jumping tach no miss ideas plz
#1
Junior Member
Thread Starter
Join Date: Jun 2007
Posts: 64
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1991 1le 5.7 6 speed
Engine: 350
Transmission: T-56
Axle/Gears: 3.73
jumping tach no miss ideas plz
ok so just got my car back on the road, and i noticed under light throttle the tach jumps up an down about 500 rpm more severely around 2000RPM.
now the car runs fine and dosent miss.
this occurred just after my new accel coil and ignition module was installed. i made a new bracket for the coil the stock one was all messed up. and the 2 wire plug from the cap to coil is tight across the front side of the cap.
now i know the tach boards go bad and cause them to act funny. i have a second board i can try but i want to know if there is anything else that can cause this IE coil interference ect, also which wire is responsible for the tach signal from the dizzy. any help will be greatly appreciated. i want to put in an msd 6a box however id like my tach to work correctly before hand so if the msd messes with the tach as they some times do i can fix it knowing its just the msd.
thank you p.s i have read https://www.thirdgen.org/forums/elec...meter-fix.html
just want to try other ideas first
now the car runs fine and dosent miss.
this occurred just after my new accel coil and ignition module was installed. i made a new bracket for the coil the stock one was all messed up. and the 2 wire plug from the cap to coil is tight across the front side of the cap.
now i know the tach boards go bad and cause them to act funny. i have a second board i can try but i want to know if there is anything else that can cause this IE coil interference ect, also which wire is responsible for the tach signal from the dizzy. any help will be greatly appreciated. i want to put in an msd 6a box however id like my tach to work correctly before hand so if the msd messes with the tach as they some times do i can fix it knowing its just the msd.
thank you p.s i have read https://www.thirdgen.org/forums/elec...meter-fix.html
just want to try other ideas first
#2
Member
Join Date: Jun 2010
Location: Florida
Posts: 338
Likes: 0
Received 0 Likes
on
0 Posts
Car: 89 chevy camaro rs
Engine: 305
Transmission: 700r4
Re: jumping tach no miss ideas plz
check all ur grounds batt to block,block to fire wall,alt,ecm,try running the car and feeling the grounds by hand if theres a bad connection they sometimes feel warm or even smoke
#3
Junior Member
Thread Starter
Join Date: Jun 2007
Posts: 64
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1991 1le 5.7 6 speed
Engine: 350
Transmission: T-56
Axle/Gears: 3.73
Re: jumping tach no miss ideas plz
will do im going to look at it when i get off today. also i believe it only jumps while actually driving i can hold it a 2000 in neutral and it doesn't seem to jump. that leads me more to some kind of interference
#4
Supreme Member
iTrader: (8)
Join Date: Oct 2001
Location: Il
Posts: 11,715
Received 766 Likes
on
517 Posts
Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: jumping tach no miss ideas plz
sounds like a bad plug wire.
#5
Senior Member
#6
Junior Member
Thread Starter
Join Date: Jun 2007
Posts: 64
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1991 1le 5.7 6 speed
Engine: 350
Transmission: T-56
Axle/Gears: 3.73
Re: jumping tach no miss ideas plz
hmm thats very interesting.. ill check the wires as they haven been on there for almost 2 years i have headers and no heat protectors. maybe when the bad wire gets hot it causes interference of some kind. ill deff check it out.
Thread
Thread Starter
Forum
Replies
Last Post
eightsixseven
Tech / General Engine
1
08-14-2015 03:09 PM
db057
TBI
10
08-11-2015 10:11 PM