Hi All,
My former '05 now belongs to my grandson, so I still have to work on it. Most recent issue is very slow start when hot. Starts ok when cold. Once started, runs good.
I changed both sides stand pipes and dummy plugs but still starts hard when hot. Started ok after the change when it was cold, then I let it sit for a few minutes after getting it up to temperature and it would only build abut 230 psi and, of course, wouldn't start. I know it takes close to 500psi to start.
I'm thinking next steps are to check IPR valve, even though numbers seem ok when it's running, then STC fitting. I replace STC with upgraded one about 4 years ago.
I tried to do an air test but broke my fitting, so will have to source another one, however, when it's running, HPO looks good. It's just getting to the magical 500 psi at start when hot.
Any thoughts?
Thanks,
Jim

 

I would start with ipr valve, look at Orings, hole in screen and also if the valve is operating correctly. Doing a bubble test would be good also, to check for leaky injectors. I had same problem and it was oring on ipr had a piece missing.

 

Thanks, That's definitely the next place to look. numbers seem ok, but you can never tell.
When I replaced the STC fitting 4 years ago it was supposed to be the "updated" one. Heck, that was a long time ago, I can barely remember last week.

 

I haven't heard any reports of the updated STC fittings failing so don't waste your time.

I would start with IPR valve as that's fairly simple to check. If that all checks out you're probably looking at nipple cup seals or injector O-rings. An air test is the best method for finding those.

 

Thanks,
So I pulled the IPR (what a pita to get to), the valve itself looks good, o rings are fine, but the screen stuck in the pump housing and didn't come out with the valve. I looked at it with a mirror and didn't see any holes, but I have to get it out somehow and check it.
I put new nipple seals in it last fall so they should be good. It has new stand pipes in it now.

After I get the screen out I'll put the original back in, I know it's good.

Next up is:
1. Bubble test.
2. Air test. (I already tried that but I broke my adapter so I have to get another one)

Got to get the screen out and put it all back together first.
We'll see how it goes from there.

 

I'm still trying to get my head around that screen cap coming off. Did it come off during disassembley or was it off when you took out ipr. I've never really herd of the whole screen cap coming off. I guess anything is possible.
. Good luck

 

If I were you, I would test the valve before re-installing.

 

Thanks, I was surprised that the screen stayed in the pump housing too. All I did was take out the IPR valve out of the pump body and the screen stayed in, *doggone* it. (trying to keep my frustration down) Crimony, that thing is hard to get to.

 

I have the original and I know it's good, so I'll put that one back in. I had replaced it about four years ago thinking it had failed when it was actually a stand pipe o ring.

 

I been looking at pics of my motor both when I removed ipr without taking turbo out and when I did air test with turbo out. Being that the cap is plastic. Magnets are out. There's very little room with turbo in. A pic off some sort might do it. But ya might have to remove turbo for better angles.(That would A pair of really suck) sharp angled forsips might work.

 

Update:
I got the IPR screen out. I used a 4" deck screw to drag it out and it came out easily. So, the reason it stayed behind when removing the IPR was that the plastic around the screen had deteriorated and was coming apart in pieces, so it wasn't attached to the IPR any longer. The screen looked clean and no holes. The IPR was replaced about 5 years ago by me. I bought one of the cheaper ones because the Ford OEMs are around $360, bad on me and I'm paying for it now. I vacuumed out the port and got a small piece of the plastic out and checked with a mirror to be sure nothing else was in there.

After all that, I replaced the IPR with a known good one and started and ran the truck until it was up to temp (198 deg EOT/ECT), shut it down and tried to restart hot, no dice. When hot it would only build about 230psi. Had to wait until it cooled down all the way to 75 deg before it would start again, and it was a long start even at that temp.

There has to be a leak somewhere, so later today I'll do the bubble and air test. I didn't get my test fitting until last weekend and I didn't have opportunity work on it much then.

It is setting a #8 contribution code so I hope there isn't some of the IPR plastic in that injector. Nipple seals were replaced last fall. New standpipes/dummy plugs installed last week.

I'll keep you updated on the progress... thanks for all your comments.

 

Update:
I did the bubble test, no bubbles at all in the fuel bowl when cranking.

I also did the air test again. With the IPR not powered, I hear a lot of gurgling in the oil fill tube on the passenger side. I can hear just a bit on the on the driver side. I can actually feel air coming from the oil fill tube. I just changed the stand pipe on both sides so maybe I didn't get it in there right. If I apply voltage to the IPR and charge with air, the gurgling stops.

I do have the passenger side valve cover off again so I'll remove the rail and check the standpipe again.

The only other thing I can think of is the upgraded STC fitting I installed 4 years ago has failed. Any thoughts?

Demoralizing, to say the least. Been under this thing for a week now and it's still not solved. Both rails have been off, standpipes and dummy plugs replaced, IPR replaced, still no hot start.

 

The IPR is essentially a dump valve to the crankcase. That is why you are going to hear air unless you close it and keep it closed during the air test.

 

That helps. So, I didn't hear any air at all while the IPR was closed. So, I suppose the best thing to do now is check the STC fitting, correct? Wouldn't that be the next place for a potential leak? Not looking forward to that, for sure.

 

I would check all of the nipple cups and the injector top seals with your air test. I've heard a lot of stories of guys replacing them only to come back and do it again. The ***** themselves can wear, or O-rings can get pinched.

On the updated STC the only failure point are the (2) O-rings on the updated fitting (one on the pump body, the other on the branch tube). I haven't seen any reports of them leaking yet but anything is possible. A long way to dig into the motor to check 2 seals so I would definitely rule out everything else up top first.

It's usually best to test from the IPR port so you aren't relying on the IPR valve to hold air pressure, but that requires the special test fitting.