Ottoman

Hey guys,

new member here,

here's my story: If u don't feel like reading the story part, I put a divider u can skip down to...

I used to live in canada, but now on the other side of the pond, (dubai)

I've always been a fan of mechanics and the rotary being so diff and unusual and unique

I've been doin most of my own wrench work for the last couple years.. and enjoy getting "my hands dirty"

my previous experience has been mostly with: 4G63, SR20DET, RB26DETT,RB25DET,B16A, amongst me and my friends we have an R33 GT-R VSPEC , 2 S13's with SR swaps, I have an eclipse GS-T and used to have a delsol... etc



but no rotary experience... as no rx7's were ever sold from the dealership around here

I found a US spec 88 FC3S TII (there's a few FD's imported as well) it was imported years ago, buy an old white guy, he's had the car here 3 years, it ran fine for 2, then expeirienced some problems and it sat unused for a year... IT"S THE ONE AND ONLY FC3S PERIOD.. one of a kind here...

i bought the car off him for 400 bux.. it has 80,000 original miles on it.. new shocks new engine mounts and bushings.. some other odds and ends.. I was shocked for what it had for an 88! power windows, power sun roof, Cruise control, power mirrors, A/C, power steering, leather shift ****/boot, alloy rims, EQ on the deck... man this thing is loaded!

I towed the car to my garage, and have begun the resurection...

Initial impressions: the engine aint so compex after all.. in fact seems simpler in some ways... (things seem easier to reach, and easier to remove, more space around the engine to work, etc)

I downloaded the FSM, and I got a copy of the Haynes manual with the car...

first thing I did was drain all the fluids and replace them..seeing as how it wasn't even cranked for a year i figured fresh fluids would be a good start

i then began removing the "unneccesaries" and simplifying the car (my intention is to make it a weekend track/dift car) I removed the whole a/c system, and began tearing apart the Emmissions controls... the Airpump, ACV, BAC etc..I'm goin to have custom block off plates/gaskets made to plug the extra holes

I removed the intercooler, and the was NO oil inside it, and very acceptable shaft play, alot of the other turbo cars I've worked on have been worse...


************************************************** ***********

So anyways... I have some ideas of what could be the problem, but I lookin for the best and cheapest ways to diagnose the problems without changing a 1000 parts till I find the issue... (that way if I have to order an OEM part from the states I can do it once and do it right)

1st problem:


the car fired up, but when it's cold it doesn't want to stay alive.. keeps trying to die.. i have to give it a little bit of gas for it to stay alive....

after about 5 mins or so... when the car begins to warm up... the car will stay idling...


2nd problem: if I blip throttle the car will just stumble and fall.... if the car is idling and give it gas... the Rpm will surge up and down upto like 2,000 then fall back down the up then down, as if someone is pressing and letting go off the gas...

if i hold very slight throttle, like 5% ,gradually increasing, then I can get the engine to rev up to like 3,800-4,000 RPM then it'll again stumble and fall...

the engines doesn't have difficulty starting.. fires up fairly easily... but the exhaust smells Terrible... but i'm guessin that's cuz it hasn't run in forever.. and needs a good thrashing to get all the carbon out...

(this was with the A/C and air pump off, but the rest of the emission stuff was on there)

I Tried to do a compression test but by the time I got my tester, I had already removed the BAC and ACV and intercooler and stuff.. so when i was cranking the engine, it was a totally cold engine and air leaks everywhere... i hled the check valve open with a screw driver... when i cranked

all 4 cyls basically bounced to the same spot (around 45-50psi but this is probably cuz it was dead cold) consistantly... and if i didn't press the valve, it would build up a 100psi in every cyl....


So i think the engine is healthy... but has a secondary problem

the original alternator belt was cracked and had slack in it, I replaced it with a new tighter one... the Voltimeter shows more then 12 volts at the battery, so I know the alternator is fine...

I changed the fuel filter with no luck...

my guesses are:

Fuel Pump
Fuel Injectors
Coil pack(s)
Spark plug wires
Spark plugs
AFM (tho i opened it and cleaned the inside of it, it used to be sticky)
TPS



the plugs and wires I'll probaly change next, cuz they're easier to find and change..

if there's some other ways of diagnosing this problem, or if ppl know what this problem is without just changing everything, I'd appreciate the help...

remember there are NO spare parts whatsoever for this car, anything I need to replace, I'll order it from the states.. unless they are universal parts or parts from other mazda's that I can use... (like oil/fuel filter, plug wires etc)

I appreciate the help guys...

