JoeBobJr

After spending many days searching and compiling a list of different resistances and volts needed to test the various sensors on a TBI engine I have finally found some of the stuff I was looking for.

I wanted to share it so maybe a moderator will make it a sticky or something for others in the future.

I forgot to write down the website and posted of any of the information I'm not claiming any of this is mine. Any of the original posters are more then welcome to claim it as theirs.

If any of the information is incorrect please be sure to tell me the correct information so that I can correct it. Anyone is welcome to add to any of this information to make it better.


Coolant Temperature Sensor (CTS):

Coolant sensor approximate resistance specifications:
177 ohms @ 212 deg. F. or 100 deg. C.
241 ohms @ 194 deg. F. or 90 deg. C.
332 ohms @ 176 deg. F. or 80 deg. C.
467 ohms @ 158 deg. F. or 70 deg. C.
667 ohms @ 140 deg. F. or 60 deg. C.
973 ohms @ 122 deg. F. or 50 deg. C.
1188 ohms @ 113 deg. F. or45 deg. C.
1459 ohms @ 104 deg. F. or 40 deg. C.
1802 ohms @ 95 deg. F. or 35 deg. C.
2238 ohms @ 86 deg. F. or 30 deg. C.
2796 ohms @ 77 deg. F. or 25 deg. C.
3520 ohms @ 68 deg. F. or 20 deg. C.
4450 ohms @ 59 deg. F. or 15 deg. C.
5670 ohms @ 50 deg. F. or 10 deg. C.
7280 ohms @ 41 deg. F. or 5 deg. C.
9420 ohms @ 32 deg. F. or 0 deg. C.
12300 ohms @ 23 deg. F. or -5 deg. C.
16180 ohms @ 14 deg. F. or -10 deg. C.
21450 ohms @ 5 deg. F. or -15 deg. C.
28680 ohms @ -4 deg. F. or -20 deg. C.
52700 ohms @ -22 deg. F. or -30 deg. C.
100700 ohms @ -40 deg. F. or - 40 deg. C.

Manifold Absolute Pressure Sensor (MAP):

Check the reference voltage supply at pin C of the MAP sensor (gray wire typically).

Measure voltage between pin A (ground) and Pin C (+5 V ref) with a DVM. It should be right around 5 Vdc.

With Key on engine off the MAP voltage (Pin B, light green wire typically) should read around 4.8 to 4.9 volts. If it reads the same as pin C the sensor is probably is history.

Also check ground reference pin A. With everything off, measure resistance between Pin A and electrical ground (stud next thermostat). It should be fractional ohms

Idle Air Control Sensor (IAC):

1. Disconnect the negative battery cable.
2. Test resistance between terminals A and B, then test between C and D.
3. If the resistance is nor 40-80 ohms, replace the IAC.
4. Connect the negative battery cable.

Throttle Position Sensor (TPS):

Test between blue and black wire.
.5v idle to 5v WOT

JoeBobJr

I have tested my TPS the way it shows and for some reason I can't get any type of reading from the TPS with volts. I set my meter on 9v and tried and also set on 20Vdc and neither will show anything it stays at 0.

The only thing I could get to show any type of reading was using Ohms. I put it on 20k and it showed 1.3 sitting still and then WOT it showed around 5.33. So 1.3k-5.3k is what it read. From what I read online you don't measure the TPS by ohms but I can't get anything out of three TPS sensors so I dunno what is going on. I tested my battery with 9v on my multi and it showed 12.5v so I know the meter works.

Does anyone have any suggestions?