Hi!

I have some issues on my TII. Here are the modifications:
- RB Rev TII full exhaust
- FCD
- Ported wastegate
- Ported Turbine Inlet
- Removal of airpump, egr, ACV, Air relief silencer
- OMP adapter with 2-stroke oil
- new Mazdatrix spark plus wires and new spark plugs (2-3000km)
Boost: 12psi

I made all this mods and then go drifting on a french racetrack. No engine issues. The problems only appear when I go snowdrifting. (I live in the mountains so I have a lot of fun roads to go playing. )

This is the problem: I have big big backfires and some flames at the exhaust, I lost all the power, the boost is 5psi max, and it's very slow to get high RPMs. Idle is sometimes stable and sometimes not.
The problem stop on his own after some kilometers and come again if I go playing on the snow. It doesn't do it everytime I drift on snow, but it only appears when I do it.

Do you have any ideas ? And is it normal that I have backfires on deceleration ? (even when the engine is running fine)

Thanks a lot!

 

STOP! You need more fuel!

12 PSI on stock injectors with nothing more than an FCD will result in a blown engine.

Just based on the symptoms I'd say your FCD is malfunctioning.

But you need to address the fuel issue.

I'd suggest the RTek if you don't want to use a full standalone, and 720CC secondaries with an upgraded fuel pump.

 

ok I'll make something for that. Would a fuel controller be ok ?

but it looks like that my engine runs too rich, no ?

 

Without AFR or EGT readings I wouldn't make a judgement to say it's running rich. If anything, it will be very lean under boost.

The "RTek" is the fuel controller. It's an upgraded stock ECU that give you some control over fuel and timing curves, plus eliminates the need for the evil FCD.

 

Is there anything I can do to limit boost ? I did'nt "choose" to rise the boost to 12psi.

I know what the Rtek is, but maybe my english is not the best (I was not sure of the word) :P With 720cc secondaries injectors, what would be best, an Rtek 1.7 or, for exemple, an A'PEXI AFC ?

 

Both! and also a wideband oxygen sensor with display!

 

If you are running 12 PSI with a ported wastegate, then the only thing you can do is restrict the intake or exhaust.

 

^ Very lucky the FCD "malfunctioned" and kept him limited to 5psi.
For once something BROKE in an FC and the car was better off.

 

How much power have people dynoed on the rtek 1.7 on 12psi for an s4?

I'm hoping for 225-250whp without needing to fine tune it with an safc.

Rotary >Pistons

 

I have 225whp with the stock ECU.

And I don't think my FCD is malfunctionning. I don't have any fuel cut.

 

Dyno sheet? If you haven't dynoed it there's no way you can say it really is that much power.

Rotary >Pistons

 

sure, I'll post it when I get back home.

 

I just got my 87 t2 today , needs a rebuild and a few other things. I'm excited to work on it.



Rotary >Pistons

 

I run a pretty similar set-up, but I use a Walbro 255 lph fuel pump and an adjustable fuel pressure regulator. I will be getting the RTek 1.7 myself, as I already have the 720cc secondaries stored away. My foot is my current boost controller/FCD. (I currently do not run over stock boost levels, just to be safe.) I'll be at ease once I have the RTek installed. It has a built in FCD.

You can read about the different RTek 1.X versions and benefits here -> Digital Tuning: RTek7 ECU Upgrade Details

 

I come back on my issues with 2 vids

On the first one you can see how bad my engine runs


on the second one, you can see the engine "cuts" while driving. The RPM needle sometimes go down to 0 and the come back on the right rpms


I have now boost at 9-10psi, rtek 2.1 (but not tuned yet - bigger injectors and AFR on the way), FCD deleted, and a 255lph fuel pump

Just a reminder, my engine issues appear and disappear without harbingers

Do you have any ideas?

Thanks a lot!

 

ECU ground, TPS, fouled plugs, blown engine. check those out in no particular order.

 

Ok, thanks I'll check that. But how can it be a blown engine if the engine works perfectly well most times?

