First off I’m not here trash anybody’s product and because of that I would not be posting if I wasn’t out of options, I have been without my truck for two months, I just need my truck! Now on with my problem, I installed a higher volume hpop(actually on the third one, manf has been working with me) to resolve a low pressure condition when towing, truck ran fine otherwise. After the install the motor idles smooth when cold but develops a rough idle when warm similar to a miss, idle speed varies about 80 rpm, and violent enough to shake the truck. Also it is much noisier hot or cold, the whole engine noise tone has changed including the exhaust. The engine used to be nosiest/loudest when idling and would quite up when throttle was applied, now it just gets louder. The truck is a ‘97 California with the stock split shot injectors, 107,000 miles, removed chip to eliminate it as a possible cause. I do have access to a Snap On scanner and have been able to monitor ICP pressures/duty cycles but have found mixed results on what the correct idle pressures should be for a Calif truck, will be receiving a mechanical high pressure gauge later this week to verify pressures. I know most of you have considerably more knowledge of this injection system then me and really hope you guys can give me a direction, thanks for your help.
SRP1 hot idle and engine noise.
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Tom S
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Did this all come about with the installation of the SRP1? I take the first two had some kind of issue so you have been swapping pumps out. I believe there was a pretty good thread recently in the SD section about the idle issue with that pump. I do not recall any other issue. I think your a good chunk of your issue is that the tunes not being a smooth fit with the pump. What have you been seeing for pressures?
woodduck97
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I will say I was having the same type of problem after the install of my SRP1. Traced and traced the problem for a couple months. Could not find anything. Did not think of it being the orings on the injectors being they were installed 3k miles ago and shown no loss in ICP before and after the HPOP. The stock 15* pump did not put out enough presure to cause any problems with the injector orings untill the new pump was installed and the new pump was able to make up for the oil blow by on the orings. I had weird idle, missing sounds coming out of the exhaust and all like you are explaining. Also when I replaced them they all looked to be normal no tears or shown weak spot. IMO I would try to replace the orings and go from there. Also before removing the injector see if all 8 injectors are torqed to spec.
The first pump had a delayed start and a weird romp off throttle along with all the current problems, the second pump fixed the start and romp problems but had the same current issues.All of these issues started with the pump install. With the SRP1, the cold idle pressure is 520-530 psi at 13%, hot 420 -430 psi at 12% and the highest I have seen is 2,550 at 37%, the stock 15* idled at 470-480 psi hot and would top out about 2,700 but would drop to around 1,650 under load. Did try unplugging the ICP and it ran a little worse. I also read on All Data today that the injector requires a minimum of 500 psi to operate, is that true?
Woodduck, along with injectors, orings have crossed my mind. What led you to check/replace the orings? Did your duty cycle change before and after the oring change?
Woodduck, along with injectors, orings have crossed my mind. What led you to check/replace the orings? Did your duty cycle change before and after the oring change?
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woodduck97
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Did not re check the DC being the orings fixed it.
Tom S
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It takes about 500psi of oil pressure in order to start the truck. I am going to retitle and move your thread to try and get you some better answers for you. Have you talked to Tony about this at all to see if he has any ideas on a tuning perspective.
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Tom, it shouldn't be a tuning issue, as he said he pulled the chip and its still doing it.
Blowby
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Let's start with the idle component and I'll keep it basic for everyone's ability to understand my logic. Think of the computer as managing the fuel for a given RPM or base values needed to idle. When the ICP or PW falls or rises, based on the tables, the computer will adjust the corresponding map value by moving up or down the table to smooth it out. When an HPOP responds at a given intensity (OEM from the factory) according to OEM programming the transition is smooth because they had the sluggish OEM HPOP to work with.
Now if you replace the sluggish HPOP with a quick responding delivery vehicle you will have the computer manipulating the tables at a faster rate trying to achieve the desired target. You have to be closer to spot on to eliminate this since we don't know exactly how fast the computer can make changes or the mechanical components can respond to these changes.
