could i have burnt out the tfi module. i had a ground wire fire the small one attached to the battery post. fix it went and bought a new solenoid cause i broke the other by over tighten the bolt on the post. now the rpms will move up and down and crank but wont fire over. it will crank slow. the solenoid gets warm and so does the battery cables
no start tfi module maybe i dont know
- Thread starter noslow1986
- Start date
Clean and check ALL the grounds for the battery and engine block. This will probably fix your cranking problems. Then do the Cranks OK, but No Start Checklist for Fuel Injected Mustangs.
Grounds are important to any electrical system, and especially to
computer controlled engines. In an automobile, the ground is
the return path for power to get back to the alternator and battery.
1.) The main power ground is from engine block to battery: it is
the power ground for the starter & alternator.
2.) The secondary power ground is between the back of the
intake manifold and the driver's side firewall. It is often missing or
loose. It supplies ground for the alternator, A/C compressor
clutch and other electrical accessories such as the gauges.
Any car that has a 3G or high output current alternator needs
a 4 gauge ground wire running from the block to the chassis
ground where the battery pigtail ground connects.
The 3G has a 130 amp capacity, so you wire the power side
with 4 gauge wire. It stands to reason that the ground side
handles just a much current, so it needs to be 4 gauge too.
The picture shows the common ground point for the battery & extra 3G
alternator ground wire as described above in paragraph 2. A screwdriver
points to the bolt that is the common ground point.
The battery common ground is a 10 gauge pigtail with the computer ground
attached to it.
Picture courtesy timewarped1972
3.) The computer has its own dedicated power ground that comes off the ground pigtail
on the battery ground wire. Due to it's proximity to the battery, it may become
corroded by acid fumes from the battery.
In 86-90 model cars, it is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire.
In 91-95 model cars it is a black cylinder about 2 1/2" long by 1" diameter with a black/white wire.
You'll find it up next to the starter solenoid where the wire goes into the wiring harness.
It is easy to overlook this ground if you do any repair work around the battery or starter solenoid.
Grounds are important to any electrical system, and especially to
computer controlled engines. In an automobile, the ground is
the return path for power to get back to the alternator and battery.
1.) The main power ground is from engine block to battery: it is
the power ground for the starter & alternator.
2.) The secondary power ground is between the back of the
intake manifold and the driver's side firewall. It is often missing or
loose. It supplies ground for the alternator, A/C compressor
clutch and other electrical accessories such as the gauges.
Any car that has a 3G or high output current alternator needs
a 4 gauge ground wire running from the block to the chassis
ground where the battery pigtail ground connects.
The 3G has a 130 amp capacity, so you wire the power side
with 4 gauge wire. It stands to reason that the ground side
handles just a much current, so it needs to be 4 gauge too.
The picture shows the common ground point for the battery & extra 3G
alternator ground wire as described above in paragraph 2. A screwdriver
points to the bolt that is the common ground point.
The battery common ground is a 10 gauge pigtail with the computer ground
attached to it.
Picture courtesy timewarped1972
3.) The computer has its own dedicated power ground that comes off the ground pigtail
on the battery ground wire. Due to it's proximity to the battery, it may become
corroded by acid fumes from the battery.
In 86-90 model cars, it is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire.
In 91-95 model cars it is a black cylinder about 2 1/2" long by 1" diameter with a black/white wire.
You'll find it up next to the starter solenoid where the wire goes into the wiring harness.
It is easy to overlook this ground if you do any repair work around the battery or starter solenoid.
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