HAILERS

What I and others know and have known about secondary transition stumble for a long time:

Buying a RTEK2.0 won't solve THAT problem.

This is a ECU grounding problem on series four na and turboII.

The fix is the same as has been mentioned many times on this forum.

Extract the ground wires 3A, 3G and 2R from the ECU plugs.

Buy some SINGLE STRAND 18-20 gauge wire, solder, solder flux and soldering iron , and a couple of RING terminals to attach one end of the wires to a common ground like one of the attach studs for the ECU bracket.

Cut three pieces of wire about a foot to a foot and a half long.

Strip one end of each wire.

Tin each stripped end with flux/solder.

Lay an individual wire inside a wire terminal and solder it in place. Do NOT let the wire fill the place on the terminal wire the plastic tab of the plug holds the terminal in place or the wire won'l lock in when reattached to the plug.

Do the other two wires mentioned above the same way. Then reinsert the wires in their respective plugs and reattach the plugs to the ECU.

Twist all three wires into one wire bundle. Then strip all three wires and crimp or solder to a single ring terminal. Attach that terminal to the ECU bracket stud and bolt down with a 10mm nut.

Done. This is nothing more than a repeat of what has been written numerous times in the past.

DOES THIS WORK? Ask a very respected member of this forum, NZCONVERTIBLE. Yes it does work. Also ask me. Yes it works. I can remove this EXTRA grounding and the hesitation will come back like magic. Reattach the new gnds and all's well.

Why does this work when you KNOW the gnd terminals on the top of the rear rotor housing are good, clean and well attached? I'm clueless. NZCONVERTIBLE thinks it might be the mechanical crimps inside the harness that are corrupt. IF you've ever taken a harness cover off you'll see numerous mechanical wire crimps connecting two or more wires together.

I've NOTHING against mechanical crimps. Airplanes have LOADS of mechanical crimped wires and they fly fairly good that way.

What I can observe with the NEW gnds not connected, is a AFR in the 9'S during the HESISTATION. With the NEW gnds there is a seamless transition and NO damned 9AFR bullshit afr. I hate 9 AFR's and low 10 AFR'S. Just venting my spleen.

HAILERS

A picture

The Wankler

iTrader: (14)

I agree, it removed my stumble at transition.

gross polluter

I'll give it a whirl tonight or tomorrow. I'll report back with the results.

rogrx7

iTrader: (11)

to bad this doesn't fix the 2800-3000 stumble

Wizz

I too will try above Hailers method.

gross polluter

Update: did not help one bit.

The issue goes away when a stock ecu goes back in, only happens with the Rtek.

The Wankler

iTrader: (14)

Interesting.

RotaMan99

Thanks Hailers, while im working on my BACV I guess I will do this too.

My theory is that there is many grounding points on one ground wire, I think this works the same as check volts at the better vs the alternator. There is a lot of draw at the bat terminal so the voltage is lower. So maybe the different gnd loads on the one ground wire at certain points causes to much resistance?

HAILERS

What happens when you reinstall the RTEK and MAKE NO ALTERNATIONS like remove fuel at certain rpm. In other words...no alterations. Just plug it in and drive it?

turbo2ltr

iTrader: (1)

Just throwing it out there... have you initialized the ECU lately?

gross polluter

The issue is at its worst when it's like this. I told Mike at DTI 2 weeks ago that I believe, in my particular case, that the stumble I am getting is caused by the type of injector I am using on my secondaries. I'm using rochester style injectors (PTE, FIC, TMS, etc) on my secondaries. It has been my experience that rochester style injectors have quite a bit more deadtime than denso injectors. This is the first time I have used them in a rotary application, however, I have used them countless times on DSMs. On ECUs that are not corrected for the longer deadtimes, the correction factor is non linear since pulsewidth needs to be lengthened at lower loads to get the right amount of fuel. Correcting the deadtime tables in the DSM ECU eliminates this correction problem.

I was farting around yesterday and applied the same correction that I used on DSMs, I richened the secondary transition point up significantly and tapered off the correction towards the top end. No stumble, If I go back to 0 correction the stumble comes back.

