New Miata has been parked for years, wants to stay that way

Sounds like an ignition problem.

Better check the spark

It was the fuel system! No change with fuel pump jumper, but carb cleaner made it go. I sprayed some into the manifold through one of the little vacuum ports with the straw, reconnected, and that was good enough for diagnosis.

I bit the bullet and drained the old stuff when I changed the filter. Tried to siphon first (for more control over the process), but couldn't get it in, as they say. I had already picked up a fuel filter, and pumped it into two five gallon jugs. I definitely had a full 10 gallons of old gas in there, and if any of you are in the Portland area you are welcome to it.

Check out the fuel filter "before" picture...did I mention this car came full of spiders? Don't worry, the lines cleaned up nicely.

I had a lucky break after posting this: I learned that it's "bring your hazardous waste to work day" on Saturday! That tipped the balance in favor of draining. I rigged up one of the spouts to use as a funnel like so, which worked nicely in the confined quarters:

Since I'm uploading pictures, I found these little Berkeleyers behind the thermostat. I've read they are probably leftovers from the original machining, so I am not too concerned for now...but I had an unpleasant moment upon their discovery.

I managed to drive the car home last night, but I get a HARD stumble around 5000 rpm when flooring it. Power cuts for a full second or two and then snaps back on. I assume my injectors are a little bit clogged, and this is what happens when your spray of fuel turns into a trickle, and then the puddle of fuel finally arrives at the intake valve. I invested in some injector cleaners, and will alternate between Chevron and Lucasoil over the next couple of tanks. Anyone had good luck with this stuff?

Oh, and I still have a check engine light for the EGR system. I cleaned the valve when I was replacing things, but not the pipe or the rest of the intake manifold...I suspect I may have to pull more things apart to get to the bottom of it, but if anyone has an easier solution, I would love to hear it. I need to get it to pass emissions in the next couple of weeks, if possible.

Thanks for all your help, guys! You're the best.

If you're interested, I think I still have a set of NB injectors on the shelf that have been cleaned and serviced by Marren Fuel Injection and never used. They're plug'n'play on an NA.

Glad to hear that it's running.

Plug and play but watch the sizes. Use red on a 1.6, purple on a 1.8.

Did the NBs come with two different injectors? I would have guessed that any NB injector would work for the NA8, is that not true?

1990-93, 230cc blue.
1994-97, 265cc tan.
1999-00, 238cc red.
2001-05 (including MSM), 264cc purple.

So if you put a red NB injector into your NA8, you'll find yourself running lean. The NB used a higher fuel pressure, but these ratings are all at the standard 43.5.

Hey Keith, how sure are you about the red flow rates? This post on the miata turbo wiki claims they are very similar to the tan tops I've got.

http://miataturbo.wikidot.com/fuel-injectors

Yet other specs found here!

http://www.fiveomotorsport.com/fuel-injectors/mazda/miata/

Nearly time to measure them myself! Or, since I'm supposed to be an engineer now, buy a few from several junkyards around the country and average the results.

In reply to BoxheadTim:

I thought those were on the car when you sold it to me, and a the originals came in the parts box.

jsymonds- I think I have some extras and am local if you want them.

What color are yours, bgkast?

In reply to bgkast:

Yes, they are, but I had more than one set .

jsymonds wrote: Hey Keith, how sure are you about the red flow rates? This post on the miata turbo wiki claims they are very similar to the tan tops I've got. http://miataturbo.wikidot.com/fuel-injectors

Flow numbers from a set that we sent off to be measured. I am not responsible for the source of other numbers found on random websites. The power number attainable from a set of reds works as a confirmation of their approximate size.

Thanks, Keith. I certainly prefer data where I can identify a source to random things on websites! I think it's interesting that there can be so much uncertainty about the spec of a part. I wonder (if I spoke Japanese) if I could just call up Denso and ask?

Just for my own reference, from https://www.injectorrx.com/denso-fuel-injectors:

| Year (color)     | Denso part # | Flow rate (cc/min) | Impedance (Ohms)

| '94-'97 (tan)    | 195500-2180  | 254                | 13.5             
| '99-'00 (red)    | 195500-3310  | 264                | 13.9             
| '01-'05 (purple) | 195500-4060  | N/A                | N/A

jsymonds wrote: What color are yours, bgkast?

Spares are tan.

Ones in my car are red (the whole body and everything). Are reds in a NA8 a good idea?

That is awesome, glad she is rolling again!

Good news, problem-solvers! I have new symptoms to report.

I removed the under-engine tray and took it through a car wash, which was a more exciting experience than in a bigger car with more insulation. When I started the car afterwards, my check engine light was gone! Thanks, car wash.

A brake light was out. I replaced it. It's out again. Weird. But on to the real issues:

Hesitations continue, and are quite pronounced when really goosing it. I have not even been to redline yet, it just cuts out too much up there.

On the way home from work today I encountered two new issues. While waiting at a stop sign, the idle was hunting around, like a vacuum leak. However, I revved it up and it seemed to stabilize, which is not something I'm familiar with vacuum leaks doing. Soon thereafter, I was going around a skid pa...er...traffic circle, and the engine died mid turn. I rolled out to the shoulder and was able to start it back up again, but I was surprised to have that happen with half a tank of gas.

