Ground strap

[mcruz]

I just noticed that the ground strap on the passenger side from the hood to the fender broke off. Don't know what caused this, any ideas?

[Punch]

mine doesn't have a ground strap????

[PToholics Anonymous]

You opened the hood too many times?

[quicksilverdon]

quote:Originally posted by Punch

mine doesn't have a ground strap????

That's my reaction, too! Why would the hood have a ground strap?? [:I]

[IRPT]

There are ground straps in several locations on the PT. Ground straps to the ABS sensor, engine, strut tower, muffler, radio, and engine hood.

Not sure why yours broke, just replace it. To replace:

Disconnect negative battery cable.
Install strap and bolt to fender, tighten bolt to 4 N-m (35 in. lbs)
Install strap and bolt to hood, tighten bolt to 4 N-m (35 in. lbs).
Connect negative battery cable.

[MX-5]

There are several ground straps throughout the PT. They are all there for noise suppression. Not only is the radio a concern, but all 9 computers onboard. Don't elliminate any ground straps.

From page 8A-6 of the 2002 service manual:

Factory-installed radio noise suppression is accomplished
primarily through circuitry or devices that
are integral to the factory-installed radios, audio
power amplifiers and other on-board electrical components
such as generators, wiper motors, blower
motors, and fuel pumps that have been found to be
potential sources of RFI or EMI. External radio noise
suppression devices that are used on this vehicle to
control RFI or EMI, and can be serviced, include the
following:
² Ground straps - This length of braided ground
strap has an eyelet terminal connector crimped to
each end. They are located in various locations on
the vehicle.
² Radio Noise Suppression Capacitor - This
component is attached to the throttle control support
bracket.
² Resistor-type spark plugs - This type of spark
plug has an internal resistor connected in series
between the spark plug terminal and the center electrode
to help reduce the production of electromagnetic
radiation that can result in radio noise.
OPERATION
There are two common strategies that can be used
to suppress Radio Frequency Interference (RFI) and
ElectroMagnetic Interference (EMI) radio noise. The
first suppression strategy involves preventing the
production of RFI and EMI electromagnetic signals
at their sources. The second suppression strategy
involves preventing the reception of RFI and EMI
electromagnetic signals by the audio system components.
The use of braided ground straps in key locations
is part of the RFI and EMI prevention strategy.
These ground straps ensure adequate ground paths,
particularly for high current components such as
many of those found in the starting, charging, ignition,
engine control and transmission control systems.
An insufficient ground path for any of these
high current components may result in radio noise
caused by induced voltages created as the high current
seeks alternative ground paths through components
or circuits intended for use by, or in close
proximity to the audio system components or circuits.
Preventing the reception of RFI and EMI is accomplished
by ensuring that the audio system components
are correctly installed in the vehicle. Loose,
corroded or improperly soldered wire harness connections,
improperly routed wiring and inadequate audio
system component grounding can all contribute to
the reception of RFI and EMI. A properly grounded
antenna body and radio chassis, as well as a shielded
antenna coaxial cable with clean and tight connections
will each help reduce the potential for reception
of RFI and EMI.

ENGINE GROUND STRAP
(1) Install strap and bolt to strut tower. Tighten
bolt to 12 N·m (105 in. lbs.).
(2) Install strap and bolt to engine cylinder head.
Tighten bolt to 28 N·m (21 ft. lbs.).
(3) Connect battery negative cable.

HOOD HINGE GROUND STRAP
(1) Install strap and bolt to fender. Tighten bolt to
4 N·m (35 in. lbs.).
(2) Install strap and bolt to hood. Tighten bolt to 4
N·m (35 in. lbs.).
(3) Connect battery negative cable.
MUFFLER GROUND STRAP
(1) Install strap and bolt to rear floor pan. Tighten
bolt to 8 N·m (75 in. lbs.).
(2) Install strap and bolt to muffler. Tighten bolt to
8 N·m (75 in. lbs.).
(3)
RADIO NOISE SUPPRESSION CAPACITOR
(1) Install capacitor and bolt.
(2) Connect electrical harness connector to capacitor.
(3) Connect battery negative cable.
STRUT BRACKET TO BODY GROUND STRAP
(1) Install strap to frame rail.
(2) Install strap and bolt to strut. Tighten bolt to
12 N·m (105 in. lbs.).
(3) Connect battery negative cable.

[quicksilverdon]

What about those with a fiberglass hood?

[mcruz]

Thanks guys, I never guessed that I would get such comprehensive information. I do appreciate it because I had no idea what a ground strap from fender to hood would accomplish, for that matter what any of them were for. Since no one mentioned it I guess I don't have to remove the negative battery cable to disconnect the ground strap from the muffler? I am installing dual exhaust tomorrow.

[IRPT]

mcruz, according to the service manual the first step in ground strap removal is to disconnect and isolate the negative cable.