SN-95

I've got a 94 mustang with a lq4, victor junior, holley 750, 234/238, patriot springs, and 1 7/8 dynatechs. Using the 6010 box. Ive tried the pills, and my own curve and the problem hasnt changed. It starts up just fine, but then stumbles and backfires through the carb and exhaust. I through a timing light lead over the plug wire to show when it was sparking, and a few of the cylinders seem to cut out completely when i hit the gas. I called msd and they dont know what it would be. I have changed cam and crank sensors, checked rockers, pushrods, timing gear alignment. Also made sure we had a good ground and constant 12v. Anybody have this problem or have any input, Im lost...

Ravenous T\A

iTrader: (12)

Coils? Is the Carb new or used. My cam is a 236/240 so it close to yours, My timing curve starts @ idle @ 25* 800rpms, by 2000rpms is 27*, then by 5100rpms it goes to 31* and stays there until my 6800rpm.

Ravenous T\A

iTrader: (12)

Im also thinking it maybe the powervalve in ur Holley

Ravenous T\A

iTrader: (12)

Also may check the plug connections that connect ur MSD box to your coil wiring...I have heard that sometimes the connector pins are not pressed in all the way so it doesnt make a good connection

SN-95

Have tried 3 sets of coil packs. Carb is used, but a guy went through it twice and said it was good. Would a power valve make it backfire from the carb?

daniel044

iTrader: (23)

I have heard sometimes the MSD box is bad.

SN-95

I have heard of a few also, but normally its just actual starting issues. Im just trying to exhaust all options before sending it back because the car will be down for 2 weeks waiting for them

daniel044

iTrader: (23)

Are you sure you have a 24tooth reluctor wheel?

Where are you located?

I have a brand new MSD 6010 box we could try.

cambirdracing

iTrader: (4)

Its not normal, but a backfire thru the carb will blow out a p/v. usually when they blow, it will idle/run rich.

SN-95

It's an iron block 6.0 with 317 heads, as far as I know, that setup was 24 tooth. I'm near Dallas, you close? The sideband shows slightly lean, but I think that's normal when not under a load. It does idle really high thought too, and the idle screw is back all the way off

Ravenous T\A

iTrader: (12)

whats ur timing look like?

SN-95

Wideband*
though*
Damn iPhone lol

SN-95

I'll have to check exactly what it is when I get off at 4. I think it's around
15@ 0
22@ 900
34@ 3000

SN-95

Also I notice when I have the dial pulled up on the pro-data software, it shows 1.1 psi on the map gauge, but I don't have the map sensor hooked up. The map curve is flat lined at zero, is that normal?

daniel044

iTrader: (23)

I am in Houston. Good luck on getting it worked out.

Ravenous T\A

iTrader: (12)

If I remember correctly my MAP is at 0 also

I'd check the plug connections within the plug, plus u should have to have ur idle screw turned all the way up to keep the car running, should idle around 800rpms, I could turn my timing down but I would have to increase my idle, and Im at 25*

SN-95

I'll check the connectors again.

With the idle adjusted out to the point that it's not even touching the linkage, it still idles around 1400rpm

SN-95

And thanks Daniel

Ravenous T\A

iTrader: (12)

yeah 1400 rpms is way high IMHO

SN-95

Agreed, but not sure why it's that high. I even turned the idle mixture screws back in, no change. They are about 1 turn out