Glowing Exhaust Manifolds 1992 454 TBI 7.4L P30 Motorhome

[fastacton]

I like RockAuto for most things, but sometimes their parts don't actually work in the application they have them listed for. I don't know why they'd test them at 14.75 psi as I don't believe any TBI system operated at that pressure. In their listing, they show these as being used in everything from '87-95 (and all the way up to 2007 for Volvo). The injector flow ratings weren't the same through all of those years on the 454 (especially '94-95), so I don't think that the data they're giving you is reliable. If I were you, I would get them tested at 13psi and see how they flow there. You may need to find another source for injectors if they don't flow enough.

[jay72]

http://www.cfm-tech.com/ USED TO have a lot of good information. It seems, as of two or so weeks ago, the site has been down.
I know the '92 uses different injectors than '94-'95, and that a 94-95 fuel pump and adjustable regulator can provide more performance when used on a '92. Thats what I've been running. All info I followed was from that site.

[Nasty-Z]

94-95 uses a lower flow rate injector @ a higher pressure . Spec for the 94-95 GM 454 TBI system was 28-32 psi . The fuel pump was different as well as the spring in the factory regulator to produce the required pressure to the injectors. Spec on the 87-93 454 TBI system was 9-13 psi .

As I have said many times in this thread , the replacement injectors have no flow data , and were parts store specials , they may or may not be of the correct flow rate for the system , the pump , lines , filter , regulator may or may not be working properly. No one knows , and no one will ever know without DATA !!!!!

As I said in post #37 this morning , using glowing manifolds as a tuning tool is a poor way to diagnose.

Ignition timing , fuel pressure and volume , and cooling system are the key areas the OP needs to address. I would use a piston stop to find true TDC , verify the balancer mark is actually # 1 TDC , that would rule out timing , pull the D/S rocker cover and use a dial indicator to check cam timing , that will rule out an incorrectly installed timing chain , use a scan tool and go for a drive , watch the O2 and fuel trim parameters , this will rule out a lean condition , check the cooling system to see if its running too cool OR to warm , both will affect EGT's in a negative way. Etc , etc, etc ................

TOM