Damn, I'll get you someday

J/K

 

I think it was the RX-6 that didn't exist

 

or was it the rx-7.....

Ahhhh, the ol' 3800 RPM hesitation. There are quite a few different methods on fixing this. I say try them all. I fixed mine, but it still does it occasionally when its cold. My fix method? Rebuild the engine .

Although the APVS starts to open at ~3800, the secondary injectors also start at ~3800. I think it is an injector or ECU or grounding problem. Maybe the secondaries are clogged up/having trouble starting. Also the current draw increases (doubles?) rapidly at that point giving suspicion to a grounding problem. With all the other bad solder points in the car, I sometimes worry about the ECU and its solder points, thus the ECU idea.

The best thing to do is buy a third gen and forget about 6 ports, hesitations, broken plastic, bad injectors, cold solder points, ect. Of course then you'd have turbo vacuum line problems... and the fact that a decent one costs more than I make a year... (cry for me)

Am I rambling?

 

...AST, 5th gear synchro, radiator, control arms, intercooler hoses, y pipes, etc

Buy a first gen.

 

you could build one hell of a 1st gen with 10grand.....300+ hp TII conversion. you could probbaly put on a wide body too for that much

 

Oh boy. lol

Okay, but really... I am not really understanding the whole concept of grounding X to X.

 

Well, heres a short and sweet explanation of electrical circuits:
An electrical circuit is a LOOP of current (flow of electrons). It is common to say the loop starts at the battery (positive terminal) where there is high voltage. The current flows from the positive terminal to what ever you want (motor, resistor, capacitor, 10,000 watt amp, computer system controlling injectors). The current flows through the device and returns to GROUND. Ground is the negative battery terminal OR the chassis of the car. The ground is the zero voltage section of the loop.

Phew. Not done yet. Getting this so far?

Now, the problem. The ground side of the loop is typically connected to the chassis (as the neg. terminal of the battery is) via different types of ground straps to carry the current. If these straps fail (old age, deterioration, break with engine removal [done that], or simply loosen up and fall off) the current going in is MUCH higher than the remaining ground straps can carry. The theory is that when the secondary injectors kick in, the demand for current increases and the weak grounding system, once working fine for under 3800 RPMs, doesn't carry enough current quickly enough for the instant demand.

I'm not so sure about that theory myself, but doing a few Electrical Engineering calculations and knowing how much of an effect a drop in current can have on the rest of the system, I can see how the ECU could get goofed up easily at that point.

SO (is he done yet?!?!?), I say strap on a few extra ground wires to the ECU, the engine, the intake, and whatever else that could be losing ground. Too many ground wires can't hurt.

Done.

 

Just a little more about the secondary injectors coming on line at 3500 rpm. Its not just a case of the secondaries being brought online . Something else happens that I've watched with two voltmeters connected to the primary and secondary injectors.

Not only do the secondary injectors come online(only if the demand is there, by the way) at 3500 but the duty cycle to the primary injectors changes at the same moment.

An example would be stomping on the pedal at say 2400 rpm. You'd see the voltage drop on the primary injectors while the secondary injectors voltage remained static. When you hit 3500rom you'd see the voltage on the primaries would have dropped down to say 5 volts, but as the secondary injectors come on line that 5volts will change to approx 7 volts and at the same instant the secondary injector voltage droppin down to the exact same voltage of 7 volts, and if you keep your foot in it, both voltages will drop evenly down to ????????????? depends.

So I'm saying, not only do the secondaries come on line, but the duty cycle of the primaries lessens at the same instant, injecting less fuel than it was a moment ago. If the secondaries are not up to the job or slow coming on line, you can expect a hesitation, because you just lessened the output of the primaries. Make sense?

 

Did I just quote myself?

Thats what I was thinking. I did clean my injectors when I did the rebuild and the hesitation stopped...

Secondaries are easy to get to, maybe you should try that first, and then let us know how it went.

 

thanks fellas, i guess mine are working then, cause i can run my boy's 240, and my gears pull all the way up to redline. aprreciate it.