MSD 6AL question

tamanaco · #1 (**permalink**) 07-12-2011, 06:35 AM

drove my Backdraft to the GoodGuy's show in Columbus this past weekend. On the way back stopped for fuel, turned off engine, fueled up, got back on the freeway...then the engine started to stumble in 5th gear with some throttle input. (this is a 302 FMS crate with a t5 0.062 ration 5th with 3.91 diff. about 1900rpm's @60mph) It also sounded a bit different. 50 miles later, was off the freeway and it seemed to pull OK thru the gears, but still stumbled in 5th. Well...the only thing that changes was the gas...bad gas?

The next day took the car for a drive ant it was back to normal 5th gear performance.

So...it not the gas. can MSD boxes get too hot and act like this? I had to replace one a year ago. Its mounted under the dash of the car and it was about 90 degrees that day. I did feel the box, it was warm, but the MSD people said they run warm. Anybody seen this issue before with MSD?

Bobcat · #2 (**permalink**) 07-12-2011, 07:29 AM

You didn`t say if it is a carbureted car or FI ... however , I would lean towards the fuel at this point . Summer fuel mixtures , heat and ethanol cause problems . If the car has a carb , check to see if the idle air corection jets have an ethanol buildup ... and the easiest way is to spray some carb cleaner through them . At 1900 rpm , you`re still in part of the idle ckt if you have a Holley , and the ethonol can cause what you are seeing . As far as the MSD location , that`s where mine is located and we have ambients here in the upper 90`s to low 100`s and no problems . Yes , the MSD boxes get warm when operation , but you should be able to comfortably hold your hand on it . Another possibility would be the MSD module in the distributor ... if you have an MSD distributor .

Bob

Hotfingrs · #3 (**permalink**) 07-12-2011, 07:53 AM

Could be the fuel, also with the temps we've been having lately, while you were stopped for gas, fuel line or something else got super hot causing fuel delivery problem. Doesn't take long for under hood temps to get super hot in this weather.

snakebittexan · #4 (**permalink**) 07-12-2011, 09:02 AM

I recently installed a phenolic spacer and I've had no furthur such issues. For a test try some Lucas Fuel Conditioner in your tank. If that solves your problem it's probably the fuel boiling in the bowls (thanks to our corn/fuel), assuming you have a carberator. As an additional benefit I've notice some performance benefits due to the spacer.
If your drive the next day was in the AM (cooler) vs. afternoon that may be why your issue improved.

DAVID GAGNARD · #5 (**permalink**) 07-12-2011, 09:22 AM

Quote:

As far as the MSD location , that`s where mine is located and we have ambients here in the upper 90`s to low 100`s and no problems . Yes , the MSD boxes get warm when operation , but you should be able to comfortably hold your hand on it . Another possibility would be the MSD module in the distributor ... if you have an MSD distributor .

My MSD box gets soo hot after about 10 minutes I can't hold my hand on it very long........been like that since day one,going on 6 or 8 years now......

David

Calicoco · #6 (**permalink**) 07-12-2011, 11:12 AM

Saw your car at the show on Sunday!! Good looking car!!

tamanaco · #7 (**permalink**) 07-12-2011, 02:58 PM

Quote:

Originally Posted by Calicoco

Saw your car at the show on Sunday!! Good looking car!!

Thanks for the comment...the Xcrossing was fun!!!

It is carburated via Holley 730cfm avenger? MSD distiuter as well. I've never experenced this in my 4 years of driving it. Have driven it in hot weather, stopped for fuel, and its performed as normal. this was my first time for this type of performance.

Hummm, fuel??? Thanks for all the input.

charles roybal · #8 (**permalink**) 07-12-2011, 03:40 PM

Heat soak issue...get one of these:

Edelbrock Carburetor Spacers - Wood Design - JEGS

WardL · #9 (**permalink**) 07-12-2011, 11:18 PM

And what exactly would ethanol buildup look like in the idle air correction jets? I have to go with the heat soak issue too. The bad gas doesn't know what gear you are in and it would run rough today and tomorrow in every gear with it. Bad gas doesn't turn into good gas after a good night's rest.

Clois Harlan · #10 (**permalink**) 07-13-2011, 06:34 AM

Do you have an inline gas filter? If so change it and also change any other gas filters you may have in your fuel line. I run a Holley gas filter before my electric fuel pump (located near my fuel cell) and then I run another inline filter before my fuel regulator. By the way your fuel pressure should be about 6.5 pounds. If that doesn't work remove your inlet fuel lines and see if you have any screens at your carb inlet with some debris in them. I would also pull my carb off and remove each of the jets and spray them and the carb with some carb cleaner. If all that doesn't help then I would change my headlight switch!!!

BAsque1 · #11 (**permalink**) 07-13-2011, 07:03 AM

All of the above are great advise. I have a 427 FE S/O and it never fails with a phenolic spacer and many more modifications my fuel still boils during hot days and at stop lights and city driving I must keep the rpms up or it will stall and then a pian to get started. I am seriously considering a cool can. Here in the Norheast we go from 65 to 100 degrees in hrs. Very annoying. I had MSD boxes in my jeeps and they do run hot.
Cheers
Basque1