454 TBI Sensors Function Location

[BigDaddy72]

The question is:
“Sensors where are all of them located on the engine, and what do they do and why?”

1990 454 ss TBI

 

[BigDaddy72]

The what and why may be similar, but please share your knowledge if you would.

My knowledge about computer controlled vehicles is very basic and elementary.

 

[PlayingWithTBI]

My knowledge about computer controlled vehicles is very basic and elementary.

You can look in the wiring manual for your year to see where they're located and wire numbers/colors, etc. It will be in a couple different sections but it should help.

www.gmt400.com/threads/88-95-service-manuals.43575/

 

[BigDaddy72]

I appreciate the link very much, however like me my phone is to old and or doesn’t have the capability to open it up. Again another area of technology I’m am very deficient in.

 

[BigDaddy72]

Maybe I can make it simpler for me to understand.

These are the sensors I know of.
1) MAP
2) IAC
3) COOLANT TEMP
4) KNOCK SENSOR
5) OXEGYN
6) TPS
7) VSS

Did I miss anything? Or add one it doesn’t have?

Thanks to any and all again for the help.

 

[PlayingWithTBI]

EGR valve - on intake manifold passenger side of Throttle Body
Oil pressure switch for fuel pump - On rear china rail near distributor
Oil pressure sensor for gauges - Driver's side of block next to oil filter
CTS for gauges - between cylinders 1 & 3 on driver's side head

I'm not sure on a 454 where they all are but on a SBC ...

1) MAP - on intake manifold passenger side of Throttle Body
2) IAC - passenger side of TB
3) COOLANT TEMP - next to T-Stat housing
4) KNOCK SENSOR - just above the starter
5) OXEGYN - Driver's side in the exhaust manifold
6) TPS - Passenger side of TB in line with the throttle shaft
7) VSS - tail housing of trans

 

[PlayingWithTBI]

This may help to understand what they do

BCC bin file, Lookup your bin file online!

BCC bin file. Lookup your bin file Online

www.gearhead-efi.com

 

[PlayingWithTBI]

I forgot ESC module - on intake manifold passenger side in front of EGR module.

Edit: if you have the A.I.R. (Air Injection Reaction or Smog Pump) the valve is mounted on it with a vacuum line from the TB going to it.

 

[Schurkey]

The question is:
“Sensors where are all of them located on the engine, and what do they do and why?”

1990 454 ss TBI

These are the sensors I know of.
1) MAP
2) IAC
3) COOLANT TEMP
4) KNOCK SENSOR
5) OXEGYN
6) TPS
7) VSS

I suggest a thorough reading of the service manual for your vehicle. This is best done via paper copies; but scans for select models and years are available on this site. I've bought most of my paper copies from eBay. I do have a couple on DVD; less satisfactory but readily available and not expensive at ~$50.

For the record, the computer receives information from sensors, processes that info based on it's programming, and commands other devices which could be called "outputs". Number 2 in your list--IAC--is an output, not a sensor. Same with EGR solenoid, AIR diverter solenoid, fuel pump relay, the variable-timing section of the ignition module, and fuel injectors.

A sensor that hasn't been mentioned is the ignition pickup coil, (RPM) the signal is delivered to the computer indirectly, via the ignition module. The computer also has a voltage reference, delivered through one of the fuses. From a certain perspective, that fuse is a "sensor" of voltage.

In all cases--sensors and outputs--the associated wire harness is integral to the operation of the system. A failure in the wire harness is often mistaken for a failure of the associated sensor or output

 

[BigDaddy72]

Just to explain my all of the sudden curiosity.

My 1990 454ss truck recently started stalling when put in gear. It would die immediately. If you feathered the gas pedal it would stay running.

A very smart buddy of mine insisted it was the IAC I replaced it and it made no difference.

I consulted another guy who was a gm mechanic when these trucks were on the dealer lots.

He said if I replaced the map sensor he was positive that would fix it since the IAC didn’t.

They both are extremely knowledgeable when it comes to computer controlled vehicles and they both ALWAYS give me a hard time because all of my hot rods street rods and street race cars all have carburetors.

However neither part/sensor mentioned was the problem.

At that point I was on my own neither one had anymore advice and insisted one or both new parts were bad/junk.

One said he thought the computer was bad.. “That’s really the only thing left it could be.”

So I went back to basics that I apply to all my carbureted engines.

It was the distributor... The magnetic pick up was shot and was wore out.

Got a new distributor from the parts store and 30 minutes later problem was solved.

When I told them what it was

They both said hmmm we’ll good, glad you got it fixed.

I appreciate everyone’s help but I don’t understand 1/2 of what you guys were talking about.

The truck runs fine now. Eventually it will get a carb too.

Im afraid it’s something I’m not smart enough to comprehend at least without taking a certified training course ha ha!!

Thank you all very much for all your input and advice!