[rls196906]

 

[rls196906]

I need to remove the dash and see why the oil pressure and speedo are not working. I hate dash work.😩

 

[bk2life]

I need to remove the dash

awesome little blazer, reminds of the one i gave to my dfaughter for her 16th..
Also there is no reason to remove the dash to check your gauges. Just pull the gauge cluster.

 

[rls196906]

Thanks, it's a fun little ride. I've seen the videos on You Tube and yes I see where I just remove the gage cluster.
I'm the last one to tackle a complete dash removal and install. With both the oil pressure gage and the speedo being on the same side of the panel, I wonder if something in the circuit board went boots up just on that side. We shall see.

 

[chevymec]

Good looking blazer!

 

[oldeerslayer]

Oil pressure in 94 is a direct wire from the ender to the gauge. Tan wire at the sender, which is what I'd look at first. Pin 9 on the cluster connector. Same tan wire. All the engine gauges get ignition power from pin 2, pink/blk, and the sender is a variable ground.
The speedo on a 94 Blazer is still cable driven. If it's not working the cable would be my first suspect. If it's OK check the gears in the trans. If they're OK replace the speedo.

 

[rls196906]

Thank you, most kind Chevymec

 

[rls196906]

Oil pressure in 94 is a direct wire from the ender to the gauge. Tan wire at the sender, which is what I'd look at first. Pin 9 on the cluster connector. Same tan wire. All the engine gauges get ignition power from pin 2, pink/blk, and the sender is a variable ground.
The speedo on a 94 Blazer is still cable driven. If it's not working the cable would be my first suspect. If it's OK check the gears in the trans. If they're OK replace the speedo.

Thanks for the tech info. I wasn't sure where to start. I need to get an assembly manual one of these days.
I'm 71 years young so my ability to work under the dash and other tight places is somewhat limited. But, I always
try to fix something myself, because you will always gain knowledge.....sometimes good.....sometimes NOT SO GOOD.

 

[oldeerslayer]

Dammed kids. I'm 76 in a month. Been retired longer than some of the youngsters on here have been alive.
Good thing with the gauges is you shouldn't have to get under the dash. If you do, pull the drivers seat. For us Septuagenarians it's a lot easier on the back. Still gonna hurt a bit.
The other trick I've used is a 2 foot wide piece of plywood at a 45° angle out the door with the outside end on a milk crate.

 

[rls196906]

Dammed kids. I'm 76 in a month. Been retired longer than some of the youngsters on here have been alive.
Good thing with the gauges is you shouldn't have to get under the dash. If you do, pull the drivers seat. For us Septuagenarians it's a lot easier on the back. Still gonna hurt a bit.
The other trick I've used is a 2 foot wide piece of plywood at a 45° angle out the door with the outside end on a milk crate.

HA HA HA HA HA......I am stocked up on Ibuprofen so I'm ready. Nice to see I'm not the only old f*rt out here still trying to enjoy life. There's few joys I have left and tinkering in cars is one. I like the board and milkcrate trick. Good place for a nap maybe?? Naps are good at our age, no matter where they happen. 😴

 

[oldeerslayer]

On your oil pressure sender, it originally had 3 wires. 2 had to do with providing power to the fuel pump relay as redundant power for the electric fuel pump. There's a real good possibility it was unplugged or the wires cut when the carbed engine was installed. I'm guessing it's running the SBC mechanical pump and the in tank electric was removed.
Cleaner and easier than trying to regulate the pressure down for a carb.
You can simply use a fuel pump connector and only connect the tan wire for the gauge if the sender is still there. If not since all GM SBC's of the era run 1/4"-18 NPT hole by the distributor. Find a single wire GM sender of that era that's just for a gauge. IIRC the senders are all 0-90 ohms.
Here's one from an 82 Camaro that should work. It the pipe threads are wrong you can get 1/8 to 1/4 adapter at a hardware store.

More Information for STANDARD MOTOR PRODUCTS PS154

The later 99 up 4.3 did away with the oil pressure to fuel pump stuff and were also 1 wire, but you need the pigtail for those because they're a Weatherpack connector. That's what I'm running on my 6.0 LS, but had to use a SAE to MM thread adapter. It's the stock 99 S10 sender.

 

[rls196906]

On your oil pressure sender, it originally had 3 wires. 2 had to do with providing power to the fuel pump relay as redundant power for the electric fuel pump. There's a real good possibility it was unplugged or the wires cut when the carbed engine was installed. I'm guessing it's running the SBC mechanical pump and the in tank electric was removed.
Cleaner and easier than trying to regulate the pressure down for a carb.
You can simply use a fuel pump connector and only connect the tan wire for the gauge if the sender is still there. If not since all GM SBC's of the era run 1/4"-18 NPT hole by the distributor. Find a single wire GM sender of that era that's just for a gauge. IIRC the senders are all 0-90 ohms.
Here's one from an 82 Camaro that should work. It the pipe threads are wrong you can get 1/8 to 1/4 adapter at a hardware store.

