Manifold explosion

Tiny
BIGGUY1962
  • MEMBER
  • 2004 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 265,000 MILES
I have had two intake manifolds blow all to pieces when it set for three hours to seven days. Runs great after replacing the intakes. My mechanic that did the work replaced two catalytic converters because they were plugged. He says I have three injectors leaking. He did a test on the fuel rail with a gauge. He then charged the system without power to the injectors and the showed signs of fuel leaking when they were not energized. Would this cause my intake to explode?
Wednesday, September 19th, 2018 AT 9:46 PM

5 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good morning.

Yes it would. If fuel goes into the intake when not commanded, it puddles in the manifold. Then all it needs is a spark and off it goes.

I am surprised that he did not replace all the injectors. If one is bad, it makes sense to replace them all.

He needs to recheck the system and pressurize the system with the fuel rail off the car and inspect for the leak.

Roy
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Thursday, September 20th, 2018 AT 1:52 AM
Tiny
BIGGUY1962
  • MEMBER
  • 7 POSTS
Thanks Roy. He did pressurize the injector off the vehicle overnight and three injector holes were full of gas and then some. That was without them being energized. The vehicle ran great before. So I cannot see it being a valve or those cam phasers (timing). Thanks again
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Thursday, September 20th, 2018 AT 7:02 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Valves or cam phasers? Who said anything about that?

If you have fuel in the manifold, then the injectors are leaking and need to be replaced and retested. The manifold should not fill up with fuel. It should be bone dry sitting overnight.

Roy
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Friday, September 21st, 2018 AT 1:08 AM
Tiny
BIGGUY1962
  • MEMBER
  • 7 POSTS
My mechanic did that and It was bone dry. I meant before he replaced the injectors it was wet. I appreciate all the advise. Thank you.
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Friday, September 21st, 2018 AT 5:30 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Okay, so after the replacement, there was no leaking fuel?

If that is the case, then he needs to dig deeper. Have him check the timing of the cam shafts.

Also, have him check the compression to see if there is a bad valve or a valve hanging open.

Spark is getting into the intake when it should not be there.

Roy
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Sunday, September 23rd, 2018 AT 6:52 PM

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