- 6,861
- 695
- 113
- Location
- Stratford/Connecticut
Two different issues. You can jump the pressure switch on the side of the air tank with a paperclip. Could be a bad ecu. They go bad all the time. Easiest way to diag that is swap a known good one in.
Steel Soldiers now has a few new forums, read more about it at: New Munitions Forums!
That's what I've done replaced with a known good one. I've bypassed the pressure switch before with no resultTwo different issues. You can jump the pressure switch on the side of the air tank with a paperclip. Could be a bad ecu. They go bad all the time. Easiest way to diag that is swap a known good one in.
I posted earlier that the connector on the manifold has a tightened collar but the rear part of the plug is loosely moving left and right. That didn't seem to be normal to me. I think the entire plug should be solid when it's tightened on the plugBad or unplugged transducer. Drop the passenger kick panel and look at the manifold. See if anything visible going on.
I posted earlier that the connector on the manifold has a tightened collar but the rear part of the plug is loosely moving left and right. That didn't seem to be normal to me. I think the entire plug should be solid when it's tightened on the plug
That's exactly what mine does. two flashes then all 5. whether there is air in the tank or not. or full pressure. Same thing with the other good ECU. I'll grab my fluke 87 tomorrow and do some checking.That connector you've pictured is for your PCU solenoids. Test by disconnecting the plug from the ECU. Test resistance between plug (not ECU) pins B to ground, C to ground, and R to ground, then B to C, B to R, and C to R. You should get around 60 Ohms when measuring pin to ground, and around 120 Ohms when going pin-to-pin. That'll test the wiring from the ECU canon plug through the harness, through your pictured plug, and through the solenoids to ground and for shorts in the wiring. If you get 0 Ohms you've got a short between wires . High resistance could be a bad wire but more likely a bad solenoid.
The other wire on the PCU is for the pressure transducer. There's no feasible way to test that other than check wiring between the ECU cannon plug to the plug on the transducer, and to check for proper voltage at the pressure transducer plug when the ECU is connected and the truck powered on (but not running). Spicer's manual has some good troubleshooting tips. I've concatenated some tests by testing the whole length of wiring.
I had a bad PCU pressure transducer that I found by replacing with another unit. When I powered my truck on, even before building air pressure. The HWY light would flash twice then all five flash from that point on.
That's exactly what mine does. two flashes then all 5. whether there is air in the tank or not. or full pressure. Same thing with the other good ECU. I'll grab my fluke 87 tomorrow and do some checking.
thx wandering neurons
All the pins on the cannon plug check out b, c and r to ground = ~60ohm
all cross connections b to c, b to r and c to r =~ 120 ohm
taht leaves a bad pcu pressure transducer? How do I check for that again?
im getting 4.75V at the transducer plug.
So if I understand the principle of operation of this transducer correctly it should be open in ambient air and closed under pressure, correct?
I sprayed it with some stuffs and let it sit upside down for a while and then reinstall and see what happens.
Actually I got the slightly low voltage on the pressure switch by the tank. At the pressure sensor by the valve block I got over 5V , which is normal according to the troubleshooting guide.According to Spicer's TFM:
"Check for continuity between PCU connector pin A and ECU harness connector J, PCU pin B and ECU pin b (lower case), and PCU pin C and ECU pin c (lower case). Also, check for short circuits in the PCU harness pins A to B, B to C, and C to A".
Later in the test you look for PCU pin B to show between 4.9 and 5.1 volts. You did that and got a slightly low voltage. That voltage is coming from the ECU. Could be corrosion somewhere causing low voltage. That should show up in the test at the top, between pins B and b - do your measurement carefully to see if there's any resistance, and compare with the other two pin pairs. There's notes somewhere on this site about using an eraser to clean the plugs, or just use contact cleaner judiciously...
There aren't any other test for the pressure transducer that I can find.
This afternoon after work, barring any rain, I'll pull my kick panel and see if I can read the numbers on my pressure transducer and post the results.
Everything else either requires a working diagnostic tool or a spare PCU pressure transducer/ECU, and you've eliminated the ECU.
Like Suprman says, the pressure transducer could have crud on the inside blocking it, mine did. But even after cleaning it, mine still didn't work right. I think that the water and crud corroded the sensor itself. But try anyway, it won't cost much other than a few minutes and could "hopefully" fix the problem.
Actually I got the slightly low voltage on the pressure switch by the tank. At the pressure sensor by the valve block I got over 5V , which is normal according to the troubleshooting guide.
I do have a working diagnostic tool. But nothing to respond to it.
The ECU pin J to Pressure transducer connector A is good. No short to ground or broken connection.
I have taken the pressure Transducer and dropped it in my ultrasonic cleaner. Maybe that's going to do something inspiring.
i think the issue might be the solenoid block itself.If you're not getting +120 psi, you may not get the pressure switch to close. The screw on the compressor turns counter-clockwise to increase pressure. But bypassing the pressure switch should fool the ECU into continuing, unless something else like the transducer is whacked.
The pressure transducer that I have is Spicer Dana part number 676505, which crosses to NSN 6695-01-509-9496
You might be able to get it directly from Spicer or through a truck repair shop...
I'd be interested to see what the cleaner does for the part!
We get it, advertisements are annoying!
Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website like our supporting vendors. Their ads help keep Steel Soldiers going. Please consider disabling your ad blockers for the site. Thanks!