25BAHIAMAN

At this point, I'm leaning towards a bad primary fuel injector(s). I will confirm fuel pressure first- waiting on fuel pressure gauge, if that checks out ok then I'm going to replace both injectors

25BAHIAMAN

Question- I have a good set of extra yellow injectors. Can I swap out the two red primaries with two yellows? I know they are bigger but at low demand at idle and streetport it may work or will it be too rich?

Loki

iTrader: (1)

The yellows are ~25% bigger than reds, so the ECU will need to run -25% STFT, which leaves no room for it to manage fuel trim properly and adding an exciting new problem, potentially in addition to the current problem. You can try it obviously, I just don't think it's a good use of time. If you believe injectors are the culprit, see if you can get some known good red ones?

25BAHIAMAN

Ok, I will try and track some down. thanks

25BAHIAMAN

Installed fuel pressure gauge and its rock steady at 60psi. Looks like I'm replacing the two primary injectors.....

25BAHIAMAN

Ok, I replaced the two primary fuel injectors and its doing the same thing. Double checked injector connector location and all is good, fuel pressure is good, no vacuum leaks. What next????????
I also checked datastream while my son was driving the car. STFT is still + 15-20, long term is at zero. Sometimes STFT will idle at zero, soon as you blip the throttle it will drop down to 500 rpms and then hunt for idle, when it does this the throttle is not responsive, then it adds fuel and STFT goes back to +18. Lambda at idle is 1.03. Wide open throttle in 2nd and 3rd gear pulls very hard and lambda is .988. That seems a little lean for WOT? Pulls hard and no hesitation or pinging.
What do you recommend next? Front o2 sensor and airmass sensor are original as far as I know.

Loki

iTrader: (1)

Yeah that's lean for WOT.. hmm. The O2 and MAF is how it knows to adjust the fuel trim, so I'd be surprised it's those. They would also throw codes from failing self diagnostics.

Difficult to make more specific suggestions without being with the car, but let's expriment. What if you unplug one at a time, the MAF and the baro sensor. Does that change the behaviour at idle?

25BAHIAMAN

I will try when I get home from work today. Seems to me the air mass sensor airflow reading is normal, if its reading 5.5-5.6at idle then that tells me the airmass sensor is ok. I'm leaning towards a bad front O2 sensor as this is the main input the ECU uses for mixture.

Loki

iTrader: (1)

O2 failures are easily detectable by the ECU though, it runs self diagnostics every cycle. And the behaviour doesn't really match how O2 sensors fail.

25BAHIAMAN

I hear you but the O2 sensor could be partially clogged or giving the wrong voltage reading to ECU. I'm running out of options at this point. Its down to O2 sensor, airmass sensor, BAro sensor or ECU. Everything else checks out ok.

Loki

iTrader: (1)

That's part of it, it's a wideband, it doesn't measure voltage but impendance and clogging/contamination would create lack of response to mixture change, which is what the ECU tests for. It's not the ECU or it wouldn't run. If your MAF reading is steady or correlates with rpm and throttle, but fuel trim jumps around, I'm still betting on fuel delivery as most likely cause, followed by baro, clutch safety switch, neutral seitch or MAF. Does it behave better if you hold the clutch down at idle?

25BAHIAMAN

ok I just unplugged Baro sensor while engine was running and idle went up then back down and then started idling the same way with same issue. Did the same with airmass and engine died and would not restart.
Here is some more data stream pics with engine idling and everything plugged in






in the last pic the fuel/air commanded equivalence ratio I assume is target lambda? If so when I rev to 7k rpm’s it will drop down to 1.00. Seems like the ECU is asking for a lean target lambda all the time. Also as you notice the baro sensor is reading 99kpa which is 14.3psi and I live in California at around 600ft above sea level so that is reading accurate. And no change with clutch in

25BAHIAMAN

Loki

iTrader: (1)

Revving without load won't require enrichment. Commanded AFR is load dependent more than rpm.

If the baro isn't it, I still think your fuel supply is the problem. You said pressure is fine, so injector, or the fuel itself? Or the fuel rail after the point where you measured the pressure? I know you said you made sure the injectors were correctyl wired... but can you confirm by listening the them, that the correct ones are firing at idle? And they're not swapped left to right? Water in the fuel? Running out of things to suggest without being with the car.

