Problem with MSD 6A Ignition module...? - 1982-1993 Mustang GT Registry Message Board

Raven68 · 07-10-2009, 03:54 PM

Just got back to the UK last week from holiday in Florida with suitcase full of parts for the 89GT

Fitted MSD distributor, MSD Coil and set the timing to 15btdc, already got MSD ignition wires, and the car runs great.

So we then wired in the MSD 6A ignition box..... engine is hard to start, smells of fuel, has a rough idle and won't tickover (unless given more throttle) and then dies after 30 seconds......... Disconnect it, car runs just fine..... Connect it back up.......... same problem every time......

A few Fox owners over here in the UK says they just fitted it as per instructions and it works fine straight out the box.

Plug gaps were re-set to 50 thou.

Does timing need re-setting or checking again? Do we need to re-set the ECU? The battery was disconnected whilst we fitted the 6A but not for long..........Any ideas guys?

93 Wht GT · 07-10-2009, 10:02 PM

The MSD 6A box is a plug 'n play item with the MSD wiring harness. I've had no problems with mine and it's been in my car since 1994. My timing was advanced months before and was not adjusted at all.

Could me a bad box, maybe? I'd return the box for another one just to rule it out.

Rick

Raven68 · 07-11-2009, 02:14 AM

Quote:

Originally Posted by 93 Wht GT

The MSD 6A box is a plug 'n play item with the MSD wiring harness. I've had no problems with mine and it's been in my car since 1994. My timing was advanced months before and was not adjusted at all.

Could me a bad box, maybe? I'd return the box for another one just to rule it out.

Rick

Thanks Rick.... everyones says they just 'plugged and played'..... thats why this is so frustrating, and I wanna be sure we haven't missed some other obvious adjustment. Maybe I could check it out on my 67 mustang and see what happens..............

MMmm, I'm beginning to think its a bad box, so I've asked MSD for a return shipping number.

DoDew87 · 07-11-2009, 08:56 AM

Could be a bad box, but it could be as simple as the problem I had with my 89 (the one in my avatar <-----)...story first! I had a 6AL on my Fox car. It wouldn't start up one day when I was out, so I had it towed home and started tinkering with the usual suspect parts there. After trying everything all the way to the ign. mod. on the distributor, the last thing I tried was the MSD box itself. Unplugged and t-harness bypassed, the damn thing would start. Stupid me, I remove the box and send it in for testing. Gets sent back, checked out okay. During re-install, when I went to screw the ground eyelet back into its hole, I noticed the metal around the hole was dingy, crappy and could stand to be cleaned up. Did that, too and guess what, she started right up. I guess long story short, check all your connections over VERY WELL first! It can possibly save you money and down-time...and a blow to your ego! I'm still recovering from that 10 years later!

Raven68 · 07-11-2009, 03:25 PM

Yep, good point DoDew... we'll check out the new earthing point we made to the shock tower...

I think the unit is giving out a healthy spark though 'cos we forgot to reconnect the ignition wire from the coil to the distributor one time and the spark jumped about 2" to the nearest earth........... !!!!

It just seems as though the ECU has forgotten how to control the engine when the 6A is connected

Raven68 · 07-11-2009, 03:53 PM

By the way we've got the 6A wired as per the MSD instructions for a Ford TFI system - bottom half below - thats right ain't it..........?

93 Wht GT · 07-11-2009, 05:16 PM

There should be a wiring diagram that uses the MSD wiring harness that plugs in between the box and the ignition coil. I'm trying to remember all this by memory. It's been 15 years ago when I did this install.

Take a picture(s) of your install. Maybe we can point out something

Rick

Raven68 · 07-11-2009, 05:25 PM

Quote:

Originally Posted by 93 Wht GT

There should be a wiring diagram that uses the MSD wiring harness that plugs in between the box and the ignition coil. I'm trying to remember all this by memory. It's been 15 years ago when I did this install.