Thanks,

Otto

scheistermeister

there are no cylinders and a special compression tool is needed to check the compression

Alex-7

Yup, no cylinders................



I vote for the TPS.


Welcome to the forum and congrats on the FC, now, where the **** did you say you were from?




--Alex

SonicRaT

iTrader: (6)

You don't 'need' a special compression tool to get an idea. As stated above, there are no cylinders. It sounds like you think each spark plug represents a chamber/rotor/cylinder? of it's own, this is not the case. There are two rotors in the car, and there are two spark plugs to each rotor. So looking down from your drivers side at the spark plugs, this is how it's arranged

T1 T2
L1 L2

The two plugs on the top are trailing, the bottom are leading. The 'leading' coil pack is the one near the battery, the trailing is back near the master cylinder. T1 & L1 are your front rotor (obviously towards the front of the car), L2 T2 are then obviously trailing. To check compression, you use L1 and L2 (bottom plug holes) for each rotor. Anyway, it sounds like you've got a couple of simple problems.

First things first, do a complete tune-up like you're in the process of doing (plugs/wires/etc), replace all filters and fluids and even gas as well (if it's been sitting with the same tank for a while), just try to eliminate common things and get it ready to run good. Anyway, after all of that I would suggest trying to adjust the TPS, there are a number of places to do this, and it's in the FSM so I won't go into much depth, but generally you set it to either 1K ohms (disconnect the plug and adjust after the cars fully warmed up), or you can set it to 1v while the ignition is on, or you can use the two LED method which is written up in various places, search if you need more help). After that if it still has some troubles idling smooth/etc, I'd suggest checking for vacuum leaks, after removing the emissions & etc, it's almost gauranteed that a few have popped up somewhere. If you keep the catalytic converter on the car without the air pump, it will clog and severely hurt performance/etc. Either remove the cat or put the air pump back on.

Ottoman

Thanks for the replies..

sorry cyl was a "piston engine" habit... didn't mean to describe it that way..

all 4 "chambers" gave basically the same reading, and bounced to the same spot on the compression gauge, no matter how many times it revolved...

When i pulled the plugs, I noticed all 4 were the 9EQ trailing style... not 2 x9's and 2x 7's... T's and L's (all 4 of them have the little T on it)

is the 2 ranges colder bad? should I try to find 2 7's and 2 9's? or stick with 4 9's?


I'm goin to pull the intake manifold off, to get to the rat's nest soon, would a custom gasket be ok? i highly doubt the oem one will seal again after i remove it... or do I need an oem one?

kenn_chan

Dubai is part of the United Arab Emirates, kinda like ali babba's stomping ground only its a costal port or island, never been there myself just heard about it, one more shithole for some porr jarhead or squid to get sent to (and the occasional civillian) So which branch are you in?

the compression tester will give you an idea best to remove the schrader valve thats in it first, its not exact but it will give you and idea of a few things. chances are your TPS is fried, its a little double throw rheostat that tells the computer how far open the throttle is when it ***** the bucket the car will have a flat spot, useually where ever it spent the most time at, IE if grandma drove it, it will be around 1500~2500 RPM. if it hunts, and wanders, but the engine desn't wuite die, take a look at the O2 sensor, those would be my first two guess's Oh congrats, Where the **** did you get lucky enough to get a 7 over there?

kenn

Ottoman

lol I'm a civilian :P

It could be worse..

If i told u that an SR20 with engine transmission and wiring and ecu was 600bux (a whole front clip of an S13 we bought for 900 bux, it had a Blitz BOV a EXEDY single carbon clutch and the digital HUD)

and an 2JZGTE was 1200

a R32 GTR can be had for about 3,500
an R33 GTR is around 10
and R34 GTR is around 22..

the port here get's sooo much **** straight from japan... containers and containers of cars, most the "JDM" engines u guys buy are probably shipped outta here...


my 7 was originally purchased in illinois... then it was imported here.. then later sold, then sold again.. then I bought it...

complete random dumb luck...

most ppl quiver when they hear "rotary" like it's some evil b lack magic, nobody wants to touch it with a 10 foot pole...

obviously there's no qualified mechanics either... i'm on my own

Ottoman

Oh, I forgot to add,

when i open the throttle plate by hand the shaft with the spring on it on the opposing side of the throttle body, is "lazy"

like i open the plate full, the sping takes a while to "catch up" dunno if the spring has worn out over the years and it's laggy now and they're supposed to open together, or if it's supposed to be that way


and the 2ndary cat is already gone, but the primary cat that practically "replaces" any form of downpipe is still there... I plan on makin the exhaust a straight 2.5"s all the way.. I just wanna get the thing on it's feet first before takin it to an exhaust shop...

