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deceleration cntrl system details - controls bucking btwn pos/neg acceleration
Well part of restoring my TII is fixing all the little nuances.
One is fixing the slight bucking between positive and negative acceleration (without boost). This is definitly noticiable in stop & go traffic in 1st - 3rd gears when your tapping or letting off the gas.
Here's a little article from haye's rx7 repair guide that may help everyone who thinks the bucking is normal realize it's not:
The deceleration control system consists of a dashpot, an anti-afterburn valve, and a fuel cut control system. The dashpot prevents the throttle valves from closing too abruptly. The anit-afterburn valve supplies air to the intake manifold during deceleration. The fuel cut control system improves fuel economy and prevents engine bucking during deceleration.
On turbocharged models, an air byp0ass valve is used to bypass compressed air during deceleration from after the turbocharger to before the turbocharger to prevent noise. If there is a problem with the system, which may be characterized bya failed emissions control test, high idle speed, stalling, backfiring, or overheating of the exaust system, and the following procedueres to not remedy the problem, take the vehicle to a qualified rx7 mechanic (not the dealer) for further diagnosis.
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Yes all very true,but not very enlightening.In the ecu software are a series of memorised DC lines which are the relationship between throttle valve opening and engine rpm.Fuel cut is activated based on the actual running condition of the engine relative to the DC lines,the running condition being determined by the instantaneous calculation of throttle valve opening (from TPS) and engine rpm.So if you have close the throttle valve at high rpm,you get fuel cut on front and rear rotors.As you slowly open the throttle(or have it less closed),you get front rotor fuel cut only.etc etc.Anyway the point of all this is that most of the jerking around occurs when the TPS is not set quite right,combined with poor set up of the dashpot--set up based on TPS resistance.
Hey thanks for the great post. Sounds like your knowlege is first hand
I've order the OEM repair manual and I REALLY hope information like this is explained. Knowing the inter-relationships between all the different systems of the 7s and what problems results when 1 or more are out of spec is the ONLY way to get the car back to the OEM new feel. The haye's manual definitly helps and I need to study it more before attempting to start a project convert 7 and TII drivetrain swap.
Next on the restore list is eliminating all steering wheel and tire vibrations. The 7s sure do absorb all vibrations from mis-allignment better than any other car I've driven, but you can still feel EVERYTHING in the steering wheel.
VAUGHNC....Try these also http://teamfc3s.org/main.shtml and this http://teamfc3s.org/main.shtml on this last one be sure to read the opening page and where it says *if your having trouble click here and go to our old page* On the old page hunt around for ARTICLES. Theres some goood reading there. By the way, did you download the factory service manual? I'm doing a survey on who did the download. Its totally free and if you want just download the section that your interested in . Section 4B, in your case. OOOOOPS, I meant to add this most highly regarded site http://get.about.com/sprinks/library...en&terms=autos
yep, I'll be compiling this type of into as well when I design the site.
I'm planning design the site to be a 1-stop-shop for everything fc3s including hard that hard to find info like:
"the reason no wide body 2nd gen rx7s were made/imported was the import tax would double if the rx7 was any bigger and mazda was shooting for a lower cost sports car for everyone theme"
plus bodykits, TSBs & recalls, and a MUCH MORE DETAILED FAQ.
Right now there's no 1 fc3s site that does it all, each has it's own good content.
Linear Mode
