Compression test results.
Fleet Owner
Joined: Jun 2004
Posts: 25,090
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From: Rio Rico, AZ.
It's the 1800 psi on the HPOP pressure that is wrong.
Post Fiend
Joined: Feb 2007
Posts: 14,541
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From: Dallas-Ft. Worth
Agreed. There's something up there. Not to mention the metal shavings on the turbo!!! I kind of skimmed through the thread so I missed some of the details. Sorry -- got in a hurry...
Anxious to see how you get this all fixed up, Kris!!
Anxious to see how you get this all fixed up, Kris!!
FTE Leadership Emeritus
Joined: May 2001
Posts: 13,653
Likes: 6
From: Cabot, Arkansas
That's good. I think the turbo is a bigger part of the problem than you might think. 1800psi, while low, is not at all uncommon when running a chip. That pump will probably do 2500+ with the chip removed.
Post Fiend
Joined: Feb 2006
Posts: 11,892
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From: Middle Tennessee
2- 400
4- 375
6- 380
8- 400
Don't know if that helps at all. Your ICP ought to at least start out higher. I know the chip will use it up quickly. Let me see if I can find the graph of mine with chip and without. That might answer Jamie's question too.
Post Fiend
Joined: Feb 2006
Posts: 11,892
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From: Middle Tennessee
I posted about ICP here in this thread.
For those not interested enough to look, here is my log of ICP on the 120 race back with stock injectors and turbo. Curious what it looks like now with the hybrids.
For those not interested enough to look, here is my log of ICP on the 120 race back with stock injectors and turbo. Curious what it looks like now with the hybrids.
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Postmaster
Joined: Jun 2006
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From: Fulltime RVer
Here's a way to do a crude road test, and I'll give my CAT ICP readings as an example of "normal" operation. On the flat at constant cruising speed I see about 2600 psi. As I increase load to pull a hill I see a slight decrease, which shouldn't exceed about 200 psi if all is well with the HPOP and injectors. Then as I crest the hill and coast in gear at idle down the other side at the same RPM, the ICP momentarily increases to about 3300 psi. This is because the injectors flow very little oil at idle, and it takes awhile for the excess pressure to bleed off and the ICP to return to normal. If you don't see this momentarily increase, it means you've got excessive flow at idle due to a leak!
Post Fiend
Joined: Feb 2006
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From: Middle Tennessee
Gene's observations seem to match my data as far as throttle position and ICP is concerned.
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Post Fiend
Joined: Jul 2005
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From: 21791
Yes, i believe the IPR also remains near closed (or at least i think) during startup, that's why the ICP skyrockets to 2500ish when started up cold, it just takes a second to bleed the whole system down to the normal 600-700 when cold. I talked to Joey about it today, and he says it's just another case of a set of very oil-hungry stock AD's. Plus i don't think the 3800psi they were seeing a few months ago helped the poppets and springs any. Maybe that just loosened them up a little too much, because it was FINE with a stock pump before that. I can still produce up to 3500psi with this at the right time and pedal position just rolling into te throttle before it falls off.
Fleet Owner
Joined: Jun 2004
Posts: 25,090
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From: Rio Rico, AZ.
Yes, i believe the IPR also remains near closed (or at least i think) during startup, that's why the ICP skyrockets to 2500ish when started up cold, it just takes a second to bleed the whole system down to the normal 600-700 when cold. I talked to Joey about it today, and he says it's just another case of a set of very oil-hungry stock AD's. Plus i don't think the 3800psi they were seeing a few months ago helped the poppets and springs any. Maybe that just loosened them up a little too much, because it was FINE with a stock pump before that. I can still produce up to 3500psi with this at the right time and pedal position just rolling into the throttle before it falls off.
I've noticed a very much more responsive engine start, now that I have a new set of Alliants installed. The truck can sit for a week and it starts right up, right now, with less than 2 seconds of crank time.
Before it would be a little bit longer, especially when hot. It would sort of taper up instead of the usual "bark" when it starts.
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