two connectors 1 on the top of the pump and one on the shut down solenoid, were disconnected so i plugged them in and drove the truck at night and the headlights blew and the interior lights will flash real bright every now and then. when i plug the one on the shut down solenoid in the truck sounds like it ads some timing or something the sound of the truck changes.

should the wires to the shutdown be hot when the truck is running?

Do yall think this is causing my headlight problem?

Could leaving them unplugged hurt my horse power?

What is the wire on the injection pump for?

 

You are confusing the shutdown solenoid with the KSB solenoid.

The wires on top go to the shutdown solenoid. Cummins used the shutdown solenoid as a kind of junction block, so don't get confused. The dark blue wire feeds 12 volts from the ignition switch to allow the engine to run, killing the power should kill the engine. The other wire is supplied with 12 volts via the dark blue wire. It goes to an air temperature switch in the manifold, it closes at approximately 90 degrees. The wire from that switch goes down to the KSB solenoid (on the side of the pump). The KSB solenoid advances injection timing at low RPM when powered up.

I don't think your headlight issues are related. That sounds more like a broken body ground, it's the wire that runs from the battery to the core support.

Plug the KSB back in. There should only be power there if the engine is cold, if it has power all the time then the switch is bad and should be replaced.

 

where is the KSB switch?

 

im so confused

 

These guys are "professors" when it comes to these old gems............

 

The KSB switch is on top of the intake manifold. It's the one closest to the firewall, the other one is the air temp sensor that the PCM uses to run the intake heaters.

 

If he is meaning the 1991.5 in his signature, I didn't think the PCM had anything to do with the grid-heaters on that and previous models.

The grid-heaters on the wife's 91.5 are wired no different than those on the other earlier trucks we have.

Please correct me if I have this wrong.

 

Is your wife's "'91.5" intercooled?

 

Intercooled, but externally regulated alternator; I thought the change came with the 1992 model.

 

The '91.5 model trucks are oddballs. They use a PCM with fewer functions than the '92-'93 trucks instead of the firewall mounted "brain box" that the old trucks have. The change was prompted by the addition of the overdrive trans, the old brain box could not run that.

The grid heater supply side is wired the same on all the trucks, but the control circuits vary.

On the old trucks, the brain box uses input from the air temp sensor (screwed into the side of the intake manifold) to control the grid heater and KSB outputs. The intercooled trucks use a simple temp switch to run the KSB, and the PCM uses an air temp sensor to determine the heater grid operation. The switch and sensor are mounted in the top of the manifold.

Sorry, Stacked. We probably just confused you further with this little off-topic excursion.

 

Look at it this way, the deeper the hole we just put him in, the more he will learn digging his way out.


Carry on.


Thanks.

 

not to much more confusing thanks for the help, but now my radio is fried so maybe that has something to do with the electrical surge. I'm just going to wire the KSB into a toggle. Also when I had the shut down solonoid unhooked the peddle was harder to push so I hooked it back up, it's not doing anything though since I have to have a pull cable anyway.

 

Alright guys, found my electrical problem it was some crappy connector on the fender well. It's a constant hot that supplies the hot wires to the cab I think through the fuse box. I guess it was grounding it's self out inside. I took some pics of the connector, I will try to get them up later. Do y'all know what connector I'm talking about?

 

Yeah, that's the fusible link mess there.

 

I just took it out, put an eyelet on the wire and wired it straight up. My interior light works now along with a few other things