Thought I'd run this problem by you folks, hoping someone has seen something similar and can share some good advice. Basically I am having this problem where my injectors are pulsing rather than spraying a continuous flow. Fearing my injectors were dirty, I've replaced them along with the fuel filter - so far, I've tried three different sets of injectors and though the brand new set showed a bit of improvement, the issue remains.
When testing the injectors, they begin spraying a continuous flow when I press a bit on the air plate, but as I press it down further they begin pulsing, and continue to spray in pulses throughout the rest of the air plate travel.
Here's a video showing the spray pattern:
My guess is a bad fuel distributor, since it was replaced (as I'll explain below). But before I get a new one, I thought it would be a good idea to hear your opinions, as I fear finding out the problem is elsewhere - maybe the fuel pump, the fuel accumulator or the pressure regulator
A little background info:
My car is a 1990 VW Fox with a .50 T3 turbo, still running CIS-E. The WOT enrichment circuit is activated via a pressure switch and I have tuned the DPR as per Jonathan's (Longitudinal) guide. Though not relevant to the fueling issue, my ignition retard under boost was taken care of by replacing the stock distributor advance diaphragm module with a advance/retard diaphragm from an old turbo Audi. Here's a link to my 5-year build thread
The car has run well using the stock FD, which later was upgraded to an Audi 5cyl unit with the 5th port blocked off for more fueling capability under boost. It still ran very well, even got it to pass emissions - but I still had to run less boost than I was hoping to, risking it leaning out on the top end. At the time, I was running about 10 psi and the car was making pretty decent power, considering what it is.
In order to provide even more fuel and also to clear out some space in the engine bay to make room for an intercooler, I moved on to a Mercedes V8 fuel distributor which is a downdraft unit. This change was made along with a big tear down of the whole car. Due to this and also due to spending some time overseas, the car stayed parked for well over a year.
I really want to get it back on the road soon, but the funds have nearly ran out and until I begin working again I won't be able to afford to keep replacing parts, so good input would be greatly appreciated!
Pics of the car just because