Fuel Cut Issue

[gaugedk]

Im not sure which Discussion this should go in so I apologize in advance if it is in the wrong one.

You guys have helped me save some big buck over the years and Im hoping you can do it again. First Off I have a 1994 turbo SS

Im having a fuel cut issue, whenever I try to accelerate quickly the car bogs down and stalls out. I ran the Codes and they came back with

35 - Canister purge solenoid valve

23 – Air Flow Sensor

45 - Pressure sensor and pressure exchange solenoid valve

I have checked the vacume lines to make sure there are no leaks and cleaned the connection points of the air flow sensor – still the same

I am hoping I don’t have to replace these parts as they are pretty expensive. Any help would be greatly appreciative. Thanks

[vrg3]

When code 45 is active the ECU will cut fuel at anything above about 50% throttle to try to keep you from going on boost.

First try clearing the codes and seeing which ones come back.

Chances are you don't need to replace the MAF sensor, for one thing. The other valves are expensive new but cheap used parts aren't hard to find.

[gaugedk]

Alright I reset and codes came back

35- Canister purge solenoid valve

45- Pressure sensor and pressure exchange solenoid valve

51- Neutral switch or Inhibitor switch

[vrg3]

Hm, okay, weird that code 51 appeared out of nowhere. But I'm glad to see the MAF code's gone.

The pressure sensing code is the one I'd deal with first. The factory service manual has useful information on how to diagnose it, but the first thing I'd do is check that the pressure exchange solenoid's actually clicking open and shut. Put the ECU in test mode and turn the ignition on without starting the engine, and you should be able to feel and hear it clicking.

If it's not clicking, chances are the pressure exchange solenoid needs to be replaced. If it is, chances are the pressure sensor needs to be replaced. It's always possible that it's a wiring issue, so you should also test continuity as described in the FSM.

[gaugedk]

Allright its clicking, so replace the pressure sensor?

[ciper]

Check the sensor for continuity and the wire harness as well before buying a new one.

[gaugedk]

how would I check for continuity?

[ciper]

Get an ohm meter. I've seen digital volt/ohm meters new for 8$ (though I prefer analog). Even without knowing the specifications its pretty easy to tell when something is not right.

The reason we both say check continuity first is because the ECU isnt too smart and often codes are triggered because of either a short (signal too high) or a cut wire (no signal at all)

[gaugedk]

Alright, Ill try that tomarrow and post up. thanks for the help today guys

[gaugedk]

Allright so I went and got the ohm meter and tryed to check the sensor out or I should say the sensor wire. its the one on top of the right strut tower correct? I took the connector off and put the connectors on the connection points. I tried it with the car running and with it off on all the various mode settings and nothing. Im I doing somthing wrong? is there a certain setting I should be using? is the green wire on the sensor positive or negative? I hope Im just using the meter wrong, I dont want it to be an electrical problem. Thanks

[vrg3]

It doesn't sound like you are following the instructions in the factory service manual... you can't perform the tests with the engine running because you need to unplug the ECU connectors. Follow the procedure outlined by Subaru.

[gaugedk]

That would make sense to follow the directions You guys help out even with the stupid questions! thanks Ill try that today

[gaugedk]

Looks to have continuity... so Im going to replace the sensor. Ill let you know how it goes. thanks again.

[vrg3]

Can you run my scan tool? That might be a way to test the sensor before springing for a replacement.

[gaugedk]

Alright, sorry it took so long.... I replace the pressure sensor and it doesnt have the fuel cut issue any more Im just getting a code 35 now.