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- #61
Builds My first 40 build - 5.3/TH350/LC-case stretched and linked (2 Viewers)
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Says the video is unavailable when I click on it....
Sounds like a leaking injector, if you cycle the fuel pump up to pressure but dont start it, let sit for awhile and check fuel pressure gauge, it shouldn't drop much.
I assume you have a fuel pressure gauge ? #1 best diagnostic tool for an LS IMO. I have a mech fuel pressure gauge in the cab. Yup, could leak and soak everything with gas, hasnt in 21 years. Knock on wood. The other suspect would be the computer you are using, not familiar with aces, I run a howell stand alone harness & comp which worked outa the box.
I assume you have a fuel pressure gauge ? #1 best diagnostic tool for an LS IMO. I have a mech fuel pressure gauge in the cab. Yup, could leak and soak everything with gas, hasnt in 21 years. Knock on wood. The other suspect would be the computer you are using, not familiar with aces, I run a howell stand alone harness & comp which worked outa the box.
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- #64
Would an injector leaking cause a high idle though? There is no fuel smell up front. It’s like I have a gremlin in there. Now rpms have dropped down to around 850. The sound is coming from the area the camera is pointing at. Although I suppose it could be coming from one of the front injectors.
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- #65
I think it’s working now.
Mike Shull
Let’s go…
I wouldn’t think that a leaking fuel injector would cause a high idle, but I’ve been wrong before. My LS idles at 500 RPMs with the factory computer, but that’s where I had them set the RPMs. Has your engine ever idled lower than 850 RPMs? Can you adjust the idle with your controller?
Have you sprayed starting fluid or similar type of fluid around where you suspect to have a vacuum leak while the engine is running?
Have you sprayed starting fluid or similar type of fluid around where you suspect to have a vacuum leak while the engine is running?
Ditcherman
SILVER Star
Maybe a job for a mechanics stethescope?
That’s an odd sound. Mine makes a similar (but VERY brief) noise when I first turn the key on. No chance it’s the TPS or IAT sensor up on the throttle body?
unplug tps and see what happens?
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- #71
I don’t have a fuel pressure gauge. I’m sure I could borrow one from a buddy though.
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- #72
Not sure, it’s not consistent either. I can’t get it to repeat every time.
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- #73
Yes felt around multiple times. Also used a hose up to my ear and went around the entire intake right there. All relays are in the cab. Pressure regulator is on the driver side in the middle of the fuel rail.
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- #74
I’ve set my idle to run at 650 since I’m running a TH350. I’ve had it down to 740 but that’s it. I have almost full programming functions with the Aces kit. Everything seems to be reading right including fuel pressure ratios and all.
Haven’t tried starting fluid or anything like that.
Are you running the OEM fuel regulator or an external one? Not sure what fuel pump you’re running
It took me calling Aeromotive to determine that if you’ve got an external regulator you HAVE to block off and remove the OEM unit on the fuel rail. Not sure that’s the issue here but I had mine plumbed wrong for years.
ICT Billet makes a pretty slick block-off, I’ve got one on the LS in the FJ40 and just installed one on the 8.1 in the M715
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- #77
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- #78
I was talking with my nephew and he said the intake seals/gaskets are notorious for leaking. So I’m going to replace those and see what happens. If there is some sort of vacuum leak that is not very consistent it seems that might be the culprit.
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- #79
So… after changing the seals it still did it.
Then my alternator died.
Did some more research and my son asked about the IAC valve.
New alternator which required a new belt and a new IAC and boom problem solved.
Idles perfect now!
Only cost $400 to fix my problem. Not the kind of week I was planning on. But hey new IAC, new seals, new alternator, another new belt. Should last a while now.
Then my alternator died.
Did some more research and my son asked about the IAC valve.
New alternator which required a new belt and a new IAC and boom problem solved.
Idles perfect now!
Only cost $400 to fix my problem. Not the kind of week I was planning on. But hey new IAC, new seals, new alternator, another new belt. Should last a while now.
Glad you figured it out. I suspected it was one of the sensors in the throttle body 