Parastie

That "laziness" is normal. Some users (such as myself) have removed the secondary throttle plates for better throttle response, but honestly, there's not real difference.

Also, there isn't "4 chambers" there's really only 2. Each set of spark plugs (top and bottum, Lead and Trailing) open to the same "chamber".

RXciting

Hey Ottoman, not sure if anyone caught this. But reading your post it almost sounds like your removing all 4 plugs at once when cranking. If this is what your doing that could also explain the low compression numbers. Just wanted to make sure your only taking out the 2 bottom plugs L1/L2 when doing the compression test.

Good luck with your TII and welcome to the forum!

Frank

Charlie

HI,
Too bad I didn't see this earlier. I finished my '87 NA rebuild about 3 weeks ago. I was over in Dubai last week working on a ship in the port or Jebal Ali. I would have been happy to swing by offer my unsolicited 2 cents. As for Dubai, I have never seen so much construction going on at one time. It really is amazing. Hope you're going to put you AC back on as it gets hot there in the summer.
Your compression is low. I don't think that even with all the ancilliary equipment removed, your compression should be that low, after all where is it leaking into?

If you can still crank the engine take another set of readings with the throttle wide open.

Take the schrader valve out of the compression tester so you can see each compression event for all three rotor faces rather than the cumulative compression results. When you do this you will note the needle bounces and does not stay at the peak pressure reading.
You may need to get someone to crank it over while you look at the needle.


You want to get three strong bounces out of the gage. If I remember correctly.
Two dead bounces followed by a strong bounce indicates a bad apex seal
Two strong bounces and a dead bounce indicate a bad side seal.

Good Luck

Ottoman

oh man, that sux, we coulda hooked up...

my check valve screw out as one unit, if i screw it out the hole left is too big...

if i leave it in, and just push the valve in, i get 3 even bounces... they're all them same... is it possible to have 3 low bounces at the same time?

Parastie

It is, but isn't usually important.
Remember, you need to do this once your car is fully warm. If you're doing this when it's cold, it's going to be lower.

The main point is the bounces are the same, if they are you should be okay.


You haven't tried doing any of the Antiflooding things have you?

Ottoman

U mean the EGI fuse trick to get it to start? or the kill switch for the fuel pump?


the car was BONE stock when i got it, there's nothing done to the car, everything was original except the exhaust which was replaced once.. even the airbox is still there.. till I tore it apart...

i've been lookin around for the "rat nest" removal guides.. best one I found was for the 1st gens from mazspeed..

is there a Visual FAQ for the 2nd gen TII? similar to the 1st gen one?

Parastie

I'm not sure if there's a Visual FAQ or not, I don't have one.

You could try pouring a small amount of ATF into the spark plug holes, that seems to work.
If all else fails, pushing starting these cars is quickest way to get them to start.

As long as you're getting even bounces the engine should start with enough coaxing

Charlie

How does your front readings compare to the rear?

Ottoman

they're all the same... within 5psi of each other...


the car has no problem starting...

the problem is it doesn't stay alive when it's cold (unless i hold the pedal slightly and keep the revs around 1,000)

after the car is warm and it idles... it doesn't wanna rev... u punch or blip the throttle the car just surges up and down, if u rev with the TINIEST bit of throttle, i can make the throttle climb slowly to almost 4,000 rpm, then it's like the rpm falls off a cliff.. it just plummets

CSM RX7

Not sure if you've figured anything out yet, so I thought I would ask if you've pulled the codes from the ECU. I was having the same problem with my car a while back and I just remember pulling all the codes and going through and fixing them one at a time until they were all gone. I recall after doing that it would no longer fall when I pressed the gas. Two things I did you might want to think about - 1. I ran new wires to the AFM because the connector would not fit on it right AND 2. replaced TPS.

Test the resistance values of the TPS and AFM to make sure they read to the specs in the manual. If they do, check the wiring from them back to the ECU.

Not sure if that will help, but what the hell.