Lateralgeez

I suspected the issue was related to driving the dragon. Maybe the old fuel strainer was stiff from sitting with an empty tank. Then gas sloshing around broke it. Oh well. Eventually I will remove the tank and clean it. I work at a chemical company and my boss said use Metal Etch (our stuff) because it will remove both rust and dirt. Not sure what the active ingredients are but I know its not phosphoric acid so it won't leave a coating on the metal. Replaced the fuel filter last night and put a new strainer on. Now it's getting clean gas.


Now I have two main issues.


1. Backfires and misses a little. Probably the pickup sensor. I bought a new distributor and timing light so hopefully that fixes it.


2. New power steering pump, still no power. I read that re-manufactured pumps are hit or miss. I think Autozone has a warranty so I'll try another one. Kinda sucks because swapping the pump is a messy pita.

ToySnakePMC

Wow! You're showing me stuff I've never seen before! Looks like a complete wiring harness re-do and clean up of fuel system is in your future. You certainly don't want to let this car burn up in some parking lot or in your garage one day! Perfected wiring harness will give you some peace of mind...

Lateralgeez

Yes, good point on the wiring harness.

I had those inline filters right before the fuel rail so i could see the fuel. The main line collected a ton of dirt. So I don't think my injectors are clogged again... but I'll check anyways because it's not that hard.

Got a new distributor and set the timing at about 12 degrees. With the timing set the idle seemed to smooth out. (set with spout unplugged)

However it still ran a bit rough on throttle. Just drove it again yesterday and so much backfire! Sounded like a war zone. At idle it would bang every few seconds. I checked the timing (spout plugged) and it looked like 22 degrees at warm idle! However, when I removed spout plug to adjust it, it went back to where I had set it and ran beautifully. This greatly confuses me. (edit: this is normal) I'll do a top dead center check to make sure it's pointing at #1.

I tested for volts at TPS - 0.7, rises and falls smoothly, returns to 0.7. Key was on. Ground from TPS to battery was good, low resistance. Also it's a new TPS. No problem here. (stangnet has good info on this).

It was running great before the busted fuel strainer & clogged injector incident so whatever I'm looking for must be somehow related / happened recently.

What I'm going to check now:
TDC to make sure I set the dizzy in correctly
Injectors for more dirt
Spark plugs - curiosity
Oxygen sensor/s - test or replace?

The computer will not give any codes so I'm on my own. If all the above turn up nothing I might send my wiring harness to McCully racing for a clean up. It's possible that somewhere in the mess a wire is grounding (might be the same one that sets off the horn).

V8MiataMike

I would look at three things at this point:

1. Fuel pressure. Make sure you have 39-40 PSI at the schrader valve on the fuel rail with the vacuum line removed from the fuel regulator on the fuel rail. If that looks good put the vacuum line on the regulator and note the change (lower) fuel pressure and the rise and fall of pressure when throttling the engine. High manifold vacuum will drop pressure to maybe 30 PSI as an example. Correct any issues if needed.

2. Engine vacuum. A stock 5.0 should get up to around 16 - 20 pounds of vacuum at idle. Cammed engines may only get to around 12 at idle. Find and correct any vacuum leaks if any. Vacuum leaks on these EFI engines allow unknown air into them (EEC does not know about the extra air coming in) and you get "lean pops" that sound like back fires.

3. EEC diagnostic codes. If you are not getting any codes (no light flashing at all?), this is a real problem. It means there is something seriously wrong with the EEC or outboard wiring/sensors and needs to get corrected. Double check your approach to KOEO testing and the MIL/check engine light connections. At a minimum, with only a "MIL" light connected to the wiring (no test jumper installed, etc.), the light should be on when you turn the key to run (have not started the engine yet). After the engine starts it should go off (unless there is a problem...)



I see no mass air meter in the original pictures so assume it is a speed density system. Look at your EEC and get the "code" off of it. For example a mass air EEC may have A9L or A9P on it. Speed density version may have something like DA1 or DB1 (there are lots of codes). Good news is speed density EECs are much more affordable these days compared to the mass air versions...

Lateralgeez

Thanks Mike, good advice. I started it Sunday and revved it. This prompted a loud bang followed by a puff of smoke from between upper/lower intake manifolds. I've used the loaner torque wrench enough - just need to buy one and be done with it apparently!

What is thread pitch of the stock clutch master cyl hardline? My replacement Wilwood is 1/8-27 npt and I'm not sure if it will fit.

Lateralgeez

I'm getting a custom stainless hose for the clutch now.

The car idles but backfires loudly under load. I barely let out the clutch and bang! So I decided to check dizzy, maybe I set it wrong.

Now we have a bit of a problem. When I turn the motor to tdc, the rotor is pointing to cyl 6. I loosen the distributor and line it up with cyl 1. Then (spout plug removed) crank the engine. It starts then dies. I rotate engine to tdc and check the rotor. It's back at cyl 6 again.

