2006 Mack CXN Fire

[DMark]

I'm a fire investigator trying to determine the cause of a fire involving this truck. The fire is centered around the Borg Warner turbocharger (see photograph), but I haven't identified the fuel load (oil, fuel, etc.) that was first ignited. The turbo oil line (A) appears to be intact, but the oxidation on the turbo above the fitting is suspicious. The actuator line (B) has a small hole in it, but it could be caused from being over pressurized. Canister C appears to have a loose hose at the bottom that has two hose clamps attaching it to the nipple. Can anyone tell me the operating pressures on the two lines and isn't the actuator line air? I can't open the turbo at this time to determine if an internal problem has occurred. I appreciate any help, Mark

[Mackpro]

Fuel injectior lines every time. I've personally seen at least 6 engine fires on the 2004-2006 CH/CHN and CX/CXN  trucks with the ASET AC engine. The injectior lines are a one time use item. Mack even has a video on them on installing them and all the techs had to watch it

[DMark]

Thanks, but aren't the fuel injector lines on the other side of the engine? If so, the driver's side sustain little fire damage and I can't put the fire there. 

[Mackpro]

The fuel supply line runs up the driver side of engine but the fuel injector lines are on the passenger side and there are 6 of them. They screw onto the high pressure EUP pumps and then go over the exhaust manifold into the the side of the cylinder heads. They are know to leak and catch fire if reused on the AC engine. The same fuel line is used on the AI engine but they never seem to catch fire like the AC engine 

Edited October 4, 2018 by Mackpro

[Mackpro]

The best fuel lines were the ones on the original ETECH engines , they had the jam nut on the end that went into the head. They never leaked and could be used on the ASET engines as well. 

[br549]

The problem with the fuel lines in my opinion were cheap junk.  Look at the lines on earlier e tech engines that never gave problems, then they have a high heat engine under the hood with the egr system and put a tonka toy injector line on it.  Later they beef the line back up and  solved the problem.  I had one truck down in Alabama that had a fuel leak on and they put a fuel line on it and it still leak so they pull the injector and put o-ring on it and it still leak. They replaced the injector and  that fixed it, I paid for 3 injector lines because they would not reuse it.  That is BS.

[fjh]

2 minutes ago, br549 said:

The problem with the fuel lines in my opinion were cheap junk.  Look at the lines on earlier e tech engines that never gave problems, then they have a high heat engine under the hood with the egr system and put a tonka toy injector line on it.  Later they beef the line back up and  solved the problem.  I had one truck down in Alabama that had a fuel leak on and they put a fuel line on it and it still leak so they pull the injector and put o-ring on it and it still leak. They replaced the injector and  that fixed it, I paid for 3 injector lines because they would not reuse it.  That is BS.

 

Yup look no farther than a faulty fuel line as stated above they a trash! They changed to a dollar store supplier back in or around the time the ac ai  engines production  began !These lines were a one use line! And even At that they failed! 

[Mackpro]

Our policy was never reuse a line and alway do a  15 mile test drive after replacing any fuel line and check for leaks at head. 

[Mack Technician]

We saw fires too. One was in a remote part of the U.P., no fire departments, burned for a long stint And ended up on the ground. 

First attempt to fix was reduce under hood temps by punching breathing holes all over and installing hood scoops. Painted scoops locally. Plastic looming under hood was melting, everything plastic was being wrecked.

second attempt was “no reuse of injection lines” and a tool kit with Mpros video.

third attempt were the cheesy little foil tubes wrapped over all six injector lines to reflect radiant heat. They started to believe the EGR AC temp was so hot it denatured the steel lines’s strength.

fourth attempt was a service bulletin labeling the #3 cylinder injector line as the troublemaker. Sometimes they would get bent during R&R because they were tricky to remove with limited access. The temptation was to bend the line which weakened it, misaligned the engagement and created internal stress. 

I believe all the above had something to do with it. Intro to CCRS pulse and pressure delivery, too much heat(recall the same AI vintages had same line, same years and no issues), hard to access/remove and install lines and poor quality injector lines. 

A. Is a nylon core line that could have caused it, but didn't. White Nylon liner is since melted out. Rust is a product of intense heat plus some rain like everything under there that was once painted, chromed or galvanized.

B. is non-flammable

c. Has Zero pressure, it is a power steering res that is open to atmospheric pressure

D. Is a low pressure emissions system port to exhaust, no flammables.

 

Edited October 4, 2018 by Mack Technician

[fjh]

Bottom line is at the time they found someone that could build a cheap line to replace the original vendors  line! They were hurting for money at that point it was just before the swedes bought in and they were cutting corners to save a buck! It didn't work!They spent more money trying to fix the problem than  had they stuck with the original supplier!Poor design poor quality materials! just My observation!We had zero problems to that point! They have obviously now enhanced the dollarstore line we now have very few if any issues! If any!

Edited October 4, 2018 by fjh

[DMark]

I bet the one with the red arrow is it. Thanks everyone, Mark

[DMark]

NHTSA has two recalls (Oct 2006 and Sept 2007) referencing ASET AC Fuel Injection Lines and stating, "A leak in the fuel injection line may spray fuel on the hot surfaces of the exhaust gas recirculation system which could result in a engine fire.