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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.
Thanks, I have the IPR test fitting. I'll do that before digging under the turbo.
If you don't find the leak, let it pressurized for hours.
Put max. shop air pressure on it.
Did you removed valve covers?
I took the IPR out again and replaced it with the test fitting and put ~125psi on it. Sounds like a massive leak on the passenger side, no way it would pressurize and stay that way. Driver side was quiet.
Took the *new* standpipe out, the top o ring looked like it was cut a bit from the install. Before I installed it I oiled it up really well so it had to be my fumble fingers doing it. I also checked the nipple motion and they weren't tight. I had replaced them last fall but they aren't *stiff* like they're supposed to be.
My plan is this while I'm that far in:
New stand pipe and dummy plug.
New nipple seals.
New IPR.
New injector seals. (alliance kits).
I'm leaving the IPR test rig in until I get all the new components in since it is a real *itch* to install, then I'll air test it again. Wish me luck.
Thanks for all the comments and suggestions and I'll keep you posted.
If that doesn't fix it, put a nickel in the radiator and push it over a cliff just to say I threw something away.
Update:
I put in new nipple seals and thought I'd try it again before pulling injectors. Well, it didn't work. New nipple seals, no change in the air noise from the passenger side.
I left my IPR test fitting in and will leave it there until I get the leak stopped.
I'll try to get a video up but it sounds like there is no restriction to the air flow. I'm wondering if the nipples themselves are worn because when I torqued them to 100 ft. lbs, some of them weren't really tight in the rail. Of course, it could also be the top injector seals. I'm at wit's end with this thing. I've had a few HPO leaks in the past, but nothing like this.
Sounds like most of the air leaking is from the passenger side. Closing IPR resulted in no change in hissing.
I replaced passenger side with new stand pipes, new nipples and new seals since that's where most of the noise is coming from.
Started the truck, the HPO came up quickly at ambient (~80 deg F)
Took it for about a 20 mile drive, including about 10 minutes of 70mph interstate time, ECT/EOT were 202/205 respectfully, let it cool to 195/197.
Coolant pressure was about 16psi, relieved that then drove it hard for 5 miles, after that, pressure was around 5psi so head gaskets are probably good.
Pulled it into garage after letting it cool back to 192/195, shut down. Attempted to start, IPC shows about 230psi.
Guess I'll air test again, take everything apart and inspect and try to figure out what's going on.
On that video. All I can really hear is shop air loading hoses. I hear a faint air sound,but can't really tell where it's coming from. Have you listened closely, back towards hpop? Try the old trick with a little piece of pvc. Use it like a stethoscope. Sounds dumb but it works. You can narrow down where the air is coming from.
Just a thought.
IPR = 85% when oil is up to temp. it is a brand new IPR.
I've air tested both ways, through the IPC and directly through the IPR. Both times it sounds the same on the passenger side.
Going to start all over, pull everything, check and reassemble.
As I said before, I replaced the STC fitting with an upgraded one 4 years ago and even when running at normal temps, the IPC values leek good. I hope I don't have to go there, that's a really dicey operation. I hope it isn't branch tubes either.
On that video. All I can really hear is shop air loading hoses. I hear a faint air sound,but can't really tell where it's coming from. Have you listened closely, back towards hpop? Try the old trick with a little piece of pvc. Use it like a stethoscope. Sounds dumb but it works. You can narrow down where the air is coming from.
Just a thought.
Thanks. I have tried using hoses to pinpoint, can't really tell much other than it does sound louder back near the standpipe.
I even tried a "smoke" test using a cigar and blowing smoke through a tube under the oil rail and still couldn't find the source.
The cigar was good, though.
The problem is the air leak is so bad that it only takes 10 or so seconds then the air compressor has to come on and I can't hear anything. When that happens I have to shut off the valve and wait for it to cycle. I'm going to put the compressor outside the garage to abate the noise, then try it again.
My stethoscope broke (it was really old and plastic had deteriorated) so I have another one on order and also ordered a borescope. That'll be here Sunday.
Injector #8 top o ring. Pics show good and bad.
These were Alliant o rings that I installed 5 years ago. I replaced all 8 then and just put new ones in during this fiasco.
Huge lesson learned, if you have to open it up, do everything; stand pipes, dummy plugs, nipple seals, nipples, injector o rings, IPR valve. May be costly, but consider it maintenance.
The hot start is fixed, but I now have a P2252 code so either the FICM is hosed or one of the connectors isn't connecting. I've never had an issue with that before now. I do know the "tangs" on the back 2 connectors were broken so they won't click in like they normally do. First time I've had any trouble with these connectors or the FICM. I'm going to repair the connectors and retest.
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