Take a picture(s) of your install. Maybe we can point out something

Rick

Yep, you're right but the harness just does the same job of orange & black to the coil and red & white to the harness though..... Will see if we can get some pics after checking it all through again, but you can't six wires wrong

skunk · 07-11-2009, 05:36 PM

I have been doing some reading on this since I don't have one but I was curious. alot of problems seem to be from bad grounds like DoDew87 stated and poor connections. make sure everything is tight and the grounds are good, it's a pretty simple system but most of the problems where this ( and bad boxes) also what you using for a 12V source.

Raven68 · 07-11-2009, 06:03 PM

Quote:

Originally Posted by skunk

........it's a pretty simple system but most of the problems are grounds ( and bad boxes) also what you using for a 12V source.

Battery in the boot with 50mm2 heavy duty positive and negative cables to the engine bay. Red to the solenoid and black to a new earthing point which also takes the engine earth cable. MSD is directly connected to the battery cables so its getting a direct 12v......

skunk · 07-11-2009, 07:36 PM

sounds like you got all the bases covered, just do quick scan of the grounds if all checks out you probally got a bad box. best of luck!

93 Wht GT · 07-11-2009, 11:02 PM

Yup! The MSD p/n 8874 (wiring harness) is what I'm using.

Well, we'll help you get this figured out

Rick

phastphil · 07-11-2009, 11:23 PM

maybe the harness was put together incorrectly, ( I know not likely, but I've seen other manufacturing defects before) why not try wiring it without the supplied harness and see if that makes a difference.

Raven68 · 07-12-2009, 04:42 AM

Thanks guys - we're not using the harness so we know where all the wires are going OK and have double checked that... I have a doubt about the vehicle ground so we'll clean that up real good.

Also reading the instructions again last night for the 10th time they highlight an issue if two plug wires are run adjacent to each other in the firing order? Guess that would be plug wires 6 and 5? These can generate interference in each other. So we'll separate them far apart and see what happens as well. The very rough idle seems like its running on 6 or 7 cylinders so maybe adjacent wires are an issue? We've also got chromed metal wire separators so I wonder if they are causing cross interference - we'll remove them as well...get some plastic ones in due course maybe

Also bought a decent timing light yesterday so we'll doublecheck all that as well..

Keep any thoughts coming and I'll let you know the outcome for sure...

Jerry: BLACK 85 GT h/b · 07-12-2009, 10:42 AM

Those wire looms can be a problem. Sometimes they have to have a rubber grommet insulating the wire from the loom to prevent shorting to gorund.

07-10-2009, 03:54 PM	#1
Raven68 Member Join Date: Apr 2007 Location: Bristol, UK Posts: 93	Problem with MSD 6A Ignition module...? Just got back to the UK last week from holiday in Florida with suitcase full of parts for the 89GT Fitted MSD distributor, MSD Coil and set the timing to 15btdc, already got MSD ignition wires, and the car runs great. So we then wired in the MSD 6A ignition box..... engine is hard to start, smells of fuel, has a rough idle and won't tickover (unless given more throttle) and then dies after 30 seconds......... Disconnect it, car runs just fine..... Connect it back up.......... same problem every time...... A few Fox owners over here in the UK says they just fitted it as per instructions and it works fine straight out the box. Plug gaps were re-set to 50 thou. Does timing need re-setting or checking again? Do we need to re-set the ECU? The battery was disconnected whilst we fitted the 6A but not for long..........Any ideas guys? __________________ Oxford White 1989 GT 5.0 mild cam, roller rockers, headman headers, side exit pipes, de-catted, de-smogged, racing clutch, 3.73 gearing, A/C eliminator, Steeda Tri-ax, Cobra grille insert, 17 x 8 Cobra R rims,45 profile tyres, Wilwood Superlite 6 big brake kit, Roll cage, rear seat delete, MM K Member, MM front lower arms, MM Coilover Koni shocks, MM caster camber plates, Hurst roll control, MSD Pro Billet distributor, MSD Streetfire Coil, FRPP ali rad

