sharingan 19

iTrader: (16)

S4 T2, fd pump, 550/720, aeromotive fpr, parralell fuel setup, vmic, Tb mod, rtek 2.1

The problem is anytime I try to accelerate the car will stumble and stutter. It feeds very similar to fuel cut, and is accompanied by a noticeable vibration (running on one rotor?). This happens @ about 4-5 psi if I go wot, but if I gradually increase rpm it will do it while still in vacuum. Also of note is the fact that this happens the split second the secondaries "kick on" as per the secondary injector indicator on the rtek. This leads me to believe that there is some electronic problem w/the secondaries.

I have all but rules out hardware failure, as over the past 3 months I have: dropped and cleaned the tank, replaced the fuel pump sock, replaced all the fuel line w/high pressure hose and -an fittings, replaced the fuel filter, added fpr, cleaned and flow tested injectors which were installed w/all new grommets and o rings and replaced the injector clips on all 4 injectors.

Yesterday I pulled the UIM and verified there are no fuel leaks anywhere and replaced the petrified gasket. Checked all the hoses and ic piping and made sure the confections were solid.

I'm beginning to lose patience as this thing should be working by now...

FC3S_nataku

iTrader: (3)

hey you didnt change that UIM gasket by yourself lol i hope this gets resolved quickly

1SWEET7

iTrader: (1)

I imagine you are verifying the lean condition with a WB right? I don't have a WB but I have seen some high injector duty cycles before my secondaries come on, nothing too scary but higher than I would like, but no hesitations though. Are your secondaries high or low imp? If low what resistors are you running?

sharingan 19

iTrader: (16)

I have a NB. As I accelerate its pegged rich then it goes lean for a split second, then when the stuttering occurs its blank. Its a pretty safe bet that if its too lean for the NB, its lean. Injectors are low imp. Stock resisters. Duty cycles aren't crazy, highest I've seen was 62% then the "secondaries kicked on" and it dropped to 3X%

texFCturboII

iTrader: (17)

This sounds very much like the issue I am having right now. I have been told it may be a clogged cat. I havent had the chance to verify it yet, but if that doesnt turn out to be the case then I'm moving on to my AFM and my TPS, then my leading coils....

Mine drives around fine, but anytime I try to go WOT or anything over 50% throttle really, it falls flat on its face, stutters, stumbles, backfires, spits, it even builds boost, but doesnt go anywhere.

1SWEET7

iTrader: (1)

So you have stock low imp injectors then. Maybe a cut wire inline with the injectors or something.

FC3S_nataku

iTrader: (3)

i think he has stock primary's. he said that when he did the parallel set up he put new injector clips on all 4 injectors. also it cant be a clogged cat because he has a RB setup

sharingan 19

iTrader: (16)

Correct.
Stock 550's....well 580's after cleaning but that's not important.
Perhaps, a cut/short somewhere before the new injector clip pigtails? If this were the case what's the best way to find/eliminate it?

HAILERS2

Do an ADVANCED SEARCH on this site.

Input the single word HESITATION.......and to the right where it says USER NAME, put in the name NZCONVERTIBLE for a search of all forum.

The result will be a list like that shown here: https://www.rx7club.com/search.php?searchid=9289654

Then read the different threads and look for a response from NZCONVERTIBLE in the thread.

HAILERS2

Read this thread https://www.rx7club.com/showthread.p...hlight=HAILERS

and READ post #20 on that thread by NZCONVERTIBLE.

HAILERS2

Or read this by NZCONVERTIBLE: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/ecu-ground-wire-questions-658615/

sharingan 19

iTrader: (16)

Allow me to clarify, what I am experiencing is NOT hesitation, it is a brick wall. The only way to make the sputtering/ vibration stop is to get off the throttle, it will never keep going.

That being said I read the threads you posted, I added the prescribed grounds and they did not fix the problem. It does seem like it drives a little smother, but that could just be the placebo affect. I am making a restrictor pill for the boost sensor, but I seriously doubt that could account for the magnitude of problem I am experiencing.

I an looking up the test procedure for the boost sensor now, perhaps that's the true problem?

If anyone has information/experience on testing the ecu to injector signal it would be greatly appreciated.

sharingan 19

iTrader: (16)

Just swapped the boost sensor (I'm not trying to read the fsm on my phone), it fixed nothing. Why do these cars have the shitiest wiring on earth?

turboIIrotary

iTrader: (9)

my friends car has the same problem we have been trying to fix it for the past 2 years so far nothing has worked, the only thing we haven't tried is a full standalone it currently has a rtek.

HAILERS2

When you hit the brick wall, does the Palm show the secondarys are on? or not?

The secondary injector signal can be watched using a digital meter probing a secondary wire at the ECU while driving. Before boosting the secondary will read batt/alt voltage. Once the secondarys open the voltage drops down. Waay down to like seven or so volts. If the secondary isn't turning on.........then the voltage will stay right where it was prior to getting into boost

So that's how you can tell if a secondary is coming on or not. You'd have to do that procedure on both secondarys to tell if the ECU secondary drivers are working or not. It's the voltage drop that tell you the injector drivers are working or not.

Say you stomp the pedal and go over 3800 rpm. What happens when you trip the secondary injectors to come on.....is that the Primarys duty cycle will drop in half as the secondarys come online. If you use just a meter to look at that you might see the primary at 5vdc prior to the secondarys coming online. When you cross the 3800 rpm trip.....the primary will come up in voltage and as an example up to maybe 8vdc and the secondary will read the same voltage. Those are not exact figures, just examples. I've done that prior to Digital Tuning coming out with the RTEK.

