Suspension wobble plus a few other questions

[XakkGrill]

So I'm brand new to the 240 world. I guess this is kinda my intro as well. Bought my first s13. I mostly work on my MR2 Turbo, so going to an FR is a little strange. Im looking for some guidance.

I got this chassis for cheap and one of the main issues that I have is a crazy wobble over bumps. The car rocks side to side and back and forth over noticeable bumps in the road. The car is on some cheap coils(Function and Form type 2's I believe?) welded diff and solid rear subframe bushings. I bought the car slammed on its ass, collars taken out, whole nine yards. I reset the preload(10mm), raised the car, adjusted the damping from full hard to manageable, and I still have this death wobble.

Now, the wobble is not in the steering wheel, it is the entire car; as if it were a chair with a short leg. I do get steering wheel shake around 45mph, but the outer tie rods and tires have seen better days(along with most of the suspension parts). I would like to not go around replacing all of the bushings and it not fix the problem.

The previous owner said it might be because the car has no front swaybar, I find that hard to believe, but Im new to this car.



Completely unrelated questions:
My coolant temp gauge doesn't work, Im assuming it is the sensor. If someone knows the part number for the sensor that would be awesome.

Also its has a KA24DE, with an s14 intake manifold. Supposedly has a s14 IACV which gives me trouble in the morning at cold start. Can I throw a s13 IACV on it and fix that issue?

Thanks.

[Croustibat]

I guess all bushings are shot due to being driven at battleship earth height. Good luck changing them...

[XakkGrill]

Thats what Im afraid of. I really dont want to invest that much time changing bushings and the problem not go away. However, that was my first guess as well.

[Croustibat]

It looks like you bought a car with tons of problems, so if you already are throwing the towel, you may as well sell the car :/

It can be (cumulative):

bushings shot
wheel bearings shot
coilovers shot (play in shaft or upper bushing/bearing)
bent wheels
poor alignment that killed tires
overlowering that cannot allow a good alignment, and that killed tires
previous owner hitting curbs badly and tire structure killed
play in lower arm ball joints
play in steering rack ball joint
steering rack shot

The first bushes to die are the front traction rods and steering rack bushings. They also are the easiest to change, so i suggest you start there if you intend to fix the car.

Have a pro check the wheels and tyre too. This is quite easy and fast to check provided you have the tools. Tyre structure cannot be truely inspected, so i suggest you change the tyres if the wheels are bent (they didnt bend without hurting the tyres badly)

You can check everything else by yourself.


Cheap car usually means "tons of stuff to fix", usually ending up with "more expensive than buying an already fixed one".

[XakkGrill]

Ive rebuilt cars from the rust up before, so Im far from throwing in the towel, I just wish there was a better answer than "bushings and shit" (inside joke). The wheels are probably bent, the tires are showing cord, the bushings are shot, I was just hoping someone could say "yes that crazy feeling is control arm bushing X", or something more specific than check your bushings. Front traction bars sounds like what I wanted to hear, I checked them and they look.... haggard.

Couple more questions:
I have a HUD, it doesnt work(go figure). I tried the capacitor swap, no luck. It flickers on (when you first turn the key) for a split second then goes away(sometimes). The cluster itself doesn't light up with the head lights, could I have shorted it out? Out of my collection of soldering irons the smallest I had was still way to big.

Found out the car has no thermostat, explains several of the problems I have found, still need that coolant temp sensor part number if anyone knows what it is. Are they different on the s14 manifold from the s13 manifold? Local dealer is clueless.

Im getting serious transmission shake from the diff being welded with solid subframe mounts, is there a trans mount that isn't solid, but maybe poly, or something harder than the stock rubber that I can buy?

I fixed the fender harness and went searching for more easy electrical fixes. Found that the radio was wired up wrong. Where the hell is the constant battery power wire? I found several that are switched, but for the life of me I could not find a constant, what is the color code for it?

I get a random check engine light, Im assuming s13's have the screw type ECU(I had a sentra of the same era), where is it located, does it store codes, and does anyone have a code list?

And last but not least, what is the go to parts brand for yall? If Im replacing parts I want to upgrade. The guy that sold it to me kept saying ISIS.

[Croustibat]

Cant answer for the HUD, i dont know, never seen one here. Same for the coolant temp sensor, we dont have that engine here, and it is engine dependant. What i DO know is the coolant temp sensor response has a table in the ECU that can be modified, meaning if you plan to go nistune someday, you can fit any sensor you want and then set the response table.

Transmission mount => get a new oem one, or a nismo one. The nismo one is little harsher but still bearable. All others will transmit a lot of vibrations. I suggest you change the propshaft bearing though, as THAT makes a lot of vibrations. Somewhat cheap part, but a pain to fit. Or just get rid of it and buy a 1part aluminium propshaft. A bit more expensive though.

Radio harness > no idea. I hate electrical stuff on a car.

On my S13 the ECU is located in to the right of the passenger legs, behind a plastic panel. It has a screw for diagnosis... but my engine is a ca18det so it may be different on this one.

Parts :
ISIS is crappy chinese rebranded items. But it is cheap.
I do prefer circuit sport, it is more expensive but build quality is also better. I track these without problem. Also they do fit like a glove, no mods required. I'd say they are the items of choice for someone who just want parts that works. Standard design, standard adjusters, a bit heavy, but good welds and ball joints are nice quality. There is better on the market, but it also is more expensive (like two or 3 times more expensive for SPL stuff -but it is lighter, stronger and has a better adjustable locking system that will not make the alignment guys cry in pain).

Then you get high quality parts, but also way more expensive, like SPL. I think they have a lifetime warranty, and an exchange policy when a new version of the arm you bought is made. Never bought these, so check before, maybe i am wrong about this. They do make high end stuff though.

You can also get aftermarket knuckles, various makes, for various usage. More steering angle, 0 ackerman, roll center correction, lowering knuckles, custom brake caliper mount, you name it.

Finally you have some engineering firms that sell a whole new front suspension system (rear also for wisefab). Not exactly cheap but still cheaper than getting a full SPL system. IMHO well worth it. Whole kits includes knuckes with various geometry changes (height correction, more or less ackerman and so on) and all suspension arms. But this is like 1200-1500€ front and about the same rear.

Check the suspension and roll center thread for more info on chassis upgrades.

Also, google GK tech, TDP and wisefab.

[XakkGrill]

Someone else told me the one wire cts is the ecu, the two wire is the gauge cluster. Ill probably replace both, but the dealer is absolutely worthless, so is there an online parts database I can look at? I dont mind looking at some diagrams and giving them a part number.

Also, is there a free online shop manual? That might help me with the electrical issues.

Ill probably just replace the HUD because that is just easier to do than messing with the boards.

Im going to put some fresh tires on the front next week, gonna look into the bushings tomorrow and see what all is obviously bad and look into replacing them.

[Croustibat]

There are manuals, called FSM. I have some links for one but it is in french, and about the S13 with a CA18DET (and no hud), so i am quite sure it cant help you :/

Just in case :
La mini encyclopdie de la RS13 (http://silviars13.free.fr/encyclo_rs13.htm#Revue_technique)