Testing Fuel Pressure

Reviewed Actron Manual

Appendix A starting on page 185 has a full list of all PID's. The full list of PID's also displays on the meter itself. It is a long list. I am sure it will take a while to get through.

Starting on page 4-4 is a write up on how to view/record PID's.

Global functioins list - Data Stream Menu - Record data.

Some interesting PID's to start out with are:

A/F RATIO
FRONT O2S
FRP
MAF
MAF RAW INP
TPS
CALC LOAD (%)
FUEL PW B1 - Fuel Injector Pulse Width (Left)
FUEL PW B2 - Fuel Injector Pulse Width (Right)

I am sure the PC interface will be needed to produce really good graphs. Some Excel would know how would come in handy I suspect. Some reasearch is going to be needed to determine what really give useful information.

Do you have a wideband o2 sensor? If not, you will not be able to measure your A/F ratio at WOT (unless it is between 14-15, which is very bad, especially with your blower).

The stock o2 sensors in the car are what the engine uses to maintain A/F ratio to around 14.6:1 during normal driving (closed loop as mentioned above).

Just a thought... but if the manifold pressure reference line to the fuel pressure sensor switch (or what ever its called on these returnless cars) is cut or missing or in anyway not sending the boost pressure reference to the computer, that would cause exactly what it sounds like your experiencing.

I'm not exactly sure, but I think it (the rail pressure sensor) is located on the drivers side fuel rail and there should be a connector to the wiring harness on it. Now I dont know if it has a manifold pressure reference line on it or if the computer has a MAP somewhere to measure manifold pressure, but either way the computer needs to know what the manifold pressure is to run properly.

I'm sure someone more familliar with the returnless system configuration can chime in and correct me where im wrong or elaborate where i left off.

Also... (correct me if I'm wrong) but wont changing the fuel pump on a returnless fuel system require a retune?

It's been stated on the other thread and I have to agree. Get a wideband and some tuning software or go to a reputable dyno tuning shop and get a custom tune.

If you decide to get a custom tune, or if you decide to tune it yourself for that matter, you need to know exactly what MAF setup, fuel pump, and injectors you have.