OK, folks, I need help if possible...I have been chasing a gremlin in my car for exactly one year now...backround info on my car...
I race a 79 Monte Carlo with a 496 pump gas motor...it has an FTI glide and a Dana 60 out back with 5:13 gears...big tire car with a four link...CO2 shifter with an Msd digital window switch for shift points...MSD 6AL2 box for rev limiter and two step rpm's...
So here is the problem...one year ago, practically to the day, I got a hesitation on launch when I let go of the button...a split second hesitation but it gives me between a 150 and 180 light...no bueno...for the last twelve months this is what we have done to fix it...
New button and solenoid...problem still there...took out the tranny and took it to FTI...they went through it with a fine tooth comb and pronounced it ready to go, no issues...they checked the solenoid as well to be sure even though it was new...we put it back in the car and problem still there...
Next up was wiring...I had the entire car professionally re-wired...every single wire is new and all grounds are only perfect...yup, you guessed it...problem still there...btw, the button is a Biondo mushroom and the solenoid is FTI's own...
This hesitation is intermittent...could happen every 5 runs or every 12 runs...yesterday it happened two times...on my second time shot and on my second elim round...
Sorry for the length of this post but I wanted to be as thorough as possible...I am at a dead end...tomorrow I plan to speak with tech at Biondo about their buttons and MSD about their 6AL2 box and the two step function but I don't hold much hope...
Is it a trans brake release hesitation or a motor stumble?
I would look at the ignition...The AL2 is still an analog ignition, and the rotary switches are nothing more than variable resistors...When you're on the limiter, it's possible that you're getting that fault due to the resistor failing....just a thought....unless you have a digital ignition, all of MSD's limiting is done with resistor chips or dials, and depending on temp/etc. they can give mixed results...and resistors and their connections fail....never been a fan of the dial...
Maybe someone has another ignition you can try to see if the problem goes away? Where in Florida are you?
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You may be looking the wrong place---how about the carb? Several conditions there could cause this. Just a suggestion.
HAVE YOU TRIED A DIFF CARB HAD SAME KIND OF ISSUE SWITHED CARBS ISSUE GONE 1ST CARB 825 DEMON 2ND CARB QF 850 THEN HAD OPP TO TRY 900 HP HOLLEY METH CARB WORKED GREAT PICKED CAR UP 2TENTHS
Have you had your carb cleaned recently? You may try to open the idle mixture screws a half turn. I have to do this on my small block if I have a stumble in cooler conditions in fall.
A lot of variables there..
Check the charging system?
I know on the older 6AL's, i had to put on the MSD 8830 on 2 cars. Bizarre problems.
When was the last time you checked the reluctor wheel/pickup for rust accumulation.
Just some of the basic items.
Ohm out the pick up coil when your in there too
That there is one item that is skeptical to change with heat. 400-1300 i believe.
All else fails>> More Beer lol
Did you try footbraking? Try another 2 step? Are you using a delay box or no boxing? If delay box remove it and wire direct from button to TB. Any possibility of something back feeding? Is linelock wired to activate with TB?
I'm just throwing ideas out, intermittents are the worst!
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I agree with checking carb first. any time car acts stupid (Back when I ran carbs) first thing I would do is blow out air bleeds and verify that they are open. They get clogged easily and car will act stupid.
Then go to your basic carb tuning, are you sure you are getting booster shot IMMEDIATELY when you hit gas?
If your idle mixture is too lean it will have stumble. Even if it is right during Summer this time of year air gets better but Idle mixture does not. Now you go stumble again. (Blow out air bleeds) and reset idle mixture.
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It is a trans brake release hesitation...no stumble and the car runs fine once it leaves...60', 33' and 660' numbers are on point as well as mph...
I am calling MSD tomorrow to see if the 2 step part of the box could possibly cause this...I am in Melbourne, Fl...I am not an electronic kind of guy...lol...
We thought about that but it is not a stumble...we cleaned the carb top to bottom anyway and put in new needles and seats...sigh...
Not yet...again, the car runs fine once it leaves...thanks for the thought...
We clean the carb every year due to gunk from the 10 ethanol in pump gas....I also use Luc as E85 cleaner regularly to keep the level of junk down...the car does this in 90* weather and 50* weather...
If it’s trans brake release, how is it wired? What else is tb bottom connected to? Any relays in circut?
I am not an electronics kinda guy so I have not done any of this....what I did do is have the entire car re-wired by a pro...every wire is now correct and every ground is perfect...pricey but the car needed it regardless...btw, I run an alternator and it shows over 13 volts at idle...
Yes, it does not hesitate when footbraked leaving at 3000 rpm...I have not tried another 6AL2 box yet...I am a no box racer...no, the line lock is not tied to the TB...yes, intermittents are awful...thanks for the ideas...I now have the button on a quick disconnect but this issue happened way before I had the car re-wired...
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Screw the transbrake solenoid out until you see it losing pressure on the TB. Screw it back in to where it gains the pressure back. With using shims, lock it down there.
We will re-check the carb after the holidays but everything was fine a couple of months ago...when I let go tghe car hesitates for a split second and then leaves all on it's own...all the numbers down track are in order as well as the mph...no stumble on launch or down track anywhere...sigh...it is a bit bizarre...feels funny when you let go and nothing happens...that split second seems like forever...
Thank y'all so much for all the replies...one would think that since when the button is pressed everything works fine but when I let go the issue happens...it seems so much like a button issue but this is the second new one...basic Biondo mushroom but, heck, it is just an on/off switch really...
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