M931A2 cranks, does not start, very little white smoke

[ichudov]

I have a new problem. I have a M931A2 semi tractor. It has always been easy to start.

I showed up at work (where it is) today. It would not start. Cranks and does not produce much white smoke. (I have a M927 that makes a lot of white smoke when it cannot start without ether).

I know the following:

1) My guys told me they had trouble starting it (and possibly they "did something" to it) around the end of this week.
2) When cranked, it makes a very small amount of white smoke.
3) The tank switches (both the one on dash and the one under the seat) are switched to the right tank, which I know is full of fuel
4) Pressing the ether button clearly did not engage the ether solenoid valve.
5) When I disconnected the electrical connector near the ether solenoid valve, I was able to operate it nicely with a 24v power supply
6) It is 54 degrees F outside today
7) I unscrewed the bottom plug on the fuel filter and fuel did come out. I closed it right away.

I understand that no white smoke means no fuel comes to the injectors. But why?

I have a feeling that something electrical is going on that prevents both the ether valve from working, as well as the fuel from being delivered.

Any ideas? I am generally OK with troubleshooting and will appreciate some pointers as to what procedure I should follow.

thanks

 

[goldneagle]

Check the kill lever and also where it connects to the IP. Maybe it is engaged or partly engaged. Otherwise pull one of the injector lines and see if you get fuel coming out when cranking.

 

[doghead]

2. ENGINE CRANKS BUT WILL NOT START

NOTE

If STE/ICE is available, perform NG30 Engine Cranks No Start

Test (para. 2-24).

Step 1. Ensure emergency engine stop control is in all the way.

Step 2. Press accelerator pedal all the way down to floor and hold, then restart engine.

Step 3. Check air cleaner indicator for air restriction indications.

a. If red appears at indicator window, inspect air intake stack for restrictions and, if

necessary, replace air cleaner element (TM 9-2320-272-10).

b. Reset air cleaner indicator by pressing button down.

NOTE

Perform steps 4 through 6 for M939A2 series vehicles.

2-64

TM 9-2320-272-2491

Table 2-2. Mechanical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Step 4. Check for white smoke during cranking.

a, If white smoke is seen, air may be in fuel system.

Prime fuel system (para. 2-22),

b. If white smoke is seen, coolant may be in combustion chambers.

Remove dipstick. If coolant is present, notify DS maintenance.

WARNING

l
Eyeshields must be worn when cleaning with compressed air.

Compressed air source will not exceed 30 psi (207 kPa). Failure

to do so may result in injury to personnel.

l
Diesel fuel is highly flammable. Do not perform fuel system

procedures near open flame. Injury to personnel may result.

Step 5. Check fuel transfer pump for proper operation.

a. Check for loose fuel supply hose at fuel filter head.

b. Operate hand primer on the fuel transfer pump and check for fuel.

If fuel is present, replace fuel transfer pump (para. 3-20).

Step 6. Check for fuel leaking from fuel pressure transducer. If fuel is present:

a. Check fuel transfer pump for proper operation (refer to step 5).

b. Check for clogged fuel injector supply line.

If clogged, clear with compressed air or sturdy wire.

Step 7. Inspect fuel filter for dirty and/or clogged condition (para. 3-30).

Replace fuel filter if clogged or dirty (para. 3-30).

Step 8. Inspect fuel lines and connections for leaks, breaks, obstructions, or damage.

a. Visually check for leaks. If leaks are present at connection, tighten.

b. If leaks are result of cracked, split, or damaged tubing, replace fuel line(s) (TM 9-243).

C. Disconnect fuel line at both ends. If fuel line is clogged, clear with compressed air or

sturdy wire.

d. Reconnect fuel line.

e. Replace fuel filter (para. 3-30).

f. Prime fuel system (para. 3-22).

g. If not corrected, notify DS maintenance.

Step 9. Check for fuel contamination.

a. Open drainvalve on fuel filter/water separator and drain approximately 1 pt (0.478 L) of

fuel into a glass container.

b. If contamination is present, continue to drain fuel up to 1 qt (0.946 L).

c. If contamination is still present, drain fuel tank(s) (para. 3-27).

d. Clean and flush fuel system. Dry with compressed air.

e. Replace fuel filter (para. 3-30).

f. Refill tank(s) with fuel (TM 9-2320-272-10).

g. Prime fuel system (para. 3-22).

