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355 P1448, Rattle from Bypass?

Discussion in '348/355' started by Kruegmeister, Jun 9, 2019.

  1. Kruegmeister

    Kruegmeister Formula Junior
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    Nov 24, 2016
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    So I've done some searching about this, but much of it seems out of Date or the Parts are Not Available.

    Drove the 355 to Work Saturday to Upgrade my Quickbooks System.
    On the Way Home I got 3 Codes that I Cleared Previously.
    I believe all 3 are Related to the fact that I have HyperFlow Cats & a Tubi Exhaust.
    I also noticed a Rattle when I started it up Today to Check/Clear the Codes.
    That Rattle Went away, but after some research it sounds like it could be my Bypass Valve.

    So I am looking into Something Like the Gothspeed Bypass Valve but it doesn't seem available.

    The 2 Things I'd like to Solve.
    1) No more Check Engine Codes for it
    2) No Rattle

    What are my Options? Goth Bypass Valve? Something to Trick the System to not Give Check Engine Codes?

    Here is a Video I took with the Rattle Noise
    http://www.intecautomated.com/blindid/20190609_105620.mp4
     
  2. Qavion

    Qavion Formula 3

    Feb 20, 2015
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    What were the codes? Have you thought about Minicat Extenders for your cats?

    The Goth Bypass Valve is no longer for sale. There have been some non-standard fixes for bypass valves such as adding a spring to the mechanism or other ways of increasing the tension on the mechanism.
    Perhaps a stethoscope (or simple section of hosepipe) will help you locate the sound. Unfortunately, that video makes your car's engine sound like a diesel. Just wondering why you weren't pointing the camera at the bypass valve itself.
     
  3. Kruegmeister

    Kruegmeister Formula Junior
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    Read about the Bypass after I made the Video.
    I also read about the HosePipe Stethoscope too, so gonna try that as well.
    P1448, the other two I'll have to wait for them to come back up, but I know they were something that was specific to Having Non-Stock Cats & Exhaust from what I've read.
     
  4. Qavion

    Qavion Formula 3

    Feb 20, 2015
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    As always, the problem is figuring out if the faults are real or just as a result of your exhaust modifications. With the bypass code P1448, I've read that it appears when the temperature probe downstream of the bypass valve is picking up too much heat with the valve closed. This logic doesn't really provide much help with diagnosis. It could be a heatsoak problem, at thermocouple problem, a valve problem (stuck open, leaking or getting the wrong command) or a thermocouple ECU problem. I had what I thought was a bypass valve rattle and bought a Goth Bypass Valve (when they were available), but before I had it fitted, my local Ferrari independent seemed to think the valve was ok. I had the Goth valve fitted anyway (because it looked so good).

    If you are getting messages for all three exhaust paths, then it makes the problem even more difficult to diagnose. You can't swap known good components to see if the problem moves. Sometimes you just have to bite the bullet and buy at least one set of good components or find a way to read the signal coming from the TCUs. If the other messages are related to O2 levels, I would at least try some of the (relatively) cheaper fixes, such a quality set of extenders:

    http://www.bigdaddiesgarage.com/

    Extenders basically fool the ECU into thinking the O2 levels are normal. Because of this, you have to keep an eye on the cats over time to make sure they are ok.

    If the problem with the main cats is not related to temperature, then you could try swapping one of the good main cat thermocouple ECUs with the bypass valve TCU to see if that clears your bypass valve message.
     
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  5. Drock28

    Drock28 Formula 3

    Jan 13, 2013
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    that rattle at the beginning of the vid, I can confirm with 100% certainly is not a bypass valve rattle/buzz..

    that sounds like something loose, perhaps the exhaust clamps at the headers/cats section or cats/exhaust section.

    its definitely something loose.. its not the bypass valve..
     
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  6. 05elise

    05elise Rookie

    Jul 20, 2011
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    I just went through a very similar situation to yours with the codes but not the rattle. It would be nice to know what the other two OBD codes you erased were but from the description of your exhaust components I am pretty sure those codes were set due to the Hyperflow cats. I have Fabspeed headers, Hyperflow cats and a Capristo exhaust on my 355 and the codes I were getting were indicating catalytic converter insufficiency. The Hyperflows do exactly what their name says and flow the exhaust gases too rapidly without fully converting them so the downstream O2 sensors are seeing too much non-converted exhaust and signaling the ECU that the cats are insufficient and have failed.

