cheezi

I originally picked this car up for 50 bucks thinking I could fix it up, drive it around a bit, then sell it. most of my automotive experience is with nissan and honda. I don't think of myself as a complete idiot but I just can't figure this one out. I have an 82 that had been sitting for 4 years. first off I changed the oil, flushed the radiator. changed the fuel pump and filter. emptied the gas tank and put 93 grade in it. changed the plugs, wires, coils, and dist. cap. rebuilt the carb. after all this was done, I can do 0 to 60 in a whomping minute flat. since then i have ripped off all the egr. plugged all the holes and put o-ring clamps to make sure it's tight. took off the air pump. blocked off acv, hot air pipe, and something at the base of the carb. looks like some sort of restrictor. gutted the cat. patched the exhaust(not a pretty job but its sealed). timed it, checked compression, and even tried talking nice to it. I don't know if there is any trick to anything that I've done but I could use some suggestions. Thanks.

peejay

First things first. EGR? '82 did not have EGR. Dump that 93 and put 87 in it. What kind of fuel pump did you put on it? Did you check the timing?

How does it idle?

Jerm982

I'll take a stab at this one,

It might be the 93 octane fuel. Rotaries run best on the lower octane. Using "premium" fuel in rotaries actually harms their performance. So unless its got some type of forced induction (turbo, supercharger) it's best to use the lowest grade octane you can find.

FuLLsMoKe

WHAAAAAA?! Have I been in the dark?! It HURTS my 7?!?! I've never ever used anything lower than 93 in my cars! ARGHHHH!

Please explain how this hurts my poor 7!

cheezi

I think it was a purolator? it was just a one step better than the cheapest fuel pump. it wasn't egr, it was emmision control vac. lines. (rat's nest). it's not idling at all. sometimes I can get it to idle at about 1500. why is higher octane gas not good for rotary engines?

peejay

The high turbulence in the combustion chamber hinders flame front travel and acts as a natural anti-detonant. The higher the octane you run, the "slower" it burns. You'd want to run 80 octane fuel if you could find it

That fuel pump kinda sucks but it'll do. Make sure you don't have any vacuum leaks. But, unfotunately, it sounds like the engine's toasted.

alien_rx7

Hmm, my thoughts on higher octane have always been different than that. Guess what I heard was wrong Anyways, I thought that higher octane fuel had a higher flash point. This means that it also burns hotter. I figured since it has always looked like it was recommended for high compression engines, the compression helped the burn rate since compression creates heat also, then the spark plug ignites and BLAM! you get a better burn because you've reached that magic flash point through compression. If you already have an internal temperature that is already extremely hotter than normal such as in the rotary or high compression engines, then cheaper (ie: lower octane fuels) end up pre-combusting causing the dreaded internal backfire/knock.

peejay

It burns slower because of the higher flash point - it's harder for the flame front to move through the chamber. Basically when you run too high of an octane, less fuel burns in the chamber and more burns in the exhaust....

crankit

Maybe a lack of air????

Directfreak

iTrader: (2)

Agreed. I used to run 93 all the time before I found out differently.

However, this is NOT the reason his car is running like crap. It's obviously something else (That I have no idea about)

82streetracer

iTrader: (1)

ATF ATF ATF

why has no one suggested this yet.

Got to mazspeed.com and go to FACTS for instruction on how to AFT your engine. Its probably got huge carbon build up.

Rotarius

If u-r sure is not intake or exhaust restrictions my stab at it would be fuel. Possibly the secondary butterflies are not getting a healthy anmount of fuel. Also Rotaries have 2timings very differently for piston engines. Check that and good luck.

Project84

You ain't in Kansas now Dorthy, the rotary engine ain't nothing like a Nissan or Honda. The exhaust from a rotary engine gets up to 400 degrees hotter than a piston engine. The air pump is on there for a reason. Why not just put on some headers, high flow cat (optional) or straight pipe and a turbo muffler? If your going to do something, do it right, don't do stuff like gutting the cat, rip this out, plug that up, cut this, splice that. Then you say you are going to sell it? Yeah, there are cheap ways of doing certain things, but not everything

cheezi

I'm going to try the atf treatment and get back to you. I'v got 88 (lowest grade I could find) fuel in it and still no better. will post my results.

