noob5,000,000's 1986 Mazda RX7 "RustBalls McGillicutty"

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noob5,000,000
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noob5,000,000's 1986 Mazda RX7 "RustBalls McGillicutty"

Post by noob5,000,000 »

Figured I might as well start a new thread since the other one was basically just a rundown of all the problems with the car, and various accounts of how it doesn't run very well. Actually, it's in basically the same position now so this is mostly a place holder for when more fun and productive stuff happens.
Here's some pics from when I first got it:
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In the middle of some work:
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Why I'm pissed off:
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Fun video: http://www.youtube.com/watch?v=OkcmOaU2O58
Last edited by noob5,000,000 on Wed Oct 13, 2010 8:52 pm, edited 1 time in total.
1986 Mazda RX-7 sport - slowly returning to the Earth
1986 Mazda RX-7 base - Project car, ???, In pieces, turbo parts around.
noob5,000,000
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by noob5,000,000 »

In case anyone was wondering, the car still doesn't run.
A while back, I checked the resistance on the TPS and found that no matter how much I adjusted it, I couldn't get it in spec. So it was time for a new one. I went to the junkyard to find one (I'm lucky, the ghetto junkyard I go to in Detroit has like 7 FCs 8) ), But only one of them had a TPS. And lo and behold it was bad too (sitting out in the elements with no hood will do that I guess.) So I got another from another junkyard, also bad (it was on a motor that was just chillin outside). So finally I bought one from a known-running car from a guy on RX7club. After alot of anticipation, I finally recieved it on Wednesday. I installed it, but couldn't get the car to crank well enough to start consistently (dead battery + crappy charger). It did act like it was running for about 3 seconds, but then died :x . Today, I got a brand spankin' new charger and hooked it up. The car cranks perfectly now, but still doesn't start :x :x :x :x I'm getting fuel, I can hear the pump turning on and fuel flowing through the rails when I jumper the fuel pump test connector, I'm pretty sure I'm getting spark, because it did start up for a few seconds yesterday and today. I'm now thinking it is mondo-flooded from all my starting attempts. I tried the 'simple' deflooding method a couple times to day to no avail. I'm going to go out tomorrow and pull the spark plugs to do the 'hard' deflood method and inspect the plugs (I supect they are bad due to possibly being flooded) Another thing I'm thinking is that the timing might be off, but I don't really think os because I've never messed with it and it ran pretty good before. So Idk, we shall see what happens tomorrow I guess. :|
1986 Mazda RX-7 sport - slowly returning to the Earth
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by ColJessip »

Verrr nice I like
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by noob5,000,000 »

Ok, so last night I went out and pulled the plugs to find them pretty soaked in gasoline. I left them out overnight, and cranked the hell out of the car today to get all the fuel out of the motor. After that, I put the plugs back in and it finally started :o... But there's a catch, it's doing the f**k idle surge thing again :x I played with the TPS some more and I got it to change its 'rhythm' but it was still surging. The TPS isn't exactly in spec and I couldn't get it there no matter how much I tried. I'm beginning to suspect something else is wrong somewhere, since it is highly unlikely that my first TPS would go bad for no reason and the next 3 were all bad. I began to suspect the BAC (which controls idle when various loads are put on the motor) I unplugged it while the car was running and nothing happened (the general rule is the idle should drop) so I think that may be the problem :x . That said, f**k buying a new one, some people just remove it altogether and just have to deal with pedaling it until it warms up. I'm about to remove all the 'cold idle warm up' shit, too much stuff to go wrong. I'm willing to deal with 5 minutes of unstable idle in exchange for simplified engine bay and diagnosis. I'm about to order a couple more block-off plates tonight or tomorrow...
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by permabanned »

lol poser. glad to hear its running
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by Tinton »

Nice. We're getting our 80's cars running :lol: its good to hear you're about ready to drive yours :).
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by noob5,000,000 »

Figured I might as well post a small update...

As you may know if you keep up with the misc thread, I nearly had an engine fire a couple days ago. 2nd gen RX7s (and most EFI vehicles, actually) have a device on the end of the fuel rail, called a Pulsation Damper, that uses an internal diaphragm to smooth out the flow of fuel throught the rail. It's is fairly common on Series 4 ('86-'88) FCs for this diaphragm to tear and allow fuel to drip out and onto the motor, often resulting in catastrophic engine fires (check your PD, kids!!)

