1990 454SS Fuel Pressure regulator

[TheRealAlBoudreau]

Hello Everyone.
I have just acquired a 1990 454SS. I'm looking for a replacement fuel pressure regulator for the TBI as I believe mine is faulty. Can anyone veryify these photos and confirm I am dealing with an actual TBI from a 1990 and not something else. I have reason to believe that a swap may have been made but I cannot prove it.

Under the hood, it looks like the wires leading to the injector connector plugs were splice not once, but it seems twice. A spacer was added at some point. When I GoogleFu the part, it only gives me rebuild kit options. I'm looking for the housing that encloses the spring.

Just digging into this truck and hoping to have it back running in short order but I'm missing a bunch of info.

I ppreciate the help.

 

[someotherguy]

RE: the splices - it's somewhat common for the injector pigtails to have been replaced by now; they usually get brittle in the "inside the TBI" area where they're in contact with fuel mist during operation.

It looks like you've got the plastic air cleaner spacer ring, which may have been swapped in at some point because the steel one is known for those same injector wires chafing against it and shorting out. Early trucks typically had steel, later ones got plastic.

That's the correct TPS style (large flat row 3-pin connector) for 1988-1990 TBI's. In 1991 they switched to a smaller round 3-pin connector. So, your TBI is at least correct for the year.

For the part you're looking for - is yours damaged? Missing somehow? I'd get the idea you'll only find one by robbing it from another TBI unit. I've never had to source that part so I don't know if it's different from the small block vs. big block TBI, or different in generations of TBI - 1988-1990, or 1991-1995. Maybe someone else here knows?

Richard

 

[TheRealAlBoudreau]

RE: the splices - it's somewhat common for the injector pigtails to have been replaced by now; they usually get brittle in the "inside the TBI" area where they're in contact with fuel mist during operation.

It looks like you've got the plastic air cleaner spacer ring, which may have been swapped in at some point because the steel one is known for those same injector wires chafing against it and shorting out. Early trucks typically had steel, later ones got plastic.

That's the correct TPS style (large flat row 3-pin connector) for 1988-1990 TBI's. In 1991 they switched to a smaller round 3-pin connector. So, your TBI is at least correct for the year.

For the part you're looking for - is yours damaged? Missing somehow? I'd get the idea you'll only find one by robbing it from another TBI unit. I've never had to source that part so I don't know if it's different from the small block vs. big block TBI, or different in generations of TBI - 1988-1990, or 1991-1995. Maybe someone else here knows?

Richard

Thanks so much Richard.
I'm wondering if it would be the same part as the 93. I can find the ACDelco 217-2900 which looks identical to the one I have. However this part is listed for trucks 93 and newer. Does anyone know what the difference is with the TBI between those years?

 

[someotherguy]

The whole TBI unit is definitely different overall, like I said there's two main generations of them - 1988-1990, and 1991-1995; there's also various small differences along the years. However, if you're just looking for the "can" underneath the regulator, I'd look at any junk TBI unit you might be able to get your hands on because it's probably the same part.

What part of yours is missing/damaged/etc? Is it the regulator body or just that round cover? If it's just the cover I'd look for a junk one to try before spending almost $100 on an assembly you just need one part from. If you were gonna spend that, you could get a ready-made adjustable one for a few bucks less, from CFM Tech, for example. https://marine-performance-parts.com/cfmtechadjustabefuelpsiregulatorforgmtbi2843505774.aspx

There's also lots of regulator assemblies on ebay cheaper than that amazon choice.

Richard

 

[TheRealAlBoudreau]

The whole TBI unit is definitely different overall, like I said there's two main generations of them - 1988-1990, and 1991-1995; there's also various small differences along the years. However, if you're just looking for the "can" underneath the regulator, I'd look at any junk TBI unit you might be able to get your hands on because it's probably the same part.

What part of yours is missing/damaged/etc? Is it the regulator body or just that round cover? If it's just the cover I'd look for a junk one to try before spending almost $100 on an assembly you just need one part from. If you were gonna spend that, you could get a ready-made adjustable one for a few bucks less, from CFM Tech, for example. https://marine-performance-parts.com/cfmtechadjustabefuelpsiregulatorforgmtbi2843505774.aspx

There's also lots of regulator assemblies on ebay cheaper than that amazon choice.

Richard

Hello Richard. Do you know if these ports on the intake are meant to have something connected to them?

 

[someotherguy]

Hello Richard. Do you know if these ports on the intake are meant to have something connected to them?

My 7.4 is a '93 model and I believe they did away with that setup by then, but I'm pretty sure your '90 model has a carb bolt pattern on the intake and the adapter between it and the TBI originally had coolant hoses plumbed into it at those points, intended to prevent icing of the TBI.

Richard

 

[TheRealAlBoudreau]

Thank you sir. That corroborates a friends opinion. I'm not going to worry about it for now. I don't live in an area that it matters.
I'm methodically going through all the portions. Tested the TPM, it's good. Going to replace the Idle Air Controller because I suspect it's not operating properly. I'll have to have my scanner connected to it to see if it's responding. Will be changing the fuel filter as well because the truck has been sitting for a while now.
The part I ordered fit onto the injector pods like a glove so i'm good there now. Eventually something good has to happen right?

LOL