What causes idle problems in a 1994 TBI 454?

At speed it runs fine, but when droping down in rpm it is very delayed in getting to 800rpm. The engine is the origional stock ’94, 454 in a 4WD Suburban. Any suggestions on where to start trouble shooting? Thanks, mike Never getting down to proper idle is likely a vacuum leak.

When did Chevy start using the 454 engine?

The LE8 454 was the most common from 1973 to 1991. The L19 TBI, or throttle body injection, powered 1987 and later trucks as the second 454 engine option. The TBI 454 had fuel injectors in the middle of the throttle body that increased fuel efficiency, power and durability. Chevy began installing 454 V-8s in its trucks in 1973.

What kind of pressure does a 1994 TBI have?

The 1994 and newer big block TBIs run at a higher pressure, 26-32psi, instead of the 9-13PSI of other TBI trucks. Did you give the model, year, engine, fuel system type, and transmission information?

How to manually invoke a Relearn on a TBI 454?

To manually invoke a relearn, you can try this with all accessories OFF. It is best if this is done with the vehicle at normal operating temperature. 1) Disconnect battery for at least ten seconds. (With the Key OFF) 2) Reconnect the battery. 3) Start engine letting it run for five seconds. 4) Turn key off for ten seconds.

What kind of fuel pump does a TBI 454 have?

Stock TBI 454 makes 230hp and 380tq so stock fuel pump is maxed out right off and a typical 454 will run better with a fuel pump upgrade even with stock chip. GAS MILEAGE. Always a big complaint with 454 TBI trucks. 90 and older is particularly bad and that is largely due to NO OVERDRIVE.

Which is better a Vortec 454 or a 454 TBI?

Both engines can benefit a LOT from higher flow cylinder heads and cams. The Vortec 454 can have conventional larger sized fuel injectors installed into it if needed unlike its smallblock brothers which need an intake manifold change to install larger injectors. lol….

The 1994 and newer big block TBIs run at a higher pressure, 26-32psi, instead of the 9-13PSI of other TBI trucks. Did you give the model, year, engine, fuel system type, and transmission information?

What causes idle problems in a 1994 TBI 454?