overworked
Senior Member
I will look in sis about filter housing, I must admit I work on more machines than trucks.
-
Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!
3176 only starts with ether
- Thread starter timbruun
- Start date
timbruun
Active Member
I am on SIS. Actually as I type I am reading compete fuel troubleshooting steps.
I have No start condition. Crankshaft turns. No smoke. Active injector codes on all 6 injectors.
Only fuel thing I have not checked is pulling the injectors. The fuel regulator in the siphon manifold I might just replace anyways since it's cheap along with the spring. And I will check oil level in pan and possibly send a sample in to see if fuel is going in there.
So onto completing my injector electrical testing.
And hopefully finding a rental/loaner ECM. Even a salvage truck ECM for cheaper wouldn't be so bad.
I have No start condition. Crankshaft turns. No smoke. Active injector codes on all 6 injectors.
Only fuel thing I have not checked is pulling the injectors. The fuel regulator in the siphon manifold I might just replace anyways since it's cheap along with the spring. And I will check oil level in pan and possibly send a sample in to see if fuel is going in there.
So onto completing my injector electrical testing.
And hopefully finding a rental/loaner ECM. Even a salvage truck ECM for cheaper wouldn't be so bad.
overworked
Senior Member
This might sound crazy,hook up fuel pressure gauge, watch rpm on ET, crank over watching rpm and fuel pressure, ad a small mist of ether or propane and see at what rpm or pressure it fires on its own,
overworked
Senior Member
50 pounds fuel pressure running is low, no complaints of low power?
timbruun
Active Member
I can't do cranking rpm on ET. It looses connection with laptop. Unless I'm doing something wrong. I did test cranking rpm by doing voltage from the timing sensor and it's within spec for voltage. Also, the tach does show rpm when cranking. Plus it does not sound slow by any means. Usually have the booster on it at the same time to make sure I'm not losing rpm or voltage to ecm while trying other things.
No complaints of low power. Although this is not a driver that is used to large trucks.
Still can't find where my loss of fuel pressure is though.
Just finished checking continuity of injector harness from head to ecm.
Quick history now that I heard it from the owner. He was just backing up slowly one day and it just died. Would not start back up. After towing it home someone mentioned to try ether and it's been that way since.
No complaints of low power. Although this is not a driver that is used to large trucks.
Still can't find where my loss of fuel pressure is though.
Just finished checking continuity of injector harness from head to ecm.
Quick history now that I heard it from the owner. He was just backing up slowly one day and it just died. Would not start back up. After towing it home someone mentioned to try ether and it's been that way since.
timbruun
Active Member
Next step is to pull valve covers and check/test all injector electrical and then either ecm or start pulling injectors.
overworked
Senior Member
On some trucks tach rpm comes from timing sensor in bellhousing, ecm uses rpm from timing sensor on cam gear, does your have one sensor for cam behind air compressor and one on crank behind front engine mount from the bottom? You could watch rpm on tach and use ether or propone to watch as rpms come up fuel pressure should rise as rpms do.
overworked
Senior Member
With key on did you try to start it at the starter leaving the key in run, could be loosing key power to ecm while cranking, with ether it might be turning over fast enough that when key returns to run ecm is powering back up?
timbruun
Active Member
This one has a sensor that is on the top right hand side of the front gear train. single 3 wire sensor.
Haven't checked to see if the tach actually does use a different sensor or not but I was getting rpm in ET showing that the sensor does work. And it was same as the tach in the dash.
I have tested power to ecm while cranking at the ecm harness. No crank I'm at 12.3 volts, cranking it's at 8 volts. That is without the booster on. Obviously the numbers are higher with the booster on.
Haven't checked to see if the tach actually does use a different sensor or not but I was getting rpm in ET showing that the sensor does work. And it was same as the tach in the dash.
I have tested power to ecm while cranking at the ecm harness. No crank I'm at 12.3 volts, cranking it's at 8 volts. That is without the booster on. Obviously the numbers are higher with the booster on.
overworked
Senior Member
I believe 8 is to low,10 plus in minimum, should have two, battery voltage all the time, key on or off and one key on. 8 volts won't fire the injectors.
timbruun
Active Member
According to SIS anything over 6 volts while cranking is good enough. The numbers are higher with the booster on though. There is no voltage drop from the batteries to the ecm.
