Codes 23, 49. EJ22T w/metal MAF. Choppy idle and misfires.

[Legacy777]

That question was geared more towards hellosubaru.

However, the 92+ Legacies should only have 12v at the injector when the ignition switch is in the ON position. Do you have 12v at the injectors with the ignition turned off?

[hellosubaru]

how did find out the injectors are staying open? mine may be doing the same thing

There is constantly +12v between the pins on the harness at the injectors.

There is supposed to be a 12v constant at one of the pins going to the injectors. The ECU "sinks" current rather than supplying it. Transistors tend to work better and last longer this way.

Depending on the year you got your harness from, the early 90's were setup to have a 12v constant going to the injectors, while the post face lift Legacies had an ignition switched 12v going to the injectors. The other lead on the injector goes to the ECU.

Do you know what year harness you are running?

Sorry for the late reply, it's been the post-holiday rush!

I'm running an early 90's harness. So what you're saying is there is supposed to be constant +12v between the two injector pins at the injector? If so, I misunderstood how the injectors pulse.

[Legacy777]

Sorry for the late reply, it's been the post-holiday rush!

I'm running an early 90's harness. So what you're saying is there is supposed to be constant +12v between the two injector pins at the injector? If so, I misunderstood how the injectors pulse.

Only one of the pins should have 12v on it. Are you saying both pins have 12v on them?

[hellosubaru]

Sorry for the late reply, it's been the post-holiday rush!

I'm running an early 90's harness. So what you're saying is there is supposed to be constant +12v between the two injector pins at the injector? If so, I misunderstood how the injectors pulse.

Only one of the pins should have 12v on it. Are you saying both pins have 12v on them?

This is how I measured voltage with the key on, engine off. I measured all voltages at the injector plug:

The common color wire (YR) has a constant +12v when measuring voltage between the - battery terminal and YR wire.

The different color wire (Br, Lg, LW and L) coming from the ECU is constant ground (0v). This is measured between the - battery terminal and the different color wire.

Measuring voltage between the pins (YR wire and Br, Lg, LW or L wire) is constant +12v.

It is my understanding that when the injector is supplied with +12v, the injector is open (spraying).

Does all that make sense? I could take pics too if that helps clarify.

Thanks,
-Jason

[Legacy777]

Jason,

What you're describing sounds normal. The YR wire will have 12v on it, and the other wires go the ECU through a transistor circuit and to ground.

The test you're doing by testing 12v between the YR wire and the other wires really isn't a good test and doesn't tell you anything useful.

Here's the factory manual's troubleshooting flow diagram.

http://www.main.experiencetherave.com/s ... iagram.pdf

[hellosubaru]

^Ok, thanks Josh. I will work through this diagram when I get home tonight and post values.

Do you know of any reason why it would run pig rich constantly? The plugs are fuel fouled constantly.

[Legacy777]

Could be coolant temp sensor, could be the ECU, or could be the injectors. Those are the three items I think would have the biggest impact.

[hellosubaru]

I've swapped between two coolant temp sensors (and also tested resistance), along with swapping ECUs. I still need to work through that diagram you posted above. I'll post back when I get a chance to do that.

[hellosubaru]

I have now performed all of the diagnostic steps from the FSM for:

Control Unit Power supply and ground line
Ignition Control System
Fuel Pump Circuit
Fuel Injector Circuit (the pdf you linked to above Josh)

All tests come back within spec. I am now totally stumped.

[hellosubaru]

Also, let me rehash my symptoms:

Car will not start, but when cranking, it at least tries to fire.
After cranking for a few seconds (10 seconds or less), the car is completely flooded (plugs are fuel fouled, gas in cylinders)

After the rebuild, when the car ran, it ran great the first day I drove it. It went downhill progressively from there as I can remember. It started missing or stuttering at cruise, then it would start hard, then started dying at idle, then eventually stopped running.

[Legacy777]

Hmmm.....I really don't know. Between the MAF, CTS, ECU, & wiring I'm not sure what would cause it to flood that badly. You mentioned this all started after the rebuild, have you checked the timing belt is still aligned properly?

[hellosubaru]

Ok, I finally have an update and some results. Last Wednesday, I was finally able to pick up some new plugs (NGK iridium's, I had NGK V-Power's in it before). I swapped them in, and it fired right up. Sweet! I let it idle up to operating temp, then shut it off because I had to leave.

The next day (Thursday), I had to start it in flood clear mode (start WOT). I let it warm up, and I drove it about 25 miles. It drove fairly smooth, but at cruise it misses/stumbles/stutters.

Saturday, I drove it another 10-15 miles. It still drove pretty well. I was able to start it normally, let it warm up for 5 minutes or so. It still stumbles at cruise.

I haven't driven it since, but last night, I pulled one of the plugs to see what we had, and it was covered in black soot:



If I get off work early enough tomorrow, I'm going to test fuel pressure.

Any idea why the plugs are getting fouled like this?

Also, this thread can be moved to a different forum if needed, as it looks like it's most likely not an electrical issue.

Thanks again!

[hellosubaru]

So, I finally got around to doing a fuel pressure test, and this is definitely the issue: 66 psi!

So, I think I'm going to end up replacing all of my fuel lines (feed and return). Does anyone have any suggestion on what to use? Can I just use regular rubber fuel hose (MPI rated), or should I use SS braided hose, or something else? I'd prefer not to use hardlines, just because I don't like dealing with unions and bending that length of line.

[Legacy777]

Why do you need to replace the fuel lines? What fuel pump are you using?

I'd suggest checking and replacing your fuel pressure regulator. Does the fuel pressure go up at idle when you pull the vacuum from the FPR?

[hellosubaru]

I thought I'd update everyone where I'm at, in case it helps anyone in the future.

After my initial fuel pressure test, I tested fuel pressure on the return line (after the FPR). The return line had ~80psi on it, it it must have been a clogged or kinked return line somewhere.

I got some PTFE SS hose, and replaced the feed/return lines. The car seems much more responsive than before, but I only have ~10 miles or so on it now. I'll update again in a week or so of how things turn out.

Josh, I can't remember the exact fuel pump I'm using, but it's very similar to a Walbro 255 lph inline pump.