I had a stupid thought this morning.

Would the fuel pump keep pumping fuel with the key on truck not running to a leaking injector? If so, I wouldn't think my fuel rail pressure should drop down as much as it does after say 5 minutes or so. If the fuel pump keeps cycling to keep up it should hold pressure. That's assuming the fuel pump works this way with just the key on truck not running.

 

From what I could tell last night while I was getting numbers for you, the fuel pump brings the line pressure to where it needs to be for the engine to start, but if you do not start it, it does not maintain the pressure(keep pumping). With that said, I do not think it continues to pump fuel again until the truck is started or the key is turned off then back to the on position. I may be completely wrong here, but its my initial "guess" until I do some more investigation.

 

8 new injectors ordered, suppose to be here tomorrow. Putting them in tomorrow night.

 

Hopefully that's the cure.

 

Huh. My '06 4.6 has a similar issue. I haven't noticed that it's in hot weather, but occationally it does the same thing...long crank to start, or two crank cycles to start. Not too often, but noticable. Fuel filter is new and air cleaner is fine. My old '92 with the 300 I-6 always started flawlessly on the first try.

 

Good luck with that bud, let us know if it cures your problem.

 

New injectors are in. Too early to tell but none of the symptoms are present that I was having before. AFRP is holding with KOEO. Problem is the freaking new injectors are the same part number as the ones that came out. Both old and new are the part number Quintin said he has been putting in as replacements. I ordered the Motorcraft Part # CM5138 which is the same as 5C3Z9F593DC. So this tells me that Deka doesn't know how to built injectors or Ford has a serious issue going on with their fuel injection system. Here's a copy and paste from Rockauto. Maybe I should have ordered the aftermarket injector from GB instead.

2006 FORD F-150 FX4 5.4L 330cid V8 FLEX FI (V) SOHC : Fuel/Air : Fuel Injector Wiki Price Core Total
MOTORCRAFT Part # CM5144 {#7C3Z9F593A}
From 12/04/06; 7C3E-9F593-AB
$22.79 $0.00 $22.79
Add to Cart
MOTORCRAFT Part # CM5138 {#5C3Z9F593DC, CM5091}
5C3E-9F593-DB,DC
Before 12/03/06; 5C3E-9F593-DB,DC

$25.79 $0.00 $25.79
Add to Cart
STANDARD MOTOR PRODUCTS Part # FJ817
8 Used

$32.79 $0.00 $32.79
Add to Cart
GB REMANUFACTURING Part # 82211198 REMAN MULTI PORT INJECTOR


$31.79 $9.00 $40.79
Add to Cart

Not sure how this cut and paste will work but it's late I'm tired and going to bed.

 

Glad things are on the up, hopefully the problem does not come back.

 

Yeah hopefully.

Knock on wood but it ran extremely well on the way home last night from my buddies and on the way to work this morning. After those two drives I can't believe how bad it was actually running before. My idle is the smoothest it has ever been. It was developing a low grade misfire, too. That seems to be gone.

We hooked it up to a scanner after installing the injectors and everything looked perfect. Monitored all the injectors and all were within correct range. He has a Genesis scanner that won't pick up individual cylinder misfires on most Fords. It will on every other make just not some Fords. I have another buddy that has two different scanners that I'm going to see at lunch today.

I'm doing that to make sure I don't have a misfire on a bad plug from the leaky injector.

Changing oil, oil filter and fuel filter tonight. I've pulled the dipstick everyday since this started to smell for gas. None that I could smell but I need to get that oil out of there ASAP just in case.

 

Ok I feel a little better now. I brought one of the old injectors into work and just looked at it under a loop. They are different numbers! 5C3E-DC is the old one. My son read it wrong last night. There's no way I can see it with the naked eye.

Took the truck up and had another scanner put on it for about 5 minutes and left the truck running, idle, rpms up to 3K, idle, so on so forth and NO misfires and injectors look to be running perfect.

Total cost was $232.00 and beer for replacing all 8. Pretty simple job actually.

 

Congrats!

You going to bench test the old ones?

 

Actually, I just came in from doing just that. The redneck way.

No idea how reliable this was but I did have one fail the test. Set my compressor up for 41psi, put soapy water on the end of the injector, inserted the air nozzle wrapped in a rubber sleeve into the injector and pulled the trigger. Like I said not very reliable but none of them should be open without voltage and one failed.

Now, is anyone wondering why I didn't test them on the truck before replacing them? The truck was displaying all the symptoms of a stuck open injector. If I was going to pull the rail (had a buddy help me) and test I might as well just replace them. I just thought it was a big waste of my buddies time and my time since I had all the signs of a leak. For $230 I took a chance. And the fact I didn't want to bother anyone to borrow a car or screw my wife's schedule up to be my taxi for a couple days.

I have already sold the old ones for $40 to a company that rebuilds them. I marked the one that failed my highly advanced test. I'm curious to see if he gets it to fail, also.

 

Is your truck still running good? My 05 does the same thing, worse when its hot.

 

Runs awesome.

 

If you have a 05 with the 5.4 3v do search for the injector letter. It's a recall for them.
Get it into a dealer so they can look at it before the motor hydro locks.

Found the letter......
http://ww2.justanswer.com/uploads/ti...call_07M08.pdf