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Well, I finally got around to changing my TPS and now the hesitation has changed significantly. The hesitation seems to be right about 3500RPM when the secondaries come on (I was feeling it from 3400-3600 rpm on the tach). If i cruise in that range I can feel it. Before I sawpped the TPS the hesitation range was much larger (anywhere from 3200-4100 rpm). I did a diagnostic check on my car and it seems that my O2 sensor is not functioning. Here is a theory, is the hesitiation happening while I am crusing because I am in open loop (because the 02 sensor is not working). I dont feel any hesitation at all when I accellerate through this zone only while sitting in this small range. Anway, if you can shed some light here maybe I can get this thing smoothed out a bit more. I will have to do the O2 sensor soon regardless, just wondering if this will fix the problem.
Thanks
Jeff
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The 02 is in CLOSED LOOP when your cruising at a steady speed. The 02 is used in CLOSED LOOP. It is not used in OPEN loop when your accelerating.
IF you have a hesitation in CLOSED LOOP, I'd suggest it is caused by a LEAN condition at the speed your feeling it. Buy a wideband 02 controller etc and you'll see that on the meter as it occurs.
In other words your hesitation is just the opposite of what most people have during hesitation.
Most people seem to have the 3500-3800 rpm hesitation when under full throttle. At approx 3500rpm the secondary injectors come on IF there is a load sensed by the boost/pressure sensor.
At the speed the primary injectors duty cycle is cut in half and the secondary injectors come online at the same duty cycle at the primary's. Such as the primarys were seeing 80 percent duty cycle and now the ECU sees 3500 rpm and LOAD as sensed by the boost/pressure sensor, so the primarys drop to 40 percent and the secondarys come online at the same duty cycle i.e 40 percent. So the same amount of fuel is being injected but now from two different sources and if you still have your foot in it the duty cycle will keep going up for both at the same percent.
If the primary duty cycles drop from say 80 percent to forty and the secondary now just coming online at forty and it does not happen right on the money, then you get a momentary hesitation.
THAT hesitation is not the same as being at a steady rpm in closed loop and feeling a hesitation. That, if viewed on a wideband would show you that your in the 16 plus afr range. Just my opinion, nothing else. Personally I think you need to richen the mixture in the area of the hesitation. With what? Got me. SAFC? RTEK2.0? Yes.
By the way, if your feeling the secondarys come online at 3500 to 3800 rpm under light throttle, that can only happen if your boost/pressure sensor has no vacuum line (functioning vacuum line) connected to it.
On any RX-7 if you remove the vacuum line on the pressure/boost sensor, then ANY time you reach 3500 rpm the secondarys will come online. See the FSM and the FUEL section and you'll see why that is a true statement. THIS sounds like YOUR car to me.
Hailers,
Thanks for the reply.
My thought was I am at a constant speed when I feel the hesitation (not accellerating). It was my understanding that at a constant speed the O2 sensor (after some time) takes over and your control goes into closed loop. Since my o2 sensor is not wokring I was thinking that closed loop is not possible and therefore the open loop control is always at play. I thought the open loop may be quick to respond to the rpm levels and i was feel the secondaries come on / off even though i was not really accellerating, thus the feel of hesitation. Anyway, not sure if what I said makes sense, does it?
I have checked my boost line and it is good. This morning i installed a mechancial boost gage in my car and it appreas that I have 18 mm/Hg at vacuum and it was stable which i am guessing is good.
I misread what your 02 sensor was doing. Yes, if it's busted then your car is in open loop all the time.
I don't think you'll be able to find out what is going on unless you have a wideband on the car or maybe even a narrow band OR a digital meter back probed into pin 2D (series four). A couple of years ago, I ran with that pin backprobed with a meter and I could tell when the car went into closed loop or not closed loop.
I can relate to that hesistaion you talk about because I've delibertly leaned my car out using either a SAFC or even the RTEK2.0. If I lean things out too much and drive at a very steady speed, I feel a hesitation and I can also see on the wideband the afr go into the 16 plus afr range.
Then again your hesitation might be another thing altogether.
I don't think it would be the normal hesitation people see at thirty eight hundred or so because that is caused by the secondary injectors coming online at the same time the primary duty cycle is cut in half.
Yeah, sometimes I just glance at a thread and then shoot my mouth off. about something that isn't relevant.
Just another note hailers, the rtek 1.7 upgrade modifies when the secondaries comes on from the stock 3800 rpm down to 3500 rpm. So I am pretty certain what I am feeling is when the secondaries come on. I hope it is not leaning out becasue I am only running stock boost now (confirmed that with my newly installed boost gage on a drive this morning) but will be putting on a 3" turbo back exhaust which will up the boost and hopeflyy not up this issue.
I would love to get the Rtek 2.0 but I need a few more mods and some more experience before I get into that, but I am looking forward to it!
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