I made a post back in January about my non-starting Cobra (GM block,
original post at bottom) and received some responses. It's now spring
time and the problem has not fixed itself :-) so it's time to revisit
it. I've done some more troubleshooting and it indicates a more general
electrical problem.

I've found that the trim does NOT work either, and that as soon as I
switch on something, say the engine room blower, there is a significant
voltage drop - down to below 6V. The gauges don't power up fully and
the tachometer doesn't return to 0 when the ignition switch is put in
the acc. position.

Voltage drops to zero when I try to operate the trim or the starter, and
the trim solenoids don't click.

Also, there is no voltage on the IGN lead which goes from the ignition
switch to the tach. With the ignition switch in the start position,
there is only about 6V on the purple lead at the starter solenoid (which
is placed on the starter motor).

Battery is new and OK. I've checked all fuses I know of, and there is
power from the battery to the instrument panel (12V).

Any ideas? Grounding problem at the ignition switch?

/P O Litby


Billgran wrote:

Do not overlook the simple things such as the neutral safety switch
inside the control box or a disconnected yellow/red wire on the key
switch. I am assuming that the gauges power up with the key to ON and
that the trim works OK.

Bill Grannis
service manager

"Per-Olof Litby - Practice Mgr - Software, Central/North Europe -
Sun Microsystems" wrote
in message ...
Greetings,

My Cobra engine won't start. Absolutely nothing happens when I
turn the ignition key - no click from the solenoid, and obviously
the starter doesn't crank. The battery is OK. Does this indicate
that the solenoid is shot?

I guess it theoretically could be the ignition switch but the
instruments come to life so I don't think that's it. What's the
easiest way to diagnose the solenoid?

thanks ahead,

/POL

"Per-Olof Litby" wrote in message
...
I made a post back in January about my non-starting Cobra (GM block,
original post at bottom) and received some responses. It's now spring time
and the problem has not fixed itself :-) so it's time to revisit it. I've
done some more troubleshooting and it indicates a more general electrical
problem.

I've found that the trim does NOT work either, and that as soon as I
switch on something, say the engine room blower, there is a significant
voltage drop - down to below 6V. The gauges don't power up fully and the
tachometer doesn't return to 0 when the ignition switch is put in the acc.
position.

Voltage drops to zero when I try to operate the trim or the starter, and
the trim solenoids don't click.

Also, there is no voltage on the IGN lead which goes from the ignition
switch to the tach. With the ignition switch in the start position, there
is only about 6V on the purple lead at the starter solenoid (which is
placed on the starter motor).

Battery is new and OK. I've checked all fuses I know of, and there is
power from the battery to the instrument panel (12V).

Any ideas? Grounding problem at the ignition switch?

/P O Litby


Billgran wrote:

Do not overlook the simple things such as the neutral safety switch
inside the control box or a disconnected yellow/red wire on the key
switch. I am assuming that the gauges power up with the key to ON and
that the trim works OK.
Bill Grannis
service manager

"Per-Olof Litby - Practice Mgr - Software, Central/North Europe -
Sun Microsystems" wrote
in message ...
Greetings,
My Cobra engine won't start. Absolutely nothing happens when I
turn the ignition key - no click from the solenoid, and obviously
the starter doesn't crank. The battery is OK. Does this indicate
that the solenoid is shot?
I guess it theoretically could be the ignition switch but the
instruments come to life so I don't think that's it. What's the
easiest way to diagnose the solenoid?
thanks ahead,
/POL



Not the solenoid! Is a bad connection near the battery. Either bad battery
connection or bad cable or corrosion on a connector at the fuse, etc. Take
a meter and put one lead on the battery negative post and then when the
starter is engaged, go along the positive path from the battery and see
where the voltage drops. You can also take a reading from the Negative
battery post to the engine block to see if there is a bad ground path.

Not the solenoid! Is a bad connection near the battery. Either bad
battery
connection or bad cable or corrosion on a connector at the fuse, etc.

agreed.

The battery could be junk too.

have the battery tested and start cleaning all electrical connections.

"Per-Olof Litby" wrote in message
...
I made a post back in January about my non-starting Cobra (GM block,
original post at bottom) and received some responses. It's now spring time
and the problem has not fixed itself :-) so it's time to revisit it. I've
done some more troubleshooting and it indicates a more general electrical
problem.

I've found that the trim does NOT work either, and that as soon as I
switch on something, say the engine room blower, there is a significant
voltage drop - down to below 6V. The gauges don't power up fully and the
tachometer doesn't return to 0 when the ignition switch is put in the acc.
position.

