Bad hpop?
Thread Starter
|
New User
Joined: Jan 2016
Posts: 19
Likes: 0
Bad hpop?
I have a 96 ford 7.3 and recently put rebuilt injectors, new ipr,icp sensor,pcm and a few other parts on it. The truck starts right up but blows alot of white smoke and after a few minutes the check engine light comes on and starts running really rough. Had it hooked up to a computer and found that the fuel pressurestarts out around 300 psi goes to around 3500 within a few minutes of running and the check engine light comes on. We unplugged the ipr and it starts right up so the guy said it is the high pressure oil pump because it shouldn't start being unplugged so he said it's probably something internal on the hpop allowing the fuel to bypass......any thoughts on this assumption?? If it matters the oil pressure sensor is buried on low till you give it some throttle then it goes to normal so it could use a lpop.
Postmaster
Joined: Mar 2004
Posts: 3,897
Likes: 9
The ipr being unplugged it shouldn't run because all your oil should go to the crankcase instead of the hpop rails. I would look at the ipr first because your hpop is working fine. Where did you get the ipr? Also you may want to put a gauge on your low pressure oil. The gauge on the dash is a glorified dummy light. But if your truck is still running it sounds like you still have pressure.
Thread Starter
|
New User
Joined: Jan 2016
Posts: 19
Likes: 0
The ipr being unplugged it shouldn't run because all your oil should go to the crankcase instead of the hpop rails. I would look at the ipr first because your hpop is working fine. Where did you get the ipr? Also you may want to put a gauge on your low pressure oil. The gauge on the dash is a glorified dummy light. But if your truck is still running it sounds like you still have pressure.
Senior User
Joined: Jan 2009
Posts: 353
Likes: 0
From: elk plain, wa
Cause with it unplugged the needle inside the ipr is not blocking the exhaust port to the crankcase. The ipr is wide open and exhausting all hpo to the crankcase. When you crank the engine the pcm will command full ipr around 95% if I remember correctly, so when it does that the ipr solinoid will push the needle and close off the exhaust port and will max out the hpop around 2500psi with no chip till the engine fires. Once it is running the pcm will then command anywhere from about 7% to 12% depending on pump and injectors. If it is starting with the ipr unplugged it sounds like the ipr is stuck. This can happen when the pump is replaced cause dirt can be enter the pump or in front of the reservoir. This occasionally happens no matter how carful and clean you think you are doing it. I would start by pulling the ipr and pulling it apart and cleaning it.
If you pull it apart pay very close attention to what way the needle is. If you get it in backwards it will still run but ipr% fluctuates and the idle is very rough.
I would check the ipr before trying to chase down any other concerns.
It sounds like the guy that told you the pump is bad may not know the ins and outs of this engine. Rarely do you get a pump that is bad from the get go.
If you pull it apart pay very close attention to what way the needle is. If you get it in backwards it will still run but ipr% fluctuates and the idle is very rough.
I would check the ipr before trying to chase down any other concerns.
It sounds like the guy that told you the pump is bad may not know the ins and outs of this engine. Rarely do you get a pump that is bad from the get go.
Thread Starter
|
New User
Joined: Jan 2016
Posts: 19
Likes: 0
The pump was never off when the new ipr was put in and it acts exactly the same as when the old ipr was in so who knows if it was ever bad. The ipr was ford replacement but the icp sensor was a cheaper version like $50 cause ford replacement was as much as the ipr. Is there a way to do voltage checks on the wires going to the icp and ipr to see if there is a short or what would be the next course of action? I agree that I don't think replacing the hpop would change anything. The guy just thought maybe something internal wasn't allowing the ipr to restrict the pressure
Hotshot
Joined: Oct 2003
Posts: 17,799
Likes: 104
From: Ashland City, TN
The IPR harness is part of the fuel bowl harness, you can remove the fuel bowl and the whole wiring harness.
You have to then check the connector for the IPR to see if the leads are starting to pull away and expose metal.
I just pushed heat shrink down mine then filled it with RTV.
Oil eventually eats up the rubber plug.
Let me see if i can find the picture.
You have to then check the connector for the IPR to see if the leads are starting to pull away and expose metal.
I just pushed heat shrink down mine then filled it with RTV.
Oil eventually eats up the rubber plug.
Let me see if i can find the picture.
Trending Topics
Hotshot
Joined: Oct 2003
Posts: 17,799
Likes: 104
From: Ashland City, TN
cannot find it easily.
But you can unplug it and look at the leads.
If you need to replace the connector, just cut the injector connector off a bad UVCH.
But you can unplug it and look at the leads.
If you need to replace the connector, just cut the injector connector off a bad UVCH.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Thread Starter
|
New User
Joined: Jan 2016
Posts: 19
Likes: 0
So u agree that it shouldn't run unplugged? So If There IsNT anythung wrong with the ipr then would u believe it could be something internal on the hpop not letting the ipr restrict?
Hotshot
Joined: Oct 2003
Posts: 17,799
Likes: 104
From: Ashland City, TN
I think you are unplugging the ICP.
the IPR is down in the valley and hard to get to.
Are you unplugging that, or the part that is next to the fuel bowl on the drivers side?
Thread Starter
|
New User
Joined: Jan 2016
Posts: 19
Likes: 0
Yes I am positive we unplugged the ipr because it is brand new. We had to take the fuel canister off to replace it. The icp is next to the drivers side valve cover and I believe it has 4 wires the ipr only has 2 and the truck started right up with the ipr unplugged.
Hotshot
Joined: Oct 2003
Posts: 17,799
Likes: 104
From: Ashland City, TN
Yes I am positive we unplugged the ipr because it is brand new. We had to take the fuel canister off to replace it. The icp is next to the drivers side valve cover and I believe it has 4 wires the ipr only has 2 and the truck started right up with the ipr unplugged.
Means its stuck inside just enough to allow pressure to the heads for it to start.
