
    A) You failed to mention that. He should do a compression and leakdown test to see what kind of shape the motor is in. And the blue color is fine for new exhaust components when they get heat in them for the first time. Put your cats back on.

    Q) And as far as the fuel lines, he replaced the fuel pump, he put on 42lb injectors because I told him that a supercharger was in my future plan. People were saying that thats too high for N/A but he said that by adjusting the tune it would be fine.
    A) I would still check the items I listed for raw fuel smell. But if your bottom end is junk which a compression and leak down test will reveal, a rebuild or new shortblock will be needed before any supercharger.

    Q) Anyone know any good tuners in the Philly area?
    A) Hold on, not so fast.
     
  7. GregT94SCC

    GregT94SCC New Member

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    42# injectors with the stock fuel pump? Stock regulator?
    Stock MAF?
    How did he/she tune for them, set scalar values for slope or adjust tables? Both? Neither?
    How does your oil smell?
    How was the cam degreed?
    Was a wideband part of the tuning process?
     
  8. Yon

    Yon New Member

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    Well its been long enough to discredit any snoke being the result of new components... That all has definitely burned off. The car always had a smell to it which was fine but it got significantly worse after he messed with the timing the last time i brought it in. Ill have him do the test to check the block, just for peace of mind.

    And as far as putting cats on, im telling you the cats he put on were regular hi flo bbk's and they were glowing. I dont know if theres any adjustment to not make that happen but he made it seem that cats with this current setup is unheard of
     
  9. Yon

    Yon New Member

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    I honestly have very little to no information about these things, he doesnt really tell me what he changed as far as the tune is concerned. I just know the MAF and fuel pump are not stock. I guess i should get that info from him.
     
  10. chris91

    chris91 Well-Known Member

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    I'd find a new mechanic. I wouldn't let him touch your car again. High flow cats do not cause too much backpressure. And backpressure wouldn't cause them to glow blue... What causes a cat to glow like that? Overly rich setups is the main cause. I'd be willing to bet your car is running insanely rich and when running that rich you can wash out the rings causing your blue smoke. You can run high flow cats on any setup. My buddies 600hp Terminator has a catted x pipe on it and his doesn't do that shit.
     
  11. GregT94SCC

    GregT94SCC New Member

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    I run the stock h-pipe, 42# injectors, lmaf, kenne bell....

    Chris is correct, your cats should never get that hot. Your mechanic is in over his head and feeding you bs IMO.
     
  12. Yon

    Yon New Member

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    I appreciate the feedback, i want another mechanic/performance shop to look at it and give me an opinion, im just not sure exactly what my next move is
     
  13. Michael Plummer

    Michael Plummer Active Member

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    Like I mentioned before, slow down and take a deep breath. If you're comfortable with your current mechanic have him perform the compression and leak down tests. This would be a good time to replace your spark plugs with new ones. And have him check your old spark plugs for oil. This is a good place to start.

    Now your mechanic is probably mechanically inclined to perform work on your car but his actually knowledge as to how things work may be lacking based on what you're telling me/us. Again, if you trust him, have him perform the tests and then you'll know if your engine is okay. This is where you should start.

    Good luck
    Michael Plummer