strwy2svn

well, I purchased a 93 Vr rx7 5spd base. 89,000 original miles, last week. After saving and reading for a literal 2 1/2 years about these amazing cars, I finally bought it. 11,000 dollars cash. I would have posted this last week, but I've been working and driving this crazy car. I switched it to mobil1 super syn and have been easing into it. This car nearly stock can scare you, I cannot imagine more power. It has a k&n, and an old RB catback from the original owner, by the way. I've been a member under Savspeed for a while and reasearched my *** of about these cars. before i get crazy on details and my joy for the car I have some minor problmes with it, that I must address. 1, the car hesitates when driven under light throttle under 3500 rpm. 2, when switching onto gears quickly, the car doesn't feel like it boosts the same as when I'm in a gear for a moment and then get on the pedal.(the point is it doesn's put you back in the seat like it usually does).
Any advice on these issues, or any comments on anything, will be warmly welcomed.

rynberg

Welcome to the club!

Go ahead and do a full maintenance on the car (unless you have proof it has been done recently).

You should do:

*change all filters and fluids, including tranny, diff, and brake

*flush coolant system

*change plugs and wires

See where you stand after doing that. Your hesitation may simply be the infamous "3k hesitation" that afflicts some of our cars. There is no fixed cure for this as completely different things fix it for different people.

As far as not boosting after shifting, you may have an issue with one of the check valves or turbo control lines. Here is an excellent turbo troubleshooting guide:

http://www.autosportracetech.com/RX-7/rx7stuff.htm

good luck

dubulup

hesitation - try unplugging the O2 sensor.

behind the left side of the UIM, single wire black clip.

pomanferrari

iTrader: (1)

You should have driven them when they're new, i.e., all the bushing and steering are tight. When I tested them new, it was like a go-cart. At 89k they're so loose that I'm doing the JimLabreck bushing.

Rynberg is correct with #2, it's one of the check valve. Also check for a vaccum chamber nested b/w the powersteering and the Alternator, the line or the check valve to that chamber is usually the cause of laggy boost when down shifting as you're not building vaccumm d/shifting as opposed to while you're in gear.

#1 I'm not sure about, it could be the dreaded 3000 rpm buckling. the only real way of getting rid of it is to go with the Apexi PFC.

PVerdieck

Get rid of the precat and put a downpipe in immediately (not that that has anything to do with your questions ).

Toadman

Now why would you do that? Besides popping a code, how does your ECU know whether to lean or richen your A/F ratio based on operating temps?

Rynberg is spot-on. Give the car a complete physical, maybe even a compression check. Sometimes a grounding kit will kill off the 3.5k hesitation and cheaper than a new ECU. The car is kinda flaky with that. A fail-safe cure is to go non-sequential on the turbos.

dubulup

I forget all the specifics...closed loop mode uses the 02 sensor...I'm always second guessing myself.

I unplugged mine and the car runs MUCH better. O2 sensor I believe is for emission purposes to reach 14.7:1 A/F while in closed loop maybe??? while cruising in 4th or 5th. You won't get a code unless you're cruising b/t 2500 and 3000 rpms in those gears for 2-3 minutes...everytime I get on the interstate. At WOT, open loop (no feedback???) mode, (from my understanding) the O2 does nothing.

ECU lean or richer...MAP and intake temp sensor, is my guess.

flame away.

RyanREX

Always good to do the resurch before rather than after, he he.

dubulup

I did my homework before I did it (there are other people running around with the O2 unplugged, trust me)...because it sure as hell didn't make sense to me at the time...still doesn't in a way, but the way my car runs speaks for itself.

I've even tried switching to a 3-wire O2...no dice. Next step wide-band, I guess. The only down fall (besides driving with the CEL on) is MPG went down, since I'm not getting 14.7:1 A/F while cruising. When did I start caring about getting a good MPG anyway???

Street King

Hesitation- Most 7's do that, I be;live people have lessoned it and sometimes eliminated it with a bunch more grounds

Boost problem- I had something like that a few years ago. I forgot the cure but I belive it was a Lazy Soleniod. The soleniod is on it's way out and would sometimes work sometimes wouldn't.

Kaotic Dan

I had the same bucking problem really badly. I added some grounds and havn't had it since. Worked for me :-)