Topic: 347 no start after warm up

[5.0FEVER]

ok guys here is a good one for ya i have a 347 36lb injectors pro-m mass air after you shut it off when it gets warm it will not start! i have checked and i have injector pulse, ignition spark and compression but no start, the only way to get it to start is to hold it wide open throttle and unplugg #4 injector i have replaced two computers, the #4 injector still no start when hot does anyone have an answer??

[Soaring]

Sounds a lot like a bad fuel pump to me. A quick and dirty check for that is to have someone wang on the underside of the gas tank with a hammer or a tire iron or something like that while you're cranking the engine. If that makes it start right up then you can be sure it's the fuel pump.

Failing that you'll just have to resort to some good old fashion diagnosis. You need fuel, spark and compression to start. Compression is unlikely to be intermitant, and is usually fairly obvious. Leaving spark and fuel. So put a spark checker in one of the spark plug wires, a fuel pressure gauge on the fuel rail and a noid light in one of the injector connectors and crank it over. See which one you're missing and go from there. Good luck!

[5.0FEVER]

thanks for the suggestion but i have already done all of those i have a gauge on the rail that reads 36lb of fuel pressure i do have spark at the plugs and i have injector pulse and i am positive i have compression car runs perfect other then the fact that it will not start after initial start up will not even hit untill i unplugg #4 injector and crank it wide open thottle thanks!! i have work on mustangs for a long time never came across something like this can anyone help?

[Soaring]

Run the numbers and see what you get.   Is the "check engine" light on?  Have you cleaned the MAF, and checked to see how clean your air filter is? 

[5.0FEVER]

compression averages around 135lb per cylinder and fuel pressure holds around 35 to 36lbs and yes the check engine light is on

[5.0FEVER]

just bought a new pro m air filter and i cleaned it when i had it off still no change

[Soaring]

Again, check the numbers to see what it tells you, and if you still haven't a clue, take the car to Autozone where will check the numbers for you for free.  If they don't come up with the answer, then take it to an authorized Ford dealership where there are trained mechanics.  I wouldn't lose any more sleep over it.  It could be most anything, but I am suspecting one or more of the coils are heating up.  If that 92 only has one coil, then that may be the culprit.  Does the engine spin over fast when it is warm?  If not, then maybe the starter is heading south. 

[5.0FEVER]

i work at a ford dealership we have checked the code it only comes up with a code because we unplugg the injector no other codes are found have replaced distibutor, coil, tps! it does spin over faster when it will not start not sure why it does that and i have tried 3 different computers as well!! trust me this is a good one!! dont understand why it only starts when you unplugg injector and holed it at wot!

[Soaring]

That #4 injector is suspicious, isn't it?  I would think it would come up as a problem when you ran the numbers. Is there anyway to test that injector? 

[5.0FEVER]

yes it is aggrivating but i have replaced that injector and still have same problem

[Soaring]

Take it in to your Ford company, and turn it over to the pros.