Aftermarket Digital Gauges
The following is an attempt to figure out exactly what each of the following sending units/sensors output - so as to properly adapt them to the new gauges. The connections for all are at the PCM and are connected to what I believe to be the primary for each. I got the pin outs from a post here.
1. Speedometer - Correct me if I'm wrong but it seems that the output from the VSS comes in two flavors - 4K pulses per mile or 129k pulses per mile. The new gauge operates in a range from 8k to 16k. Current solution is to buy a GPS speed unit that outputs 16k. Did I miss something?
2. Tach - I'm told that the new unit is looking for 5V Square something or other... What does the Engine speed sensor actually output? The new gauge is doing absolutely nothing.
3. Temp - This one came with a replacement sensor. (One wire type). I know that the factory sensor serves the gauge and the fan. Hoping to t-tap the gauge side and keep the all too important fan switch intact... same issue, what is the actual output at the sensor?
4. Oil - Issue is identical to temp. I have a new sending unit but I'm betting that the factory sensor serves more than one purpose and that the signal from the sensor may not be compatible...???
5. Fuel - The new fuel gauge has multiple setting that are based on resistance ranges. All of which were industry standards - at least until 1995. What is the output from the fuel gauge at the PCM??
Coolant temp has 2 available ports. Drivers side port is near the front of the head and the passenger is near the rear. You can use the available one for the gauge and keep the other for the ECU
The tach puts out pulses not a 5v curve. I believe its pulsed like a 4cyl 2 pulses per cycle. I can look that up for sure if i know what your donor engine is from
The oil pressure sensor can be taped into the oil filter housing. Oil is drawn from the pan, to the pump then through the filter so you will see oil pressure at the filter housing
fuel gauge - what is the donor vehicle? i can give you the range data for it.
If you need any other diagram info just let me know your donor engine's vehicle and also what the engine is in
No swap here. It's my 2004 Silverado with the 4.8. I only changed the gauges. Some of you may be familiar with the stepper motor fiasco. Ive been without speed, tach and temp for several years.
So, on the temp issue - there are two in use and therefore I can replace one or will I find an unused port?
No swap here. It's my 2004 Silverado with the 4.8. I only changed the gauges. Some of you may be familiar with the stepper motor fiasco. Ive been without speed, tach and temp for several years.
So, on the temp issue - there are two in use and therefore I can replace one or will I find an unused port?
At rear of the passenger head is a round plug with an internal hex for an allen wrench to fit into. It is on the same face as the exhaust manifold, just past the last exhaust port. This is a M12 threaded hole. Get an adapter if needed to screw in your sender for the gauges. The adapter would be something like this:
Or this one:
For the Oil Pressure, find this part: This one has been drilled a tapped for a sensor.
http://i529.photobucket.com/albums/d...1/71ff1a76.jpg
IF you cannot drill and tap yours, here is a replacement part for adding a sender:
https://images-na.ssl-images-amazon....L._SL1296_.jpg
By the way, you guys are awesome. I've gotten more info today than I have in two weeks on my own.
Trending Topics
No swap here. It's my 2004 Silverado with the 4.8. I only changed the gauges. Some of you may be familiar with the stepper motor fiasco. Ive been without speed, tach and temp for several years.
So, on the temp issue - there are two in use and therefore I can replace one or will I find an unused port?
The Best V8 Stories One Small Block at Time
*********STILL NOT SURE WHAT TO DO ON THE FUEL GAUGE**************
THE FIRST TO SOLVE THIS ONE FOR ME GETS DINNER FOR TWO
(AT MCDONALDS) :-)
Also, given that the ECM puts out 4cyl signal I cut the orange wire. Correct?
Gauge info below:
https://static.summitracing.com/glob...sum-g2981w.pdf
Engine, harness, and ECM are from an 03 Envoy. (5.3l LM4)
I tried talking to Summit Tech support and they are about worthless. Their advice was to try the tach on another car or I have a bad ECM....


