First Miata
 

Just purchased a 1990 Miata 5-speed. Love the car already. It is such a dream to drive. I'm looking forward to updating everyone on my new additions to her and seeking advice when needed

welcome to the forum. What are your plans for the car?

Yo, 90miata, finish filling out your profile so we know more about you AND the car! welcome aboard

I don't have any concrete plans yet. Just got out of the Marine Corps so I've gotta take it easy on the spending for a while. But eventually either a turbo or V-8 swap.

First and foremost, welcome home soldier and thank you for your service! Congrats on your recent purchase of a MIATA. It, in my opinion, is one of the best values in a two seat sports car and you will lots of fun putting it into whatever state of personal customization you choose. That is what is so great about this car, there are so many things you can do to it to improve the ride, handling and look. This forum will be an excellent resource for you as you travel through its' pages.

There is a Miata with a 5.0 Mustang swap and a full roll cage down here in Tampa for $3500 on the local forum.

So I went out to the Miata to go to school and as soon as I started her up I knew something was wrong. When I started driving something was making an awful racket and rattling like crazy. Thank god for the ST otherwise I probably wouldn't be at school today. I'm gonna dive into it when I get home. I'm hoping it's nothing major

Yikes! Please let this forum know what you were hearing and where it was coming from: engine, drive line or rear end. Check all of the belts, fluid levels, especially the oil. These are the areas I would check first and do avoid running long until you discover where these sounds were coming from! You may be needing this forum's help sooner than you thought. We'll be waiting..........fingers crossed.

I appreciate the advice. I left it parked the rest of the day. Probably won't have time to tear into it until Saturday. I'm very into cars but still a newbie so I'm sure there will be plenty of questions once I get into it.

The hydraulic lifters sound a lot like a rod knock when they collapse. Only one will make you think the engine is coming apart. Use Rotella T6 synthetic oil and it will help clean everything up. It is a diesel oil so it has a lot more detergents than even the best gasoline oils do. Miatas are very sensitive to oil quality.

Interesting sixshooter. Does that hold true of just high mileage cars or is it good for normal mileage cars too? Better than most synthetics as well? How long should 90miata keep that oil before changing it back? Always, ALWAYS change the oil filter when you change the oil,no matter what! No sense in having new clean oil going through a dirty filter!

Hey 90miata, I just viewed your four photo's and your car looks great. It has obviously been taken care of! In the gas station shot I noticed that your headlight covers looked to be in need of minor adjusting. I have found that if you pull up the cover on the hood-side you can make flush with the hood. Also, in the dashboard view the photo came through upside down. My guess is that maybe you took that one with an Ipad, giving that view. Looking forward to discovering what you find out about your "noisy" engine.

I have been using Rotella T6 in everything except my boat and lawnmower for years. My engines never seem to wear out and stay very clean inside. Almost all of the Miata turbo guys use it because of the better additives. If you are truly interested in oils and want to spend some days reading, bobistheoilguy.com is the leading resource on the net.

Yes It is in pretty great condition for a measly 2500 bucks in my opinion. The guy that owned it was one of those guys that is always away from home so the car was always just sitting in the garage. I was so happy when he finally said I could take it off his hands.

Ok so some good news and some not good news. The noise I believe was coming from the new exhaust I installed. One of the rubber hangers split and the piece that goes into the hanger was vibrating against the underbody. Got that all fixed up. But then the weird feeling when taking off got worse. Not really sure how to explain it. It started off hesitating I guess in the lower rpms. Not real bad but felt like the power was gone for a split second then back to normal. Today I took it for a lap around the block and when I took off it hesitated so bad it almost stalled. It was bucking and felt like it had no power.
I wish I knew more about cars so I could explain better. If anyone has any ideas please share. And again it was only doing it at low rpm. Once it gets above like maybe 2700 rpm it runs normal

Do a compression test, check for vacuum leaks, See if the AFM door is sticking, clean the IAC valve, read the spark plugs and tell us what they say.

I started by checking for vacuum leaks. I found one black hose that had a crack on one end and was pretty much crumbling apart on the other end
. I put some tape around both ends just to see if that helped. I didn't feel any hesitation after stopping and taking off a few times. Would anyone know what that part is called so I can buy a replacement or does it even have a name?

Took care of the minor adjustment on the headlight covers. Thanks for pointing this out.

That hose coming out of the valve cover looks like a "PCV" hose but I don't see the actual valve! The "positive crankcase ventilation" valve helps to re-burn any vapors coming from that area and then put into the intake for re-burning. It is NOT a vacum hose so should not have an effect on the engine performance UNLESS it was totally blocked with sludge. Glad to hear the quick fix on the covers worked for you. Hope your investigation turns up something minor.

Isn't the pcv valve on the other side of the valve cover going into the intake manifold? And I'm guessing since that's not a vacuum hose that my problem isn't really fixed. I'm going to test drive it again when I get home and see if it does it again. Maybe it just felt like behaving when I drove it this morning.

OK you got me! These old eyes didn't bother to see the PCV valve on the other side just like you said. All I can think is that the tube is some sort of "re-breather" for the valve cover fumes.

I appreciate the help. So either way that hose shouldn't be the cause of my issue?

On my way home I'm going to grab a compression gauge so I can test my compression and thinking about buying a timing light as well because I remember someone mentioned I can advance the timing tj get a little more pep out of the engine.
As far as the spark plugs I believe they are still good. The tips are a little bit rounded which I don't think is good but it's not horrible. One spark plug did have quite a bit of oil on the threads. Is this something I should be worried about or is it ok?

Threads are fine. Oil on the electrode would have been an issue though.

So 90miata, how are things going with your issues?