Gauge Installation S-15 4.3
Question:
I have an ‘89 GMC Sierra Classic S15 4X4 4.3L Auto.
I want to install oil, temp and amp gauges.
My question is 3 parts.
1- are there 2 temp sensors on the engine (one for the computer and one for the existing idiot light)?
2- if the answer to 1 is yes, where is the sensor for the idiot light located?
3- if the answer to 1 is no, where can I get a fitting to accommodate the existing sensor and the sensor for my new gauge, and where is the sensor located?
Thanks.
Response:
I noticed your posting in html, some people can’t or won’t receive html messages, posting in text will improve your chances at getting a response; weather you or I think ignoring .html posts is worng or right is irrelavent, I don’t care either way, both my cable modem and system are fast enough to read html posts, but not everyone else can. Anyway My 88 with the 2.5L has two, one comes out of the side of the thermostat housing and the other is in the back straight into the head. both are single wire connectors. The pics in my chilton book are not real clear about the sensors, but the pages with the schematics list two for my year/engine, try looking there, I would look in mine, but its in the truck and I’m only wearing underwear <G> Eugene
I’m re-posting this as no one has replied. I really need to know this. No one I’ve asked has an answer. I have the Chiltons book, but can’t find an answer there either.
I have an ‘89 GMC Sierra Classic S15 4X4 4.3L Auto. I want to install oil, temp and amp gauges. My question is 3 parts. 1- are there 2 temp sensors on the engine (one for the computer and one for the existing idiot light)? 2- if the answer to 1 is yes, where is the sensor for the idiot light located? 3- if the answer to 1 is no, where can I get a fitting to accommodate the existing sensor and the sensor for my new gauge, and where is the sensor located? Thanks.
Response:
I was looking at mine and you right, the computer sensor has two wires and the gauge sensor has one. I was going by memory and I guess its not very good Eugene
> I have identified the ECM coolant temperature sensor, it is at the front
of the engine to the left (looking from the front) of the thermostat housing It has yellow and black wires which agrees with the wiring diagram in the Chiltons book. The instrument cluster temperature is supposed to be a single dark green wire. I have found a dark green wire running to near a sensor located between the 1st and second spark plug on the left side of the engine (front to back). However it appears that this sensor is damaged and the wire is not connected to it. Can anyone confirm that this is the instrument cluster temperature sensor. (89 S15 4.3L Auto 4X4). > TIA
> snip> > Thanks for the inf. on your 88. I’ll check the wiring diagrams and
update with what I find.
– Hide quoted text — Show quoted text -> > I noticed your posting in html, some people can’t or won’t receive html > > messages, posting in text will improve your chances at getting a response; > > weather you or I think ignoring .html posts is worng or right is irrelavent, > > I don’t care either way, both my cable modem and system are fast enough to > > read html posts, but not everyone else can. Anyway My 88 with the 2.5L has > > two, one comes out of the side of the thermostat housing and the other is in > > the back straight into the head. both are single wire connectors. The pics > > in my chilton book are not real clear about the sensors, but the pages with > > the schematics list two for my year/engine, try looking there, I would look > > in mine, but its in the truck and I’m only wearing underwear <G> > > Eugene > > I’m re-posting this as no one has replied. I really need to know this. No > > one I’ve asked has an answer. I have the Chiltons book, but can’t find an > > answer there either. > > I have an ‘89 GMC Sierra Classic S15 4X4 4.3L Auto. > > I want to install oil, temp and amp gauges. > > My question is 3 parts. > > 1- are there 2 temp sensors on the engine (one for the computer and one > > for the existing idiot light)? > > 2- if the answer to 1 is yes, where is the sensor for the idiot light > > located? > > 3- if the answer to 1 is no, where can I get a fitting to accommodate > > the existing sensor and the sensor for my new gauge, and where is the sensor > > located? > > Thanks.