Repeat three times.

Voodoo magic. Car is possessed.

tneyman

backfiring from exhaust,is ignition,dist pickup is bad,put motorcraft in only,had same problem,on mine,aftermarket went bad,started backfiring really bad

V8MiataMike

The crankshaft rorates two times for every one turn of the disttributor (and camshaft). Be absolutely sure you have TDC on the compression stroke before setting the dist to number one.

Lateralgeez

Ok if replacing the harmonic balancer doesn't fix it I will buy motorcraft dizzy.

Guy on Stangnet suggested balancer slipped and it looks like it did.

I still don't understand how it could start out lined up but then be 180 degrees off.

Lateralgeez

To clarify, here is tdc and the rotor pointed directly at cyl 1. After cranking and returning to tdc, the rotor would point at 6.

I suppose the balancer is slipping quite a bit. Now I wonder what made the balancer start slipping.

The night I fixed the dirty fuel issue I drove it to the car meet. On the way back it backfired progressively more. Seems random the balancer just wore out seeing as I didn't drive it for 3 months and it was ok before.

Lateralgeez

Can't believe I haven't heard this before! So I probably had tdc on the wrong stroke (exhaust stroke?)

That helps a lot... would it also explain why the rotor ends up 180 degrees off?

5.0MX5

Easy way to make sure you're on TDC compression.....pull number one plug, then turn the engine over via the alternator nut...with you finger stuck into number one plug hole. When you feel compression just starting to build, stop....insert a screwdriver of whatever you're comfortable with into the sparkplug hole and slowly turn the engine while watching the insert into 1. When it stops rising, you're on TDC compression and the rotor should be pointed at number one plug wire on the distributor.

V8MiataMike

Balancers can slip when they deteriorate however it does not change any spark/valve timing relationships as far as engine components. The timing degrees will be off related to the timing pointer which makes it impossible to time with a timing light. Vibrations will begin if it is slipping as it has a weight on it to complete the overall rotating assembly balance.

Lateralgeez

Back when I drove it daily, the whole car would shake badly beyond 4k rpm... someone said it was the motor mounts. Looks like they used hockey pucks or something. I guess it was caused the balancer too now that you mention it.

The plan is new harmonic balancer, arp bolt, and set the dizzy correctly.

Thanks for the help guys.

Totally unrelated, those giant warehouse fan blades would make great spoilers. They have an airplane wing shape to create down force. Extruded aluminum. However, the manufacturers only sell replacement blades in full sets which is pricey. Also they don't look very wide.

Lateralgeez

Mike you nailed it. Removed #1 spark plug and covered hole with finger. Rotated engine until I felt pressure build up. Now it's set on compression stroke tdc.

Starts and idles great!

Lateralgeez

It's runs ok but still misses and hesitates slightly. Nothing major. One of the header bolts was missing and I could feel exhaust leaking. After putting a bolt in it ran better. Now I just need another nut for the driver side header collector. It currently has one and leaks a bit. I understand this messes with the o2 sensor. However, I couldn't find a nut with the right thread pitch. They are bbk shorties. 12m 1.175 i think.

Lateralgeez

Time for some glamor shots!

Oil pan shows impact spots and may be leaking



Glasspacks. Not much ground clearance here



Motor mounts



Clutch fork and slave mod



How on earth does a header/exhaust pipe get down through here? The passenger side is even worse.



Didn't see any o2 sensors...

Lateralgeez

Hmmmm

Lateralgeez

3/4" clutch master

Lateralgeez

Removing the clutch pedal was a horrible experience. The push rod has same diameter but different thread pitch. I just forced the wilwood in and re-threaded it.

The mounting studs don't line up so I'll widen the holes with an air grinder.

V8MiataMike

Do it!

Lateralgeez

Been looking at Awd systems. Unfortunately the best performance wise is a skyline attessa system. The trans are readily available and not too expensive. It's the axles, front diff, subframe, and hubs that are a pain to find. However, with ets-pro from full race you can select rwd. No other platform is capable of that. Also can support a lot of torque.

Alternatively I could use an aerostar transfer case and cyclone/typhoon front diff, axles and hubs. The torque split is rear biased. I'd want an open front diff.

WolfGT

The part when you said the horn would honk when you pressed on the brake/clutch made me laugh. Dude you got yourself a fixer upper. Same boat here, mine was wrecked, didn't know it . Looking forward to the transformation.

Lateralgeez

Haha yep it was kinda funny, hoping I didn't confuse people as I went honking by.

The funny thing is I started looking seriously for a miata when I realized I was running out of things to do on the sti. I'm not the smartest person lol.

Would like to see your thread if you have one.

WolfGT

Here is my Build Thread.

A lot of reading. Just so you don't get disappointed at the end, spoiler, it's not done yet.