Fuel Pump Failure

I have a "new" 2023 Texas Aircraft Colt with a 912 is sport. After the plane was delivered (in early December) and during my first flight I ran into low fuel pressure problems on final. by the time I had it back in the hanger, pump B had completely failed. It turns out that this is the second time this plane has had a pump failure (the first was during the airworthiness check rides). According to the planes manufacturer the symptoms of the first failure were exactly the same as my experience.  This morning, a new pump unit was installed and we witnessed the following. Pump A turned on (prior to starting the engine) produces a psi of 43. When the engine is started that drops to 36.5psi. When pump B is added the psi climes to 37.5.

The manufacturer purchased the new pump unit, as there seems to be a pissing context going on between Rotax and themselves in terms of warranty, which I am caught in the middle of. 

I personally do not think that the chances of two pump units going bad with the same symptoms is likely, there is something else that is the root cause. This is also the view of Texas Aircraft who have actually been very responsive so far. In any case, my plane is still currently grounded, as I seek a reasonable explanation. 

Thoughts??

Did the pump actually fail or maybe with a new plane there is debris in the system and clogged the pumps?

Just food for thought.

This sound like Texas Aircraft is using a gauge type fuel pressure sender instead of a differential pressure sender.  A gauge type sender reads fuel pressure in relation to ambient pressure, but to read accurately, the 912iS engine requires a differential type sender that references airbox (manifold) pressure. This is necessary because the Rotax fuel pressure regulator adjusts the fuel pressure in reference to the airbox pressure, not ambient pressure.  

A standard gauge type fuel pressure sender will have the greatest error at low throttle settings because in that condition manifold pressure is much lower than ambient pressure.  36 psi is typically about what you would see at an idle with a standard gauge pressure sender, then as you advance the throttle and the airbox pressure approaches ambient, the reading becomes more accurate. 

Some EFIS units can compensate for this, but they must be configured to do so. Alternatively, the manufacturer could (and should) install a differential type fuel pressure sender with a reference to airbox pressure, and the problem goes away.  I believe the Colt has only been recently offered with the 912iS engine, and a lot of manufacturers got this wrong when they first installed the injected engines. I thought the industry was past this problem, but it would seem that it’s not. I suspect the pumps are fine.    

Jeff:

Thanks very much for the info. The pump unit that caused problems for me (i.e. the second unit) was taken off the plane and sent to Leading Edge. They found that pump B had actually failed. I still cannot get my head around two pump units failing with both the same symptoms. 

I believe that my Colt is actually the first to be sold to a customer with a 912iS Sport engine, so I certainly expected some teething problems, but nothing like this. Moreover, the difficulty in getting Rotax engaged in helping has been disappointing to say the least..

Yes they thought about the potential for debris. The filters were checked and the sealed micro filter replaced.