fc3schick87

iTrader: (1)

ok ok ok ..... i've posted befor but now i have done more work on the issue with NO result

i have an 87 n/a with tii swap. n/a harness with tii ecu. extended tps wires to make harness work.
have about 2800 miles on the rebuild. runs GREAT except for ONE issue


idle is 9 a/r way to rich. idle is a tiny bit rough. only about 100 rpm bounce. quick bounce.
there is NO vac leak.
there is an n/a fuel pump on there (is this the cause to run rich? and yes i need to replace it and no i dont lean out at top boost only high rpm over 5.5)

i've already tuned and retuned tps. i used test light this time. last time i just used the volt meter. test lights show perfectly fine one light on one off.

and yes i already totaly messed with the idle air mix screw. that thing does absolutely nothing for my cause.

Icemark

spark plug, and plug wire condition?

fc3schick87

iTrader: (1)

mmmm. well they are from rebuild they were brand new when i rebuilt. and then i have cleaned them 2 times with a carb cleaner soak and medium brissle brush.
wires have been changed

ramses666

iTrader: (1)

There is a "pill" in the vacuum line going to the variable resistor. If the line was replaced perhaps this "pill" was left out and therefore your idle mixture is screwed.

Ramses666

fc3schick87

iTrader: (1)

mine doesnt require a vac line. there is no nipple on it for one.

10AEturboII

The pill actually goes in the line from the pressure sensor.

fc3schick87

iTrader: (1)

so if i dont have this "pill" for my pressor sensor .... my idle mix screw is f*ed? that makes little sence.

is this true though? because i know i replaced that line with a new one. and that i dont have this "pill"

is this just a one way check valve?

ramses666

iTrader: (1)

ok... I am confusing the two things... sorry my baaad. Still the pressure sensor line has the "pill" thingy in it. Just trying to help. if you replaced all the vacuum lines and forgot to transplant this little "thingy" you might get some strange idle ratios but I don't know.

Ramses666

RETed

Check to see if the idle mixture screw sweeps from 0 to 5k-ohm cleanly.

I thought the idle mixture screw is only for turbo?
How did you get it to work with the non-turbo harness?

Other thing that could be screwing it up is that you don't have the two-stage fuel pump voltage system, right?


-Ted

ramses666

iTrader: (1)

I have idle mix screw on my NA - right next to the pressure sensor. It should do something but you have a swapped setup so who knows?

Ramses666

fc3schick87

iTrader: (1)

on the screw what 2 wires do i test between. ign on or off?

as far as the 2 stage fuel pump voltage system...... noooooo idea....... all i know is i have an fd fuel pump ready to pop on but not including this problem, i havent needed to swap it yet.

RETed

Unplug the idle mixture screw and check resistance off of both leads.


-Ted

SpeedOfLife

iTrader: (16)

The BAC is adjustable only on the TII's, but I think both NA and TII have the idle mixture screw.

fc3schick87

iTrader: (1)

So what should I do about it being there but in no use. That explanes it a lot. Because I've tried everything short of taking the thing apart.

So on an na it is there but not used and if u do a tii swap. Though it seemingly runs with out the proper hook up. It runs way rich with a flood problem.

How can I make it work for me!

lax-rotor

iTrader: (1)

Not quite sure what you're asking here. I'm going to gander a guess and say that you're wondering if the fail-safe of the failed Variable Resistor is causing you to run rich. Yes. It's causing you to run rich. Is it causing your oscilating idle? Couldn't say really. It might be a few things, one of which is the pill for the vac line to the pressure sensor. I'm going to assume you've already adjusted your idle correctly. If you can jump the couple to negate the BAC and see if the oscilations stop. If they do chances are it's your BAC trying to compensate for your idle. Other possibilities for running rich would be a bad O2 sensor, but I think that would cause a Cell condition.

The main causes of oscilating idles (at least on an NA) are as follows:
TPS
Vac Leak
BAC
...I'm pretty sure there's others, but I'd have to search for them. There's a really good thread which covers just about everything for all the idle adjustments you'd need to do.