All of this has got me thinking fuel pump, plus some miscellaneous gremlins. Anything jump out at you?

Go to the parts store and rent a pressure test kit.

A wise man once told me: "Go to the parts store and rent a pressure test kit."

So I went to the parts store and rented a pressure test kit. But I did not use it! Oh no, that was slightly less convenient than throwing parts at it. Behold, the fuel tank!

Pretty gross. Look what came out of it!

That's a good coating of rust-mud on there. The low pressure filter was about 90% clogged, so I am not surprised I had trouble delivering the fuel.

I actually have a fancy Denso replacement pump, but one look in the tank and I was afraid to put it in without some more work.

I replaced the low pressure filter alone, and the car now pulls nicely to redline. However, it still dies a sudden and absolute death if you apply lateral g-forces, so the pressure tester kit will see action after all while I hunt that down.

Two questions come to mind: in case the test comes up negative, is there something besides fuel delivery that could kill the car in a corner, only to let it resurrect 10 seconds later?

Second, and maybe taking the pump out again will tell me this, do I need to do something about that tank? Drop it and rinse it with vinegar, perhaps? I don't think my HOA is going to be thrilled about it. Thanks, everyone!

That looks like the inside of the tank of my latest motorcycle purchase. On that one I ended up draining the tank completely, let it dry out and then with the application of a nylon brush, lots of elbow grease and a little brake cleaner, proceeded to the dried-on gunk out. Worked pretty well.

as far as the tank, I'd see how much of that stuff I could wipe out of the tank with rags and vinegar or diesel or something. You might be able to reach most of the surfaces through the pump hole.

Might be better than dropping the tank at least.

I still want to know how the car wash fixed your CEL... any ideas on that?

could be losing an electrical connection at high-lat, which kills fuel, which slows down car, which reduces lat, which restores electrical connection.

i had a similar problem with the wire from the coil to the points on my '72 monte carlo.

I once had a ground wire that would pull free under engine movement, so every time you loaded up the engine the engine would move, the ground would come loose, the engine would cut out, the engine would move back, the ground would restore and the engine would come back. That was fun. As Angry said, I can see that being the case here as well. Does it happen on both left and right turns, or only lefts?

Some Miatas have a drain plug in the bottom of the tank. I forget the year cutoff, but that'll let you flush the tank without pulling it.

rcutclif: I'm working under the assumption that the car wash was a coincidence, and the code (from too-high exhaust pressure) cleared itself somewhere along the way. Car passed emissions a few days later no problem. Thanks, OBD-II! I would have been surprised if the dyno test passed, running as it was.

AngryCorvair and Keith: Thanks, I will investigate the electrical angle further. I suspect that if the problem is electronic, it may yet be impacting the fuel system...it just takes so long to get going again, once dead, so something must need time to wake back up once connection is restored.

I'll also check for a drain plug! That would be convenient.

The bullet-biting started today. Remember how the original fuel strainer looked? Here's its replacement after a few miles in the dirty tank:

That thing is brand new! The strainer gets clogged, and the fuel pump sucks it into itself, resulting in the deflated appearance you see here. I guess it stays that way. Amazing!

I had run the car until it seemed empty (starting to stall) and managed to limp it into my garage. Turns out there were still two gallons in there, it had just become so concentrated with TankCrap™ that it wouldn't run. I was glad I picked up this handy siphon bulb thing, made it pretty painless:

Meanwhile, in the tank, a piece of wire hanger helped keep the tubing straight:

...What a sight. This is the forward part of the tank, which was not quite visible in the other pictures, and mostly submerged previously. I am now feeling less smug about this purchase, but I did want to learn the lessons a neglected car could teach me, so I am not yet disappointed. Well, time to get to work!

Don't worry, that's a dedicated grill brush I picked up just for this purpose. The bristles were too soft and awkwardly placed, but the scraper on the end was fantastic. If I were to continue, I might just try a putty knife on a stick.

I reached what I could, but it was still pretty gnarly in there. In the process, I pulled out about three fistfulls of this stuff:

The tank does have a drain plug (hooray!) so when I finished I gave it a rinse with water and then drained out whatever loose stuff I could. Refilled with 3.5 gallons of water and then about a cup of "The Must for Rust", which appears to be a bottle of phosphoric acid with some compound that is supposed to leave deposits where the rust used to be to prevent future corrosion. Sounds good! Remember: "do what you oughtta, add acid to watta!"

Now, 200 ml in 3.5 gallons works out to be about a 2% solution of this stuff, which sounded weakish to me. However, it got a bit fizzy in there as it went to work, so I am planning to leave it overnight and see how it goes. Acid bath in progress:

The waterline was above most of the rust I could see, so I declined to add more water to prevent further diluting my solution and having a big clean up job tomorrow. I think I will siphon out one gallon at a time until there is not much left, add a lot more water, and then drain through the plug. Not looking forward to having acid splatter all over me through that plug (conveniently located directly above a splatter-producing crossmember).