07-11-2009, 08:56 AM	#4
DoDew87 Senior Member Join Date: Aug 2002 Location: Davenport, Ia. QUAD CITIES Posts: 943	Could be a bad box, but it could be as simple as the problem I had with my 89 (the one in my avatar <-----)...story first! I had a 6AL on my Fox car. It wouldn't start up one day when I was out, so I had it towed home and started tinkering with the usual suspect parts there. After trying everything all the way to the ign. mod. on the distributor, the last thing I tried was the MSD box itself. Unplugged and t-harness bypassed, the damn thing would start. Stupid me, I remove the box and send it in for testing. Gets sent back, checked out okay. During re-install, when I went to screw the ground eyelet back into its hole, I noticed the metal around the hole was dingy, crappy and could stand to be cleaned up. Did that, too and guess what, she started right up. I guess long story short, check all your connections over VERY WELL first! It can possibly save you money and down-time...and a blow to your ego! I'm still recovering from that 10 years later! __________________ Last edited by DoDew87; 07-11-2009 at 08:58 AM..

07-11-2009, 03:25 PM	#5
Raven68 Member Join Date: Apr 2007 Location: Bristol, UK Posts: 93	Yep, good point DoDew... we'll check out the new earthing point we made to the shock tower... I think the unit is giving out a healthy spark though 'cos we forgot to reconnect the ignition wire from the coil to the distributor one time and the spark jumped about 2" to the nearest earth........... !!!! It just seems as though the ECU has forgotten how to control the engine when the 6A is connected __________________ Oxford White 1989 GT 5.0 mild cam, roller rockers, headman headers, side exit pipes, de-catted, de-smogged, racing clutch, 3.73 gearing, A/C eliminator, Steeda Tri-ax, Cobra grille insert, 17 x 8 Cobra R rims,45 profile tyres, Wilwood Superlite 6 big brake kit, Roll cage, rear seat delete, MM K Member, MM front lower arms, MM Coilover Koni shocks, MM caster camber plates, Hurst roll control, MSD Pro Billet distributor, MSD Streetfire Coil, FRPP ali rad

07-11-2009, 03:53 PM	#6
Raven68 Member Join Date: Apr 2007 Location: Bristol, UK Posts: 93	By the way we've got the 6A wired as per the MSD instructions for a Ford TFI system - bottom half below - thats right ain't it..........? __________________ Oxford White 1989 GT 5.0 mild cam, roller rockers, headman headers, side exit pipes, de-catted, de-smogged, racing clutch, 3.73 gearing, A/C eliminator, Steeda Tri-ax, Cobra grille insert, 17 x 8 Cobra R rims,45 profile tyres, Wilwood Superlite 6 big brake kit, Roll cage, rear seat delete, MM K Member, MM front lower arms, MM Coilover Koni shocks, MM caster camber plates, Hurst roll control, MSD Pro Billet distributor, MSD Streetfire Coil, FRPP ali rad

07-11-2009, 05:36 PM	#9
skunk 2010 Donating Member Join Date: May 2008 Location: Massachusetts Posts: 925	I have been doing some reading on this since I don't have one but I was curious. alot of problems seem to be from bad grounds like DoDew87 stated and poor connections. make sure everything is tight and the grounds are good, it's a pretty simple system but most of the problems where this ( and bad boxes) also what you using for a 12V source. __________________ 1991 GT white/ Titanium. 5.0. mild H,C,I, built Astro T5, built 8.8 w 3.73s, FRPP 31spline termi diff, 31 splines axles, plenty of MMS stuff both suspension and braces, Bullitt springs& agx adjustables, Ford racing wheels, Dunlop star spec tires & plenty more stuff. Her resto thread: http://www.mustanggt.org/forums/showthread.php?t=51391 2011 Lincoln MKX elite 2008 Ford explorer EB 2000Ford contour. modded, dyno tunded

07-10-2009, 10:02 PM	#2
93 Wht GT 2009 Donating Member Join Date: Jun 2003 Location: San Jose, CA Posts: 1,221	The MSD 6A box is a plug 'n play item with the MSD wiring harness. I've had no problems with mine and it's been in my car since 1994. My timing was advanced months before and was not adjusted at all. Could me a bad box, maybe? I'd return the box for another one just to rule it out. Rick

