We upgrade the fuel supply of our 1991 Lada Signet wagon project car!

 

Everything had been going well with IVAN2104, we had taken care of some issues, successfully competed in ice racing (VIDEO), and even did a little hot-rodding.

But ever since we installed our Stinger exhaust header we had a persistent problem, on a long acceleration pull, we would suffer an abrupt loss of power, and the car would stop accelerating. We first noticed this ice racing, and later it became present during street operation, finally it would occasionally happen while overtaking another vehicle.

Shawn and I did all the basic check, new fuel filter, sparkplugs, removed the fuel-shutoff solenoid, and even overhauled the mechanical fuel pump, but nothing improved the condition. Finally we were down to two working theories; either the ignition coil was unable to recharge quickly enough to provide proper spark at high load, or the fuel pump was unable to properly supply the carburetor.

 

It was a solid idea that with the improved power of the Lada engine that we were draining the fuel bowl in the VAZ ozone carburetor, resulting in a fuel starvation issue, killing power. This was also backed up by the in car Wideband Air-to-Fuel ratio meter which displayed a lean condition during the issue. We elected to replace the stubbornly leaky mechanical fuel pump with a locally sourced electric model as our next step.

 

We used a Facet brand POSI-FLO 60104 fuel pump because it is a common part in our area, and if we ran into trouble, would be able to source another quite quickly. Any pump that meets the low-psi requirements and is self-regulating would work, check your local vendors to see what is available.

POSI-FLO 60104, 1.5-4 psi, 23 GPH (87 LPH)

 

Here are the pump stats from the manufacturer:

 

• Fuel Compatibility:All models of the Facet^® POSI-FLO^® Pumps are compatible with gasoline, diesel, biodiesel, blended alcohol fuels and fuel additives.
• Reliability:Proven on thousands of original equipment applications. No bearings, electrical contacts, or diaphragms to wear out or fatigue. Lasts four to five times longer than many other electric pumps.
• Easy to Install-Easy to Service:Two bolt installation plus the small size makes installation easy. For best results, mount the pump close to the fluid or fuel tank and below the liquid level.
• Eliminates Vapor Lock:When properly installed on most vehicles a constant, smooth, dependable supply of fuel under pressure is assured in the hottest weather or in high altitudes.

Available Features

• 12 inches minimum dry lift
• 23 – 40 GPH
• 1.5 – 10 PSI
• ESD compliant
• 1.5 amp average

 

The install was simple, but a little time consuming mainly because we wanted to ensure this was no cobble-job. The factory fuel supply lines were reused as much as possible, and a perfect match pump block-off plate was sourced from our spare Fiat 1.8L Twin-Cam engine. The wiring was routed inside the cabin with the chassis harness, to an engine bay relay. This relay was triggered by the coil power wire using the old fuel-jet cutoff solenoid circuit, which had power when the key was on.

Everything fit quite well and on the road test we were rewarded with restored power, and clean acceleration throughout the RPM range. With everything good to go we can now look at heading back to the dyno for additional testing.