1986 K30 - Rapid Learning

[shima]

Do you have a vice?

Take the old sensor out.

Martin

I don't have a vice, no. I think they're pretty cheap at HF... I've thought about getting one a few times. My "workbench" is so damn flimsy though.

 

[Wes Harden]

I am not sure that is the correct switch to replace the the stuck one. What is brand and part number of new one.

 

[shima]

I am not sure that is the correct switch to replace the the stuck one. What is brand and part number of new one.

Uh oh... part number is AC Delco D8050.

 

[Wes Harden]

Isn't that sender a duel terminal?

 

[Wes Harden]

New Herko Engine Oil Pressure Sender With Gauge Standard PS-220 Herko OPS802 https://a.co/d/hJTY6cv

Does this look like what you have.

I see this has 1 terminal

 

[shima]

Alright, I finally have a little bit of an update on the truck.

Oil Pressure

• I connected the new junction block, oil pressure sender, and oil pressure switch.
  • The new oil pressure switch is 1-terminal. My old oil pressure switch was 2-terminal. I connected power to it and left the ground wire disconnected.
• After reading the recent responses from @Wes Harden and watching some more YouTube videos, I found a link to this oil pressure switch and ordered it.
  • This new switch is 2-terminal like my old one and uses spade-type connectors so it will be easy to hook up. It has not yet arrived in the mail.
• With the new sender connected, the K30 shows ~15 PSI of oil pressure on startup.
• I let it warm up and also put some fuel system cleaner straight down the carb while blipping the throttle. I checked the oil pressure afterward and the gauge showed ~3 PSI.

Voltage

• While waiting for the new oil pressure switch to arrive I moved on to trying to diagnose my voltage gauge. It is pegged at zero at all times.
• I looked at the wiring diagram in my Haynes. I found the "brown" wire coming off of the alternator post and traced it into the bulkhead. My understanding is that it goes to the fuse block.
• I looked at my fuse block and it was a mess. There were wrong fuses in a few slots. Some fuse slots were empty. A couple had what looked like hornet nests in them.
  • I checked all of the fuses to make sure they were good. I put the correct amperage fuse back in if the wrong fuse was in place. The only exception is the INSTR LPS fuse because I don't have a 5A fuses on hand.
• I found this old thread about the voltage gauge on an '86 truck like mine. After reading through that, I decided to pull the gauge cluster out of the dash and take a peek at the back side of the voltage gauge.
  • Getting the gauge cluster out of the dash has been a major PITA, I keep cracking the old brittle plastic. I fussed with it for about an hour and called it quits.

Here are some photos and videos:

My fuse block before I started trying to fix things up:



Oil pressure gauge on startup:



Oil pressure gauge after warming the truck up:



After putting fuel injector cleaner down the carb:

View attachment PXL_20230225_191133715.mp4

My old oil pressure switch (confirming 2-terminal):



The current oil pressure setup:



Bonus pic: Looks like the manifold vacuum port on my intake is plugged... I am thinking I should fix that if I want to be able to control defrost / floor vents / chest vents:

 

[mrk5]

You can buy terminals that will snap into the open spots on the fuse block.

Pardon Our Interruption

www.summitracing.com

 

[Wes Harden]

I wouldn't worry about the oil pressure readings until you get the correct sender.

Take the dash pad off to get the instrument bezel and cluster out. It will make it so much easier.

 

[shima]

I think my sender is correct - it is the switch that was wrong.

I chatted with @ZooMad75 and @Capt Ron a bit about the oil pressure on Instagram. There isn't much drivetrain noise while it is running, and the mechanical gauge showed 50 psi on startup and ~14 psi after warming the engine up. I am going to double-check that when I install the new switch.

There must be some other reason that the gauge is wrong.

 

[Wes Harden]

If you want to be sure you can put a mechanical guage in place of either of those senders.
I believe the big bell shaped sender is for the gauge

 

[shima]

Got my new two terminal oil pressure switch ready to install. This is the dumbest question and I apologize for it... how are you supposed to know which terminal is positive and which is negative? I can't see any markings on it anywhere. Should I look online for the product sheet or something?

 

[6872xtc]

It doesn't matter if it just connects the two terminals to each other.
If either one grounds to the switch body, then it would make a difference.
I don't know how your truck is wired, so I ain't much help past this, ATM..

 

[shima]

Confirmed good oil pressure with the mechanical gauge and got the voltage gauge going again. Turns out my actual gauge was bad and simply swapping it with one from the cluster that @Bent77 gave me long ago fixed the problem.

