H_M

iTrader: (7)

I'm looking for some help because I can't figure this out.

I was driving around on Saturday night when I pulled in to a parking lot and my FD stalled & cut out. I restarted the car and it ran rough and then cut out again. Couldn't get it to restart and had to tow it home. Got home and did the normal deflooding with new plugs. The car fired up but only on one rotor. Since then I have tried everything but the car still only runs on one rotor.

Things that I have tried:
New plugs.
Pulled plugs to make sure that they are getting spark. They are and the spark is strong.
Checked primary injector plugs with a noid light to see if they are getting a signal. Both primary injectors are getting signal and the noid light flashes.
FPR shows that I have ~40psi fuel pressure.
Pulled primary injectors and cranked the car. Both primary injectors spray fuel (not clogged or stuck closed).
Tried another ecu. Didn't resolve the issue.
Did a compression test. All faces show around 100psi compression on both rotors (still a new engine)
Checked all sensor plugs and wires. All plugs are good. No lose ones.
Checked all the vacuum lines. Also all good.

Car details:
1/2 bridgeport
RA Super seals/ solid corner seals/ oem side seals/ oem springs
550/2200 injectors
Aeromotive 340 pump
HKS twin Power
4 x BUR9EQ plugs (brand new)
3 bar map sensor (made sure the PFC was set up for a 3 bar map sensor)

Engine is brand new. Only has 560Km on it. Never seen boost and always kept in vacuum because I'm still breaking it in. Never ran above 3500rpm. It's never given me any issues and has never failed to start (hot or cold) until it cut out on Saturday night. The car has never overheated or seen temperatures above 93*C.

Any help is appreciated. I feel like I've covered all the trouble shooting bases so I don't know where to go from here.

Molotovman

iTrader: (49)

Did you try bypassing the twinpower to rule it out?

H_M

iTrader: (7)

Yes, I bypassed it to rule out a faulty Twin Power. Didn't make any difference. Still ran on one rotor.

Molotovman

iTrader: (49)

Are you sure a secondary injector isn't faulty and stuck open? How old is the engine harness, any chance it could have an internal short somewhere or if the wiring to the CAS' are bad?

H_M

iTrader: (7)

The secondaries are new. I installed them 250Km ago. They were flow tested before I received them.

The engine harness is original to the car. It was converted to a single turbo harness by the previous owner. It's not the best and has given me problems in the past. However, I checked the harness and didn;t find anything out of place or any exposed wires / shorts. Ironically, I have a Rywire harness on the way but it's not here yet.

I will take a look at the CAS sensors tonight. That's a good point.

DaleClark

iTrader: (55)

What ECU? PowerFC?

May want to go through the sensor check screen to see if anything looks funny. That should also show the RPM when the car is running, see if that looks right.

+1 on CAS connections/wiring.

Also make sure plug wires are on properly (L1 to L1, T1 to T1, etc.) - they obviously were before but double-check to see if something got messed up when you were looking at the plugs.

Fuel pressure good?

Dale

H_M

iTrader: (7)

Yes, running a Power FC.

CAS wiring looks good. Connection on both sensors are secure. And sensors are secure on the front cover.

I checked the plug wires too. They are in the correct positions.

TwinCharged RX7

iTrader: (14)

Might double check the connectors. I had one that the noid light would test fine on but then then still wouldn't run correctly. Turns out the connector was slightly messed up so whenever I put it back on the injector it would stop working.

After days of trouble shooting I finally just repinned it to a new connector and it worked fine.

NEWGENRX7

Check your primary injector connector. Sometimes they don’t make proper contact.

H_M

iTrader: (7)

I will check them again. I have them pulled out of the centre iron so it'll be easy.

I'll take a look at the connectors. I just replaced them with brand new ones because the old connectors were brittle and falling apart.

Molotovman

iTrader: (49)

At this point you may just want to wait until the new engine harness shows up. I'm willing to bet that your old engine harness is the culprit.

H_M

iTrader: (7)

I'll most likely do just that. It should be here in about two weeks.

silverTRD

iTrader: (37)

Whats your OMP situation? Are you premixing? I would try adding a cap oil to help restore compression on that rotor.

I had similar issues when my motor was new when I was running RA Classics. Those seals like A LOT of premix. It would die once in a while and start on one rotor and I'd have to do oil in spark plug hole trick. The real fix was getting through my break in miles and getting the car tuned.

Good luck. My .02

H_M

iTrader: (7)

Both rotors have good compression. I have tried the oil trick twice but it still only runs on one rotor.

I've been using 100ml/10L of premix with the RA Super Seals (1.3oz/gal)

H_M

iTrader: (7)

Update:

Installed the Rywire harness this weekend and put everything back together. Used fresh spark plugs and made sure that there weren’t any vacuum leaks. The car starts up and runs on both rotors but it idles very rough. It sounds almost like there’s a ton of fuel being poured in to the engine but the wideband reads 11-11.5 afr at idle. I’m not sure if this is a correct reading or if the wideband is being tricked by the half bridge port. There is also much more smoke coming out of the exhaust (blue smoke) than is normal for the amount of premix that I’m using.

When driving, the car bucks and chugs until I give it some gas and the engine gets some load. Then it runs like a champ as if nothing ever happened. No more smoke out of the exhaust either. I don’t think that the smoke is turbo related because I’m running a brand new S363sxe with 500km on it.

