wheelie-schizes
Junior Member
- Joined
- Apr 22, 2025
- Posts
- 1
- Reaction score
- 0
- Location
- Germany Göppingen
- First Name
- Paul
- Truck Year
- 1991
- Truck Model
- V 3500
- Engine Size
- 454 7,4L
My 454 TBI starts and idles low, but after about 2 minutes (once it warms up), it starts backfiring through the air filter and won’t take throttle.
Here’s what I’ve done trying to fix it:
- Replaced spark plugs, wires, ignition coil
- New distributor (installed by someone else)
- New fuel injectors and fuel pressure regulator
- Also found the EGR valve was loose and leaking — I resealed and tightened it
Timing is set to around 4° BTDC, but it’s hard to adjust properly because it seems to shift on its own.
There’s no vacuum advance on the distributor, so I assume timing is electronically controlled.
**Do I need to disconnect the timing advance wire when setting base timing?**
Any input or ideas are appreciated!
Here’s what I’ve done trying to fix it:
- Replaced spark plugs, wires, ignition coil
- New distributor (installed by someone else)
- New fuel injectors and fuel pressure regulator
- Also found the EGR valve was loose and leaking — I resealed and tightened it
Timing is set to around 4° BTDC, but it’s hard to adjust properly because it seems to shift on its own.
There’s no vacuum advance on the distributor, so I assume timing is electronically controlled.
**Do I need to disconnect the timing advance wire when setting base timing?**
Any input or ideas are appreciated!
