Engine wiring/vacuum connections!

[jgasca]

Does your oil pressure sender connector have one or two connections? Most of the time the oil pressure sender is located right under the distributor. I have only seen the two prong one on trucks with fuel injection setup. Do you have the one that came off the 305? It will work on the 350.

Do you have a picture of the 305?
Did the 305 have all of the emission equipment on it?
Do you have a emission testing requirement where you live?

Most of those wires and vac hoses look to be for emissions. If you don't have emission testing where you live you won't need them.

As the others said above, I took too long hitting the reply

I took everything off the 305 and I only sent the core. I kept the intake as well. The 305 was missing some vacuums that seemed to go to the 4bbl carb. And no we don't need to pass emissions here in New Mexico.

The connector near the distr fits the two prong oil pressure switch. As you can see from the pics I posted, I took the little cap I found right under the distr off and I screwed in the two prong oil pressure switch. Not sure if its a bad switch or what but I'm not reading any oil pressure.

 

[Jims86]

Yeah, he's computer, but not much of one. All he should have is ESC, Electronic Spark Control. So he'll have an ECM with a small harness that goes to the dizzy, and a wire to a knock sensor and that's about it. In fact you can use the original ESC dizzy, do a little wire twisting by pass and runs just like an HEI old shcool dizzy. All the ESC system is allow for the maximum advanced timing possible for performance, but will retard it if a knock is detected. The other purpose for for ESC was when fuel started getting cut back on octane. So you could go with the good high octane but if it wasn't availalbe, then that was OK to run the **** octane too.

No, there is a mixture solenoid plug there too...the green and wite wires i belive. M4me carb, I think.
But if it runs good enough for him, and he doesn't need the other stuff....should be ok.

 

[HotRodPC]

No, there is a mixture solenoid plug there too...the green and wite wires i belive. M4me carb, I think.
But if it runs good enough for him, and he doesn't need the other stuff....should be ok.

Guess I didn't look at the pics. If it's an 85 and has the C4 computer, then it must be a CA truck, not a Federal 49 states.

 

[Swims350]

the big 4 wire plugin on back of the valve cover is the esc dist. plugin so yours must have been bypassed since it runs and that's unhooked.

looks like a knock sensor wire up front, oval shaped plugin, then I'm thinking electric choke wire, one of the small square or almost rect. plugins.

vac. stuff is emissions them pods and crap on the front of the motor.

silver round thing next to the carb with a sticker on top of it white stickers looks like is a REPLACEMENT egr. and it's unhooked, how dumb is that? somebody change it then leave it unhooked? come on why change it then lol.

Anything else I missed, ask.

 

[HotRodPC]

I didn't see the Carb wires Jim was talking about, but I did the ESC plug for the dizzy. Someone may have just put a standard HEI in his truck.

 

[chengny]

Oil pressure senders:

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The one visible (with 2 connectors) is to activate the choke heater (can't see if you have one). The harness connector is a snap-fit. This switch will also illuminate the "choke" light on the cluster when the key is in the ON position. IT DOES NOT DRIVE THE OIL PRESSURE GAUGE.
It will extinguish the choke light when oil pressure is established. Also acts as an idiot light - if the "choke" light comes on while driving - shut down. You may have lost oil pressure.

The bell shaped sender (single stab) is a variable resistance type. This is the one that drives the oil pressure gauge. The wire that connects to the sender has a rubber boot and should be hanging out of the harness right behind the distributor (maybe a little over towards the RH side).

The purple? (I'm color blind so don't quote me) wire on the RH valve cover is power to the choke heater - it's the one with the thick square connector. Goes to a 4BBL Q-jet with electric choke.

The connector next to that on the valve cover (with the gills/serations) would go to the AIR diverter valve solenoid - if installed.

Bottom line - to run that engine and be able to monitor temp/pressure at the dash you need to connect:

1. Ignition switched power to the primary side of the distributor/coil - spark

2. The green? single lead to the coolant temp sender between spark plugs #'s 1&2 - temp indication

3. The oil pressure sender with the single connector - oil pressure gauge

If you want to charge the battery from the alternator, you need to connect that as well.

 

[Jims86]

the big 4 wire plugin on back of the valve cover is the esc dist. plugin so yours must have been bypassed since it runs and that's unhooked.

looks like a knock sensor wire up front, oval shaped plugin, then I'm thinking electric choke wire, one of the small square or almost rect. plugins.

vac. stuff is emissions them pods and crap on the front of the motor.

silver round thing next to the carb with a sticker on top of it white stickers looks like is a REPLACEMENT egr. and it's unhooked, how dumb is that? somebody change it then leave it unhooked? come on why change it then lol.

Anything else I missed, ask.

