I've been working on a 2006 and have had the o-ring underneath the STC fitting blow out 3 times already. Have replaced the HPOP, the stand pipes, dummy tubes, the top O-rings on the injectors and the oil rail O-rings. Everything checks out when get the vehicle hot, and restart. No prblems. But when test drove got bout half a mile and it stalls out and wont restart. Tear it down and air check and its leaking under the STC fitting again. Am I having pressure come from somewhere to cause it? Im installing it correctly I believe and torqueing it correctly. PLEASE HELP!!!!!!!!!!!!!!!!

 

This is a stupid question I know, however what kind of HPOP did you buy and did it come with the updated STC?

Did you install the STC fitting properly using the tool provided.

Sarge

 

Purchased the STC fitting from Ford and put that just on and had a problem still, then purchased a new HPOP from Ford that had the STC fitting already installed on it.

 

stc fitting off kilt a little with pump not seating square on oring when units mounted maybe.

 

I was thinking maybe so. Whats my best bet? Loosing nut and installing in truck and tightening after screwing down the small 8mm nuts knowing its flush?


Also Im leaning towards potential branch tubes bent but don't know how to test it. When installing the pump bolts went in smooth. The STC ones screwed in a few times then had to ratchet down the rest each time. they were never pulled, but couldn't hand spin all way down. is that indication of bent branch tubes?


Thanks!

 

If you have a STC alignment tool see that its aligned properly? Was the original complaint a no hot start? If so did it have the old style STC fitting on the original pump?

My guess is that if that is true perhaps it blew apart and damaged the branch tube, but they normally damage the back cover. Use a mirror and check to see if the branch tube is bent, if its not sealing like you said it should be pretty obvious...or install it and see if the branch tube and STC fitting are flush. If its blowing the O-ring out it will be obvious that its not sealing. If that's the case Id say you've defiantly got a bent branch tube.

Sarge

 

Yes original complaint was no start. When pulled the cover the old pump had the updated STC fitting. Pulled the pump and found half the oring gone under fitting. Replaced the fitting and oring on old pump. Did test drive for over 10 miles, restarted each time. thought checked out. gave to customer and it wouldn't restart when they got home.


Had it towed back and pulled it down to find fitting leaking with air check. replaced the HPOP pump and it came with new fitting on it. installed and got vehicle hot in shop and it restarted. went to test drive it around block and stalled out. Brought back and just tore down this morning to find it leaking at fitting with air check.


looking at it right now everything looks kosher with a mirror and my eyes. is there a certain place to look? or a test I can do? I don't know if its so small of a bend of the branch tubes or not. I would hate to sell a branch tube job to the customer if its something like back pressure from somewhere causing this.


thanks so much!

 

another stupid question, you are commanding the IPR closed when air pressure testing? is the back engine cover cracked?

 

Second this as I stated before about the back cover check it for cracks and also command the IPR closed when air testing.

Is the O-ring physically gone, or is it pushed out, or torn? Can you try and snap a picture of the pump the way its sitting on the branch tube. You should be able o run the bolts down by hand in theory if everything is lined up strait. Do the threads look good? I'm wondering if it was cross threaded and when under pressure its pulling the STC fitting up just enough to spit the O-ring out or cause the leak?

Just thinking out loud. Ive never heard of a bent branch tube, its possible I suppose but not common. Id check that rear cover for sure though.

Sarge

 

Another idea is maybe the bolts holding down the fitting to the branch tube are too long and bottoming out giving a false torque. I wish I could remember if the factory STC ones were the same as the ones that came with the updated fitting

 

All the bolts that come in the FORD STC kit are the same length as the factory installed ones. I just did mine last week and they were identical.

My truck has an 05 engine in it FYI.

Sarge

 

Old on the left, new update on the right.
Maybe your setting it too deep in the pump, so when mated to the branch tube the port is misaligned and blowing out the oring. I could see this happening if the old STC fitting blew apart and bent the branch tubes.