Response:
I have the same book then. I looked at the schematics, yours being fig. 137, mine fig.135. Mine shows the oil pressure switch having three wires from it, and the case is grounded. yours doesn’t show the tan to inst cluster.. They also both show two fuel pump prime connectors one from the relay and the other from the pump. I unplugged mine and the engine started and ran just like always. I didn’t even get a warning light on the dash, which I think I should have if the thing was disconnected, but I guess not. A long time ago I added mechanical gauges which were cheap and don’t work anymore, but the line is still there for the oil. I bought a T and a couple adapters and put both the line to the gauge and the oil pressure switch off the side of the engine so both are connected. I have some more schematics somehwere but couldn’t find them. I found the one for our kitchen stove though <G> Eugene
> Thanks for the help. There are a lot of circuits in the book, and I’m
getting dizzy following them. One comes from or goes to the EGR Vacuum Regulator valve solenoid and the Fuel Pump relay (450). > Have you ever tried running your truck with the Oil pressure unit
unhooked? Just temporarily of course 
). – Hide quoted text — Show quoted text -> BTW my Chilton’s book is Part No. 8141 > snip
Response:
Thanks for the help. There are a lot of circuits in the book, and I’m getting dizzy following them. One comes from or goes to the EGR Vacuum Regulator valve solenoid and the Fuel Pump relay (450).
Have you ever tried running your truck with the Oil pressure unit unhooked? Just temporarily of course ).
BTW my Chilton’s book is Part No. 8141
snip
Response:
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Response:
In the schematic I have it shows the fuel pump connected to the common on the fuel pump relay. then one end of the fuel pump relay is connected to the +12V and the other goes to the oil pressure switch. This way when the switch is turned on the relay pulls in and runs the pump for 2 seconds from the +12v then switches back to control from the oil pressure switch. The ASD relay is in series as well to shut the whole thing down if needed. But then my Chilton book has been wrong in other places so it could be here.
> Thanks for replying. > I was mistaken in my post about the Oil pressure sensor being ECM input.
According to my Chiltons manual there is output from the ECM (12 volts) to the Oil Pressure unit (the book calls it "oil pressure switch’). I think it’s just power to activate the unit. > There is a lead from the Oil pressure switch that goes to the Fuel Pump
Prime, but there are other leads going there as well so I don’t think that replacing it with a manual Gauge will be a problem. > Even with the Oil pressure switch removed the fuel pump activates for
2-3 seconds when the key is turned then stops, and my truck seems to run OK. > If anyone thinks converting to manual Oil Pressure Gauge and
disconnecting the switch will be a problem, please tell me and provide an explanation. I like to know why
– Hide quoted text — Show quoted text -> on mine it controls the fuel pump. when you first turn the key the relay > pulls in for a couple seconds, then releases. After the engine is running > the oil pressure switch keeps power to the fuel pump so it shuts down if the > engine stops or looses oil pressure. > Eugene > snip
Response:
Thanks for the confirmation, I hope the sensor that came with the gauges I bought will reach over to the passenger side head. It does seem to be a strange place to put a water temperature sensor though.
The oil pressure sensor has 3 wires. One is for the instrument cluster light/gauge, the other 2 are ECM input. Can anyone tell me why the ECM uses oil pressure information.
> I was looking at mine and you right, the computer sensor has two wires and
> the gauge sensor has one
snip
– Hide quoted text — Show quoted text –
Response:
on mine it controls the fuel pump. when you first turn the key the relay pulls in for a couple seconds, then releases. After the engine is running the oil pressure switch keeps power to the fuel pump so it shuts down if the engine stops or looses oil pressure. Eugene
> Thanks for the confirmation, I hope the sensor that came with the gauges I
bought will reach over to the passenger side head. It does seem to be a strange place to put a water temperature sensor though. > The oil pressure sensor has 3 wires. One is for the instrument cluster
light/gauge, the other 2 are ECM input. Can anyone tell me why the ECM uses oil pressure information.
– Hide quoted text — Show quoted text -> I was looking at mine and you right, the computer sensor has two wires and > the gauge sensor has one > snip
