496HO Down on power
07-12-2022, 07:04 AM
#11
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I've got a new belt and tensioner arriving today. I'm hoping not to have to change the tensioner, because it's gonna be a PITA to change. I've got NO room to work with. The belt should be pretty easy. I've also acquired a compression gage. What's the best way to prevent the injectors or plugs from firing while cranking the engine? I've gotten a couple of suggestions from people. Just wondering what the experts say.....
Thanks. Brad.
(937)545-8991
07-12-2022, 07:05 AM
#12
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Guys,
Another question....
Looking through the ProCharger manual, it states that idle fuel pressure should be ~38lbs, and 62-65psi at full boost. I am reading ~40psi at idle, but only reading ~50psi at "boost" RPM. It seems appropriate to adjust the regulator to get proper WOT pressure, but the engine would appear to already be running rich, and increasing fuel pressure would obviously (I think) make it run even richer. Yes/No?
Thanks. Brad.
(937)545-8991
Another question....
Looking through the ProCharger manual, it states that idle fuel pressure should be ~38lbs, and 62-65psi at full boost. I am reading ~40psi at idle, but only reading ~50psi at "boost" RPM. It seems appropriate to adjust the regulator to get proper WOT pressure, but the engine would appear to already be running rich, and increasing fuel pressure would obviously (I think) make it run even richer. Yes/No?
Thanks. Brad.
(937)545-8991
Cog belts can’t slip by design. Serpentine belts can snd will when worn some especially turning something that requires a handful of load to turn like a supercharger.
Last edited by SB; 07-12-2022 at 07:08 AM.
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Griff (07-12-2022)
07-12-2022, 07:11 AM
#13
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AHHH... I think I understand how that would work. So, you're saying the fuel pressure will increase when the boost is back up....? I'm only down about 1.5lbs of boost (I stated incorrectly previously.... It's only a 3lb system). Will the fuel pressure increase 12-15 lbs from just 1.5 lbs of boost? I get that liquid pressure is different than air pressure. Just want to make sure I understand the concepts.
Thanks. Brad.
(937)545-8991
07-12-2022, 07:18 AM
#14
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ATI will have to let you know.
They use raising rate FMU’s. Some 6:1, some 7:1, some 10:1, and etc. Unlike standard regulators that are 1:1. Ie: 1 pound fuel psi is added from 1 pound fuel psi.
They use raising rate FMU’s. Some 6:1, some 7:1, some 10:1, and etc. Unlike standard regulators that are 1:1. Ie: 1 pound fuel psi is added from 1 pound fuel psi.
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articfriends (07-13-2022)
07-12-2022, 07:21 AM
#15
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Here’s a more exact reply from me to a thresd in 2015.
Oh, another BTW: The ATI regulator is an FMU. Meaning, it has a different rate of fuel pi increase than most referenced regulators. Sometimes , they are 3:1, sometimes 5:1, and in some applications something crzy like 10:1 and 15:1.
FMU's are so 1980's and 90's.
All EFI systems with returns need manifold referenced pressure no matter what. But normal style. It's all about correct net psi at injector tip. Ie: manifold vac/psi vs fuel psi to the injector.
FMU's are so 1980's and 90's.
All EFI systems with returns need manifold referenced pressure no matter what. But normal style. It's all about correct net psi at injector tip. Ie: manifold vac/psi vs fuel psi to the injector.
07-12-2022, 07:27 AM
#16
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Use a remote starter button on the slave solenoid to crank it over.
there’s no point at guessing what may or may not be wrong until you pull the plugs. Once you see the plugs it should be a lot easier to head in the right direction.
had a customer ask 100 questions and guess at everything else except what I told him to do first, check the plugs. 2 days later into his vacation he found he knocked 2 plug wires off while cleaning the bilge.
there’s no point at guessing what may or may not be wrong until you pull the plugs. Once you see the plugs it should be a lot easier to head in the right direction.
had a customer ask 100 questions and guess at everything else except what I told him to do first, check the plugs. 2 days later into his vacation he found he knocked 2 plug wires off while cleaning the bilge.
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SB (07-12-2022)
07-12-2022, 07:28 AM
#17
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SB,
FMU... Fuel Metering Unit?
So, it's really starting to look like this is all stemming from the apparent loss of boost. I have closely inspected the intake tract between the blower and the throttle body, and can find nothing that would indicate a possible leak. The hoses are intact. The hose clamps are tight. I'm REALLY hoping its just a worn/stretched belt and/or a weak tensioner.
Thanks. Brad.
(937)545-8991
FMU... Fuel Metering Unit?
So, it's really starting to look like this is all stemming from the apparent loss of boost. I have closely inspected the intake tract between the blower and the throttle body, and can find nothing that would indicate a possible leak. The hoses are intact. The hose clamps are tight. I'm REALLY hoping its just a worn/stretched belt and/or a weak tensioner.
Thanks. Brad.
(937)545-8991
07-12-2022, 08:04 AM
#18
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Thread Starter
Use a remote starter button on the slave solenoid to crank it over.
there’s no point at guessing what may or may not be wrong until you pull the plugs. Once you see the plugs it should be a lot easier to head in the right direction.
had a customer ask 100 questions and guess at everything else except what I told him to do first, check the plugs. 2 days later into his vacation he found he knocked 2 plug wires off while cleaning the bilge.
there’s no point at guessing what may or may not be wrong until you pull the plugs. Once you see the plugs it should be a lot easier to head in the right direction.
had a customer ask 100 questions and guess at everything else except what I told him to do first, check the plugs. 2 days later into his vacation he found he knocked 2 plug wires off while cleaning the bilge.
I can certainly check the plugs, and fully intend to do so. But.....
The only problem I see with this is that, according to the ProCharger manual and the interwebs, I should have run the boat hard and shut the engine off immediately, letting it coast to a stop (seems kinda scary to me), and pulled the plugs, which I didn't do. We idled into the ramp, dropped the wife off to retrieve the truck and trailer, and put it on the trailer, all while idling. Is this gonna muddy any useful data that can be had from the plugs?
Thanks. Brad.
(937)545-8991
Last edited by Brad Christy; 07-12-2022 at 08:12 AM.
07-12-2022, 12:07 PM
#19
Yes and no, a very successful "plug chop" would be done as instructed. Cruising along in the meat of the power curve the spark plugs are going to show a burn pattern for that range. By slowly cruising to the dock , loading the boat and such the last picture the plugs will show will be the burn pattern of how the engine is idling. Think of a plug chop as a picture of the last time the engine was running, do you want a picture of the engine running at cruising speed or at idle?
07-12-2022, 12:31 PM
#20
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Yes and no, a very successful "plug chop" would be done as instructed. Cruising along in the meat of the power curve the spark plugs are going to show a burn pattern for that range. By slowly cruising to the dock , loading the boat and such the last picture the plugs will show will be the burn pattern of how the engine is idling. Think of a plug chop as a picture of the last time the engine was running, do you want a picture of the engine running at cruising speed or at idle?
Oh, I get it. It's just the prospects of turning the key at nearly full throttle, assumingly in gear and under load, scares the crap outta me. And it's definitely not the condition I have at the moment.
Thanks. Brad.
(937)545-8991
