Hi,
I am trying to help a friend who is low on cash to get his truck running again. I am a mechanical engineer but by no means an auto mechanic, so I told him there was a 1 in a 100 chance I could help. Anyway his truck died on him while driving on the interstate with no prior warning.
This afternoon I went out to where the truck was parked and with a boost in place I asked him to crank the engine over. As soon as the engine turned over, a small bang occurred and smoke appeared at the intake manifold. I think this engine has throttle body fuel injection and this is where the back firing like bang emanated from.
I then checked for spark by removing a plug and had him crank the engine one more time. No back firing sound this time and there was spark.
Prior to me arriving he had replaced the fuel filter, but this did not cure the problem. The engine has 135,000 miles and my best uninformed guess is timing chain (or belt - not sure on this engine). This might explain the back fire and certainly account for the engine not starting as it appears it has both gas and spark. I am not sure the easiest way to rule this guess out and then proceed along some systematic path to arrive at the root cause.
Any advice / suggestions would be much appreciated! Many thanks.
Craig