Voltage drops to zero when I try to operate the trim or the starter, and
the trim solenoids don't click.

Also, there is no voltage on the IGN lead which goes from the ignition
switch to the tach. With the ignition switch in the start position, there
is only about 6V on the purple lead at the starter solenoid (which is
placed on the starter motor).

Battery is new and OK. I've checked all fuses I know of, and there is
power from the battery to the instrument panel (12V).

Any ideas? Grounding problem at the ignition switch?

/P O Litby



Your voltage drop is possibley due to a bad battery cable, poor connection,
or internal corrosion.

Grab the battery cables and flex them along their length. If you feel any
"crunchy" areas, they are corroded internally. Inspect the ground stud on
the back of the motor. Usually water drips down thru the engine cover to
transom area and rusts the stud and terminals. Look closely for rust and
corrosion around wiring or their connectors and fuse holders.

A voltage drop test using a voltmeter will tell you where the problem is.
Read a service manual or enlist the help of a knowledgeable person to
perform it.

Bill Grannis
service manager

Billgran wrote:
"Per-Olof Litby" wrote in message
...

I made a post back in January about my non-starting Cobra (GM block,
original post at bottom) and received some responses. It's now spring time
and the problem has not fixed itself :-) so it's time to revisit it. I've
done some more troubleshooting and it indicates a more general electrical
problem.

I've found that the trim does NOT work either, and that as soon as I
switch on something, say the engine room blower, there is a significant
voltage drop - down to below 6V. The gauges don't power up fully and the
tachometer doesn't return to 0 when the ignition switch is put in the acc.
position.

Voltage drops to zero when I try to operate the trim or the starter, and
the trim solenoids don't click.

Also, there is no voltage on the IGN lead which goes from the ignition
switch to the tach. With the ignition switch in the start position, there
is only about 6V on the purple lead at the starter solenoid (which is
placed on the starter motor).

Battery is new and OK. I've checked all fuses I know of, and there is
power from the battery to the instrument panel (12V).

Any ideas? Grounding problem at the ignition switch?

/P O Litby




Your voltage drop is possibley due to a bad battery cable, poor connection,
or internal corrosion.

Grab the battery cables and flex them along their length. If you feel any
"crunchy" areas, they are corroded internally. Inspect the ground stud on
the back of the motor. Usually water drips down thru the engine cover to
transom area and rusts the stud and terminals. Look closely for rust and
corrosion around wiring or their connectors and fuse holders.

A voltage drop test using a voltmeter will tell you where the problem is.
Read a service manual or enlist the help of a knowledgeable person to
perform it.

Bill Grannis
service manager



OK, this thing is giving me gray hairs. I've done the voltage drop test,
and the voltage drop (which varies depending on what you switch on, from
a 2-3 volt drop with the cabin lights on to a 6-7 volt drop with the
ignition key in the start position) actually starts at the battery
positive terminal and remains the same at other points forward.

Measuring directly between the battery terminals, the voltage drop is
right there whenever something is switched on.

The trim solenoids (just barely) trigger when a direct lead from the
positive battery terminal is connected to their trigger terminal. The
starter solenoid does not (suspect it needs more current). Doing this
drops the voltage (direct at battery) down to 6 volts.

All ground points (I tested several) have the same potential as the
negative battery terminal, so ground seems fine from that point of view.
The main ground wire from the negative battery terminal to the engine
ground point seems OK, no obvious corrosion or damage.

So this to me indicates either a faulty battery - which seems strange
since I tried a different battery last fall when the problem showed up
the first time and that didn't help - or some problem with the grounding.

Am I correct?

/POL

On Mon, 25 Apr 2005 18:39:45 GMT, Per-Olof Litby
wrote:

~~ snippage ~~

So this to me indicates either a faulty battery - which seems strange
since I tried a different battery last fall when the problem showed up
the first time and that didn't help - or some problem with the grounding.

I assume it's a new battery as in brand new battery? Off the shelf?

Have you tried jumping the battery from a separate source like a
battery charger or jump start box and testing the drop then? The only
reason I say that is because of your experiment with the starter
solenoid. If you are getting that kind of drop with a direct
connection to the battery, then it's got to be the battery.

Have you tested the battery with a real load type tester and not just
a volt meter?

Later,

Tom

"Shortwave Sportfishing" wrote in message
...
On Mon, 25 Apr 2005 18:39:45 GMT, Per-Olof Litby
wrote:

~~ snippage ~~

So this to me indicates either a faulty battery - which seems strange
since I tried a different battery last fall when the problem showed up
the first time and that didn't help - or some problem with the grounding.

