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Unusual sound after I shut off the engine?

Discussion in 'Boxers/TR/M' started by jpanz, Mar 29, 2020.

  1. jpanz

    jpanz Karting
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    I have an 89 tr US car. I drive at least once a weekend roughly 25-60 miles. The cars runs flawlessly in cooler weather 35-50 degrees F.
    On warmer days it starts right up than after about 10 seconds I get a rough idle and sometimes stalls in the 500rpm range. It usually sorts itself out as the water temp comes up than Is fine. The last two times I went to take out 65+ degrees it really had a hard time warning up with poor power and poor throttle response. Than the next day it ran perfect. However at the end of the ride when I shut down the engine it made an usual sound for 3-5 min. The sound was pretty loud coming from somewhere near the passenger rear wheel well.
    Originally I suspected suspected it just needed a retune (which is out of my hands mechanicallly) But this sound was something totally new? The second video was prior to me headed out!

    Any ideas?Vacuum? Maybe it’s common I searched “noise after shut off” and got nothing. Wasn’t really sure how to search it? Forgive my mechanical inexperience.
     
  2. vincenzo

    vincenzo F1 Rookie

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  3. jpanz

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    Thanks! Is there a reason why that might happen
    All of a sudden? I have put 4K + miles on it since a full service 3/18 and never heard that before. Could it be an indication of a problem?
     
  4. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #4 Steve Magnusson, Mar 29, 2020
    Last edited: Mar 29, 2020
    +1 -- Just remove the gas cap and see if (a lot of air rushes out and) this stops the noise (but I don't think this related to the OP's runability problem -- just a noisy/maybe sticky valve in the charcoal canister).

    This (poor power and poor throttle response) is a symptom of the protection relay not supplying +12V power to the KE-Jet injection symptom, and then it starts working and things are fine. Can be the protection relay itself or just a bad connection. Easiest first thing to do is just unplug and replug the round C12 and C13 connectors on the black box over the RR wheel well to wipe the connections (these connectors are a little tricky as the captive locking ring needs to be "unscrewed" as the body is withdrawn out -- and these locking rings often get broken -- the connector can just be pushed back in without the locking ring and still sort of work, but not good for long-term connection reliability). If you do a search on "red wire water thermoswitch protection relay" that should get you many threads about how to measure the voltage at the red wire on the water thermoswitch to confirm/deny if this is causing your problem.
     
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  5. vincenzo

    vincenzo F1 Rookie

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    It is a simple system. Go to the ricambi site and identify the various pieces in the system both on the parts sheet and on your car. Then identify the exact location from which the sound emanates. Once you identify the part, pull it and see if you can fix it. If not - buy it and replace it. Take note of the parts that are no longer available... don’t be ham handed.

    You may need to pull the valence (body panel below the exhaust pipes) for easy access.

    Voila ... you are a mechanic.
     
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  6. vincenzo

    vincenzo F1 Rookie

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  7. 302Tim

    302Tim Formula 3
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    That's definitely your fuel system pressurizing/venting--mine does the same, more on a hot day with little fuel in the tanks. Like Steve said, loosen the gas cap and you'll hear the pressure release. Not sure the cause, I have replaced both charcoal canisters. Doesn't affect how the car runs (at least in my case).
     
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  8. jpanz

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    Thanks to all that replied. It makes perfect sense.
    And my rough idle issue started before this ever sound ever happened.

    Everytime I open the gas cap to fill the tank I get that huge release of vapor from the tank. No other car I ever had does that? I assumed it was normal for the tr. Maybe it hasn’t been venting al along and now vapor finally made its way out??
     
  9. jpanz

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    Thanks Steve

    Im going to look into the protection relays soon as I get a chance. Ironically I had just read a recent post about a rough idle and it talked extensively about the protection relay.
     
  10. jpanz

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    So this covid thing has my job totally screwed up so I’m afraid to dig into a project I can’t complete at the moment. The weather was decent two days ago so I tried again to fire up the tr. it wouldn’t start at all. I waited two min and it fires right up and ides well. I went for a ride and after about 7 miles of running perfect and at full temperature I came to a red light and noticed my idle was rough in the 500 range border line stalling. I looked it off the road into a parking lot. And shut it off I restarted with the same rough idle and limped it home with very little power. At one point I could barely get it going after a stop sign. I got it home and parked it on the lift.