More Information for STANDARD MOTOR PRODUCTS PS154

The later 99 up 4.3 did away with the oil pressure to fuel pump stuff and were also 1 wire, but you need the pigtail for those because they're a Weatherpack connector. That's what I'm running on my 6.0 LS, but had to use a SAE to MM thread adapter. It's the stock 99 S10 sender.

Ahhhhhhh well thank you for the helpful information on the oil pressure issue. At least knowing where to start is always a help. I'm electronically challenged thus my desire for the old rides. But this S10 conversion just talked to me and said, step out and challenge myself. Bless you for your sharing. I hoep I can return the favor someday.

 

[rls196906]

 

[rls196906]

Well, well, well...looky here.........oil pressure. Seems the wire or wire connector was touching the header and once I moved it away, TUH DUH............look at that. OKAY............good day so far.

Now, for the speedometer next. My 94 has a 700R4 in it, not the 4L60E. I think 94 was the first year for the 4L60E.
If I'm mistaken please correct me.

I'm not even sure the 700R4 will make a difference but I try to seek help with the best and most accurate information possible. This way I'm not down a rabbit hole trying to fix something with advice and information that won't work for certain applications.

 

[oldeerslayer]

I was wrong and stand corrected. 94 uses a VSS in the trans. If your 700r4 is older it might have a cable setup. Jags That Run (JTR) has VSS's that will connect to them. You may still need to correct the gears to get an accurate speedo. Or you might be able to get a adjustable DRAC. It's between the VSS and the speedo.
Look on the side of the trans case on the passengers side oilpan rail there is a number stamped into the case giving the year of the trans. While you are down there see if it has a threaded fitting for a cable or a VSS to connect 2 wires to. On the drivers side tailhousing.

 

[oldeerslayer]

Here's a list of the gears available for a 700R4. Just need to do some math.
700R4 Speedometer Gears

Drive Gears​	Driven Gears​
15 teeth - gray	18 teeth - (truck) brown
17 teeth - red*	19 teeth - (truck) dark aqua
18 teeth - blue	20 teeth - (truck) silver
19 teeth - yellow	21 teeth - (truck) red/chartreuse
20 teeth - brown	22 teeth - (truck) gold
	23 teeth - (truck) maroon
	24 teeth - (truck) dark blue
	34 teeth - light green
	35 teeth - orange/pink
	36 teeth - white
	37 teeth - red
	38 teeth - blue
	39 teeth - brown
	40 teeth - black
	41 teeth - yellow
	42 teeth - green
	43 teeth - purple
	44 teeth - dark gray
	45 teeth - light blue

Here's how to do the math:

TCI Speedometer Gear Calculator

Leading provider of high performance automatic transmissions, torque converters and drivetrain components for race, street/strip, hot rod, street rod and towing

www.tciauto.com

This site has a calculator:

Speedometer Gear Calculator"

Speedometer Gear Calculator, Speedometer Gear Calculator Click Here

transmissioncenter.net

An adjustable DRAC might be less trouble. That's what I used on my 94.

UD Module DIY User Configurable DRAC VSSB Module Dip Switches

Do It Yourself DRAC VSSB Module from UD Module modified with dip switches for user configuration manually

www.udmodule.com

 

[Brawndo]

I think your information is wrong on the speedo being driven by a cable and gear setup. My 90 has a 700r4 and definitely uses a vss sensor in trans. I think gm used same dash in the s10 and s10 blazer

 

[oldeerslayer]

Thanks for the heads up.
I just saw a speedo cable listed for a 94 and assumed that's what was still in use. Turns out it was a Lokar for guys who want to put a TH350 in a 94. Then you need a cable speedo also.
Been a long time since I actually owned a 1st gen. Like the creature comforts most later 2nd gens have.
I corrected the #15 post to reflect what you reminded me of. My 94 pickup although a 2gen body was still a 1st gen underneath and I remember having to change out the DRAC for an adjustable one to correct my speedo. Hence it had to be VSS equipped. The VSS listing says 89-94 S10.
Nice thing about this forum is there's usually someone to correct you if you make a mistake.
The more I think about it I don't know how I could have forgotten about the DRAC. Being 76 might have something to do with it. Although us old guys know a lot more than most youngsters, we still do make mistakes. Sorry!

 

[rls196906]

Whew.......all this technical verbage flying around.....I was concerned that when I checked I didn't have a place for a speedometer cable in the back of the instrument panel. I did buy a very nice instrument panel on EBay and I kept looking going, "did I buy the wrong panel or did someone swap in a different one?"

The panel I purchased is in very good condition. Clear lens and it appears a lot less fading than what panels look like here thanks to Mr. Sun and his fading properties of anything plastic.

But hey, I am learning. You're never too old to learn. Now you can be too old to remember. Now, what I was saying???

 

[rls196906]

I think your information is wrong on the speedo being driven by a cable and gear setup. My 90 has a 700r4 and definitely uses a vss sensor in trans. I think gm used same dash in the s10 and s10 blazer
View attachment 365336
View attachment 365337

This is what the back of my replacement panels looks like........thanks for posting.