He said the new engine came complete, maybe with a regular dizzy.
They will run fine with the dizzy unplugged on the CCC setups, just no timing control, and since its a carb, no need for reference pulses from the dizzy for fueling.

I didn't see the Carb wires Jim was talking about, but I did the ESC plug for the dizzy. Someone may have just put a standard HEI in his truck.

The white plug hanging over the Pass side exhaust manifold.

 

[HotRodPC]

He said the new engine came complete, maybe with a regular dizzy.
They will run fine with the dizzy unplugged on the CCC setups, just no timing control, and since its a carb, no need for reference pulses drom the dizzy for fueling.


The white plug hanging over the Pass side exhaust manifold.

Seems long to be the Carb plug and I don't remember it being white. Doesn't mean it couldn't be though. I'm not seeing the ESC wires come out of the firewall either.
BTW, I did mean CCC when I said C4 up there. C4 was done with well before 85.
For those who are wondering, C4 was the first Real production GM computer system other than just (ESC) electronic spark control, C4 is Computer Controlled Catalytic Converter on some late 70's CA cars that I am aware of, then the CCC, Computer Command Control units in the early 80's for CA vehicles.

 

[jgasca]

Wow thanks alot guys. This is a huge help!!
I'll take a look and compare things tonight and this weekend.
I'll post my feedback

 

[jgasca]

ok people I made "some" progress. I purchased the following oil pressure switches from autozone
http://www.autozone.com/autozone/pa...zZ8znc6?itemIdentifier=123521_44645_9889_5835
http://www.autozone.com/autozone/pa...Z8znc6?itemIdentifier=123828_111359_9275_5835

I slapped those babies in and it ended up looking similar to a pic posted above.

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So i take the truck out for a test drive and see if the oil pressure gauge works. The gauge showed little to no oil pressyre. I took out the instrument cluster and find a bit of a mess of wires. These might not have anything to do with the instrumental cluster but my gas gauge doesn't work either(it bounces when the truck turns on and when you tap on the gauge). So i'll be replacing the cluster this week and see what happens.

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I'm open to any other suggestions!
Thanks!

 

[HotRodPC]

Is that the clutch safety switch I see bypassed??? The yellow and purple wires? I think it is. But, you are certain your truck does have oil pressure right? Make sure you do get the right cluster. There are differences even though look close to the same. Retro probably know more about which ones will interchange with yours.

 

[jgasca]

Is that the clutch safety switch I see bypassed??? The yellow and purple wires? I think it is. But, you are certain your truck does have oil pressure right? Make sure you do get the right cluster. There are differences even though look close to the same. Retro probably know more about which ones will interchange with yours.

I guess what I failed to mention was I just bought this truck abour 3 weeks ago so I'm finding all this as we go. What could have been the reason to bypass the clutch safety switch?

Should I reconnect these wires?

 

[HotRodPC]

Maybe the switch went bad. It's all up to you if want to recconect. Just don't forget to push the clutch in when you start it, and no problems. I woudln't mind it that way one bit. But if some kid unattended jumps in the truck with keys, and turns the key, then you know what happens.

 

[chengny]

One thing jumps right out - nothing is connected to the main grounding block. There should be at least 3 black wires clipped on to the indicated stabs.

Look around for black wires with ends like the one in the square (that one is not one of them - it's just an example of factory wire terminations).

The entire cluster is (normally) grounded directly to that block and none of the gauges will function unless the ground wire is connected. I'm surprised your coolant temp gauge is working. These gauges require two paths to ground - one variable through the associated sender and one unrestricted back to the battery negative. If it's working, don't trust it - it's probably not accurate:

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Gauge failures are often caused by defective wiring or grounds. The first step in locating trouble should be a thorough inspection of all wiring, terminals and printed circuits. If wiring is secured by clamps, check to see whether the insulation has been severed, thereby grounding the wire. In the case of a fuel gauge installation, rust may cause failure by corrosion at the ground connection of the tank unit.

VARIABLE VOLTAGE TYPE
The variable voltage type dash gauge consists of two magnetic coils to which battery voltage is applied. The coils act on the gauge pointer and pull in opposite directions. One coil is grounded directly to the chassis, while the other coil is grounded through a variable resistor within the sending unit. Resistance through the sending unit determines current flow through its coil, and therefore pointer position.
When resistance is high in the sending unit, less current is allowed to flow through its coil, causing the gauge pointer to move toward the directly grounded coil. When resistance in the sending unit decreases, more current is allowed to pass through its coil, increasing the magnetic field. The gauge pointer is then attracted toward the coil which is grounded through the sending unit.

Temp gauge diagram - typical of all the gauges:

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[HotRodPC]

Good Chit. I wasn't aware that's were the interior grounds went. I'll sure be checking mine to make sure I have 3 hooked up. Maybe that ground is not hooked up on the power windows of the K1500.