GSXRATED

iTrader: (12)

Ok, I've searched around a while, and found a few answers to some of my questions but I still have a few. I had massive vacuum line problems on this car, they were hard, and many were shattered into pieces. Some of the check valves were damaged also. Does leaving out a few check valves cause any serious problems? Also, there is a blue connector near the two solenoids that are bolted to the front of the intake manifold. I cannot find where this connector attaches to, or does it not have anything it connects to? I started the car with a 3" downpipe, and the stock midpipe, and I get some popping (backfires). Is this due to low backpressure without the muffler attached, or old plugs possibly? This car need ALOT of work, but i'm doing my best and trying not to condemn this rotary to the junkyard.

Joe Geiman

The popping you describe could have many causes.

You should not do anything unless or until you understand the systems in the car well enough to know what the consequences are of deleting things like check valves.

If I were you, I would put the engine and controls back to stock condition and then you will have a baseline stock condition to work from.

There is plenty of tech information on this forum to fix anything on your car.
There are plenty of people who are members here who will give you good advice.

Don't do something stupid with the control circuits and make the $6000 blown up engine mistake.

GSXRATED

iTrader: (12)

I'm trying to put the controls back to stock condition, but several of those check valves are broken. Where can I purchase those, or is the dealer the best bet?

Mahjik

iTrader: (1)

Yes, not having the proper check valves can cause turbo control related problems. For replacements, check here:

https://www.rx7club.com/group-buy-center-69/now-available-viton-check-valves-much-cheaper-than-stock-391766/

As for the popping, replacing the pre-cat with a aftermarket downpipe will allow the car "some" popping. However, it should not be in excess. If it is, start with basic maintenance:

* change/clean the spark plugs
* inspect the plug wires and change if needed
* replace the O2 sensor
* replace fuel filter

Sgtblue

iTrader: (16)

Most of the popping/backfire should go away when the car is up to operating temps.
As for the blue connector near the vac chamber at the front of the UIM, you can ignore that. It's something that was specific for California emissions.

GSXRATED

iTrader: (12)

Ok, thanks alot. I thought it was probably emissions related or was for automatic cars. Anyways, I changed the plugs today and she fired up like a champ! Now the idle jumps between 1k and 1500 rpm, and the turbos spool, but no boost builds on the gauge. I'm thinking that it is vacuum line or solenoid related, and I am getting new check valves to replace the stock ones that were in pieces. I'm off to search some more now, and get this car back up to perfect condition.

GSXRATED

iTrader: (12)

OK, a brief update. I replaced one of the check valves and the car boost only 2-3 lbs now.

alexdimen

iTrader: (13)

did you put it in the right direction?

and you only replaced one? why not all if they are broken? dale clark has a set of viton valves he sells, which are excellent.

GSXRATED

iTrader: (12)

Well, I would have replaced them all last night had NAPA had more than one. I bought two more today and I think I should be able to replace all the broken ones now. I did put it in the right direction, lol. The arrow means that air is free to travel in that direction on the stock valves, correct?

GSXRATED

iTrader: (12)

Hmm, it is a little better, but I still have issues with the idle slightly bouncing and the car only makes 4lbs of boost.

jmadams74

You've got to get all the vacuum lines and solenoids working properly before you will know what the turbos are doing or not doing. This is a pretty big job if you are not familiar with the car. Perhaps let a mechanic (RX-7 expert) do this for you and then you could take it from there? Spending a little now may save a lot later.

alexdimen

iTrader: (13)

or DIY

print/save

jmadams74

Going from "does leaving out a few check valves cause any serious problems" to doing a complete hose job and checking all solenoids/actuators for proper function/perfomance is too much of a leap for 99% of new owners. . .this is why god created money! lol

alexdimen

iTrader: (13)

you've got a point there.

GSXRATED

iTrader: (12)

Lol, believe me, I'm no newbie when it comes to cars or even turbo vehicles. I have a 500+ whp Eclipse GSX, and have owned several turbo eclipses, f-bodies, and hondas, and do all of my own work. I was merely asking what effect the check valves would have or if they were emissions related more so than turbo related. I'm more familiar with large single turbo setups, and this overly complex sequential twin setup is a PITA to get working well. I replaced most of the hoses, and just left the solenoid rack alone because my screws holding it down are extremely tight. I spent about 12 hours already working on the car, and those damn vacuum lines require tiny hands to get to everything, not to mention all of my lines are baked on and are hard. Have some faith though, I'm determined to get this poorly treated FD back into shape with a properly functioning sequential setup. You should have seen the car when I got it, it's quite a project. I may remove all of the emissions since i live in an area with no testing, and do the simplified sequential mod if I still have problems with the car. I won't have time to work on it again until my winter break in 2.5 weeks, and then paint is becoming a priority.

fendamonky

iTrader: (6)

As far as all those baked vacuum lines.. I'm pretty positive Mazda put out recalls on those, and (unless it was already performed) you can take it in and have the dealer replace all the fucked hosing for free.. there were two more recall aswell. I forget what exactly though.

GSXRATED

iTrader: (12)

Wow, well that is certainly something that I will look into! Hopefully I can get the recall done if that's true and be rid of all these problems.

Sgtblue

iTrader: (16)

Good luck with that.
AFAIK, MAZDA never recalled vacuum hoses, or solenoids or check valves. They may have had to stand behind some of them if they were emissions related for a few years past warranty, but that deadline has also come and gone.

GSXRATED

iTrader: (12)

Oh, well that's a bummer, I guess I'll go back to checking solenoids and hoses when I get back for winter break. Thanks for all of the help guys.

jmadams74

I'll admit I'm being a bit of a purest here, but unless you are really shooting for a super-high horsepower (425+RWHP) or racing/tracking the car regularly, the sequential turbo system is at the heart of this car's unique performance. Stock through BNR stage 3 sequential twins, nothing can beat this car's low end and transition to high end power. Don't just pull everything off and go non-sequential because it takes a bit (yes, a good bit) of work work to get it running properly. You'll be really pleased at the result of properly functioning sequential twins. (OK, back off my soapbox now)

Monkman33

iTrader: (28)

It sounds like you are willing/able to put the time/effort into this car. Just be sure that it is as much as the car deserves. I am in agreement with the person who posted above me... as soon as Mazda made it, FD3S translates roughly into: Rotary Powered, Sequentially Turbocharged (for the sweetest powerband ever) best handling combination ever made... with timeless looks.

Perfection in a car is not being the best in one field, and slacking in the rest..... it's being so good in each field that you are always competitive.