Hot Rod Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
Im doing a 4.3 to 5.7 carb swap in a 2001 chevy blazer 5 speed manual tranny and im trying to find some advice on how to do all the wiring and connections to be able to still use all my stock gauges.any help would greatly appreciated
 

·
Administrator
Joined
·
9,809 Posts
Im doing a 4.3 to 5.7 carb swap in a 2001 chevy blazer 5 speed manual tranny and im trying to find some advice on how to do all the wiring and connections to be able to still use all my stock gauges.any help would greatly appreciated
Gamby : I moved your new question posted in an olde thread over to Basics forum and a new thread. Lets get some fresh ideas and information for you. thanks
 

·
Registered
Joined
·
3,107 Posts
These are stepper motors they need a ecm(or manual control that uses a ecm) to run them. You can not "trick" them into working without some form of computer. The factory gauges are hit and miss as far as reliability goes. Going aftermarket would be recommended.

Most people just pull the gauges or entire cluster and replace them with mechanical. I perfer to use a old android phone for speed, mileage, traffic alerts, and music(spotify) all using the Waze app. While your fuel, temp(s), pressures, and volts can be done using pods or just having a "plate" where the old cluster sat. If you had the computer controlled engine you could see all your gauges(except fuel) through the same android phone/tablet using torque or similar app. Even have alerts come up if say one of your temps went out of range. The fuel gauge was not controlled by the computer in 01. You may be able to trick that into working mechanically.
 

·
Registered
Joined
·
13,679 Posts
After 1995 doing what you are doing is a huge hassle. That was the last year of OBD-I, actually the 4.3 models transitioned a year earlier than the V8’s to OBD-II. OBD-II is a quantum step into far more than engine and transmission management of OBD-I, it is a total vehicle systems integration!

It is difficult to isolate the instruments from the engine and transmission sensors and the computer. It’s a bit less complicated with a manual transmission but still a good size pain in the butt.

You’re going to need the detail wiring diagrams for the year and model vehicle.

I’d recommend you visit the S10 forums as there are a lot of guys over there doing this kind of stuff.

Bogie
 

·
Administrator
Joined
·
8,192 Posts
Gamby, I am looking at the wiring diagram and it should work pretty easy.
Oil pressure is a Tan with white wire, from the sensor and runs right to the Instrument panel.No computer needed for that
Fuel level sensor goes through the PCM ( engine computer) so the computer will need to be left in place to run that
Speedometer (Speed sensor) will also need the PCM to run. No problem, leave the pcm on the car and hooked up.
Coolant temp also tuns through the PCM. There are 2 coolant temp sensors. The one with the yellow and black wires between the last 2 spark plugs on the drivers side of the motor, and, the one at the front of the engine with the brown and yellow wires. IIRC the one on the engine side back between the last 2 spark plugs is for the gauge. Easy to check.Turn on the key and watch the gauge. Unplug one or the other and watch the gauge.
Park switch is also through the PCM.
Use the same wiring to the alternator as the PCM will turn that on too.
Tach output comes from the PCM.
Tach input is formed by the PCM and needs a signal from the crankshaft position sensor.
You Might be able to hook up the wires from the sensor to a basic HEI .Might. It could work. Chances are yes.
You will likely need to hook to the pickup coil in the HEI with the old wires from the crank sensor.It may or may not work depending on the voltage level/requirements

So, in summation, leave the PCM in and hooked up.
Use the coolant sensor and existing wire for said sensor
Use the Oil pressure sensor from the 4.3 and use the existing wiring.(1 wire woohoo)
Fuel level sensor will take care of itself, just leave the PCM
Same for PRNDL
Same for speedometer.
Tach is a maybe.But likely.