    The easiest fix for this as mentioned in Qavion's post is to install O2 sensor extenders or mini-cats on your Hyperflows to position the downstream O2 sensors out of the direct exhaust stream. This will keep the O2 sensors from directly sniffing the exhaust gases and they will stop sending the signals to the ECU that are setting off your OBD codes.

    I installed O2 sensor extenders and I no longer get any codes but the only downside to this is if your car needs to pass emissions testing where you live. The extenders keep the O2 sensors from sending enough data to the ECU to ever set the O2 sensor and catalyst readiness monitors so your car will not pass an emissions test. The only way to get the car to pass emissions testing is to remove the Hyperflows and reinstall the stock cats or get aftermarket EPA compliant cats that flow like the originals.
     
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  7. Kruegmeister

    Kruegmeister Formula Junior
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    Thanks for the insight, need to put the Car on my Lift anyways to give it a full checkout cleaning underneath, lots of cover removal inbound.

    Michigan I think stopped this a while ago. Havent taken a car for emissions in over a decade.
     
  8. 05elise

    05elise Rookie

    Jul 20, 2011
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    Seeing as that is the case just install extenders on the downstream O2 sensors and that should fix the OBD codes problem.
     
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  9. Ferrarium

    Ferrarium Formula 3
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    Jul 28, 2018
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    It sounds like exhaust rattle somewhere like heat shields unil it heats up and expands then stops. Had that happen on previous cars.

    Sent from my LM-Q710(FGN) using FerrariChat.com mobile app
     
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  10. kenneyd

    kenneyd Formula Junior
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    Sep 30, 2014
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    The best way to tell if it is the bypass is to start the car and literally grab the bypass actuator with your hand and manually open/close it. (you may have to remove the heat shield) do it before it gets too hot.
    Some have had success with adjusting the preload on the bypass rod. That didn't work for me.
    I ended up installing a twin sound to fix mine :)
     
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  11. Kruegmeister

    Kruegmeister Formula Junior
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    I think I am gonna do the Extenders to fix the Codes. Anyone know if I'd need "MiniCat, Straight or Angled" from Big Daddies & how many?

    Looking at this pic which locations am I looking at?
    Image Unavailable, Please Login
     
  12. Qavion

    Qavion Formula 3

    Feb 20, 2015
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    One each side at the end of item 73.

    Opinions vary. Some swear by one type. You'd have to find someone who has a similar setup. The previous owner of my car had gutted the main cats and I didn't realise. I noticed there was some right angled extenders with some steel wool inside in an effort to fool the Motronics ECU. I now have some new high flow cats (Larini) which seem to be ok without these. Right angled extenders may give you better clearance, but it's probably not too difficult to check clearance yourself before buying a plain (straight or right angled) extender or straight minicat extender (I didn't see an option for a right angled minicat on the BigDaddies website).
     
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  13. 05elise

    05elise Rookie

    Jul 20, 2011
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    I have straight tube hollow extenders and they work fine but the clearance between the frame and the wiring from the O2 sensor on the LH side is a bit tight. There is no need for the mini-cats and if I did again I would go with the 90 degree extenders for better clearance. You only need two of them and they go between O2 sensor #73 in the diagram above and the rear bung in your Hyperfows as Qavion stated above. Mine are just cheap stainless steel extenders off eBay for less than $20 for the pair.
     
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  14. f355spider

    f355spider F1 World Champ
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    Rattle is definitely not the bypass valve. P1448 means the bypass valve is either open when the Motronic expects it to be closed, or it is closed when the Motronic expects it to be open. I would check for proper function of your bypass valve. Can you hear it open at WOT above 4,000 rpm?
     
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  15. Kruegmeister

    Kruegmeister Formula Junior
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    It takes a number of miles to show up, it sounds great at high RPMs so i believe it is opening properly
    Ordering some 90 degree sensors today for the other part
     
  16. Qavion

    Qavion Formula 3

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    Did you upload a second video (using the same link)? The video that's there now may offer some better clues for the experts.

    How long have you had the Hyperflows?

    Would cat core material flapping about cause that noise?
     
  17. Kruegmeister

    Kruegmeister Formula Junior
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    No that's the Same Video that was there.
    Bought the Car this year & it came with the Hyperflows on the Car.
    It did also come with the Original Exhaust & Cats as well so I have the option to return to the Original Cats... but it sounds so sweet WOT I'd rather only use those for process of elimination
     
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  18. Kruegmeister

    Kruegmeister Formula Junior
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    So my Codes were p1448, p0422 & p0432
    BigDaddies 90 degree installed x2 & now I only get the p1448
    Plan to take the Bypass off when I do my oil change & see if it moves freely, etc...
    Additionally I noticed that on the Passenger side there is 2 ECUs, 1 has 2 plugs plugged in, the other has just 1 plugged in??? I assume I need to plug something into that?
     