There's a small chance that the outer set of throttle plates are not full open when your boosting. You might want to make sure they are going full open....... or not. That would be my second guess after the clogged cat. I've had that happen to me before. The Black, flat cam the linkage rides on started breaking up and not working right. The outer plates would not open resulting in too small a throttle opening. Something like that.

sharingan 19

iTrader: (16)

Yeah, it seems that the only way to win is to get a whole new harness :-/. I talked to a local shop and that's what they had to end up doing...

Yes, the secondary flag comes on right when the problems start.

Sounds tedious, but if that's the only way...

Interesting, makes sense though when u consider how the duty cycles pretty much mirror that relationship.

I highly doubt any of that is the problem as I inspected the tb thoroughly when I did the tb mod, I have no cats. Plus, if the throttle plates weren't opening, wouldn't the symptoms be a bit different?

HAILERS2

I don't know what you've have/have not done to the throttle body, but the stk throttle body should have the outer set of plates not SNAP open, but open in a delayed fashion. If memory serves there's a damper that the seondary linkage rides on the slows the opening of the outer set of plates. It's been a while since I've looked at a turbo throttle body. I'll go look at a spare body tomorrow. I agree there's something lacking in my description. Memory says the primary plate open *right now* when you step on the pedal, but the secondary two have a slower opening due to the damper the secondary linkage rides on. DAmper as in a round mushroom shaped outfit with a nipple in it's center that the linkage rides on.
Probably not the plates but one of the secondary injectors not opening.

Seems you could take a meter and key to ON and see if there is batt voltage at the two secondary injectors prior to doing anything else. I'm talking backprobing the secondary wires at the ECU itself...with the plug on the ECU (not really required but why not).
I'd check out the secondary injectors wires one at a time with a meter while going into boost and see if they are both showing a voltage drop when going into boost. Kinda sounds like one or both are not *injecting*. I don't know of a better way of checking out the secondarys.

If the car flat won't go after the car hits boost and hits a wall.........to me it has to be one of the secondary injectors not opening.............although I remember a thread or two where the secondary plates would not open due to ??? broken secndary throttle plate linkage/damper/black flat cam. In other words just the single primary plate open and not enough air getting in the engine. Secondary two plates stuck closed or only partially open is what I'm saying. Just pulling the intercooler off and working the throttle linkage would show if it's good or bad. Not too much time wasted. I'm not sure who I'm talking to on this thread anymore. matters not.

sharingan 19

iTrader: (16)

The tb mod eliminates the secondary throttle plates. Plus, if the throttle plates were sticking closed and the injectors were working, wouldn't it read rich, not lean?

When I installed the injectors, I replaced the injector clips. To make sure they worked I verified that they showed 12v w/ key on. However the symptoms make it seem like they aren't coming on...

I need to verify the voltage drop when in boost, but that might be difficult to execute by myself.

texFCturboII

iTrader: (17)

Subscribed. I'll let you know if my problems cease after my troubleshooting. I'm convinced we are experiencing the same issue. It wasn't a clogged cat for me, it has to be wiring / sensor related. Mechanically everything is intact and working properly. Question, are you building boost at all?

FC3S_nataku

iTrader: (3)

Hey when you want to check the voltage let me know. I can go over and lend a hand

sharingan 19

iTrader: (16)

Yes, if I go wot I can get to about 5-6 psi. If I gradually try to build boost it will cut out sooner, sometimes while still in vac, sometimes @ 2-3 psi.

how bout now?

HAILERS2

This is addressed to TexTurboII...................When I'm talking about the secondary plates, I'm not talking about the outter set of throttle plates. I'm talking about the inner set of two plates and they, on a stk turbo car, have a delayed action that is determined by a black cam riding on a damper.

Then it depends on how much of a throttle body rework has been done on the car. That outfit might have been already removed. But the two inner plates must still exist. They never get removed. Car wouldn't run if they were removed.

Then again there's something Shan.... said that does not compute. IF your in vacuum and it cuts out, then I don't see it being a secondary injector issue 'cause the secondarys don't come on unless there is a Load plus the 3800 rpm. I believe the Load is determined by the output of the boost/pressure sensor. Somewhere up there you said it also happens in vacuum and that's why I wrote this. EDIT: Oh, you did say the secondary flag came on soooooooooo, the ECU is seeing the load plus whatever rpm you put in for them to come on. Never mind.

sharingan 19

iTrader: (16)

Oh!, that's what u meant by secondary their plates...gotcha. Yes those are still intact and working properly. My tb only has the secondary plates and corresponding dashpot removed, thermo wax is still functional.

You can still be in vac above 3800 rpm... Roll onto the throttle instead of mashing it.

I think that's why I can build more boost when I mash the throttle. It starts building boost below 3800 where the primaries can handle it, and then leans out when the secondaries are supposed to come on (somewhere after 3800)

However if I gradually increase rpm past 3800 (still in vac) and then step on it, it will stumble immediately and never build boost. Since it is already above 3800 it needs the secondaries to build boost, since they aren't coming on = no boost/immediate stumble. My theory anyways...

HAILERS2

Then ..........................your pal who's offered his services sitting in the right seat with meter in hand showing batt/alt voltage on a secondary wire at the ECU and you stepping on the throttle and going into boost.

He sees perhaps a solid 13-14vdc prior to going into boost.........and once in boost that voltage will immediatley drop to ??? depends..about seven or so vdc showing that the ECU is pulsing a gnd to the secondarys and that they are coming on (the voltage drop).

I'm outta ideas other than that. Boost sensor vacuum line going to a good source of vacuum? Something other than a nipple on the throttle body. ACV probably been removed so if it was my series four car I'd have it goiing to he vac nipple that on a stk turbo is used for the BOV or as they call it a bypass valve .

satch

iTrader: (1)

He has stated there was no restrictor pill in the Boost sensor vacuum line. Is this perhaps a red flag?