Jehuty77

Regarding it needing a rebuild, your probably right but it gets confusing because some people are saying it should run fine. Which is it :S

ibeljin

iTrader: (1)

that engine bay looks like all sorts of bad. Missing components and a hacked wiring harness is a nightmare. Depending on how long the car has been sitting you might see a bump in compression from running the car again, but given the car is so screwed up it would really be easier to yank the engine and start fresh

Jehuty77

Like i mentioned in my first post, its not my car, its actually my buddies but he doesnt use forums so im trying to find out all the info i can,

that being said I 100% agree, i honestly would like my buddy to just start with a fresh harness and swap/rebuild motors, i hate trying it hack things to work.

Whats really weird is where the previous owner chopped the harness, the harness he spliced it back together with has different wire colors(some wires), i dont know whether its like turbo vs non turbo harness or S4 vs S5 harness or some jdm mismatch.

I know this is a strech bu is there maybe a series of diagrams that would indicate wire colors or something?

Trigger Happy

The car was originally 4 lug, the 5-lug up front was swapped in by the previous owner.

Jehuty77

So here is my notes from the cut harness

For unknown reasons the owner cut the harness and swapped motors, the new motor has different colored wires, they dont match up, my concern is maybe its a totally different motor(say from an s5) or the harness is wrong

I've made two columns,
1 - Engine - this is the harness that runs along the front of the intake manifold
2- FW(Firewall) - this is the harness that runs behind the intake manifold

What I've done is written down the color and then the color it was spliced to in the next column

Jehuty77

So we swapped ECU's which didn't really make a difference, when we fired it up from cold it idles for a good 2 minutes and then the car got real grumpy and went back to its old habbits.

Maybe its a Temp Sensor? Input is appreciated

sctRota

iTrader: (2)

Highly doubt that it needs a rebuild, check if the grounds that bolt on the starter. I had this exact problem with my 89 fc and it was a loose ground that caused it to backfire and stall when it got hot

Jehuty77

Today We didn't get around to working on the engine at all but I did get a new Brake Master Cylinder installed and bled all 4 brakes.

What a messy job :S

ROTRY PWR

iTrader: (13)

I would say swap out the harness, not hard to to get at all. In the process of doing it you can check everything under the intake manifold.
The engine might be from one with high impedence injectors, hence the reason for hacking up the harness, the injector plugs are slightly different.
The 86 originally came with low impedence injectors...
At this point its starting, so it looks like its all matched up you just have to find the electrical gremlin thats causing it to stall out.

Bac does some weird stuff when not working properly but will still idle
Water temp sensor if bad will still run just rich.
TPS if bad can also make run but not idle properly and very little power

Bad grounds might cause what you are describing:
1. behind the engine
2. Near the air flow meter
3. Under the cat near the rear mufflers
4. Near the fuel pump assembly
5. ground in the engine bay fuse compartment.
6. Near the Ecu, kickpanel area.

My bet is the harness has been roughed up and has a short somewhere else.

Jehuty77

Finished Servicing the brakes today, regreased all the pins and new pads.

Kept working on engine but still not much progress

thewird

iTrader: (8)

Sounds like it started running on one rotor. Possibly try changing coils and plugs/wires if you haven't already. Make sure the coils are bolted down properly as they ground to the chassis through the mounting points. Maybe pull the injectors and have them cleaned or check the connectors to them. Check the sensor connections for coolant and air temp etc.

But I should say it again if compression is low, it could be flooding out the bank thats low once it gets warm. Low compression engines run worse when they're warm and better when they are cold.

thewird

Jehuty77

Thanks Dude!

Jehuty77

Oh

Someone also suggested that the timing may be off and thats why it will barely idles when cold and once warm it advances the timing too much and screws up.

Jehuty77

Jehuty77

So apparently my buddy got a full 5 bolt rear end to put in, ughhh so much work :|

Someone who has done this before please lend a hand.

He also got the full stock exhaust which should shut this dam car up... hopefully.

misterstyx69

iTrader: (142)

you should just buy my car man!..lol!
5 lug swap done..brakes have new ****(flex lines,steel lines)..I got 2 exhausts..
The engine is GREAT... synthetic in the N/A LSD and the trans.TII hood and s5 tails..what else can you want?..lol!

Yep,I'll lend you a hand,,you put 1200 in my hand and I will give you a car!

