CK5
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Help With Ongoing Project
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Alright, well I suppose that can effect your fuel pump relay for sure. Now this is starting to add up. That fuse block has so many different grounds and power supplies that it is beginning to sound like your harness has some issues my friend.
Thankfully these guys that are watching are really well informed and armed to give you the correct pin locations and wire colors but little electrical gremlins like this can be a killer unless each test is done methodically, and in the right order.
Again, I'm no expert but if that ECM has power and ground jumpered in right from the battery to the correct pins (I'd fuse that power lead just for safety sake) my guess is that you would see more reliable results. You can simply jump the relay for the fuel pump too and make sure that it cycles up with power and ground in the same way too.
I don't know, maybe this sounds like a broken record to what I've said already, but we're going back and forth with the same concept - bad wiring...
Ahh, I know what you mean. Wish I were closer so I could come have a peek at it with you. Most of the time, a second look from somebody else can be a big help to put a new perspective on things.
Lets see if the other guys have better advice than I've offered so far. It isn't fixed, so obviously my suggestions aren't getting you anywhere.
Lets see if the other guys have better advice than I've offered so far. It isn't fixed, so obviously my suggestions aren't getting you anywhere.
Ok, so here is what works and what doesn't:
Works:
Blower for heat
Signals
Brake lights
Dash
starter engages
I get spark from the dist. and coil
Yes, the seat belt buzzer.....great.
What doesn't:
ECM does not have power - therefore no power to injectors and fuel pump
running lights
Interior lights
Works:
Blower for heat
Signals
Brake lights
Dash
starter engages
I get spark from the dist. and coil
Yes, the seat belt buzzer.....great.
What doesn't:
ECM does not have power - therefore no power to injectors and fuel pump
running lights
Interior lights
ChadRay13
1/2 ton status
Check and make sure when your key is "on" you have power coming out of the ignitions switch.
How would the starter or ignition (dist/coil) work if I didn't?
Great idea! But it won't solve your under dash electrical problem.
I don't have a wiring diagram... at all. But pretty sure those circuits get fed from a fusible link. Either at the starter or the one on the firewall. And through the ignition switch. And I think they are seperate feeds from the coil and crank circuits. I could be totally off base, just going off memory.
Great idea! But it won't solve your under dash electrical problem.
I don't have a wiring diagram... at all. But pretty sure those circuits get fed from a fusible link. Either at the starter or the one on the firewall. And through the ignition switch. And I think they are seperate feeds from the coil and crank circuits. I could be totally off base, just going off memory.
For the 5.3 I would just pull the fuse block and harness of my '84 K5 parts truck.
The part I really don't understand is that there are items that are being powered through the same fuse able link.
ChadRay13
1/2 ton status
Edit: try and track down where the key on supplies power to the fuse block, if that's not the same power source you tacked before.
that is what kills me with this, I have things that work and others that don't from the same supply
Ok, lights issue solved. There is a direct link from the battery to the alternator. The fuseable link was sporadic and once replaced the issue was solved.
Ok, the 3amp purple wiring coming off the switch terminal off the starter, does power come from there or go to there? To there, right?
What is that dam sensor on the passenger side of the block with another purple wire that fits into a plunger style connector.
Ok, the 3amp purple wiring coming off the switch terminal off the starter, does power come from there or go to there? To there, right?
What is that dam sensor on the passenger side of the block with another purple wire that fits into a plunger style connector.
Sounds like that purple wire to your starter is switched power for the solenoid.
The sensor...
Knock sensor???
Does it look like this??
Sounds like that purple wire to your starter is switched power for the solenoid.
The sensor...
Knock sensor???
Does it look like this??
Yep, that is it.
So, the switched power is powering or being powered?
The switched power for the solenoid comes from (I think without looking at a diagram) the key switch. It is effectively "powering" the solenoid when prompted.
ChadRay13
1/2 ton status
Signal wire for the starter to activate the solenoid. Should only have power when they key is set to on. Goes to a little tab on the starter.
Just surprises me that it has a fuseable link at the starter being if it burned away and grounded on the exhaust for example, it would still be live.
I think its only hot when you turn the keyswitch to cranking position. Is yours hot all the time?
No, just during cranking
ChadRay13
1/2 ton status
There's very low amperage that flows through that wired. The solenoid is like a relay allowing the big amperage to flow through the primary thick wire.
Back to the "power into the fuse block but not out of it"
Where did you test each of these. Did you test directly at the fuse block? Are you referring to the main power into the fuse block?
This is important because if you checked at the device itself then you may have a break in the wires. I don't recall you saying you ever traced that ECM wire down to figure out where you lose power. You may have to start cutting wire loom/wrapping away and piking the insulation with a sewing needle or sharp test leads.
Start at the ecm and follow it backwards.
If you had power directly into the fuse block but not out at the component lead, then pull apart the fuse block and find the damaged part.
Work one circuit at a time.