This ECM only has 2 key on voltages and 2 grounds. The positives come from the same wire on a harness farther up and the grounds go to one wire which is grounded on the cylinder head.
This ECM only has 2 key on voltages and 2 grounds. The positives come from the same wire on a harness farther up and the grounds go to one wire which is grounded on the cylinder head.
Shimmy1
Senior Member
You need to get that fuel pressure resolved. 20-30 cranking is way to low. 50 running is terrible as well. The fitting where the actual return line that goes to tank hooks onto that housing on the head; turn that fitting out. That little poppet under it is your return check. Either replace that poppet and the spring, or change the whole housing. I believe it's around $200. I firmly believe that is your starting issue. After your fuel pressure is solved, you can fix the injector faults.
timbruun
Active Member
I have ordered the relief valve and spring for the transfer pump as well as the poppet/regulator valve and spring in the siphon manifold.
Should have it all tomorrow and will put it all together and try again from there.
Didn't think I needed the whole manifold but I will see how the poppet fits when it shows up.
Should have it all tomorrow and will put it all together and try again from there.
Didn't think I needed the whole manifold but I will see how the poppet fits when it shows up.
Shimmy1
Senior Member
Yeah, what happens is the seat gets hammered out and the poppet doesn't seat. Can you see wear around the tip of the poppet? Mine looked pretty good, just some scratching, but when I changed it my pressure went from 40 to 70 cranking. Runs about 80-100 while running. Cat told me if the poppet didn't fix it I would need to change the housing. Hope it fixes yours.
timbruun
Active Member
I hope it fixes it as well.
Still going to have to deal with injector codes at one point I assume though. Can't see fuel pressure fixing injector codes.
Still going to have to deal with injector codes at one point I assume though. Can't see fuel pressure fixing injector codes.
Shimmy1
Senior Member
Be prepared if you pull injectors the injector tubes should be done as well. Injectors on a 3176 are not as simple as a C12, which has stainless tubes. The 3176 has copper tubes. They like to leak. Good luck.
Mobiltech
Senior Member
Can you get a full serial number.
Fuel pressure should be 70 to 80 at least.
ET should not lose power while cranking. You may have to feed power to the power supply terminal on the plug so you can read it while cranking.
There should be two keyed and at least 1 battery fed terminal on the ECM I will get you the power supply terminal numbers later.
Fuel pressure should be 70 to 80 at least.
ET should not lose power while cranking. You may have to feed power to the power supply terminal on the plug so you can read it while cranking.
There should be two keyed and at least 1 battery fed terminal on the ECM I will get you the power supply terminal numbers later.
overworked
Senior Member
Wireing I have is for a 3176b shows one key power pin 6 and one constant power pin 4. You will have to use alternative power when cranking with the key, should be able to jump solenoid at starter and be OK I believe.
timbruun
Active Member
Serial number I have is 7LG10625. Can't see arrangement number.
Should get parts today to see about the fuel pressure.
This is not a 3176B. 1 and 11 is battery positive, 12,21 battery negative
Should get parts today to see about the fuel pressure.
This is not a 3176B. 1 and 11 is battery positive, 12,21 battery negative
timbruun
Active Member
Just found out parts are earliest tomorrow. They are in the US, so hopefully tomorrow noon.
This plug is not in the truck either. It is on the block, above and to the left of the ECM. It is a different 9 pin than usually on trucks. I think it's what gensets might have? It's a 9 pin but doesn't have the notch on the one pin.
When I get the fuel parts I will put everything back together and put the ECM back in and try it all again. I will try putting power straight from battery to data link connection and see if that fixes ET losing connection.
This plug is not in the truck either. It is on the block, above and to the left of the ECM. It is a different 9 pin than usually on trucks. I think it's what gensets might have? It's a 9 pin but doesn't have the notch on the one pin.
When I get the fuel parts I will put everything back together and put the ECM back in and try it all again. I will try putting power straight from battery to data link connection and see if that fixes ET losing connection.