tach wire shorts ignition -- help!
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From: Ft Worth, TX USA
Car: 2016 Ram 1500
Engine: 3.0L Diesel
Transmission: 8sp
tach wire shorts ignition -- help!
I have had this problem once before and my mechanic fixed it.
ok -- driving normaly and the engine just cuts out. try to restart and it wont lite at all and the tach is resting on 0 the whole time.
when my mechanic fixed it the first time he said it was the ignition module (mine is the '86 and up with 8 connectors.
but of course he also replaced cap and rotor.(free - hes anice guy)
when I was helping him we found that the engine would run with the white tach wire ( the one coming off the external coil) disconnected.
anyway the car has run fine with only those 3 changes until now when this happend again.
so I ordered the replacement module from accel and looked at the cap+roter which were fine. BUT now the car will not run with the new module unless I again disconnect the tach.
when I tried to start it with everything connected the tach wire got searing hot and I assume this circuit has grounded. I thought the ground was through the module like last time (or was it?) but this time that seems untrue.
Help me if you have simmilar experience.
It still runs just with no tach. my info is in sig.
another guy told me to unplug the filter lead from the tach and just connect the tach right to the white tach coil lead.
however I cant seem to find the filter.
this problem is getting wierder by the day,.
I can plug everything the way It was and it will run for x-amount of time then die, then All i have to do is unplug and replug the white tach lead and it does the same thing.
------------------
88 T/A 305 TPI--
K&N,Air foil,hypertech chip, thermostat+fanswitch
no MAF screens, no cat, dynomax exh, urethane motor+trans mounts,
SSM frame con, Bilsteins
homemade ramair.
ok -- driving normaly and the engine just cuts out. try to restart and it wont lite at all and the tach is resting on 0 the whole time.
when my mechanic fixed it the first time he said it was the ignition module (mine is the '86 and up with 8 connectors.
but of course he also replaced cap and rotor.(free - hes anice guy)
when I was helping him we found that the engine would run with the white tach wire ( the one coming off the external coil) disconnected.
anyway the car has run fine with only those 3 changes until now when this happend again.
so I ordered the replacement module from accel and looked at the cap+roter which were fine. BUT now the car will not run with the new module unless I again disconnect the tach.
when I tried to start it with everything connected the tach wire got searing hot and I assume this circuit has grounded. I thought the ground was through the module like last time (or was it?) but this time that seems untrue.
Help me if you have simmilar experience.
It still runs just with no tach. my info is in sig.
another guy told me to unplug the filter lead from the tach and just connect the tach right to the white tach coil lead.
however I cant seem to find the filter.
this problem is getting wierder by the day,.
I can plug everything the way It was and it will run for x-amount of time then die, then All i have to do is unplug and replug the white tach lead and it does the same thing.
------------------
88 T/A 305 TPI--
K&N,Air foil,hypertech chip, thermostat+fanswitch
no MAF screens, no cat, dynomax exh, urethane motor+trans mounts,
SSM frame con, Bilsteins
homemade ramair.
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Joined: Jul 1999
Posts: 1,335
Likes: 2
From: Tucson, AZ, USA
Car: '92 Z28; Dk Teal; Her Pkg
Engine: 305
Transmission: Richmond 6 Spd
Axle/Gears: Moser 9", Detroit Locker, 3.70
Sounds like either the tach wire is grounded somewhere between the coil & the instrument cluster, or the tach itself has a short to ground. Use an ohm meter to check for continuity to ground on the tach wire. If the resistance is on the order of a few ohms to tens of ohms, the short to ground is still there. The wire is getting hot because current is flowing from the coil through the wire to ground. The hot wire may actually help solve the problem. The wire will not be hot past the point that it is shorted to ground.
Tim
Tim
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