Long time since the last update...the car has been going great and I haven't been doing any work on it. However recently I noticed loss of power at high revs. The wideband sensor was showing it leaning out from 4000 up which is not good for the engine. After a head scratch I figured it may be a fuel supply problem and fitted an ebay purchased generic sensor into the fuel inlet...
The fuel pressure should hold constant at 60psi all the time. The bad news was it was falling to less than 50psi at high power; good news that I have easily found the problem and can fix it. The pump I had fitted was a Walbro 255 and I'm really not sure whether this has always been marginal for the engine, or had started to degrade not giving full flow. Other cars have used the Walbro 255 successfully so I'm stuck on that one. For my car I needed a new pump so figured I may as well upgrade to the Walbro 450. That's good for 800hp cars so should do the job! The new pump is a bit bigger than the 255 as seen here:
Fitting the new pump was not so straightforward. Its larger diameter on the inlet end and this stops it fitting into the tank. Progressively cutting more away from the bottom of the pump housing allowed the pump to be fitted higher in the assembly and I got it in ok with some jiggling around. This is the final fit of the pump before it went in...
Another problem I have been having is the Innovate wideband sensor. This has always given erratic readings and at WOT I just treated the reading as a guide not being accurate anywhere near the intended 12:1 AFR. I was recommended the AEM wideband so decided to give that a try. The AEM unit doesn't ever need calibration and is supposed to give a true reading out of the box. Here is the car today up in the air getting the new sensor installed.
After fitting I took it for run and happy happy days! Fuel pressure holding up pretty well, although not perfect. AFR showing 13 to 15:1 AFR at cruise (a bit erratic). At WOT though the reading goes rock solid steady and holds 11.9 and 12:1 through the whole rev range. The engine sounds better and its pulling like a beast. Its never been as fast before so I figure I have never had enough fuel pressure to get full power out of it. On the dyno it gave 530hp but was running lean then to 13:1 at the top end. Fuel supply fixed then 3 years after the conversion!!