gummyAvenger

I've got a previous thread about this, but a lot has happened since then, so I wanted to start fresh with a new thread.

If anyone feels up to solving a puzzle, I could really use your thoughts.

I'm going to try and pretty concise here:

Current symptoms:
Car starts, revs to about 2k RPM, starts to settle down, then dies after a few seconds. Feels like it's trying to keep itself running. It will try to rev up a couple times as it's dying, before it finally sputters out. As if someone was feathering the accelerator pedal trying to keep it running.

Prior symptoms:
Car wouldn't start one day. I inspected the spark plugs, then hooked up my spark tester. Car started right up, so I put everything back together and the car ran for another couple of weeks without complaining. Then one day it did the same thing, only this time it wouldn't start up for anything. I suspect the spark plug issue is a red herring, given the troubleshooting I've done since then.

Codes: None of these are PCM codes, and none show up on a regular cheapo reader. I used Forscan to get these.

• U1900 - CAN Communication Bus Fault - Receive Error (Power steering module... when the car was working, sometimes the power steering would shake the wheel as I was turning)
• U0073 - CAN communication bus fault (Power steering module)
• B1342 - ECU defective / internal fault (Google shows this doesn't actually mean the ECU is defective, but that there's a problem with one or modules... probably related to power steering)
• C1306 - Steering Wheel Angle - No Center Found During Initialization (ABS... I assume due to disconnecting the battery and not turning the wheel to the left and right yet)
• C2778 - Sensor Power Supply Failure (ABS... would this possibly cause the ECU to shut the car off?)

Parts I've replaced:

1. All 4 spark plugs
2. All 4 coils
3. MAF sensor
4. Both fuel relays (the blue ones at the front of the main fuse box)
5. Fuel pump
6. All 4 yellow fuel injectors

Troubleshooting steps taken:

1. Push start (wouldn't start, but it's not flooded anyway, since it starts up right away)
2. Smoke (vacuum leak) test
3. Fuel pressure test (fuel pressure was 5 psi, so I pulled the fuel rail and pressurized it, and 3 of the yellows were dripping, which is why I replaced all 4 yellow fuel injectors. fuel pressure is now around 50 psi.)
4. Removed intake hose and can see butterfly valve moving as the engine starts up
5. Spraying starting fluid into the butterfly valve allows the car to run and throttles rpm up and down depending on volume of starting fluid. Ran it this way for about 10 seconds to make sure it wouldn't sputter out like it does normally.
6. Shorted the fuel pump relay connection to have fuel pump run constantly (was able to hear it running). No change in symptoms.
7. Unbolted cat temporarily. Pulled it out about 1-2 inches to create a gap right before it, in a move of desperation, thinking maybe a squirrel crawled up my exhaust and died, blocking air flow.
8. Tested spark with spark tester on all 4 spark plugs (spark is good)
9. Unplugged MAF temporarily. Not sure if the car would start up normally with the MAF unplugged anyway, but wanted to give it a shot. No change in symptoms.

What else could it be? It's got spark, it seems to be getting oxygen, it's got fuel pressure, and it's got fuel in the engine for at least a few seconds before presumably the fuel stops for whatever reason.

jer2911

iTrader: (1)

When I installed my new engine, I reversed the primary fuel injector plug on rotor 2 with the number 3 secondary injector plug. I hate to admit it but I fought an idle/ stall issue for about a month before finding my problem. I also believe that the fuel pressure should be around 60-65 psi. I was told 62 was nominal. Neither may be a factor in your case, just sharing a similar issue.

gummyAvenger

Thanks for the suggestions. I'm fairly confident the injector wires are correct because it was running smoothly up until this issue started, and before I removed the wires when I replaced the injectors, I labeled them with a sharpie. The 50 psi is what I got it to by turning the key to the on position over and over. I suppose I should test again with the fuel pump forced on the whole time.

gummyAvenger

Problem solved! I think the original issue was that the fuel injectors were leaking, and it just couldn't build enough fuel pressure. I did find and fix that, but I also created 2 additional problems for myself along the way.

The biggest oops was that when I reinstalled the fuel pump (replaced it under warranty because I thought maybe that was the problem at one point), I apparently kinked the fuel line. Once that was solved, the car started up and ran great, except that once it was warmed up, it would die at idle. So I had to hold my right foot on both the brake and accelerator at stop lights.

The second problem that I had created for myself was installing a new MAF. I bought the MAF from Advance Auto, but apparently the MAF they sell there for the RX-8 is no good. I even replaced the Advance Auto MAF under warranty, just in case. I happened upon the factory MAF last night in my garage, which had I thought was long gone. After installing it, the car idles great now.

So my expensive lesson is this: diagnose and verify FIRST before replacing parts. I knew that, but I wanted a shortcut.

And here's a tip to future troubleshooters: do not buy the Spectra Premium MAF (part number MA102) from Advance Auto Parts. It's not compatible with the RX-8, even though it's listed as an "Exact Fit".