 

stuck/cracked seals can cause erratic issues that may even seem normal at some times. you've been running the engine harder than it should have ever been. if you want to disregard checking the compression on the engine because you want to trick yourself then feel free, you'll just run in circles trying to find the problem and wasting not only your own time but the people's you ask for assistance from.

 

I'm just asking ;-) I tought when you said "blown" that an apex was broken. English is not my main language.
What do you mean by "you've been running the engine harder than it sould have ever been" ?

Another question, assuming one of my seal is stuck/cracked and I want to check the compression, will the results be different if I run the tests once the engine works fine and once the engine works bad?

 

it means almost everyone i have heard of running a stock fuel system to 12psi eventually blows up their engine sooner or later, that is nearly twice the factory boost with a bandaid over the boost gauge which causes timing to advance even further than it should(it tricks the ecu into thinking the engine is still running less than 7psi, but timing an engine to 7psi versus 12psi is a whole different matter even if it is only by a few small timing degrees). a FCD doesn't create a more ideal situation, it creates less of one. the compression would likely vary depending on how well the engine is working at the time.

 

As quickly as the tach needle drops during the misfire it seems like your ignition system is dropping out.

Check CAS connector, ECU plugs, Coil plugs, wires, spark plugs.

 

i do think it is a CAS or ignition related issue primarily, but it may have already done some damage if he keeps pushing it the way it sits. if the engine is ok at least i may have scared him into either lowering the boost or upgrading the fuel system to handle the power.

backfiring is unburnt fuel in the exhaust. meaning the fuel system is working but either the ignition is cutting out, the TPS is not going into decel cut, or the engine is limping.

it may have multiple issues that need to be addressed.

 

Just one information, I started this stread almost one year ago ;-)

I didn't run 12psi more than 1 or 2 hours before correcting it (thanks aaron cake). My engine has run about 8-9 psi for almost 1 year now. It makes 239hp. I took really care of my engine, always let it heat more than enough, never stopped my engine while it was cold to avoid any risk of flooding ,etc. I installed a 2 stroke oil OMP, used good synthetic oil for the engine lubrication, changed it very often.
I also made a steam cleaning (0.5L of demineralized water injected in each rotor) , decarb or I don't know how you call it in english.
Fuel used was 95octane (it's the lowest we can find in switzerland. We have 95, 98 and 100).
I ran this engine with this setup for one year now and made like 10 drift days.
The engine has now more than 140k so it's very possible that my engine's loosing his compression. I'm not afraid of that and I'm currently rebuilding an engine. It should be ready this winter.

So, it's absolutely possible that my engine's blown, but I think I still have one (or more) electrical issues.

I took these videos about 2weeks ago. When I stopped the engine, I couldn't start it again because my starter didn't work anymore.
Today I get back to my car. I turned on the key and could hear the fuel pump relay and one (or more) of the solenoids making clac clac clac clac fast and at the exact same time. I waited for the noise to stop (like 90 or 120seconds) and then started the engine. The starter works perfectly fine again, and the engine runs smoothly.
I let the engine runing at idle while I was testing a few electrical connectors to se if there was a bad contact somewhere. Nothing.
Suddenly (engine hot), it starts running bad like on the video (misfires, flames, etc.) I could hear the fuel pump relay slapping but not the solenoids.
The RPM needle was working good at this time.

Are all these informations helping? Is there a ground issue ? Or a few electrical issues at the same time? I don't know what to control, how to control in what order should I control things... I'm a bit lost :P
I'm a car mechanic so I know a lot of things about car, electricity, etc but we can't find any information in French about rotaries so it's sometimes hard as it's not functionning exactly as "standard" engines^^

thanks for helping

 

sounds like an ignition circuit/main relay issue according to your description. the fuel pump relay shouldn't be making any noise unless power was being interrupted.

 

Are you talking about the fuel relay under the dash? A poor ground could also cause it to make a noise. You can jumper a wire from the Black ground wire to the Brown ground wire. The Brown wire provides the ground to the relay w/the car running. The Black wire is a constant ground and you can borrow off of this ground to see if that's your problem.