Thread: D2 not starting correctly

D2 on sequential gas. starts on PULP runs on gas.

While the D2 is now relatively reliable,,
it still has a starting problem,,
The symptoms are---
car may start normally(timewise),, then next time require 5-6 seconds cranking.
But each first internal combustion is wrongly timed. Every Time. Its like it fires over TDC.
There is a subtle miss off idle,, like the first cylinder to receive extra fuel misses.
The Pulp tank is a 45L jobbie in the rear drivers quarter panel. This pressurizes enough to deform the tank. I bought another cap (admittedly second hand) but made no difference.
Sometimes there is a fuel smell at the rear.
The gasses are supposed to be purged into the inlet manifold but that is a ECU thing. Yes there is a cannister to absorb gasses in-line to the manifold.
The pump has recently been replaced, made no difference.

I really, really dislike the D2 fuel system for dual fuel. While on gas the fuel pump does nothing other than run off at its relief pressure and heat the fuel. For one D2 I designed a simple circuit to disconnect the pump whenever the engine was running on gas and the injector pulses were present. That way the pump ran occasionally during the drive time and kept the fuel system primed, ie it ran every time the engine was in overrun/cutoff condition.

With injected gas I set the gas programming to use a small amount of petrol under acceleration to relieve fuel pressure occasionally. Not sure if this is available on most injection software.

In your case I would see if driving with the fuel cap released reduces the problem. Check the charcoal canister hasn't been filled by petrol. Some aux tank breathers are terrible and allow neat fuel to poison the canister. Disconnect the canister purge line and let it vent to the wheel well, see if that helps.