Clutch safety switch can cause stuff like this if it's loose or noisy. If just pushing the clutch in doesn't do it, see if the switch and connection to it are happy.

25BAHIAMAN

I guess you didn't read my post, I replaced the fuel injectors already and yes they are plugged in correctly. I don't see why people get this confused the wiring isn't even long enough to switch them the other way Fuel pressure was measured at the hard line in engine bay. How can the plastic fuel feed line and metal fuel rail be faulty and even if they were there would be major lack of power at high load. This engines pulls like a freight train through all gears and rpms.. How can safety switch effect fuel mixture in all RPM''s?

Loki

iTrader: (1)

I did read it, I'm giving you my opinion based on the symptoms. We've tried stuff and it hasn't helped, so we haven't excluded any specific cause.

You'd be surprised what a noisy clutch safety switch can cause. It doesn't affect mixture itself, it affects the ECU's perception of whether it can run. Maybe it's not that, I'm not really expecting it is, but something to check and eliminate.

25BAHIAMAN

OK, I was referring to when you said " injector itself or fuel supply".... I had already replaced the injectors so we can rule that out, also, it seems to be running lean through out the entire rpm range under high load as well so the primary injectors wouldn't cause that, I also swapped the yellow injectors with a good set too and it didn't change. I guess its possible that fuel pressure could read ok but fuel flow can be low but you'd think that wouldn't effect idle and you'd think the engine would have lack of power under WOT, which it doesnt'. I have a hunch its air mass sensor or front o2 sensor. Wish I had some I could test but I don't so I'm going to have to bite the bullet. Probably best anyways as they are the factory 2005 sensors as far as I know.

Loki

iTrader: (1)

Make sure you get an OEM MAF or at least from the original manufacturer. Aftermarket MAFs can create new and exciting problems.

Do you have the ability to collect logs? Either at idle or at WOT?

25BAHIAMAN

Didn't you see all the pictures I posted above, thats all live data stream at idle. I don't have the ability to log but I can monitor the data stream while my son is driving

Loki

iTrader: (1)

I did, and a log would be more useful since it covers a period, not a one time snapshot. Where are you located? Maybe it's time to find someone local who can look at the car or has better equipment.

25BAHIAMAN

I'm two miles away from Racing Beat, Anaheim California. I'm actually a mechanic for Mercedes for 30 years now, Drag raced RX2 for 10 years, ran world record stock chassis so I know a thing or two. But this has me stumped and Mercedes diagnostic equipment is much different than Mazda so I can't use any of it other than a voltmeter and hand held scanner. and to be honest I don't have much time working on Renesis systems.. What I don't know I research and learn and figure it out..Today I tested the clutch switch and its working just fine, I even disconnected it and it didn't change anything, so we can rule out another thing. One thing I have a question on, is there is three hoses that go to the accordion tube, one goes to oil fill neck and the one goes to the bottom of the intake and the other goes to the oil injector vacuum block. What is the purpose of the one going to the bottom of the intake? It goes straight to the accordion and doesn't seem to serve a purpose. Also the other one that goes to the oil injector block when I disconnect it from the accordion tube while the engine is running, it has pretty loud whistle and when I install it back on the accordion tube you can still hear the whistle noise from t inside the accordion tube. Don't know if this is normal?

Loki

iTrader: (1)

Some cars have that whistle, not sure about all. But healthy cars without other symptoms also have it. The line going to the lower intake manifold is idle jet air. It should split into 2 lines towards the end, one for each rotor. Not to be confused with the service ports higher on the intake manifold, which should be capped. The jets are there to smooth out the idle. Could be a clue?

25BAHIAMAN

What do you mean by split into two lines? At which end and do you have a pic. If I remember I only have a single line and vacuum diagrams only show single line. Are you referring to the two metal tubes inside the manifold that go into the primary ports?

Loki

iTrader: (1)

Yes. That vacuum line should go down to the nipple on the outside of the LIM that feeds both of those tubes. I forgot the split is inside the manifold.

25BAHIAMAN

Ok, you had me scratching my head there for a second. It's all hooked up correctly and no leaks. I have and airmass sensor and o2 sensor on the way. This is getting ridiculous
I work at a MB dealership and its very easy to diagnosis issues like this because we have computers and if we think it may be a sensor we just walk out to the lot of 100 cars and pull on off and test it. No one around here drives rotaries. Very rare to see one on the road