Installed MSD coil and car runs terrible.

428CJ · January 14th, 2012, 07:18 PM

I recently installed an MSD coil on my car and it ran terrible. It idled between 1200 and 1800 rpm, surged badly and bucked violently off throttle. I decided to put the stock coil back on and it ran a little better but not much. It idles no less than 1000 and at times up to 1600. Still bucks and surges, but not as severe. Also when i let of the clutch and throttle, like after i put it in neutral or something, it surges up to 1500 rpm and falls back down. Also, it falls back to idle very slow (after i rev it or put it in neutral while driving). It's getting like 13 miles to the gallon and feels really weak.

Anybody have an idea as to what happened after i put that coil on?

FastStang91Lx · January 14th, 2012, 10:50 PM

Sounds like somehow you gave yourself a vacuum leak.

428CJ · January 15th, 2012, 12:21 PM

Well i guess i got some searching to do, lol

FastStang91Lx · January 15th, 2012, 12:56 PM

It could also be sheer coincidence that another sensor shit the bed at the same time. Check your tps, clean the maf, check your fuel pressure and timing. Just go one by one until you find the issue. I was constantly chasing down a vac leak that had me completely frustrated, and it happened to be one of the plastic studs that secures the HVAC vac lines to the back of the controller in the dash. One of the studs broke and it was kind of coming off the tubes, but was on just enough to be able to still change my settings.

428CJ · January 15th, 2012, 01:19 PM

Ya, i was planning to check my tps and timing today anyway, but i'll check my vacuum lines aswell.

428CJ · January 20th, 2012, 05:30 PM

Well, in my search for vacuum leaks i found out that my car runs much better- not quite perfect- when my A/C is on max. when i turn it down it runs bad again. Is this a sign of a vacuum leak?

January 14th, 2012, 07:18 PM	#1
428CJ Regular Join Date: Oct 2010 Location: Boise, Id Posts: 142 iTrader: 0 reviews	Installed MSD coil and car runs terrible. I recently installed an MSD coil on my car and it ran terrible. It idled between 1200 and 1800 rpm, surged badly and bucked violently off throttle. I decided to put the stock coil back on and it ran a little better but not much. It idles no less than 1000 and at times up to 1600. Still bucks and surges, but not as severe. Also when i let of the clutch and throttle, like after i put it in neutral or something, it surges up to 1500 rpm and falls back down. Also, it falls back to idle very slow (after i rev it or put it in neutral while driving). It's getting like 13 miles to the gallon and feels really weak. Anybody have an idea as to what happened after i put that coil on? __________________ 1988 Mustang: 5 speed, hurst shifter, plenty slow.

January 14th, 2012, 10:50 PM	#2
FastStang91Lx I Post Entirely Way Too Much 1991 Mustang LX 5.0 Join Date: Jan 2010 Location: Minnesota Posts: 5,572 iTrader: 2 reviews	Sounds like somehow you gave yourself a vacuum leak. __________________ Point made in less than a few hours with minimal response. http://www.moddedmustangs.com/forums...ml#post4465184

January 15th, 2012, 12:21 PM	#3
428CJ Regular Join Date: Oct 2010 Location: Boise, Id Posts: 142 iTrader: 0 reviews	Well i guess i got some searching to do, lol __________________ 1988 Mustang: 5 speed, hurst shifter, plenty slow.

January 15th, 2012, 12:56 PM	#4
FastStang91Lx I Post Entirely Way Too Much 1991 Mustang LX 5.0 Join Date: Jan 2010 Location: Minnesota Posts: 5,572 iTrader: 2 reviews	It could also be sheer coincidence that another sensor shit the bed at the same time. Check your tps, clean the maf, check your fuel pressure and timing. Just go one by one until you find the issue. I was constantly chasing down a vac leak that had me completely frustrated, and it happened to be one of the plastic studs that secures the HVAC vac lines to the back of the controller in the dash. One of the studs broke and it was kind of coming off the tubes, but was on just enough to be able to still change my settings. __________________ Point made in less than a few hours with minimal response. http://www.moddedmustangs.com/forums...ml#post4465184

January 15th, 2012, 01:19 PM	#5
428CJ Regular Join Date: Oct 2010 Location: Boise, Id Posts: 142 iTrader: 0 reviews	Ya, i was planning to check my tps and timing today anyway, but i'll check my vacuum lines aswell. __________________ 1988 Mustang: 5 speed, hurst shifter, plenty slow.

January 20th, 2012, 05:30 PM	#6
428CJ Regular Join Date: Oct 2010 Location: Boise, Id Posts: 142 iTrader: 0 reviews	Well, in my search for vacuum leaks i found out that my car runs much better- not quite perfect- when my A/C is on max. when i turn it down it runs bad again. Is this a sign of a vacuum leak? __________________ 1988 Mustang: 5 speed, hurst shifter, plenty slow.

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