Here are some other things to check as well:
https://www.rx7club.com/showthread.p...ht=bouncy+idle
https://www.rx7club.com/showthread.p...ht=bouncy+idle

The search function will return over a 100 hits, happy hunting. Let us know if there's any other developments that can aid in the diagnosis of this for you.

well uhhh

hmmm what about the fuel pump resistor that ted spoke of? wouldn't it cause rich condition if the turbo ecu thinks you have the resistor and you dont? my car ran richer at idle after rewire, instead of ~8v at idle i see like 11, but i had my injectors cleaned at the same time so i dunno. it just seems like getting a full 12v at idle may be causing too much fuel to be thrown at the injectors.

lax-rotor

iTrader: (1)

Running rich will not cause a bouncy idle. It may foul the plugs which in turn may cause an idle issue, albeit not an oscilating one.

HAILERS

AFR at nine is something I don't believe I could duplicate even if I turned the variable resistor full anti clockwise.

Variable resistor will work just fine if you use a non turbo EM harness on a turbo engine with Turbo ECU. The output goes to the same pin on either Turbo or non turbo ECU.

I'm guessing a bit, but if you unplug the variable resistor it most likely will make it's input to the ECU default to mid range. Just a guess, but probably right. Anyway, do what RETED said and check the thing out.

What AFM are you using on the engine/car? IF you look at the large plastic cover that covers the internals of the afm, does it look as if someone messed with it? LIke been in there fiddling around in a daze? Also. Is the air adjust screw on the afm visable. It should be covered with a blind cap to keep Dazed Heads from messing with it.

You NEED to have a Turbo ECU and Turbo boost sensor on that car/engine.

TPS probably has close to zip to do with the high afr at idle. A RX with stock injectors that idles good, will have a idle of approx 13 afr and even 12 afr, but 12afr is unusually too rich. It's too rich at 12afr and much too rich at 9afr. But you know that and are trying to fix it.

Timing pretty much right on? At a idle below 800rpm??????

My guess is a failed variable resistor (only part of the problem if at all) or more likely the afm/ boost sensor being for a non turbo car.

The vacuum line b/t the pressure sensor and intake is supposed to have a orifice in it. But this cannot and will not cause a rich idle. It might cause a hesitation when driving. Search for ORIFICE and HAILERS and you'll come up with a part number or look for ORIFICE and NZCONVERTIBLE and he suggests how you can make your own orifice to put in the liine.

Personally I wouldn't waste my time on that right now. It isn't going to fix the 9afr. Sooooo, What is the afr when driving at a steady speed? Say 60mph.

The non turbo fuel pump isn't your problem. When I converted my na to turbo I used it for sometime. The fuel pump resistor relay outfit that is on a turbo car isn't going to do squat for your problem. You don't need it. The FPR is going to regulate the pressure in the rail to, what? 28-32 psi at idle. Guaranteed if that is a stock non turbo pump.

But if your going to boost, then you NEED to get a turbo fuel pump.

I'd say it's the primary injectors being wrong in size or the afm/boost sensor being the wrong ones. Enough scribbling.

HAILERS

Tell you what, pull the plug off the variable resistor and see if it has approx 5vdc on it's brown/white wire. Should. Might be as low as 4.5vdc. Not a big deal. Then, since your there with the plug off, go to the resistor itself and ohm it out to the FSM, Fuel and Emissions seciton.

fc3schick87

iTrader: (1)

i do not have the pill on the pressure sensor

my a/f is normal 14-11 depending on low load or full boost. only rich while idleing

my fuel pump is still n/a

my harness is n/a but my ecu and engine is TII.

my timing is spot on at idle of about 800-1000

my bumpy idle is not more then 100 rpm so its not my concern, the a.f at 9 is, the bumpy idle is just mentioned to help diagnostic

my idle does randomly go to 1200 then back down to around 800 and it cycles back and forth over a long wait for the light. but will not do this if just idleing in my driveway ( ) not much of an issue. just putting it out there to help diagnostic

i do have a turbo boost sensor and afm

i dont have a BAC

my tps is one light on durring idle with test lamp, and roughly 1ohm while off

my idle does not like to be below roughly 800. it loves to be at 1100

i have a fuel cut switch to eliminate flooding (which i do if i dont use it)

if i turn off my car by this switch the idle raises about 100rpm and runs extreamly smoother befor it shuts off in about 8-12 secconds. the a/f is roughly 12-13 while it does this. runs out of fuel. and dies.