2-65

TM 9-2320-272-24-1

Table 2-2. Mechanical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

WARNING

l
Ether is extremely flammable. Do not perform ether start

system testing procedures near fire. Injury to personnel may

result.

l
Eyeshields must be worn when cleaning with compressed air.

Compressed air source will not exceed 30 psi (207 kPa). Failure

to do so may result in injury to personnel.

Step 10. Check ether start system.

Perform malfunction 16.

END OF TESTING!

3. STARTER CRANKS ENGlNE SLOWLY, HARD TO START

Step 1. Press accelerator pedal all the way to floor and hold, then restart engine.

Step 2. In cold weather, ensure proper engine oil is being used.

Add or replace oil (LO 9-2320-272-12).

NOTE

If STE/ICE is available, perform NG80-Starter Circuit Tests

(para. 2-24).

Step 3. Check starting system (Electrical Troubleshooting, para. 2-22).

END OF TESTING!

4. ENGlNE STOPS DURlNG NORMAL OPERATION

Step 1. Perform malfunction 2, steps 2, 8, and 9.

Step 2. Check for restrictions in exhaust system.

Ensure exhaust

 

[ichudov]

Check the kill lever and also where it connects to the IP. Maybe it is engaged or partly engaged. Otherwise pull one of the injector lines and see if you get fuel coming out when cranking.

I like your way of thinking, and I also suspected the same. However, the kill lever is pushed all the way in (normal operation).

The kill switch seems to pull a lever on the injection pump. That same lever is also engaged by the solenoid that stops the engine. It retracts when I start cranking and it pushes the lever down when I turn the engine switch to OFF. All that, superficially, seemed functional.

 

[M35A2-AZ]

Sounds like you may of lost your prime.

 

[Suprman]

If you didn't loose your prime before you lost it now by draining the filter housing. On the back of the injector pump, closest to the front of the motor is a bolt head I believe its a 10mm. Loosen the bolt head around 2 turns don't go too much it can fall out. Press the primer pump on the drivers side of the motor till fuel starts flowing out of the bolt you just loosened. Tighten bolt and try to start. Best not to let either tank go below 1/4 full. Sometimes when you switch tanks you can suck in some air. There are o-rings in the valve that can need replacement from time to time. If you prime it more than 100 pumps and you still do not have fuel then it is possible the filter is clogged or you have a break in a line somewhere taking in air.

 

[M35A2-AZ]

What he said is right on.

 

[M925]

2. ENGINE CRANKS BUT WILL NOT START

NOTE

If STE/ICE is available, perform NG30 Engine Cranks No Start

Test (para. 2-24).

Step 1. Ensure emergency engine stop control is in all the way.

Step 2. Press accelerator pedal all the way down to floor and hold, then restart engine.

Step 3. Check air cleaner indicator for air restriction indications.

a. If red appears at indicator window, inspect air intake stack for restrictions and, if

necessary, replace air cleaner element (TM 9-2320-272-10).

b. Reset air cleaner indicator by pressing button down.

NOTE

Perform steps 4 through 6 for M939A2 series vehicles.

2-64

TM 9-2320-272-2491

Table 2-2. Mechanical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Step 4. Check for white smoke during cranking.

a, If white smoke is seen, air may be in fuel system.

Prime fuel system (para. 2-22),

b. If white smoke is seen, coolant may be in combustion chambers.

Remove dipstick. If coolant is present, notify DS maintenance.

WARNING

l
Eyeshields must be worn when cleaning with compressed air.

Compressed air source will not exceed 30 psi (207 kPa). Failure

to do so may result in injury to personnel.

l
Diesel fuel is highly flammable. Do not perform fuel system

procedures near open flame. Injury to personnel may result.

Step 5. Check fuel transfer pump for proper operation.

a. Check for loose fuel supply hose at fuel filter head.

b. Operate hand primer on the fuel transfer pump and check for fuel.

If fuel is present, replace fuel transfer pump (para. 3-20).

Step 6. Check for fuel leaking from fuel pressure transducer. If fuel is present:

a. Check fuel transfer pump for proper operation (refer to step 5).

b. Check for clogged fuel injector supply line.

If clogged, clear with compressed air or sturdy wire.