Any wiring from the PCM that is not hooked up to a sensor that is no longer present, like a MAF or MAP, is not needed, nor needs to be hooked up. Ignition coil wiring , Idle air control and a few other pieces will not need to be hooked up.
Dont just get in there and start ripping. The transmission may need to see some other inputs to work correctly.Like MAP and MAF, but they can be arranged to work with the 5.7 even if carbed. You could use a 350 with a similar fuel injection and run everything , Like a 99 5.7 SFI with the PCM,( engine VIN code "R") which will plug in with the wiring harness. So a few options here
Keep in touch
 

·
Registered
Joined
·
168 Posts
After 1995 doing what you are doing is a huge hassle. That was the last year of OBD-I, actually the 4.3 models transitioned a year earlier than the V8’s to OBD-II. OBD-II is a quantum step into far more than engine and transmission management of OBD-I, it is a total vehicle systems integration!

It is difficult to isolate the instruments from the engine and transmission sensors and the computer. It’s a bit less complicated with a manual transmission but still a good size pain in the butt.

You’re going to need the detail wiring diagrams for the year and model vehicle.

I’d recommend you visit the S10 forums as there are a lot of guys over there doing this kind of stuff.

Bogie
I thought 1997 was the last year of OB1 and '98 was when everything had to be obII.
Or were you speaking of the change over on the s-10 model line , itself?
 

·
Administrator
Joined
·
8,192 Posts
Yes 1995 was OBD 1, 1996 up was obd 2
I have heard 95 called OBD 1.5 . Must be. It was a mess
 

·
Registered
Joined
·
3,953 Posts
If going carb I have a 96 chevy s10 and I run a turbo 350 so no electronics needed there as mine is not a lockup convertor style and as far as gauges goes I just bought an aftermarket fuel level gauge and took out the electric fuel pump in the tank and then bought a $30 mechanical volt, oil pressure and temperature gauge and then I bought a mechanical speedometer and made a plate to hold them all in the dash for less then $300 bucks and also just run a 12 volt wire to a toggle switch for my power to my distributor and I also even have a transmission temperature gauge as well for my build and all the stuff has worked excellent for me.

For me it was worth it to modify and rip out the factory gauges and put in aftermarket ones which gives me even more reading on what is going on compared to what my factory cluster had.
 

·
Registered
Joined
·
13,679 Posts
I’m in the Eric camp with my personal daily driver being an 89, shortbed, standard cab S-15 with a 95 block 350. This was combination daily transport and test bed for many years so it went through several iterations of GM fuel injection including the 454 TBI mod, the TPI systems both factory and aftermarket, and carburetor. It ended up after I retired with an Edlebrock Thunder AVS, the Procomp 7000 doghouse distributor (no space for a big cap HEI) with their E core model 90 coil. The trans is bit more modified by me 700R4 Nemesis from Trans Dept that I had shipped from Florida to Washington state which has a 2800 stall lockup converter, this replaces the 4L60E originally behind the 350.

The 89 used a DRAC to drive the speedometer that system is really square wave analog which is not integrated into the computer so even the 700R4 swap was simple but I use a Speedway electric speedometer but the factory speedo would also work. But when you get to OBD-II the DRAC goes away and the function gets integrated in the computer.

OBD-II was mandated for integration on the 1996 model year, it has evolved into an increasingly high level of integration ever since. You can start seeing it coming around in 1993 as components and functions start to become integrated on various lines and models. The only exception that I know of is the G30 Chevy/GMC van which carries into 1997 with an L30 or L31 Vortec engine with TBI. It is not quite fish nor fowl being a bit OBD-I and OBD-II.

Bogie
 

·
Registered
Joined
·
3,107 Posts
Nope not even marine applications. Everything inside a junkyard was fuel injected by 01.

If you want to run carb all you need is the intake and distributor. People have done it several times. Most of them switching back to fuel injection with a lighter bank account and the knowledge that fuel injection is not so scarry once you play with it for a bit.

Running a 2001 engine standalone is easier then converting it to carb and much cheaper. Lots of benefits of keeping a 2001 fuel injected. Especially if you want to make power or throw a couple psi into the intake.

You can run a 01 5.3 or 4.3 easily enough. Keep the factory gauges or run them all off a tablet. Frankly I learned that you can run the gauges manually from this thread. Which would come in handy if I ever wanted to drop a turbo diesel into something that had a 5.3 or 6.0.
But the factory gauges are known for being junk as far as reliability goes and I would still use a tablet to get my info.
 
1 - 14 of 14 Posts
Top