  19. WATSON

    WATSON F1 Veteran
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    #19 WATSON, Jul 28, 2019
    Last edited: Jul 28, 2019
    If you have a way to pull a light vacuum, you can check the valve in the car.

    I used my brake bleeder and a small hose.
    Just unplug the existing hose and attach a same size tube to the valve.
    Stuff the other end of that tube into your brake bleeder fitting and pull the trigger.
    It pulls enough vacuum to make the valve move.
    If it doesn't move, then you know where you stand.
     
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  20. Kruegmeister

    Kruegmeister Formula Junior
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    To Correct my Above Post, Everything was plugged in on my ECUs. But my New ECU was Just Hanging By the Wires and the old one was Mounted.
    Bill if your Listening, You may be Super OCD like me, but Your Mechanic maybe not so much, the other 2 things he missed was Plugging in the Ash Tray (which I replaced cause the flag was upside down) and the Rear View Mirror Control was not Plugged in...

    Everything Mounted Proper & Plugged in, so we'll see if the Dangling of the ECU may have made some "Ghost" p1448 Codes???
    Both seem to have 2018 written on them so it seems Previous Owner went thru this Exercise Already. So if I want to swap any of this which of these Connectors are Pertinent?

    For Future Reference these are all on the Passenger Side from Underneath right above the Exhaust Tips:

    Before 3 ECUs 1 New Hanging
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    After 2 ECUs Properly Mounted
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    Upper Horizontal ECU
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  21. Qavion

    Qavion Formula 3

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    Correct. I just hope you have the plugs on the right devices. If lots of work has been done on the exhaust system, you can't even be sure the thermocouples are plugged into the right ECUs. First check which thermocouple feeds which thermocouple ECU, then you'll have to figure out which plug goes where. The harnesses are probably sealed, so you may not be able to check the wire colours. If you can see the wiring, the bypass valve has a violet/black wire, the right cat has just a violet wire. If no colours are visible, you can just go for a test drive.... or if you want to do wiring checks at the ECU, I can provide you with a diagram.

    Sorry.. crossposted... what a mess :p
     
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  22. f355spider

    f355spider F1 World Champ
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    If everything is working correctly and you continue to get the P1448, then it is possible you have a bad catalyst ECU or thermocouple. That happened to me once. Just swap the ECU with one of the others, and see if the problem moves. It is does not, then try swapping a thermocouple. If the problem does not move, then I would focus on the bypass valve operation.
     
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  23. WATSON

    WATSON F1 Veteran
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    The bypass valve is set to open when the car hits a certain RPM in a certain gear and is dependent on the throttle position.
    I had a chart back in the day that had the exact details, but basically if you are over 3,000 RPM and 70% throttle (or something like that), the bypass is supposed to open.

    At one point I actually spliced a "T" into my bypass vacuum line and ran a tube into the cockpit and hooked it to a vacuum gauge and went for a ride.
    I could watch the vacuum change as I changed speeds, gears and throttle.

    The 1448 code is triggered by a temperature change as read by the thermocouple in place after the bypass valve.
    So if you get a code, the system THINKS the bypass valve is closed when it should be open because the temp probe is not seeing hotter exhaust gases.

    What can cause this?

    - Bad Bypass valve - duh

    - Bad thermo couple (doesn't register a temp change despite the valve actually being open)

    - Bad vacuum solenoid on the air pump (solenoid fails to engage and no vacuum is sent to the valve so it does not open)

    - Cracks or breaks in the vacuum line (check the metal tube that is brazed to the support bar. It cracks)
    ---- Not sure? Run a separate tube from the solenoid to the valve

    - Bad Air Pump (clean the filter on it)

    (The previous three possible problems is what caused me to run the vacuum line & gauge into my car. I could check all of that in one 10 minute drive)

    - Temp sensor ECU (cracked ones fail and the temp signal is not processed so the temp change is not detected)
    ---- As mentioned swap leads with the other ECU and see if the code changes with it.
    ---- Green packing ECU's are the newer style. The older style was known to be a failure point.

    - Thermocouple connected to wrong ECU (yup...hooking the bypass thermocouple ot the R/H Cat ECU will cause a problem)

    Probably missed something, but that was the list I worked with.
     
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