#7 injector tip cracked and piston grenaded???

lmorris · February 5, 2011

The truck has around 45000 km and engine hours match KM. Truck is parked everyday in a heated shop. It was on a run up from Red deer, just passing through Leduc and started running rough and smoking, then power dropped right off and he limped it into us at 20 K/Hr. After diag, #7 low compression, pull head and piston is grenaded to the point that you can see the second compression ring. The head is also damaged. We found a split injector tip also, barely visible with out aid. Just over time for Ford warrenty and they denied any assistance.

Anyone have an explanation as to what may have caused the concern?

I have heard of water getting into the fuel system and splitting the injectors, but this fuel system is spotless.

Bruce Amacker · February 5, 2011

IH has a TSI letter out on several HEUI engines stating that improper fuel system bleeding (after a filter change or opening the system) allows air into the injector plunger area which allows the plunger to descend too quickly. As there is usually some fuel in the chamber along with the air, the pressure rise is too fast for the fuel to be delivered through the nozzle orifices and the pressure rise splits the injector tips. I've seen it a few times and it's REALLY fugly. This will also happen if the truck is run out of fuel and not properly primed. It usually splits the injector tip off requiring a head, piston, sleeve(?), etc. I have pics, I'll see if I can find them.

Ugh!

Posted Image

TSI Number: 04-12-01R

Replace: 04-12-01

TSI Date: June, 2004

Subject File: ENGINE

SUBJECT

Correct Fuel System Priming Procedure To Prevent Injector Tip Failures

APPLIES TO

Engine Family: DT 466 DT 466E 530E DT 530

DESCRIPTION

Because "dry starts" cause injector tip failures, a procedure that primes the fuel system before starting the engine must be followed. When the fuel injection system is dry after engine service, cranking the engine to start without first priming the fuel system will result in an overload condition in the injector tips. This overload occurs because there is no fuel present to cushion the needle valve as it lifts and seats. To avoid this condition, follow the procedure below after performing any maintenance, including fuel filter replacement that may allow air to enter the fuel system.

FUEL SYSTEM PRIMING PROCEDURE

WARNING:

Always place transmission in neutral, apply parking brake, and chock the wheels prior to engaging the engine starter. Failure to do so could result in unexpected vehicle movement and cause property damage, personal injury, or death.

CAUTION:

Do not start the engine without priming the fuel system.

1. Disconnect the injector harness at the valve cover.

2. Use the hand primer to fill the fuel system. NOTE: Pump until hand primer is hard to depress.

3. Crank the engine three times for 15 seconds each. Re-apply the hand primer after each crank cycle.

4. Once the hand primer remains hard to depress after the 15 second crank, reconnect the injector harness and start the engine.

5. Clear fault codes 513 (low side to bank 1 open) and 514 (low side to bank 2 open) that was logged by cranking the engine with the injector harness disconnected.

Bruce Amacker · February 5, 2011

I've seen fine hairline cracks that overfuel, and catastrophic failures like this one. I have several pics like this, I think Damon shot this one.

I have a customer in the UK with a bunch of rental DT466E gensets that kept having this problem caused by the rental customers not keeping the fuel tanks full.

The TSI doesn't apply to the 6.0 (VT365) but you gotta believe the principles of hydraulics do....

Keith Browning · February 5, 2011

I have read once or twice that water could possibly cause this too. I havent heard anything official about that though. Anyone?

Jim Warman · February 5, 2011

I can't offer any insight into the failure.... but I must suggest that we understand the difference between Fords warranty and Navistars warranty.

Ford isn't playing the part of a saint... but we shouldn't blame them for ITECs decisions.

Keith Browning · February 5, 2011

I don't see this as a warranty issue unless I missed something. The fact that air in an injector while it is actuated allowing the pintle makes sense but I don't see pressure being the culprit. I see the lack of fuel that can dampen the action of the moving parts allowing the pintle to hammer the nozzle tip. Ultimately you are always going to have some air in the system after opening it up but I think the idea here is to ensure that we take steps to properly purge the system after a repair or a filter change.

I see the Navistar bulletin Bruce posted includes engines with hand primers. Something only a few Ford techs have had to deal with. The electric pumps in the Ford trucks eliminate the need to manually pump and prime the system but we still need to cycle the ignition several times to effectively perform the same function. I don't recall Ford ever posting anything like this but do you think they would deny a claim for a cracked or broken tip citing dry starts as the cause? I know, I wouldn't put it past them anymore either.

The only problem I have with a 6.0L is that sometimes the air in the system does not purge by itself and despite cycling the key, the truck will start and run then stall after about a minute. It is then necessary to remove the primary filter cap and relieve the pressure with a loud "pssssst" after which you can cycle the key to fill the housing... screw the cap back on and off you go.

I am not sure that scenario is enough to increase the chances of cracking an injector tip. I view this as a rare failure however proper bleeding is always the right thing to do.

cbriggs · February 6, 2011

I have had one do that, and the customer told me staight out that his wife had run it out of fuel a few months before. Didnt really atribute the failure to that at the time, but it makes total sense.

I have also had a few 6.0 trucks trap air in the fuel system after filter changes or being run out of fuel.

neilly · February 6, 2011

all of the injector tip failures we have seen, have been caused by low fuel pressure, and lack of maintenance. same idea hair line crack in tip and melted piston and head.