At this point, I am pretty confident that my injectors are causing the problem. The same style correction that I had to use on stock DSM ecus fixed the stumble problem that I am having.

Mike, I have been doing alot of work on the car over the past few weeks. Every time I dive into another project I disconnect the battery, so it gets disconnected at least once a week for a few hours. Should be enough time to initialize the ecu?

turbo2ltr

iTrader: (1)

Unplugging the battery does nothing to the NVRam where all the configurations and maps are stored.. I meant tapping the "reset ECU" button in the software that clears out the NVram, resets the timing and fule, and puts it back to stock. Sounds like you have.

gross polluter

I have 1.7, not 2.0

Any correction I refer to is done with an SAFC.

Toxindude

Okay so you leave the grounds all connected up and just solder another wire on to all three terminals and reconnect then crimp them all together and bolt down to the bracket ? Sorry im kinda tired and lost atm I think I just repeated what you said to do

boost_its_what_for_dinner

my stumble is getting better, i have richened up the first four bars on the graph to about 5% at the lowest and 10% the rest. i have left the high rpms alone since i cant rev that high yet. i also figured out that my car was running warm because the fan blades where in backwards and i had it wired up the right way and it pulled air through but not the way it was supposed to so no that it fixed it stays around 178-198 but more 185 average. not thats it runs cooler it doesnt stuimble bad at all,also tonight i was driving back home and it did it a little but it was pretty cool out so i dont know if that had something to do with it.

The Wankler

iTrader: (14)

Sounds very rich to me. Are you running a wideband to measure the AFR's?

AllMotorRotor

Doesn't the stumble cause an excesive rich condition anyways? So adding fuel to reduce the stumble would only cause you to loose power around that area.

boost_its_what_for_dinner

well its is a richer mix but im breaking in still. not boosting. i going to reset ecu again soon to verify conditions, and no wideband yet im trying to learn more about the zeitronics. like a price?

and my stumble causes excessive lean.

Toxindude

When you guys are talking about stumble do you mean its like if you were to keep pressing the gas pedal over and over ? I did this fix just now it didnt seem to fix my problem . If I have the pedal slightly pressed the car will go past 3800 but if I get on it the car will instantly start studdering or just bog right down and go nowhere no acceleration at all . I redid the grounds once before recently to the ECU and under the hood it was fixed ran like a top but then 2 days later it was back to running like crud again and here I am . I am also kinda wondering if the three big holes in my rear cat would cause the car to not get enough back pressure to kick the ports open and get past 3800 or what ever the rpms are at ? Thanx for any advice you can give .

gross polluter

The symptoms that Hailers described was rich during his transition, mine happens to be lean. It can go either way.

mzrx7man

iTrader: (9)

im gonna go through all my grounds, replace my o2 sensor, richen the lower rpms, and do this ground fix. if this doesn't fix this im gonna be pissed.

btw mine gets REAL lean when it stumbles.

boost_its_what_for_dinner

when you all say cold/hot maybe posting specific degrees.that could narrow it down to something temp realted..mine was bad when temp got to 213-226 but now my car doesnt get that warm andthe problem kinda went away.. 4th gear low rpms in vacuum it still does it some what but its getting better

[MOD EDIT: This was moved from the "do you have the secondary stumble" thread]

boost_its_what_for_dinner

see where you say it happens at 2800 mine is not steady its any time vacuum 2-3k, it almost seems like when the motor is under a load in vacuum like 16-5 inhg it wants to go lean... so maybe i need to data log my load index and add fuel..???

turbo2ltr i need info on the zeitronics too



[MOD EDIT: This was moved from the "do you have the secondary stumble" thread]

AllMotorRotor

Its difference for everyone, mine is more of a pause in acceleration for about 3 seconds. It very slowly accelerates and after it gets past 4000rpm or so it start to accel hard again.

Eh, its possible. You wont have much power above 4500rpm without the aux ports operational. So if it feels like your engine has no power after that and seem to take forever to climb, then your ports may not be opening. Take some black grease or any grease and put a glob on the actuator shafts , then go for a ride, if the glob has not moved, then your ports are not moving.