Step 7. Inspect fuel filter for dirty and/or clogged condition (para. 3-30).

Replace fuel filter if clogged or dirty (para. 3-30).

Step 8. Inspect fuel lines and connections for leaks, breaks, obstructions, or damage.

a. Visually check for leaks. If leaks are present at connection, tighten.

b. If leaks are result of cracked, split, or damaged tubing, replace fuel line(s) (TM 9-243).

C. Disconnect fuel line at both ends. If fuel line is clogged, clear with compressed air or

sturdy wire.

d. Reconnect fuel line.

e. Replace fuel filter (para. 3-30).

f. Prime fuel system (para. 3-22).

g. If not corrected, notify DS maintenance.

Step 9. Check for fuel contamination.

a. Open drainvalve on fuel filter/water separator and drain approximately 1 pt (0.478 L) of

fuel into a glass container.

b. If contamination is present, continue to drain fuel up to 1 qt (0.946 L).

c. If contamination is still present, drain fuel tank(s) (para. 3-27).

d. Clean and flush fuel system. Dry with compressed air.

e. Replace fuel filter (para. 3-30).

f. Refill tank(s) with fuel (TM 9-2320-272-10).

g. Prime fuel system (para. 3-22).

2-65

TM 9-2320-272-24-1

Table 2-2. Mechanical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

WARNING

l
Ether is extremely flammable. Do not perform ether start

system testing procedures near fire. Injury to personnel may

result.

l
Eyeshields must be worn when cleaning with compressed air.

Compressed air source will not exceed 30 psi (207 kPa). Failure

to do so may result in injury to personnel.

Step 10. Check ether start system.

Perform malfunction 16.

END OF TESTING!

3. STARTER CRANKS ENGlNE SLOWLY, HARD TO START

Step 1. Press accelerator pedal all the way to floor and hold, then restart engine.

Step 2. In cold weather, ensure proper engine oil is being used.

Add or replace oil (LO 9-2320-272-12).

NOTE

If STE/ICE is available, perform NG80-Starter Circuit Tests

(para. 2-24).

Step 3. Check starting system (Electrical Troubleshooting, para. 2-22).

END OF TESTING!

4. ENGlNE STOPS DURlNG NORMAL OPERATION

Step 1. Perform malfunction 2, steps 2, 8, and 9.

Step 2. Check for restrictions in exhaust system.

Ensure exhaust

You typed that from memory didn't you?

 

[ranchhopper]

I may be wrong but the shut off solenoid may be the plunger type if it is make sure the plunger retracts when you put the power to it that was a common problem with john deere rubber tire loaders with the plunger type shut off solenoids.

 

[ichudov]

The end was kind of boring. Turns out that the pump was out of prime (as some of the people said), after 200 or so times I pressed the hand pump, it did start and ran fine.

I identified another issue. The fuel gauge does not work, specifically when I switch it to the right tank, it shows almost empty, whereas the tank is completely full. I was bitten by this once when my driver ran out of fuel in another truck, and I want to fix it. How hard is it to find replacement parts, such as the sender?

thanks

 

[Suprman]

Eriks surplus has the sender. It is easy on a 923. On a 931 you will have to first remove the stuff over the tank first.

 

[ichudov]

Eriks surplus has the sender. It is easy on a 923. On a 931 you will have to first remove the stuff over the tank first.

This is a 931A2

 

[doghead]

I can't help but to notice that you thanked others for their ideas, but not me for posting the TM(specific troubleshooting section that directly covered your problem).

Had you started by reading the TM, and following it, you would have solved your issue in a few minutes.

As for the parts needed, if you simply look the part numbers up in the TM(-P), then google the part number, you would also find places to buy the parts online.

 

[ichudov]

Doghead, I did read the TM section. Thanks for posting it.

 

[doghead]

Thanks for the reply.

I was wondering if it was helpful. It is methodical.

 

[turnerman]

Dont forget on some models the solenoid on top of the fuel injector pump goes bad. It should have a knob that can be screwed in buy hand to hold open and then it will crank if that is bad. Try that it is a one minute job.

 

[ichudov]

Thanks for the reply.

I was wondering if it was helpful. It is methodical.

Doghead, which TM specifically were you quoting, I want to read it fully. thanks

 

[doghead]

TM 9-2320-272-24-1, in the service and troubleshooting section, table 2-2.