FuLLsMoKe

So while I am saving money, I'm also getting more performace?! SWEET!

Keaponlaffen

I know this'll sound funny, but is your gas tank dented? mine was, right where the fuel pickup is, and it was restricting fuel flow into the feeder line, and to the pump. The car would run for like 5 minutes, empty the float bowl, and the do the lawnmower syndrome best descrived as 0-60 in a minute, and then die, then I'd wait for 5 minutes with the key on "on" and start her up, drive her for another 5 minutes, and it'd do it again. This definately sounds like Fuel, or Seals.

How did the compression test turn out?
Have you pulled the main (biggest) fuel line off the carb and turned the key to the "on" position? 1.1 litres or more of gas should come shooting out in a minute (so a beer can should be filled in about 20 seconds). If any less than this, you've got

A) A blocked fuel line
B) A kinked fuel line
C) A dented tank
D) A defective fuel pump
E) A defective fuel filter (if that's possible)
or F) An airlock

If the fuel coming out is good, check the little screen under the carb fittig to make sure it's not clogged

If none of the above works, it's the engine, a vacuum leak, or something I've never heard of...

Jeff

V8kilr

if his compression is good atf is not the answer,

it may help though

V8kilr

OH ****** YEAH,

I JUST REMEMBERED THERES A LINE YOU DO NOT PLUG WHEN YOU REMOVE THE RATS NEST,

thats right remember my rx7 woes thread ??????

i will update it when i get a digi in hand to take the picks,

im serious here if you plug this "thingy" it will rape you bad,

to bad nobody ever puts that in the rats nest removel threads

SilverRocket

are you talking about the vent solenoid on the top of the carb? I don't think that would cause the symptoms he's talking about, but yeah, you don't wanna plug that

V8kilr

no its on the bottom driver side and has this little plunger if you press it to the left your intake manifold will gasp in a bunch of air and stall,

its really loud,

but when your driving it make a diferent noise all together ,
kinda like a horn or something and try's to stall along with the noise,

unplugged a little line that was capped and voila

Sterling

If your carb was "de-enviroed" correctly, you would'nt have "that little plunger thingy".

I like what Keaponlaffen said...but with something a bit different in mind...
This car sat for 4 years? Then I guarantee that the whole fuel system needs attention from the tank to the carb. Could've sucked rust chunx into the hosework.

Even if the line is good, and the carb is good (4 years?), the hoses that go from the cut and check valve, the inside of the valve itself; all of that can be sticky with varnish and not allowing fuel to come thru easily. When you get right under the tank, you see that the fuel really does go on quite a roller-coaster ride before it even gets to your pump.

Flakes of rust are just perfect little baffels.

That would explain the 0-60 in 60 sec.s problem.
As far as the 2K idle...that sounds like a typical cracked hose/gasket thing.

cheezi

alright, I'm not sure what I did, but when I first got it I checked the compression. all I have is a normal compression tester and the I took out the trailing spark plug. that's what I was told to do by a couple web sites. anyway the compression read 40ish on the front rotor and 50ish on the back. I just check 10 minutes ago after all this and now the front rotor has 0. Still not sure if it's something that I did or if it can, an apex seal just broke off. can you just replace the apex seals on one rotor or if you got it out might as well do two?, or should I try the atf?

damon

hey v8kilr are you talking about the decelleration valve that buried at the base of the carb (where the 'nest used to be?

damon

ATF! ATF! ATF! also you should have more then one reading for each rotor ( a rotor has three sides )

cheezi

the way that I read up on how to do it is have someone crank the engine why the other person holds the air release valve on the compression tester. the front rotor there was a 0 reading even if I didn't hold the air release on the comp tester. the rear one jump to the same pressure everytime. within a few psi.