I just finished putting in a Mazda reman into my 2004 6spd and was taking it on test drives to verify everything was working correctly. The car has a cat-back, no cat and air pump, and ls coils. The intake is stock. I was on the freeway going 70mph and the cel started flashing and I had no power so I pulled off and checked the codes. It has always had codes for no air pump and cat, and after putting the engine in it has p2004, but that's a different issue. The important codes were both pending, p0301 and p0171. I tried to fix it on the side of the road by looking for a loose vacuum hose and resetting the spark plug wires, but it was only running on one rotor. Now I got it towed into my garage. The forum posts I saw seem to suggest a bad fuel pump or vacuum leak, but I feel like a fuel pump would affect both rotors and a vacuum leak would not be this bad.

 

I just took a datalog, the MAF is reading 1.77 lbs/min at idle. Seems the MAF is bad or I have a huge vacuum leak. Whoops, forgot to check my units, seems like its actually reporting high, 1.77lbs/min is 13.3 g/s. To my understanding this would point to a fuel delivery issue, right?

 

Just used a timing light to verify the coils are working, and they all are. Also took a datalog until it died with no intervention. Also gained a p0506 code, but I think that's just a symptom of the misfire I don't know where to go from here.

 

Two things to do/check:

1. Replace the fuel pump. Its easy, and the pump is almost 20 years old. And I've seen peoples fuel pump fail well before.
2. Compression check? Mind as well.
3. Swap the injectors for the front rotor to rear rotor and vise versa. Do the primaries first, then the secondaries. Or just buy new injectors. To me it does sound like a fueling issue.

 

I had the same issue a while back, flashing CEL and everything. It only happened at high stress (for the motor) times, so I suspected fuel pump.

After some troubleshooting, checking coils, I decided to change my fuel pump as it was the original unit from 2004. About 67k miles on it.

I used a DW200 pump and it solved it. I haven't had the issue since.

Hope my anecdote helps.

 

I just did a fuel pressure test at the engine bay with the injector side blocked off because I had the wrong fitting, with the first prime it got to 20 psi and the second got to 60. I guess I'm going to have the take the uim off and get new injectors.

 

I'm not sure if this is correct, but versa tuner says my injector pulse width is 7 seconds. Is this because it can't read data correctly with only the primary's firing or is it really firing the injectors for 7 seconds?

 

I did a "compression" test by removing a spark plug after taking the uim off swapping injectors and finding my ssv was completely stuck and cleaning it. The video sounds like 2 faces of the front rotor have 0 compression, but I don't want to believe it. What do you guys think?

 

You gotta clean any and all extremities from the block, all the intake pipes, valves … anything that would collect carbon buildup. I used a bucket of any heavy duty cleaning solution, bought a few bendable soft brushes let it soak and started scrubbing. While you have it apart take care of any check valves they are inexpensive enough and will save you the trouble from having to disassemble the upper intake again.

 

Another long time SARX member (Hoss-05) had a freshly installed reman fail on the ride home from the dealer. My first reman last like 24,000 miles. It's not uncommon if it ends up being a bad engine.

 

It could be the fuel pump. I think I have the same problem. Before the fuel light kicks on, my engine completely shuts down on the road. Good luck

 

Did you ever get this sorted out? My son and I installed a Mazda reman and got hit with a stack of codes initially. I was about to dive into tracking down multiple fuel and vacuum issues when someone suggested we reseat all of the connections on the PCM, and that did the trick. It looks like you are deep into the troubleshooting process, but it can't hurt to recheck the simple stuff. Crossing my fingers for you.