But seriously,Here is a MR STYX: HOW To Drop a Subframe Write up!

Your exhaust is off already?good..that is half the battle.
Make sure you got the car jacked up and the subframe supported and you are capable of lowering it from the car.
Hang the brakes on the shocks.Brakes:12mm bolt on brakes,Tilt caliper off rotor,slides off the pin.,undo the shocks at the 17mm bolt on the lower pin.They will come off of you suse a small pry bar.IF you do not feel like having the shocks in the road at all then 2 14mm nuts at the TOP of the Shock,inside the speaker area of the shock tower will allow you to take the shock OFF.(but you will have to find an alternate place to hang the brakes.
Undo the Link at the back of the subframe.Move it out of the way.
The brackets at the front of the subframe have 14mm under the rockers that need to come off.Then you can remove the 21mm nuts from the Front of the subframe when you are ready to drop the assembly.The brackets will come off then.You may have to pry them a bit,as they were on the car at 2 mounting points,so they need a bit of wiggling!(But they will just drop after your 14mmnut and the 21mm nut are off)
Undo the Driveshaft from the Diff,using 14mm rachet and wrench.Mark the driveshaft if you want to.(mark flange on shaft and Diff to align shaft to original position when putting it back on).Give the flange a Whack,then use a pry bar and put it in between the 2 flanges(Diff and shaft) this will separate the 2 parts.Watch your face!
Let the driveshaft hang.DO NOT pull the driveshaft OUT of the trans or Fluid will leak out.
Now,remove the 2 17mm nuts on each ear of the differential and get the cups off the bottom.

You should by rights be ready to lower the whole subframe.Are The main bolts off(Diff ears and front subframe bolts).???Brakes hung.driveshaft off,Subframe link off?

It will or may require a little prying at the mounting points but it will come down as one unit.
I usually put a board on the jack, between the subframe "U" and the very Bottom of the Diff,to make the whole unit a little more steady.Then the only thing that you worry about is tilting off to the side.
If you are doing this alone(Which I DID,so this is NOT new,and has been Approved by the MR STYX Differential removal crew!),then just do everything Slooowly!!.
If not have a person just hold the assembly while you lower it.

There ya go..Have fun..I take cash or Paypal!!..lol!

ROTRY PWR

iTrader: (13)

Subframe is not too difficult, you will need two solid jacks to raise it into position.
Try to get as close as posssible to the front mounting points.
Use a third jack to keep the pumpkin steady.
Raise and wiggle into position.

Make sure the car is on sturdy jackstands!!!

Good Luck.

Jehuty77

Installed new TPS Sensor today

Runs better now but still feels rough, we didnt do any kind of setting it up, i know there are adjustments you should do, i literally bolted it in and took it for test drive as it was able to rev.

Still once it reach operating temperatures it felt like it was searching for idle like previously but now it can rev.

Rathmar

iTrader: (8)

it feels gutless because you probably need a full tune up and a turbo

Jehuty77

Been a while since we updated this, we got the full rear end out of the car switching over to a 5 lug setup, redoing the bushings and finding replacement Diff and subframe bushings are hard to find and that there is alot of mixed information on how swithcing to delrin int he back will lead to vibrations.

OEM part Numbers:
RX7 FC3S Rear Diffenetial Bushing: #FB01-28-890C
RX7 FC3S Rear Sub Frame Bushing: #FB43-28-840

http://www.racingbeat.com/RX7-1986-1...ial/12053.html



We seen these solid bushings but i dont think we'll be going with those
http://www.partsshopmax.com/page.php?66

misterstyx69

iTrader: (142)

That solid front differential mount may be a problem.

The design has been debated.
It puts the pressure and flex totally on the tab of the subframe(where it bolts the diff to the frame) and therefore it can sheer it off and you'd end up having to drop the subframe all over again.

sctRota

iTrader: (2)

Was about to say the same, grab poly urethane bushings or get oem stuff. Unless you are going all out high performance, its like putting a full roll cage in a all stock car. Sure it improves the rigidness, but just makes it more uncomfortable to drive

Scrodes

With a read interior

Jehuty77

LOL! ya its a bit bizare

Jehuty77

So this deal popped up and we had to snag it

I know since this is the build thread for the banana rx7 not the ideal place to put this but owell

$500 for an all original Rx7 FC GXL

Original Owner, 110,000 KM











So basically now double the trouble :S