Slow2k

iTrader: (9)

Just purchased this RX7 and been having a few issues. I did a decent amount of research before purchasing.

1994 Touring Model, 5spd.
Stock engine, rebuilt 8,000 miles ago by Rotary Doctor.
All seals replaced. Front iron replaced.
Used rotors were used.
Stock Twins rebuilt by BNR.
Car has a downpipe.

Waiting on my fuel filter to come in so I can have that replaced. Replaced the plugs, and going to get to replace my wires soon.

So off to the issues,
During hard acceleration the tachometer stops at 4500. It doesn't feel as if I've hit a wall or anything and I can still hear and feel the motor continuing. Last time I drove the car I didn't have a boost gauge yet. The car will rev past 4500 in neutral and if I use light throttle I can pass 4500. I have noticed however that when I get on it at around 3000rpm it seems like it starts to break up a little.

-Not sure if this pertains to it but I have been getting lots of fuel in my oil and also it takes a second of cranking longer than it should. It smokes out a light amount of grayish smoke that smells heavily of fuel until the car reaches near operating temperature. I've been suggested that it could be a leaking injector.

Video here: If you watch, even though the RPM stops the speedometer still climbs.

Second issue: I get this weird air noise, as if purging air from an air compressor (not as loud though) when I left off the gas, or even when I am lightly on the gas.
No. It's not a BOV. lol. I have no idea what it is, and I'd like to know.

Happens at about 3.5k RPM or 7 seconds in the video (coming down from rev)

Car idles okay, it doesn't die. It does idle a little high though, at around 1k-1.2k, lightly fluxuating.
Any input is appreciated. Thanks!

davlilly

I am having a similar issue. I found a broken check valve under the vacuum tank ( little black box in front of UIM) I fixed that and it worked great for a couple weeks now it is doing it again!

I think it's a vacuum issue just not sure. And not sure how or where to start checking either.

Slow2k

iTrader: (9)

Sorry which problem? The 4.5k RPM problem I'm guessing?
Have you checked it again? I'll look into that first. Thanks.

XLR8

iTrader: (52)

The tach gets its signal from the leading coil. If it was just the RPM guage being weird, I would say the capacitors could be going in your gauge cluster. This ia a common problem with the speedometer as well. However, since you are getting actual breakup, I'm definitely leading to the ignition. Plugs are a good place to start. I would also test your coils per the FSM. You may also want to check the coil harness. With it all residing in the stock location, everything gets pretty crispy after years of heat soak. The ignitor rarely goes bad, but it could be worth testing as well. It is flat and mounts beside the cruise control module.

I have a good set of coils and ignitor if needed. Just PM me.

As far as the noise on decel, it definitely sounds vacuum related. You mentioned the idle high which is another sympton. Get some carb cleaner and spray it around to check for leaks. If the car hasnt had a complete silicone line job, it may be times. It is possible the BOV is leakimg as well. Though they are not known to leak, everything is old and can fail.

davlilly

I think they are the same problem. From what I understand the whole sequential system works off of the vacuum lines and if something vacuum wise is messed up it can affect everything. I am gonna start trying to troubleshoot tomorrow.

Here is a pic of my faulty check valve.

davlilly

XLR8,

Just saw your post. Good idea about using the carb cleaner to check for leaks. I will be doing that tomorrow! I am also gonna go ahead and change my spark plugs and check that side too, although I think my problem is definitely a vacuum issues. I just bought the car recently and chasing all sorts of little upkeep & update type of things. Just trying to get it sorted and smoothed.

Thank you,
David

Slow2k

iTrader: (9)

At very first I was suspecting the gauge as well however I noticed that it will rev past 4.5k in neutral. What also bothers me is that 4.5k is such a specific RPM for a wide range of problems, turbo, vacuum/solenoid, secondary injectors, and thought it would be too coincidental for a gauge problem.

I have changed the plugs, they were pretty fouled, still drives the same, however there were 4; 7 heat range plugs in there previously. I may look into your coils and ignitor in the future however I'm currently suspecting some kind of rich condition that might be causing the breakup. I'm quite confused at the moment however.
It's funny you mention crispy, turns out there was harness damage during an engine fire years ago. I was debating replacing with another used good condition harness, but labor pricing for that is steep. Will probably have to though. Might consider Rywire. Although after the harness fire it was repaired slightly and drove great. Possible that age might've taken its toll on the harness now though.

I've never had a vacuum related noise that was so loud before, it annoys me, hah. I'll try the carb cleaner trick for sure though.

Thanks for the input, if anyone has any other ideas please let me know.

davlilly

The second video you posted shows your stock oil gauge hitting zero on deceleration, is that normal?

**I just noticed mine does it too.** So I hope it is normal! It also goes to zero at idle sometimes.... again is this normal?

Slow2k

iTrader: (9)

Yeah it usually means your oil pressure sensor is dirty or needs cleaning.

davlilly

I saw that another thread. I cleaned the contact under the oil filter and its reading steady again. My car is thankfully working like a dream again. My only issue now is my hks boost gauge is reading no boost. I know it's boosting fine though. I don't like the hose on it right now so I am gonna replace that and see what happens.

Good luck with everything and thanks for the great info.

-David

davlilly

Oh and be sure to check out around the LIM for vacuum leaks. I had one there too.