Now to hook everything back up and make sure there are no leaks.

View attachment PXL_20230322_031452024.mp4

 

[Wes Harden]

Grats, the gauge in the video is voltage. Temp gauge is showing cool/cold. Check the lowest oil pressure at full temp just to be safe. Also the volt gauge looks a little low.

The mechanical gauge reading is great, 45 psi plenty.

 

[shima]

I've had a solid past couple of nights with the K30:

• Gauge cluster put back together.
• New voltage gauge in place along with new oil pressure gauge (pulled from the same cluster Bent gave me).
  • Both gauges are still reading a little bit low.
    • Oil pressure mechanical gauge reads ~45 psi, the dash gauge reads ~35 psi.
    • Voltage dash gauge reads ~10 volts, which I think is accurate. I should figure out why it isn't showing 13v.
• Oil pressure sender and switch installed and are leak-free.
• All fluids checked and topped off:
  • My radiator was super low on coolant.
  • My clutch reservoir was low on brake fluid.
  • My brake fluid reservoir was EMPTY in the front compartment and super full in the back compartment (?).
    • The fluid was basically black, so I think it's about time I bleed the brakes anyhow.
  • Power steering looked fine.
  • Engine oil is fine.
• I figured out why my windshield wipers weren't spraying wiper fluid (clogged t-fitting). Fixed that.
• Adjusted the timing to 8 degrees BTDC.
  • I was shooting for 4 degrees, went to 6 on accident, and then just kept going to 8.
  • After turning the distributor counter-clockwise, my vacuum advance thing (at the distributor) is basically touching my intake. I don't know that I could reach 12 degrees BTDC without changing something.
  • I haven't driven it yet, going to let it cool down tonight and cold start it tomorrow for a test drive. I want to see how it starts when cold and how it drives with the timing changed.

Here is a video of my gauges on startup, I am happy that they seem to be working. Thanks as always for everyone's help and support.

View attachment PXL_20230414_032357742.mp4

 

[Wes Harden]

be careful of the brakes if a reservoir was empty, you have a leak. Just refilling an empty reservoir will trap air in the system.
The vacuum can hitting the manifold, is common if the dist wasn't stabbed in the correct factory orientation.
the 10v reading may accurate if your battery is low state of charge and heavy electric load. Use your volt meter to check at battery and compare to instrument meter.

Factory gauges are not intended to very accurate, more like you have oil pressure or no you don't. Hi resistance in any of the many connections can effect the reading.

 

[shima]

I test drove it last night with the advanced timing and it did great. One thing I really noticed was that when letting off the throttle, the truck used to lurch hard. It does that dramatically less now. No clue whether the timing has anything to do with that but I'm happy.

@mrk5 I wanted to let you know that I've been using the technique you mentioned in this post when cold starting the K30 and it's working perfectly. Thanks for the tip.

There's no reason to hold the throttle open when you're cranking it cold. Kinda defeats the purpose of the choke. With the 66 I pull the choke full on, crank it for a bit to fill the float bowls, pump the pedal 6 or 7 times, and then crank it until it starts. Other than pumping the pedal as mentioned, I don't touch the gas. Once it fires off, I back the choke down until it's idling smoother. If it's jetted for lower altitude, you may be flooding it. Either way, they are definitely much harder to start when they've sat a long time and it's cold.

 

[shima]

I had a fun time learning how to tune the carburetor. I used this video:

The idle speed is between 7 and 8 Hz on my voltmeter, so between 840 and 960 RPM. It sounds great in my opinion and I'm pretty happy with it. Will report back when I get the chance to test drive it, but for now I'm going to start looking into how to properly shim the starter.

Here's an Instagram video I took of it:

View attachment VID_60851024_051824_342.mp4

 

[shima]

I quickly took a peek at my steering before starting to dig into the starter shim stuff. My steering is really loose - I can move the wheel pretty far in either direction and the wheels don't turn much. I recorded this video and it looks like my steering box might be worn out. The pitman arm doesn't seem to move as much as the steering shaft. What do you guys think?

View attachment PXL_20230415_184418923.mp4

 

[mrk5]

I test drove it last night with the advanced timing and it did great. One thing I really noticed was that when letting off the throttle, the truck used to lurch hard. It does that dramatically less now. No clue whether the timing has anything to do with that but I'm happy.

@mrk5 I wanted to let you know that I've been using the technique you mentioned in this post when cold starting the K30 and it's working perfectly. Thanks for the tip.

I'm glad it's helping.