    Is this still a symptom of a protection relay or is this more likely an ignition issue. At times the exhaust was very rich (burn you eyes rich). Both exhaust pipes got equally?
     
  11. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Yes, still sounds related to operation of the protection relay. On the ignition side of things:

    If you lose bank 1-6 spark = the idle RPM will be low, but still very smooth. Power will be 1/2, but very smooth.

    If you lose bank 7-12 spark = the tachometric relay will open = both fuel pump relays will open = both fuel pumps shut off = engine stops (won't idle at all).
     
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  12. jpanz

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    Thanks Steve, that’s reassuring!!
     
  13. jpanz

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    So I pulled out the triangular box. Upon opening I could see that the protection relay was Seated all the way. I removed it and checked the fuse which is good. I put it back in properly and reassembled. No success wouldn’t start. I ordered a new protection relay from pelican. I guess we will see what happens. I’m not to good with a volt meter so I figure 100 bucks was cheap enough to just give it a try. If that doesn’t work I’ll have to pull out the voltmeter and try my best to follow the very detailed directions in these threads.

    Prior to pulling the box. The car started well and idled well for about 4 min than got rough and stalled. Restarted right up than stalled after two min. Than wouldn’t start at all.
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  14. jpanz

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    Allegedly the protection relay is being delivered today. Looking forward to trying it out and seeing what happens.
     
  15. jpanz

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    Update: Pelican sent me a BMW bike roof rack by accident. So I’m still waiting for the relay to come. Allegedly it’s coming tomorrow.
     
  16. jpanz

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    So I installed the new relay tonight. Initially the car wouldn’t start. I tried again and it fired right up. It ideled well cold perfectly at 1000rpm. After a min or two it dropped down to 600 untill water temp came up. I took it for a 24mi ride and it ran perfectly. I hope that was the issue. Thanks Steve Magnusson for the tips. I’ll keep ya posted.
     

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  17. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Glad it's (hopefuly) running OK, but, please make a measurement next time BEFORE buying a part ;)
     
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  18. jpanz

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    Steve I have limited experience with the volt meter. For example what setting to put the meter on etc and where exactly to touch to properly get a reading. I had read all the post regarding the protection relay. Some of the reading required having a second person crank the car and I’m usually by myself. So I figured the part was cheap enough that if it didn’t work it wasn’t a terrible loss. At that point I would be forced to try the meter. I would never do that with a pricier part. Looking forward to learning a little more about the cars electrical components and will try to learn a bit more about using the meter.
    Thanks again!!!
     
  19. jpanz

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    So I took out the car today. I did 26 miles with a nice warm up. Car ran amazing initially but smelled like it was running rich. At 18 miles into the ride I noticed I was lacking in torque in 2nd gear and as I rolled to a light the idle dropped to about 650-800 (normally 1k even) and I had less power than normal. However, not like last time where I could barely get out of my own way. It didnt feel like I lost a bank this time. Maybe just fuel air mixture.

    I saw Steve’s comments prior about mechanics altering the mixture to compensate for the failing relay. I assume the car wouldn’t have run so well initially? Maybe just needs to go in for an overall checkup? Any ideas?

    The car was serviced at classic coach in NJ in March 2018. Major service and a clutch and had run exceptionally well since. Just recently having some issues.
     
  20. Steve Magnusson

    Steve Magnusson F1 World Champ
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    No, those are exactly the symptoms of losing a bank of ignition -- low idle, low power, but smooth running. A TR won't keep running if the 7/12 bank loses ignition (as this shuts off the fuel pump relays), so first diagnostic thing to do is confirm/deny spark on the 1-6 bank using a timing ight or spark tester.
     
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  21. jpanz

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    Update:
    It took some time to get the car into a shop.

    It appears my injectors were old and corroded a bit. They were dripping and at time were putting out a straight stream of fuel at 50 psi. In addition I believe the heat sensor was replaced. I still don’t have the car back but that’s the gyst of it.

    The repair was definely out of my hands. I also elected to put a “loud tubi” and tubi pre cat test pipes in (already have fabspeed main cat test pipes)

    Will see how it sounds!
     
  22. vincenzo

    vincenzo F1 Rookie

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    What happened with the noise from the evap system?
     
  23. jpanz

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    Nothing. It’s never done it again? The mechanic saw the video and agreed it was fuel vapor. But not much to do about it now.
     
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