Well I'm no kid 50 years old. Sure I've owned a SUV but never a truck. I was given a 2003 extra cab and was told the motor is blown. This was part of a deal. My friend had two trucks at his inlaws. 2001 F250 5.4 and the 03 with 4.6. He has no budget to buy a motor and the 250 was supposedly driven to it's parking spot last year. He put gas in it and it did not run. I went over and we put a squirt in the throttle body and it started. Tried this till my squirt bottle was out always the same result. I said it would be easier to fix over at my house. Now both trucks are here. I pulled the tank and put a pump in 250/5.4 and the rear brake line was toast so I fixed that. Went to crank it and got a little sputter so I thought I'd help it along and put a squirt in the throttle body. Went to crank it and got a backfire. Now just clank, clank no crank? I pulled the plugs and still clank no crank. ????? I just was browsing this forum and saw posts about AC locking up holding back the starter or bad/weak starters. I'm pretty mechanical but at a loss at to why it went from starting to nothing, right when I though all the work was done. I did put a battery on the 4.6 it it sounded the same....clank. I wonder if the motor is really blown? First I have to fix the 250 for my friend. No way the motor got hurt by one backfire?

So glad I found this forum. I can't wait to fix my first truck. Red 2003 ex cab 4x4,

 

Well it's not the AC, took belt off still goes clank. Either starter or motor? Funny it would start just the other day with a squirt of gas.

 

crawl under the radiator and put a socket on the crank center bolt and turn it... or take the flywheel tin cover off and use a 18 inch screw driver to move the motor 90 degrees ?

 

I put the longest wrench I had on it a torque wrench. No plugs tried to turn it clockwise and nothing? I could not budge it. It ran before it backfired??????

 

you have the spark plugs out.. I would take the fan belt off so you have no drag from the AC / alternator / steering pump....... if you cant bar it over then, you have a big problem. I don't see how a backfire would do something major, but I would look at the cam chain area on the front end.
----------im wondering if it had a problem when it was parked... did you ever see the oil psi gauge jump up ?

 

Yes when it ran with the squirts of gas you could see the oil pressure come up. Fan belt was off when I tried to turn it. I'm with you I don't see how a backfire would lock up an engine. I was going to take the starter off and have it tested or buy one since I have the other truck to put an engine in anyway.

Ideas? What could possibly be holding it?

 

well, the starter is a long shot, but backfire might have bent something and locked it up......... its an easy check ! Remove starter, then bar the motor over.

 

Removed Starter, still have belt off and plugs out. Stood on torque wrench and only turned bolt. Engine never moved. I could try a screw driver on flywheel but think it's toast?????????

 

OK was about to call the guy and tell him it's dead, but my never quit attitude said try one more time. I took a screwdriver and low and behold the engine turns backwards. I can put a regular 1/2 inch ratchet on it and turn it. It will turn multiple revolutions backwards but seems to catch something at the same spot on a forward revolution. Sounds like the thud is coming form the transmission/converter area. Took inspection cover off, no sign of anything abnormal?

Any Ideas??????