my o2 sensor is not hooked up. it is burnt out. i have NEVER EVER ran a o2 sensor on the n/a engine and had no issues. i have read up and found that o2 sensor will not effect idle. only shave off few mpg on highway

i am about to test the resistance on veriable resitor screw

oh and my spelling sux but i am sure you all can see that.

fc3schick87

iTrader: (1)

oh and most importantly . the resistance showed as nothing threw all 3 pegs. i tried checking the resistance on the idle mix screw . never got any numbers to show up at all.

RETed

No BAC valve is causing all the idle headaches.
I've found that the stock ECU + BAC valve is extremely important for idle quality.
Once you remove the BAC valve out of the mix, you get things like this described above.
Either you live with it or put back the BAC valve into operation.

When I didn't use my BAC valve, even with the throttle stop hard set at it's best, the idle speed changed all over the place.
I tried to shoot for a 900RPM to 1,000RPM idle speed, and it did stay there MOST of the time.
Sometimes it'll kick up to 1,200RPM for no reason...no pattern - hot engine / cold engine, didn't matter.
I think the throttle body was sticking slightly.
Some cavaets - I know my air bleeds are not working; having the primary air bleeds work does wonders for idle smoothness.
I do have small vacuum leaks - not enough to find them with starting fluid, but I know they are there -this is why my idle is not absolutely stable; it fluctuates about 20RPM trying to idle.

Now that I'm trying to dial-in my BAC valve with my Haltech E8, I can appreciate the time Mazda put in getting the engine to idle nicely.
It's NOT easy!
But I'm slowly getting the engine to act civily, but it's taking a lot of time and effort dialing in all the programming parameters.
The car will cold-start up to 1,200RPM - just enough to drive around with no hiccups.
The idle will slowly drop down to stock-like 750RPM.
The only problem I got now is that when the BAC valve does engage, it sounds like it wants to shoot out of engine bay!
Sorry for the tangent!

Another thing to check is fuel rail pressure?
Maybe the FPR is screwed?
Is the FPR vacuum line connected right?
The FPR vacuum line needs to see vacuum at idle.
If you connect the vacuum line to the wrong fitting, it will never see vacuum.
If the FPR never sees vacuum, the engine will run rich at idle, as you're running about 5psi (actually more like 10psi - 15psi due to effective "pressure" at the fuel injector tip) more fuel rail pressure than stock.


-Ted

RETed

The TPS?
Are you sure the DMM is set right?
You should see something in between 0 and 10k.
Only one combination pair should show infinite resistance / nothing.

Like I said above...are you sure the DMM is set right?
Quick test...touch both test leads - does the DMM show "0"?


-Ted

fc3schick87

iTrader: (1)

oh oh oh sorry. the tps is great. its hooked up to a test light as of last night and today. its one light only so i know its good. i also used my volt meter.


as for dmm being set right. i am sorry. i have no idea what that means.



for the fuel pressure regulator... i have it connected to the upper intake manafold inside nipple. i could move it to around the other side of that manafold to where i have my bov hooked up. or pull off the vac line and feel suction from it to verify. but mabey the FPR is shot?
as far as the idle bump. yep confermed that its only a 20-50 rpm bump. nothing bothering to me. small vac leak

and for the idle raise at stop. well that makes complete sence. bav it is!


i think tomarrow i am going to remove the vac line off the rail plug the rail and turn on the car and verify i am getting good flow to that vac line. if not . theres my problem right? but if i do have good flow to the fpr. then it may very well be a bad FPR... u think ted?

RETed

Doh!


Yeah, those sound "normal" with the BAC valve not working.
I dunno if anyone else can confirm?


FPR rarely fails, but I've heard of people having problems with them.
That's why I suggested to check fuel rail pressure with a gauge...
It is possible the FPR is bad.


-Ted