| Symptom |
Possible Causes |
| Dying at idle with engine cold. |
Not unusual - idle setting must be adjusted when engine is
warm. Without engine heat to evaporate idle fuel, the throttle must be opened slightly
until the oil warms up. |
| Dying at idle when engine is warm on a warm or hot day but
idle behavior stable on cool days or when engine is cold. |
Vapor formation caused by fuel lines absorbing engine heat
when fuel rate is very low. This problem is common with fuel injection systems and
may be prevented by:
- Careful insulation of all fuel system components
- Blast cooling pumps, gascolator, filter, and flow transmitter.
- Install vapor return line to tank per EFS instructions.
Leak in fuel system on suction side of fuel pump allowing air to be drawn into fuel
systems. |
| Idle setting seems to change. |
Throttle slipping or unsupported. Ice: apply carb
heat.
Induction air leak between TBI and cylinders.
Leaking throttle slide seal. |
| Acceleration unsatisfactory |
Idle mixture too lean. Induction air leak between TBI and
cylinders.
Mixture not in full rich position.
Metering tube holes clogged. |
| Flat spot in throttle response when slowly opening throttle. |
Plugged holes in metering tube. Induction air leak between
TBI and cylinders. |
| Excessively rich at idle conditions of visible moisture or
high humidity. |
ICE - apply induction heat. |
| Excessive idle RPM when idle throttle adjust screw is backed
out fully. |
Induction air leak between TBI and cylinders. |
| Excessive leanness at high power. |
- Full rich metering tube adjustment set too lean.
- Inlet air turbulence caused by bad airbox configuration. Review section 2-9 of this manual.
- Fuel system flow capacity limit (see section 2-2, item H).
- Induction gasket or airbox flange blocking bellmouth reference probe.
- Leak in fuel system on suction side of fuel pump such as leaking primer or pump lines
which allows air to be drawn into fuel system.
- Clogged fuel filter.
- Clogged metering tube holes.
- Vapor formation.
- Defective fuel pump.
|
Leaking fuel after engine shutdown:
- Less than 1 tablespoon
- More than 1 tablespoon (leak continues)
|
- Normal.
- This sometimes occurs on new TBI units but should disappear after fuel inlet control
valves have seated (usually within the first 10 hours of operation).
|
| Engine roughness at wide open throttle. |
Same cause as excessive leanness at high power. |
| Engine dies when throttle is slowly opened from idle. |
Induction air leak between TBI and cylinders. |
| Engine roughness at wide open throttle (WOT) that tends to
smooth out when mixture is leaned. |
Inlet turbulence (see section 2-9)
or rich stop set too rich. |
| Rich idle that persists after idle mixture screw is fully
seated. |
Indicates worn slide seals caused by ingestion of unfiltered
air. Return TBI to Ellison Fluid Systems, Inc. for repair. |
