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Discussion Starter #1
at first, I thought this was the transbrake solenoid backfeeding the two step limiter causing the car to stall down, but it looks like the tires are actually locking up so it sounds to me like it is the tb. I cant think of what else it could be but it is very frustrating.

is it possible for a transbrake to somehow reengage after its been disengaged? I am not touching the button after launch.

http://youtu.be/CR8jJHEByc0
 

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What is the solinoid made of . I had one made of aluminum and was sticking. Now lightweight steel all good now!
 

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Yes the brake is coming back ON. I recall having to deal with a customer who had this same deal going on and kept bringing the trans back destroyed calling me an asshole. Somehow it was found that the 2 step wire was connected to the wrong side of a relay which controlled the transbrake as it were wired that way. I don't know how but there was enough voltage coming from the msd to make the relay latch. Where is your 2 step wire connected? Hopefully not before a relay.


Hutch
 

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Discussion Starter #4
Yes the brake is coming back ON. I recall having to deal with a customer who had this same deal going on and kept bringing the trans back destroyed calling me an asshole. Somehow it was found that the 2 step wire was connected to the wrong side of a relay which controlled the transbrake as it were wired that way. I don't know how but there was enough voltage coming from the msd to make the relay latch. Where is your 2 step wire connected? Hopefully not before a relay.


Hutch
the tb button has a split output. one output goes to the solenoid, and the other output goes to a relay which activates the two step(built into the holley efi box). the relay was recommended so the solenoid wouldnt back feed the efi box

alteredbob, i believe it is aluminum. i'll have to double check
 

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Discussion Starter #5
What is the solinoid made of . I had one made of aluminum and was sticking. Now lightweight steel all good now!

would it even release initially, or would it not release at all?
 

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Discussion Starter #6
bump
 

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Seen this before, the relay is a bad deal unless you to create a dump circuit,, when the magnetic field in the solenoid collapse there is a voltage spike, it feeds back into the system with enough current to momentary raise hell with your electronics and possibly reapply the TB soliniond and 2 step.. Sometime you can get away with simply wiring the backup lights into the TB hot side as a dump circuit, otherwise you will need the get a resistor diode with the appropriate specs and wire into the TB hot side.. Also helps to ground the TB soliniod directly to the batery with 10ga wire..
Using a diode with a dump circuit in place of the relay to protect the ECU would work better too..
 

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Seen this before, the relay is a bad deal unless you to create a dump circuit,, when the magnetic field in the solenoid collapse there is a voltage spike, it feeds back into the system with enough current to momentary raise hell with your electronics and possibly reapply the TB solenoid and 2 step.. Sometime you can get away with simply wiring the backup lights into the TB hot side as a dump circuit, otherwise you will need the get a resistor diode with the appropriate specs and wire into the TB hot side.. Also helps to ground the TB solenoid directly to the battery with 10ga wire..
Using a diode with a dump circuit in place of the relay to protect the ECU would work better too..
Might consider placing this in the eletronics forumn,, Joe from Hyperactive could help you with this problem... Also Spagette menders sells a TB box that will help with this problem..
 

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Since the trans is toast now , you can always put a gopro on the tb solenoid to watch it reactivate showing you its a wiring problem and not a trans problem. If you dare try it again as it is.


Hutch
 

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Discussion Starter #10
Seen this before, the relay is a bad deal unless you to create a dump circuit,, when the magnetic field in the solenoid collapse there is a voltage spike, it feeds back into the system with enough current to momentary raise hell with your electronics and possibly reapply the TB soliniond and 2 step.. Sometime you can get away with simply wiring the backup lights into the TB hot side as a dump circuit, otherwise you will need the get a resistor diode with the appropriate specs and wire into the TB hot side.. Also helps to ground the TB soliniod directly to the batery with 10ga wire..
Using a diode with a dump circuit in place of the relay to protect the ECU would work better too..

the tb is grounded straight to battery. i will do the diode you speak of. funny thing is i asked the ecu mfg if i should just do the diode and they were the ones who recommended the relay.
 

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Discussion Starter #11
Since the trans is toast now , you can always put a gopro on the tb solenoid to watch it reactivate showing you its a wiring problem and not a trans problem. If you dare try it again as it is.


Hutch
hutch, have a question. could it be the trans, and not the tb??? the reason i ask is that this never happened when leaving on lower boost, and the one time it didnt happen last sunday was when i turned the launch rpm down to 3500. I raised it 3800 (normal 4200) and that was the last pass in the vid I posted.

so the question is, could it be an internal trans issue, and if it is, what is the problem?

thank you
 

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the tb is grounded straight to battery. i will do the diode you speak of. funny thing is i asked the ecu mfg if i should just do the diode and they were the ones who recommended the relay.
If you are going to use a relay use a solid state relay,, but you still need to create a dump circuit with the backup lites or a resistor diode, we use NTE-5817 diode wired between the TB hot wire and ground. the white stripe goes toward the hot wire.. If you wire it backwards it will blow the fuse.. Not sure witch diode would be best to isolate the ecu from the TB circuit,, I'll ask my electronics guru what to use there..
A properly wired dump circuit not only protects your electronics but can improve reaction time...
 

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Discussion Starter #13
If you are going to use a relay use a solid state relay,, but you still need to create a dump circuit with the backup lites or a resistor diode, we use NTE-5817 diode wired between the TB hot wire and ground. the white stripe goes toward the hot wire.. If you wire it backwards it will blow the fuse.. Not sure witch diode would be best to isolate the ecu from the TB circuit,, I'll ask my electronics guru what to use there..
A properly wired dump circuit not only protects your electronics but can improve reaction time...
thanks. im definitely going to add a diode.they are dirt cheap so no reason not to.

ive normally wired a diode inline with the power wire(facing the right way of course) . ive havent heard of it being wired to ground. is this correct?
 

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thanks. im definitely going to add a diode.they are dirt cheap so no reason not to.

ive normally wired a diode inline with the power wire(facing the right way of course) . ive havent heard of it being wired to ground. is this correct?
Yes, wired between the switch 12v side of the TB button and ground it will catch the voltage surge created by the TB release and short it to ground{provided you are using the correct resistor diode},, that is what we call a dump circuit. Back up lights make a good dump circuit too..
 

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Damn bro I hope you get this figured out you were just starting to make progress.
 

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Make sure you don't have a wire that is vibrating and causing the TB to re-engage. I had one do that once. It was causing the 2-step to activate in high gear. I couldn't find the cause of the engine miss until the wire finally broke. Fixed the TB button, miss went away.
 

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We had the same problem with a line lock and it was the 2 wires were hitting some times and the brakes were slowly locking up, ofcourse the trans brake will react a lot quiker look at all the wires.
 
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