07-11-2009, 05:16 PM	#7
93 Wht GT 2009 Donating Member Join Date: Jun 2003 Location: San Jose, CA Posts: 1,221	There should be a wiring diagram that uses the MSD wiring harness that plugs in between the box and the ignition coil. I'm trying to remember all this by memory. It's been 15 years ago when I did this install. Take a picture(s) of your install. Maybe we can point out something Rick

07-11-2009, 07:36 PM	#11
skunk 2010 Donating Member Join Date: May 2008 Location: Massachusetts Posts: 925	sounds like you got all the bases covered, just do quick scan of the grounds if all checks out you probally got a bad box. best of luck! __________________ 1991 GT white/ Titanium. 5.0. mild H,C,I, built Astro T5, built 8.8 w 3.73s, FRPP 31spline termi diff, 31 splines axles, plenty of MMS stuff both suspension and braces, Bullitt springs& agx adjustables, Ford racing wheels, Dunlop star spec tires & plenty more stuff. Her resto thread: http://www.mustanggt.org/forums/showthread.php?t=51391 2011 Lincoln MKX elite 2008 Ford explorer EB 2000Ford contour. modded, dyno tunded

07-11-2009, 11:02 PM	#12
93 Wht GT 2009 Donating Member Join Date: Jun 2003 Location: San Jose, CA Posts: 1,221	Yup! The MSD p/n 8874 (wiring harness) is what I'm using. Well, we'll help you get this figured out Rick

07-11-2009, 11:23 PM	#13
phastphil Senior Member Join Date: Jun 2002 Location: Levittown, Pa Posts: 1,041	maybe the harness was put together incorrectly, ( I know not likely, but I've seen other manufacturing defects before) why not try wiring it without the supplied harness and see if that makes a difference.

07-12-2009, 04:42 AM	#14
Raven68 Member Join Date: Apr 2007 Location: Bristol, UK Posts: 93	Thanks guys - we're not using the harness so we know where all the wires are going OK and have double checked that... I have a doubt about the vehicle ground so we'll clean that up real good. Also reading the instructions again last night for the 10th time they highlight an issue if two plug wires are run adjacent to each other in the firing order? Guess that would be plug wires 6 and 5? These can generate interference in each other. So we'll separate them far apart and see what happens as well. The very rough idle seems like its running on 6 or 7 cylinders so maybe adjacent wires are an issue? We've also got chromed metal wire separators so I wonder if they are causing cross interference - we'll remove them as well...get some plastic ones in due course maybe Also bought a decent timing light yesterday so we'll doublecheck all that as well.. Keep any thoughts coming and I'll let you know the outcome for sure... __________________ Oxford White 1989 GT 5.0 mild cam, roller rockers, headman headers, side exit pipes, de-catted, de-smogged, racing clutch, 3.73 gearing, A/C eliminator, Steeda Tri-ax, Cobra grille insert, 17 x 8 Cobra R rims,45 profile tyres, Wilwood Superlite 6 big brake kit, Roll cage, rear seat delete, MM K Member, MM front lower arms, MM Coilover Koni shocks, MM caster camber plates, Hurst roll control, MSD Pro Billet distributor, MSD Streetfire Coil, FRPP ali rad

07-12-2009, 10:42 AM	#15
Jerry: BLACK 85 GT h/b Ambassador 2009 Donating Member Join Date: May 2002 Location: Winter Haven, FL Posts: 9,106	Those wire looms can be a problem. Sometimes they have to have a rubber grommet insulating the wire from the loom to prevent shorting to gorund. __________________ Jerry: BLACK 85 h/b To compel a man to subsidize with his taxes the propagation of ideas which he disbelieves and abhors is sinful and tyrannical. Thomas Jefferson “The best government is that which governs least.” variously attributed A/R "Swirl" wheels FRPP clutch/flywheel subframe connectors BBK catted H-Pipe Flowmaster American Thunder exhaust Edelbrock Performer Intake Manifold *Click HERE to REGISTER YOUR* GT!**

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