So I'm just minding my own business a couple days ago, trying to figure out why the eff my idle still surges (I eventually figured out I had a vacuum leak from the throttle body gasket, new one on the way from Mazdatrix right now) and to give the exhaust I finally installed a good listen and a leak test (I think I have one at the Y-pipe too :x ) So I'm ricing out in the garage video taping the mad tyte flames that a catless rotary allows when I suddenly see smoke billowing out from the engine bay. I'm like "SHEEEIT!!" as I kill it and jump out. I took a look under the hood and saw this smoke/steam coming out from under the intake manifold. I immediately suspected the PD and sure enough, that shit was leaking when I checked it out the next day.

Rather than spending $150 on a new failtacular PD, I decided to tkae the high road and buy a $10 banjo bolt to totally eliminate the whole thing. This is a highly debated method, some arguing that the lack of smoothness in the fuel rail could cause the A/F ratio to lean out unexpectedly. That said, that really on matters on turbo cars and I doubt it will hurt much on a stock n/a. So now I have to pull off all the intakes to get to the primary fuel rail.

My +5 hp andonized blue banjo bolt (Summit had it to me in 2 days! :shock: )
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While I have all the intake stuff off I decided I'd do the throttle body mod as well. The throttle body mod consists of getting rid of the thermowax, which opens and closes a second set of throttle plates under cold conditions. I also lightly ported the throttle body while I was in there. I didn't go too crazy with it (since it doesn't do much for an n/a anyway) but it gave me something to do in the downtime.

Here's all the junk that comes out/off of the TB after the TB mod
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Getting the second set of throttle plates out was a major bitch, since the screws holding the plates in completely stripped immediately. :x Drilling out screws FTL

Here's the TB after all was said and done. I still need to smooth out the walls a little after the porting and clean it out.
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I kept the dashpot (bulky thing on the lower left side) This slows down the closing of the throttle plates if the driver quickly lets off the gas pedal. I've heard elimination of the dashpot can cause stalling in those conditions (panic braking, ROC shifts, etc.)

I need to go out and finish tearing down the intake and fuel rails tomorrow and continue waiting for my TB gasket (should be here Monday or Tuesday)


Oh yeah, here's dramatic footage of the near-fire:
http://www.youtube.com/watch?v=Mi0K0wZ6fUI
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noob5,000,000
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by noob5,000,000 »

Bam, son!!
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by watkins »

Look at all those fresh new ponies waiting to gallup
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by noob5,000,000 »

Oh hell yeah. Just thinking about it makes me want to burn a techno CD.
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by Leedeth »

Lol wtf is that pink stuff on your pipe?
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by watkins »

noob5,000,000 wrote:Oh hell yeah. Just thinking about it makes me want to burn a techno CD.
Do it! :roll:
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by mtheis »

Leedeth wrote:Lol wtf is that pink stuff on your pipe?
That's what she said.
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noob5,000,000
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by noob5,000,000 »

mtheis wrote:
Leedeth wrote:Lol wtf is that pink stuff on your pipe?
That's what she said.
:lol: :lol: :lol:

But really, it's an ancient sticker that has not fared well against 20 years of heat and weather.
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Re: noob5,000,000's 1986 Mazda RX7 sport

Post by noob5,000,000 »

Image http://www.youtube.com/watch?v=X7siCy64w7g Image

So it's finally running great.
Since the last post, I've replaced the throttle body o-ring (the old one... wasn't there at all) and replaced the leaking pulsation damper with a banjo bolt. I also did the throttle body mod for better flow and simplicity. So no more vacuum leaks, therefore a solid idle. And there's no fuel dripping onto the hot motor and exhaust manifold, which is always a plus. It starts up pretty easily, when it's not flooded (more on that later) and revs smoothly all the way to redline. There is a slight bog if you just romp on the throttle, but I've heard this is normal on cars with the TB mod. Something to do with abrupt changes in intake velocity not being smoothed out by the secondary throttle plates (which are now gone).
As for the flooding thing, it's pretty common for FCs to have hot start issues (ie, flooding if you try to start it while the engine is warm). It did it after I shut it down for the first time today, the 2nd time I did the 3k rpm shutdown, which is supposed to stop it from happening. I haven't tried starting back up, so I'm not sure if it worked or not. I'm looking up solutions on RX7club right now.
But overall, I'm stoked it runs. :mrgreen:
1986 Mazda RX-7 sport - slowly returning to the Earth
1986 Mazda RX-7 base - Project car, ???, In pieces, turbo parts around.
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