Hi All -

1994 RX7, I've had it since late last year. It looks like it had sat for quite some time and I've been chasing a few bugs. One issue is an occasional lean "blip" while driving. Not always when under load, but more often under boost than when cruising.

I previously tested fuel pressure at the FPR under simulated boost and the needle wasn't steady, so I went hunting for a restriction. Replaced the FPR in case that was an issue (it wasn't). Then opened the tank and the pump looked pretty crusty.

Replaced the fuel pump with a Walbro 450 (overkill, yes) and swapped out the fuel filter. The fuel filter dumped out some pretty nasty stuff.

When I saw that I drained probably almost a pint from the tank drain plug and the fuel looked clean.

How bad is this and does this mean I need to dig into the injectors and get them tested/cleaned? When I swapped out the FPR I ran the pump for a few secs and captured some fuel. I didn't notice any sediment at the time. It certainly wasn't as bad as what came out of the filter.

 

Which end of the filter did it come out?

 

Both sides. I'm still getting the same lean 'blip' when driving. The only thing left in the fuel system is the injectors, or there's an electrical issue I suppose.

Single-turbo conversion, Apexi Power FC with the PFC Master.

 

Wonder if one of the injectors is getting stuck occasionally. Run a few bottles of techron fuel system cleaner through to see if there is any change.

If the injectors haven't been cleaned and balanced in a long time, might be worth it.

 

I think there's some threads on how to fix it already, but from what I understand the wiring to the fuel pump is also undergauged, so if you beef that up you'll get more current to the pump and more performance out of it (same for the grounds in the engine bay; mazda went with thin wires for weight/cost savings I guess but it can cause electrical issues).