Bracket Talk
Random SLE activation.
May 14, 2022, 08:02 PM
SP 124XRandom SLE activation.
Like the title says struggling with random SLE activation. A few weeks ago it happened almost at the finish line. Last week in the staging lanes.
Originally started happening with a mega 475 swapped to a mega 450 this morning and it seemed to happen more.
Then changed the button and solenoid still happening.
Checked the tap pb wire to make sure it wasn't bare and grounding out in any spots. Also checked all the power and grounds to make sure nothing was broken or loose causing electrical interference.
I'm out of things to check and the car sucks to race without an enhancer because it stumbles (I know it's been back to apd with no luck and is deadly once it's on the chip
Denis LeBlanc
May 14, 2022, 09:09 PM
markemarkWhat MSD model ignition are you using? I can possibly show you how to band-aid it during the run for the time being. If you have MSD Grid it’d be easy to do.
May 14, 2022, 09:11 PM
Big SteveWow that can be a very dangerous, whatever is causing you need to find it quickly. May be one of those situations where you just replace everything and every wire related to the SLC
May 14, 2022, 09:24 PM
SP 124Xquote:
Originally posted by markemark:
What MSD model ignition are you using? I can possibly show you how to band-aid it during the run for the time being. If you have MSD Grid it’d be easy to do.
Old 7al gold box
Denis LeBlanc
May 14, 2022, 09:29 PM
SP 124Xquote:
Originally posted by Big Steve:
Wow that can be a very dangerous, whatever is causing you need to find it quickly. May be one of those situations where you just replace everything and every wire related to the SLC
Agreed 100%. Car was rewired over the winter and probably put 50+ runs on it before this started happening.
Denis LeBlanc
May 14, 2022, 09:31 PM
markemarkquote:
Originally posted by SP 124X:Old 7al gold box
If your tap button on the steering wheel is wired with a coiled 2 conductor cable, remove the coiled cable inspect or replace.
Not much you can do with old 7al2. You need a RPM activated switch to disable the SLE during a run.
May 14, 2022, 09:38 PM
SLICKSTERMotor has weak signal to the boosters. Agreed on dangerous on the sle. I have used the sle to time the blade opening since 1992. If in doubt wire it direct to the delay box and also run both side of the little Humphrey valve straight to the box. + and - right at the box. Usually not needed but you are having trouble and lets not take a chance.
May 15, 2022, 06:04 AM
SP 124Xquote:
Originally posted by markemark:
quote:
Originally posted by SP 124X:Old 7al gold box
If your tap button on the steering wheel is wired with a coiled 2 conductor cable, remove the coiled cable inspect or replace.
Not much you can do with old 7al2. You need a RPM activated switch to disable the SLE during a run.
Replace the button and cord yesterday with no luck.
Denis LeBlanc
May 15, 2022, 07:33 AM
1320racerWhose SLE and Have you always used a SLE on this engine/car?
That said, why are you racing with a carb that has a stumble? Is this a new or older carb? Did it always have a stumble or recently developed one?
May 15, 2022, 09:11 AM
SP 124Xquote:
Originally posted by 1320racer:
Whose SLE and Have you always used a SLE on this engine/car?
That said, why are you racing with a carb that has a stumble? Is this a new or older carb? Did it always have a stumble or recently developed one?
Shifnoid SLE and yes this combo has always had an SLE.
As for the carb it's had a stumble since day one its been back to APD with no major improvement on the stumble. We don't super comp race and it comes up clean off the SLE at 2500ish.
I can race the car without the SLE and stumble but my daughter struggles a little.
Denis LeBlanc
May 15, 2022, 09:44 AM
markemarkSLE activates with a ground input from the Tap or TB buttons with both the Mega 475 and 450 boxes that have exact same problem of SLE activating per-maturely.
Maybe it’s the TB button that is activating the SLE
May 15, 2022, 10:59 AM
1320racerquote:
Originally posted by SP 124X:
Shifnoid SLE and yes this combo has always had an SLE. Replaces the button and cord yesterday with no luck. Checked the tap pb wire to make sure it wasn't bare and grounding out in any spots. Also checked all the power and grounds to make sure nothing was broken or loose causing electrical interference.
Then I’d say it’s the SLE solenoid gone bad.
May 15, 2022, 11:29 AM
rustyi think while i was hunting the sle issue i would make the idle air bleeds smaller
honesty is the best policy,insanity is a better deffense
1.036, 6.16@ 224
May 15, 2022, 12:04 PM
SP 124Xquote:
Originally posted by rusty:
i think while i was hunting the sle issue i would make the idle air bleeds smaller
Down to .023 I believe the idle restriction jet is the problem.
