What kind of idle does a Chevy 454 have?

Remember me. I forgot my password! Can’t get my 454’s idle below 800 rpm, during warm-up it will run at 1100-1200rpm then drop down to 800. 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?

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 do I need to relearn the idle position?

When you remove and cleaned an IAC, or unplugged the IAC with the key on, the ECM may need to relearn the IAC position. This will not happen without driving the truck and meeting specific conditions or taking other steps the cause it to relearn the idle.

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’s the fuel pressure on a 1994 Chevy 350?

The ’94 350 has a much lower fuel pressure spec (9~13) than the ’94 big block (26~32), the fuel pumps are different parts. Did you install the complete engine including the TBI unit?

Why are my GM 454 backfires breaking down?

If you see any white stains around the ground bracket, the coil is breaking down due to being over worked ( too long at max voltage). Another thing to check is fuel pressure. The system is already a low pressure system to start with. Unfortunately you have to tee into the pressure feed line to get this info.

What’s the problem with my GM 454 engine?

I have a 1984 Itasca SunFlyer with the GM 454 engine that has heavy duty spark plug boots and wires. My problem with the hot engine has been vapor lock and hot starter problems. The vapor lock problem has taken a winter holiday.

When did the GM 454 TBI 220 come out?

I’m having problems with my engine which is a gen 5 454 tbi 220 model made in 1992. It has the OBD1 system which was the predecessor to the OBD2 system that all cars 1998 I think and newer have now. With the OBD1 system you don’t need a code reader to get your codes.

Why does my 454 spark plug keep failing?

The previous owner told us that there was a small problem, it would “pop back through the carb” under load. I tried lots of things and finally found the culprit. Manifold heat was so hot it would cause failure of the number 7 spark plug boot.

Is the GM 454 a throttle body injection?

I’mpretty sure Tim’s is a throttle body injection like mine. These look like a carb but are far from it. For that period it was GM’s answer to a carb and I think they worked better than a carb, but they came with their own problems. I’m having problems with my engine which is a gen 5 454 tbi 220 model made in 1992.