turbo2ltr

iTrader: (1)

You've mapped the voltage output of the GM sensor vs. pressure and compared it to a map of the stock sensor? That is the only way to tell if it will work.

13b-series

iTrader: (1)

That would so be the $h!t if that would actualy work, cause the stock sensors are more rare than some of these cars.

13b-series

iTrader: (1)

Hailers - black/white wire 12.2v, brown/white 5.01v, brown/red .716v an 2b at the ecu .706. And for the ground I need to do some more digging or recheck it, at one point I thought the ohm's were high, then they were fine the next time or maybe it was just me not being all there when I was going thru this. As to making sure that the vacuum is geting to the sensor, I'm prety sure that the sensor is getting vac/boost since my boost gauge is T'd into the same line.
Sensor pluged in---v

Sensor unpluged an NO error code---v

SMKNRX7IL

This page has some data from a GM 2 Bar MAP Sensor:

http://www.robietherobot.com/storm/mapsensor.htm

HAILERS

As you already know........something is amiss here. The BROWN/RED is the output wire of the sensor and it should read 2.3 vdc to 2.7 vdc if the key is to just ON engine OFF or still read that figure even if the engine is idling and the vacuum hose is off the boost sensor.

The three quarters of a volt you have as the output to the ECU is enough to keep the RTEK/PALM from chunking a code out. I'd bet if you disconnect the boost sensor and then go look at the Palm you'd find a code. Pretty sure 'bout that.

Maybe it is your ground. I'd pull the plug off the sensor. Then meter on ohms. Negative meter lead held against the L shaped bracket that holds the sensor on to the chassis (I"ve found that is a good gnd point in the past) and the positive lead to the pure black (will be brown/black on earlier cars). Should read will under 1 ohm. IF not, then somehow runa new wire to that socket and ground its other end on the boost sensors bracket and see what happens.

Odd being the ground though. That ground wire is spliced to the ground wires for all the other sensors in the engine bay (TPS, AFM, varible resistor if applicable, water thermosensor, air intake sensor, boost gauge etc).

Series five cars.......boost sensor does not use the black/white. Is it possible you have a series five boost sensor on your series four car??? Got a number on that sensor anywhere?

Once again, the RTEK isn't kicking a boost sensor code 'cause it's seeing a .7 vdc input. The ECU as far as I know..on a series four......only kicks a code if the wiring is disconnected NOT if it's seeing a value that is other than what it should be.

13b-series

iTrader: (1)

That second picture is with the boost sensor disconnected an still no code. I'm not to sure what the sensor actually is since whoever I bought the sensor said that it came out of their dd an claimed it was a 318. The top of the sensor looks like a scotch brite pad had been run over it. I figured out a way to test the sensors out of the vehicle, but still by fsm. I used a old computer power suply since it has 12v+, 5v+ and ground. Hook up the sensor like it would be in the vehicle, pull the 3.9inHg of vacuume and the sensor should fall within factory specs. Unfortunately none of the sensors I purchased never passed.

HAILERS

What do they read prior to pulling a vacuum on them? Seems that would settle things a bit. They're supposed to read two something volts with no vacuum on 'em. See CONTROL UNIT in the Fuel and Emissions section of the FSM for the real value with no vacuum on 'em.

If the sensor is disconnected, what does the brown/red wire read in voltage? The same as with it connected? Or?

HAILERS

The idea here is that the brown/red ouput wire of the sensor is also spliced to another wire that goes to the boost gauge in a turboII car, so one wonders if that wire has some voltage on it that is backfeeding into the ECU on pin 2B. It would also show up at the brown/red wire of the boost sensor plug if it were disconnected from the sensor.

13b-series

iTrader: (1)

My sensor disconected the brown/red gives me 344 mV an connected is the .7 volts. I remember seeing the same thing that you said about the wiring, that the tps, afm an boost sensor are on the same line. So I unpluged the afm, key on engine off an it showed a code for the afm then pluged it back in an reset the check codes. Then I tried the same thing with the boost sensor an no code an didn't have to reset. As to the back feeding issue would it be possible for the factory gauge to feed something back since it does'nt even move anymore?

13b-series

iTrader: (1)

Well I took out the instrument cluster today an checked the boost signal on the cluster harness (KOEO) an got 4.54v, turn key off unplug the the ecu then try the same thing an nothing. But heres the odd crap, the sensor defaults to 15.something when unpluged then pluged in is reads 3.2 I think(forgot to write it down). I need to do some more checkin tomorrow.

gxl90rx7

iTrader: (1)

how many s4 boost sensors have you tried? or is that the problem that you only have the one? Look like bad sensor to me.. as hailers was saying it should read about 2.5v at 0psi (port disconnected)

13b-series

iTrader: (1)

I've gotten 3 marked 318 sensors that all failed an one supposed 318 that also failed, an I dont have another "good one" to do all my hunting. I'm not to sure on those findings, from what I read an understand the voltage that should come out of the sensor is 2-2.5v at 3.9inHg not zero vaccume/boost. Oh, an the findings in post #35 was all done with the sensor unplged.

gxl90rx7

iTrader: (1)

i get 2.3V with engine off/ignition on. when you tested the sensor out of the car with the PC power supply, what voltage were you getting?

13b-series

iTrader: (1)

When I tested the sensor with the pc supply I got .7 volts the same I got when I put the same sensor into the vehicle. After doing a good amount of digging I think I may have figured out some of my issues. Now the palm reads 3.5 with the sensor pluged in an 15.8 unpluged, but bounces 19.5 - 19.7 with the cluster pluged in. Then the map on the palm reverts to 3.5 when I unscrew the boost signal off the back of the cluster. Now the map shows 11.0 - 13.1 between 690 - 832 rpm.