Denis LeBlanc
May 15, 2022, 12:04 PM
SP 124Xquote:
Originally posted by 1320racer:
quote:
Originally posted by SP 124X:
Shifnoid SLE and yes this combo has always had an SLE. Replaces the button and cord yesterday with no luck. Checked the tap pb wire to make sure it wasn't bare and grounding out in any spots. Also checked all the power and grounds to make sure nothing was broken or loose causing electrical interference.
Then I’d say it’s the SLE solenoid gone bad.
Changed it yesterday as well
Denis LeBlanc
May 15, 2022, 12:12 PM
rustyquote:
posted May 15, 2022 12:04 PM Hide Post
quote:
Originally posted by rusty:
i think while i was hunting the sle issue i would make the idle air bleeds smaller
Down to .023 I believe the idle restriction jet is the problem.
very posible i have had to change or drill them before
honesty is the best policy,insanity is a better deffense
1.036, 6.16@ 224
May 15, 2022, 12:13 PM
rustyquote:
quote:
posted May 15, 2022 12:04 PM Hide Post
quote:
Originally posted by rusty:
i think while i was hunting the sle issue i would make the idle air bleeds smaller
Down to .023 I believe the idle restriction jet is the problem.
very posible i have had to change or drill them before
opinions are worth what you pay for them
be sure you are chnging the correct bleed
honesty is the best policy,insanity is a better deffense
1.036, 6.16@ 224
May 15, 2022, 04:11 PM
markemarkLike I wrote prior, the only inputs that activate the SLE are the Tap and TB buttons to Mega 475/450. The OP wrote that the Tap button and cable were changed.
Here’s a simple way to determine if the TB button is at fault activating the SLE. Leave the Mega programmed as is and remove the Tap button wire going to the Mega Terminal. Now the only thing that can trigger SLE is TB button input.
See if this continues to randomly activate using in this manner. If it continues to randomly activate it would point to the TB input. If the false activation stops, it points to the Tap button.
If you had a faulty SLE solenoid, it would not cycle on/ off on its own. The solenoid would do nothing when +12v was applied if solenoid bad. The only thing energizing that solenoid is the +12v coming from the SFO terminal of Mega.
You can also enable the SLE Starting Line Mode which will not require a Tap input or move the pedal to the floor
S.L.E. Starting Line Mode
The Starting Line Mode only affects the S.L.E. in Bracket Mode. When turned on and in any P.B. Mode except 5, the S.L.E. will activate with the Transbrake solenoid or the Tap Down button. This feature is used when the driver wants to stage the vehicle without having the gas pedal on the floor. Or if a Tap Down button has not been installed in the vehicle. With the S.L.E. line selected, use the ^ or v key to turn the starting line mode on or off. When turned on an “L” will be displayed just before the S.L.E. time.
May 15, 2022, 04:17 PM
Big Stevequote:
Originally posted by markemark:
Like I wrote prior, the only inputs that activate the SLE are the Tap and TB buttons to Mega 475/450. The OP wrote that the Tap button and cable were changed.
Here’s a simple way to determine if the TB button is at fault activating the SLE. Leave the Mega programmed as is and remove the Tap button wire going to the Mega Terminal. Now the only thing that can trigger SLE is TB button input.
See if this continues to randomly activate using in this manner. If it continues to randomly activate it would point to the TB input. If the false activation stops, it points to the Tap button.
If you had a faulty SLE solenoid, it would not cycle on/ off on its own. The solenoid would do nothing when +12v was applied if solenoid bad. The only thing energizing that solenoid is the +12v coming from the SFO terminal of Mega.
You can also enable the SLE Starting Line Mode which will not require a Tap input or move the pedal to the floor
S.L.E. Starting Line Mode
The Starting Line Mode only affects the S.L.E. in Bracket Mode. When turned on and in any P.B. Mode except 5, the S.L.E. will activate with the Transbrake solenoid or the Tap Down button. This feature is used when the driver wants to stage the vehicle without having the gas pedal on the floor. Or if a Tap Down button has not been installed in the vehicle. With the S.L.E. line selected, use the ^ or v key to turn the starting line mode on or off. When turned on an “L” will be displayed just before the S.L.E. time.
I knew there was good reason I like the K&R Pro cube delay box, its sooo much simpler
May 15, 2022, 04:55 PM
markemark^^^^^^ I’m not a fan of the Negative Trigger boxes. But in Mega defense, it does have RPM activated functions that K&R lacks.