You wanna see 13-15 psi. Maybe try another pressure gauge just to verify
CK5
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**FIXED!!**DEFINITELY***Super HIGH idle after multiple parts replacement - TBI 1990 K1500 350engine
- Thread starter ZombieK5
- Start date
Replaced regulator... Actually replaced it TWICE
Unfortunatly, that doesn’t mean it’s good.
Well, I have to believe in something. I'm gonna try and find an aftermarket fuel system. That will fit on the OEM TBI intake
did this have low compression or did you fix that?
I didn't do anything to fix the compression.
However before I rebuilt the tbi, replaced the fuel lines, fuel tank, fuel pump, there were zero issues with the engine running fine. While I agree the compression is a definite issue, the fact that the engine was running fine, not spectacular but it ran without any issues, I think the problem is something that I did to it. I have replaced every single piece of equipment on top of that engine and some of the things I've replaced twice. Somewhere earlier in this thread I go down the list of what I actually replaced. But there isn't a part on it that I haven't replaced other than the actual aluminum body of the TBI unit.
I fought a lot of rabbits out of hats in my day when fixing vehicles of different make model and design but this one has me absolutely stumped.
I know its frustrating. It’s hard to believe but “new” parts are about a 50/50 chance of being bad right out of the box. And I’m not even exaggerating.
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I've replaced it twice. GM GENUINE and aftermarket. Both seem to work.
Did you ever have the intake manifold off?
Is it possible their is an intake gasket leak from a backfire or something when it wasn't running correctly early on?
Is it possible their is an intake gasket leak from a backfire or something when it wasn't running correctly early on?
Yes, I actually replace the OEM intake manifold with a Edelbrock version of the OEM intake manifold that includes an EGR port.
And the heads have been decked?, so now the intake angles don't match. Which always makes sealing a bit harder
It has not been decked. The issue I'm having is still going on even after I replaced the intake manifold. It was occurring before the intake manifold replacement. I do not have any leaks where the new intake manifold attaches to the heads.
The new pump is putting out 10 to 11 PSI which is about the same PSI as the pump I had in it. If I turn the key to accessory it doesn't pressure the system until I start the engine.
New as of today, I can start the engine but it will not remain running. It struggles and dies.
I'm thinking now it has to do something with the TBI. I did something when I rebuilt it that it doesn't like. This isn't the first one I've rebuilt.
Maybe I pinched to see you when I was putting it back together or one of the gaskets didn't seal correctly. I'm spraying carburetor cleaner around the TBI and I'm not getting any changes in RPMs which tells me that it doesn't have any leaks. I'm about ready to throw the whole TBI unit through a window. FolkenHeath has me lined up with a new Sniper or Edelbrock fuel system with an adapter for the TBI intake manifold.
I keep going back to the fact that the engine ran pretty much correctly before I replace a bunch of things while working on the engine accessories (water pump, PS pump, etc...)
I may just put a new engine in it too. I'm kind of fed up at this point. If I'm going to do a parts cannon I might as well go all the way
What would I do for a fuel pump if I got one of those fuel systems? What would I need for a fuel pump if I decided on a new engine, with my existing intake manifold, and one of those fuel systems.
you could replace the in tank fuel on the tbi sender hanger with a higher pressure pump.
I just put in a new pump that Heath sent me. It's supposedly supposed to work at a higher PSI but I'm only seeing 10 psi on the fuel rail immediately before the fuel filter. It was a pain in the ass getting it out of the tank but I'll do it again. I'm afraid of putting too high of a PSI pump on there since I'm not sure if the system can handle it. Did you have one in mind?
This is what it sounds like now. That's what 11 PSI showing on the fuel pressure gauge.
View attachment 20260607_163722.mp4
11 is to low, still I would expect it to idle better than that. Did it stall, or get shut off ?
I ment if you changed efi systems many of them run at much higher psi.
The fuel pressure regulator controls the pressure. Not the pump. You could have a pump capable of 30 psi, if the regulator is is not functioning correctly the pessure will be wrong.
Pressure is resistance to flow, thats it. Volume, gallons/liters per hour, forced into a pipe make pressure
Stall