I did notice that the water temperature on the Power FC was reading a bit weird. I have a Davies Craig EWP setup, which comes with it’s own sensor & temp readout so I have something to compare to. The water temp on the PFC (stock sensor) is very slow to increase and reads about 30C lower than the Davies Craig sensor. Before this whole thing happened, the two were within a few degrees of each other. I’ve never heard of a water temp sensor failing but I know that an FD will not start if that sensor is unplugged.

ZE Power MX6

iTrader: (157)

Don't know if the Rywire has a plug for fuel temp sensor, if it does then make sure you didn't swap the fuel temp sensor connector with the water temp sensor as they look the same.

As far as your driving symptom goes, it is identical to my car when it had a busted secondary injector O-ring in the stock rail, it would run extremely rough until the engine get some load. I pull the secondary rail off and primed the fuel pump, found out gas was spraying out of one of the injector from the side. Might be worth it to check the secondaries even if they are new, just to make sure the injectors aren't stuck open or have issue with the wiring.

Narfle

iTrader: (16)

11.5 is a ridiculously rich idle.

H_M

iTrader: (7)

That's a good point about the secondaries being stuck open. I figured, since they are brand new and have been tested, that they were fine. I'm flying out for a wedding this week but will pull the secondaries and check them after I get back home.

It was running well at 12-12.5 before this happened so I thought that 11.5 wasn't too bad.



I think that you guys are on to something. Low AFR and a possible stuck injector(s). I'll test everything once I get back.

silverTRD

iTrader: (37)

I once verified a stuck open injector by rolling up paper towels long ways and putting them down in the the LIM runners. Primed the fuel system and then pulled out the towels. One was drenched with fuel. I didn’t feel like taking out the secondary fuel rail and trying to line everything back up.

j9fd3s

iTrader: (3)

the bridge will throw off the o2 sensor, at low load, basically when it braps. it will read leaner than actual, but its consistent enough you can tune it.

for instance my P port idles at about 14.3:1 AFR indicated.

CREEPENJEEPEN

iTrader: (7)

When you fix your car, please update us. I'm curious if you found the problem.

scotty305

iTrader: (2)

A bad coolant sensor could cause the overly-rich idle since the ECU would need to add fuel to run correctly if the temperatures were actually 30 degrees colder. I've heard of coolant sensors failing on other 80's or 90's cars, a new sensor is not a bad idea.

I would think a fuel injector stuck open should result in wet spark plugs for that rotor. How do your spark plugs look before & after idling for a little while?

H_M

iTrader: (7)

So it's been a few weeks so it's time for an update. I got back from the wedding and both kids got sick that evening, which turned in to a week of sleepless nights. I also bought an NSX, which I've been finalizing. I finally got a couple of hours of spare time yesterday to work on the FD.

I tried rolling up a paper towel, putting it down each of the secondary runners, and priming the system. The paper towels came out dry.

I pulled the spark plugs a couple of weeks ago after letting the car idle for a bit. I forgot what they were like. I will do it again next time that I'm in the garage.

One major thing that I noticed was that the fuel system was not holding pressure.I primed the system and it immediately drops to ~10psi...and then to 0psi a little more slowly. When the car is running, the pressure is a steady ~38psi. I crimped the return line after the FPR, primed the system, and the pressure still drops just as fast as before. So there is a leak somewhere. I discussed it with a friend and he mentioned that the fuel feed at the pump end might have become disconnected/torn.

I also had a chance to switch primary injectors. I had a spare set of primary/secondary rails & injectors. With the new(er) primaries, the car still runs rough but the idle is much better. I can also set the idle at the normal ~1800rpm without the car stalling (half bridge engine). Before I had to either press the gas pedal or set the idle to ~3000rpm for the car to stay running. The AFRs are now also in the mid 13's and the exhaust is back to normal (no more huge clouds of blue smoke). The car, however, sounds like a normal rotary engine instead of having the distinctive brap sound that a bridgeported engine makes. Sometimes it'll brap for a second or two but then go back to sounding "normal."

While switching the primary rail/ injectors. I unplugged the water temps sensor. After plugging it back in, it seems to work again and seems to be reading just like before. Weird...


When I have some more time, I will pull the pump to check the fuel line at the pump. I will also pull the Bosch 2200cc secondaries and put my old 1600cc secondaries back in to see if that makes a difference.

H_M

iTrader: (7)

Another update:

- Pulled the fuel pump to check the feed for cracks or leaks. Everything looked good.

- Checked the TPS. Voltages were too high but then I remembered that I had manually set the idle high on the throttle body seeing how it is a half bridge engine and the idle is set to around 1800rpm.

- The rear leading plug was wet so I assumed that I had a leaky injector. Pulled the new 2200 secondaries and put in my old 1600 secondaries. No difference. So it's not a leaky injector and most likely not a fuel thing.

- Unflooded both rotors (front rotor was dry while rear rotor had a lot of fuel in it). Replaced the plugs and the car fired right up. Ran on both rotors for about 1-2 minutes and then one rotor started to slowly cut out until the car was back to running on one rotor. Pulled the plugs and the rear one looked a little wet while the front one was dry.

Tried with and without the Twin Power (no difference). Also tried a spare set of coils (also no difference).

So now with fuel being ruled out. I'm going to put my attention towards spark. When I have some more time I will check all the coils and the coil wiring.

Project88Turbo

iTrader: (22)

On my old Turbo II I had a similar issue, it would start up fine and as it warmed up, it would go to 1 rotor. If you revved the **** out of it (sitting still in neutral) it would run on 2 again when the secondaries came in.

The primary injector was bad on my rear rotor, the resistance was way too high and as it got hot with the engine, the resistance increased until it could not work. Might be worth checking the resistance on your primaries to rule that out.

Vince