I did a stupid thing and helped my son buy a 01 ZR2 that has an aftermarket alarm and had an amp.

We towed it home and when we started out the alarm would go off due the bump circuit. So we disconnected the neg battery cable.

When we got home we reconnected everything and the truck started and run well enough to get it off of the trailer. During the the shakedown run the truck began to run rough and stall at idle.

As long as it was moving it started running better and better...thought the comp was relearning the truck.

Stopped a stop light and it died. No more cranking but all accessories work.

So found the fuse block for the removed amp had come disconnect. It appears to be a new wire for the amp i.e. no butchering of the harness.

I put in a battery we had and cleaned up the cable connections. The truck doesn't start in either park or neutral.

So I begun the diagnostic process pulled fuses and didn't find any issues. Multimeter verified voltage across the battery, at the alternator and at the under hood fuse block at the B+ terminal.

I didn't find voltage at any post on the starter with the key in the run position even the connection from the battery. Shorting the solenoid terminals did nothing not even a spark.

I tested the alarm functions and it unlocks/locks the doors, unlatches the rear glass, attempts to start the truck i.e. unlocks doors and the accessories come on (heater motor)

Oh I don't hear the fuel pump.

Tomorrow with help I will have some turn the key to the crank position and verify the voltages or lack of them. I will use an alternative wire to get power to the solenoid.

I have the feeling the issue is simple and I haven't looked in the right place.

I did read swarlkk responses on another thread but didn't follow when they started talking about pin 87 and pin 30.

Any help would be appreciated.

 

I'd be real suspicious of that. Fuel pump problems are common with these, especially if it's been sitting.

Do a fuel pressure test. If nothing else, ruling that out goes a long way in helping troubleshooting.

 

You should have full voltage at the starter thu the main positive lead at all times - acc. gets it's power thu a smaller lead
, either a almost dead battery, loose posts in battery, bad positive cable, bad negative cable { may have unseen internal corrosion in either }
If you actually have no voltage thu main lead to starter I would start with looking over the positive and negative cables well.

 

Seems to me You have some of the different issues and paths to follow:
For solving this one, You may want to hook up the dongle and list the codes, fuel trims, etc. Ofc, when Your truck cranks and run.

That may be another one. In general, You should have B+ on the thick post of Your starter. This one goes directly from a battery. The negative supply goes through a chassis (battery negative->engine chassis, as I remember nearby alternator mount).
Third one? Hm... Strange.. It could be another story here, but all the two above and this one could be also related to a ground/power issue. I wouldn't care much of this one right now, until Your ride cranks properly.

 

Thanks all I did an Ohm check on starter lead, charging lead and ground. All had zero resistance.

I have tried two batteries with the larger one the PO installed getting check at AutoZone. Checked good and the one we had was charged and will start other vehicles.

The plan for today is clean the connections perhaps order a new positive cable. The temptation is do the big three upgrade but I would like to have a working vehicle before I do that.

I think a relay or in line fuse let go in the starting system. Perhaps the ignition module.

 

If you would like to take an analytical approach to fix your problems I will be glad to help you, along with the other helpful members here. You will have to take multiple voltage measurements, pull fuses, retest, etc, We can get to the bottom of all of your problems but its not parts swapping. If you prefer to parts swap, no problem, that is a common approach so no hard feelings. If your game:

One thing at a time.

Make sure that you have a fully charged battery that will hold 12v with most of the loads turned on.

Make sure that the same voltage is found at the large black cable at the starter which is a direct connection from the battery positive. Run back to the battery negative post not the truck frame to rule out a ground problem. If that shows 12V then ground to the frame and see if you still get 12V.

Turn to the start position and see if you have 12V at the purple wire at the starter, again ground back to the battery.

Report back and we will go from there.

George

 

Just a quick comment; 95% of aftermarket alarms include an ignition interrupt relay which of course prevents the starter from engaging. Relay is usually under the steering wheel in the trim panel....I believe purple wire....but don't hold me to that one.
If there is no voltage at the starter solenoid terminal when the key is turned to START, then either the ignition switch has failed or the alarm starter interrupt relay.
I strongly suggest throwing the aftermarket alarm into the neighbor's back yard.......LOL....

 

LOL well said. I used to rip off all the aftermarket alarms I had. Not a big deal if they "somehow" triger while You ride. But when I cannot start the vehicle, and I am damn sure ther's no other reason, then it triggers me and I teach them to fly As far as I remember there was a member saying of some aftermarket that has to be installed in UK which turned bad due to a nearby radar station..

But before You start opening panels, do the quick check advised by George above.

 

PS

Post a picture of the '67 Camero

 

I was able to clean up the ground under the battery tray and the lower was very corroded.

Reinstalled the battery and test the voltages again.

Battery fully charged off the changer 12.46 volts.

Key on and the battery cables connected 12.02-12.04 volts across the battery, at the alternator post and the B+ post at the under hood fuse block.

Working the probes in deep at the starter connection from the battery get 11.76 volts again a dirty connection. The outside of the connect reads Zero volts but post and inside have voltage.

At the coil post on the starter solenoid get 10.76 volts with key in start position and similar voltage at the battery connection.

The next step will be for my son to drop the starter and solenoid to clean connections and have the starter/solenoid tested. He needs to learn but I think this the next problem to be resolved.

Assuming this fixing the starting issues then then we'll do the lower intake manifold gasket. Check the cap, rotor and wires to see if they need to be replaced.

I would replace them t but my son has limited funds.

No photos of the 67 easy to get to so not today maybe in future.