I assume it's a new battery as in brand new battery? Off the shelf?

Have you tried jumping the battery from a separate source like a
battery charger or jump start box and testing the drop then? The only
reason I say that is because of your experiment with the starter
solenoid. If you are getting that kind of drop with a direct
connection to the battery, then it's got to be the battery.

Have you tested the battery with a real load type tester and not just
a volt meter?

Later,

Tom

Pull the battery connector and clean it really well. Make it shine. If
they are the wing nut type connections, clean them and use a nut and washer,
that you can put a wrench on.

"Per-Olof Litby" wrote in message
...
Billgran wrote:


A voltage drop test using a voltmeter will tell you where the problem is.
Read a service manual or enlist the help of a knowledgeable person to
perform it.

Bill Grannis
service manager

OK, this thing is giving me gray hairs. I've done the voltage drop test,
and the voltage drop (which varies depending on what you switch on, from a
2-3 volt drop with the cabin lights on to a 6-7 volt drop with the
ignition key in the start position) actually starts at the battery
positive terminal and remains the same at other points forward.

Measuring directly between the battery terminals, the voltage drop is
right there whenever something is switched on.

The trim solenoids (just barely) trigger when a direct lead from the
positive battery terminal is connected to their trigger terminal. The
starter solenoid does not (suspect it needs more current). Doing this
drops the voltage (direct at battery) down to 6 volts.

All ground points (I tested several) have the same potential as the
negative battery terminal, so ground seems fine from that point of view.
The main ground wire from the negative battery terminal to the engine
ground point seems OK, no obvious corrosion or damage.

So this to me indicates either a faulty battery - which seems strange
since I tried a different battery last fall when the problem showed up the
first time and that didn't help - or some problem with the grounding.

Am I correct?



You are not performing a diagnostic voltage drop test. Refer to a service
manual or enlist the help of a knowledgeable person to assist and guide you.

I am not going to type the whole procedure, as that is in many reference
books, but what you want to check using a voltmeter along each section of
wiring and connector sis the voltage drop in that area when under a load.

Good luck, let us know what you find out.

Bill Grannis
service manager

Billgran wrote:
"Per-Olof Litby" wrote in message
...

Billgran wrote:


A voltage drop test using a voltmeter will tell you where the problem is.
Read a service manual or enlist the help of a knowledgeable person to
perform it.

Bill Grannis
service manager

OK, this thing is giving me gray hairs. I've done the voltage drop test,
and the voltage drop (which varies depending on what you switch on, from a
2-3 volt drop with the cabin lights on to a 6-7 volt drop with the
ignition key in the start position) actually starts at the battery
positive terminal and remains the same at other points forward.

Measuring directly between the battery terminals, the voltage drop is
right there whenever something is switched on.

The trim solenoids (just barely) trigger when a direct lead from the
positive battery terminal is connected to their trigger terminal. The
starter solenoid does not (suspect it needs more current). Doing this
drops the voltage (direct at battery) down to 6 volts.

All ground points (I tested several) have the same potential as the
negative battery terminal, so ground seems fine from that point of view.
The main ground wire from the negative battery terminal to the engine
ground point seems OK, no obvious corrosion or damage.

So this to me indicates either a faulty battery - which seems strange
since I tried a different battery last fall when the problem showed up the
first time and that didn't help - or some problem with the grounding.

Am I correct?




You are not performing a diagnostic voltage drop test. Refer to a service
manual or enlist the help of a knowledgeable person to assist and guide you.

I am not going to type the whole procedure, as that is in many reference
books, but what you want to check using a voltmeter along each section of
wiring and connector sis the voltage drop in that area when under a load.

Good luck, let us know what you find out.

Bill Grannis
service manager



OK, after some more voltage drop measurements and battery tests I
replaced the battery, and for good measure the main ground wire. Now
everything works except the starter - starter solenoid triggers but
starter does not run.

There is a 1.8V drop under starter load across the wire from battery +
to starter and that wire gets very hot so I will replace that wire (old
and corroded) - had no 4 awg wire so will get some tomorrow.

I hope that will solve this final problem and that it isn't the starter.

/POL

Open up that 8 pin cluster on top of the engine. Clean up the male pins
with very fine sand paper (crocus cloth), then roll the paper up
tightly and clean up inside the female contacts.

I have a 1988 305 Cobra and have had to do this every year for some
time. The symptoms seem to be the same with me as you're describing.
Also, it could be the 50 amp fuse on top of the engine.