Now think about the scenario above as you drive. Look at the transition up the map with ICP pressures rising and the time it took to hit target with the sluggish HPOP and now the HPOP with the delivery time reduced. If you've ever driven in a truck with advanced timing you will understand the loud engine noise you are hearing. ICP pressure rise effects more than fuel volume.
Now a disclaimer: I do not work on the programs for the OBS so the information above could be useless. Ask Tony if it is valid since he works on your tunes. I know it's hard to make adjustments long distance to control the fine tuning needed with certain HPOP's.
Now if you replace the sluggish HPOP with a quick responding delivery vehicle you will have the computer manipulating the tables at a faster rate trying to achieve the desired target. You have to be closer to spot on to eliminate this since we don't know exactly how fast the computer can make changes or the mechanical components can respond to these changes.
Now think about the scenario above as you drive. Look at the transition up the map with ICP pressures rising and the time it took to hit target with the sluggish HPOP and now the HPOP with the delivery time reduced. If you've ever driven in a truck with advanced timing you will understand the loud engine noise you are hearing. ICP pressure rise effects more than fuel volume.
Now a disclaimer: I do not work on the programs for the OBS so the information above could be useless. Ask Tony if it is valid since he works on your tunes. I know it's hard to make adjustments long distance to control the fine tuning needed with certain HPOP's.
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Tom S
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I was kinda more thinking along the lines of some tweaked tuning might be able to get some of that idle problem out of there. This one is really interesting. The injector noise does not sound to be tuning related. I need to find that other thread to link these.
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Tom S
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Derek@Vision Diesel
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You mentioned a delayed start with the first pump, did Gary ever mention what the delayed start was caused by?
I am tracking a similar problem
I am tracking a similar problem
Thanks Tom, I have contacted AzPsd55 and after changing injectors, he still has problems. Tony hasn't returned my calls for three weeks, probably taking care of family matters. If there are tuners reading this, please chime in, is this possibly a tuning issue. I hate throwing parts at a problem, expensive and a waste of time. If it does not rain tomorrow I will verify ICP pressures with a mechanical high pressure gauge. How much should ICP pressures fluctuate at idle?
Installed mech gauge to oil rail and found mech gauge reading 100 psi higher than ICP readings on scanner. Though it doesn’t seem like much, I will replace it to eliminate it. Does anyone have the ICP part#? Have there been a string of updated sensors like the CPS.
Tom S
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F6TZ-9F838-A I think that is right.
Patrick Feeley
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I don't know if this will help out at all, but here's a link to an old thread I remembered from way back:
"Stage I Injector O-Rings"
Maybe the newer pumps can exacerbate the problem? Don't know, but it's worth a look as many folks don't replace the steel backer rings when replacing the injector o-rings. Cheers!
"Stage I Injector O-Rings"
Maybe the newer pumps can exacerbate the problem? Don't know, but it's worth a look as many folks don't replace the steel backer rings when replacing the injector o-rings. Cheers!
People are not replacing the steel backers thats just dumb and asking for issues.
Thats like me not putting the backer on some of the hydraulic parts I build daily, jeeze id get my butt in a heap of trouble,those backer rings are there for a reason.
Patrick Feeley
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Possibly you misread what I put. I'm saying they are just leaving the old ones in and not replacing them with the new ones that come in an o-ring kit (not leaving them out entirely). Cheers!
Well I have been driving this hunk of crap for 4 months now, knowing it won't fix itself, just not having the time or money to deal with it. This is by far the most expensive mistake I have made modding this truck, idles rough, smokes, lost a solid 2 mpg both empty and towing, sounds worse than a Dodge. To top it off, I cant drive it any farther than I can afford to have it towed for fear the pump will chew itself up. You really do not want to know what I think of this pump and its maker. Thanks for letting me vent guys, anger grows by the day but I already feel better. I do need to borrow some of your knowledge and try and make some progress with this. The truck ran the worst with the first pump, could it have contaminated the injectors? Any ideas would be very much appreciated. Warm idle is worsening, it’s time to $^*# or get off the pot.
