Mikel

So, I'm ready to stab a baby. I inherited a miata that has been sitting for 5 or so years. I put a fresh battery in it and tried to fire it up but I wasn't getting fuel. I pulled the fuel pump and it was totally trashed:



At that point I didn't even think to look for spark, because the pump is so clearly garbage. I replaced the pump with a walbro and replaced the tank as it was full of **** too and I found a good clean one for $100.

Today I dropped the tank and pump in. Put a freshly charged battery in, and it turns over but won't crank. The fuel pump is working, and getting power. I'm getting power to the coil connectors. I luckily bought another 96 Miata parts car, so I pulled the coils from it. Same. I thought it might be the CAS, so I pulled that off the parts car and replaced it too. No change.

My plugs are dry, so the injectors aren't firing. I'm getting pressure at the rail though.

I pulled a plug and wire and turned it over, no spark either.

The CEL comes on when I turn the key on, as it should, but it has no codes, probably because it won't run. Anyone have any ideas? I'm running out of them.

Godless Commie

iTrader: (2)

Have you checked the fuses underhood? I mean the big ones.
Also, how about the main relay - also under the hood?

Also, check ground connections just below the TB and the one between the IM and the valve cover, again, just behind the TB. Those are important ground points for fuel and spark.

If you have jumper cables, attach one end to the engine bare metal, and the other end to unpainted chassis member. Try that for the hell of it, you'd be amazed at what happens to electrical connectors if a car sits for too long in adverse conditions.

Godless Commie

iTrader: (2)

Also, if what's pictured in your post happens to a fuel pump, consider the fact that the same thing just may happen to your injectors, which are not too dissimilar in terms of structure (windings and moving bits) and environment.

I would definitely change the oil before I circulated that stuff too much in the engine.

Mikel

All the fuses seem fine, I'll check them with a multimeter tomorrow. I'll also check the grounds, but I didn't see any that looked bad.

Mikel

Yeah I considered the injectors, but it seems unlikely that they are all so clogged no fuel at all gets through, and that doesn't explain the lack of fire. I already out clean oil in it.

triple88a

iTrader: (2)

step 1 would be undoing the injectors, getting a hose to flush the crap out of there. Most motorcycles get gummed up over the winter without stabill and this sat for 5 years.

Mikel

I flushed the lines. I'll pull the injector rail tomorrow, but that still wouldn't explain the lack of spark. I was hoping I was overlooking some main relay or something that would kill both spark and fuel.

Godless Commie

iTrader: (2)

If you have a multimeter, check the resistance between the block and the chassis first. A lot of ground connections may look OK, but you would not know for sure unless you physically remove and clean them.
I use dielectric spray just to be on the safe side.

Please remember this is a very "cold" car and assume the weirdest might have happened.
I would tap and wiggle the relays under the dash, too.

sleepjay

is the fuel filter clogged?

Mikel

Replaced today, pulled off the line in the engine compartment and verified fuel is getting to the rail.

Mikel

I'll try checking the grounds tomorrow.

Mikel

So far I've checked every ground I can find, all looked fine, but I took them off, hit both sides with a little bit of sandpaper, and reconnected snugly. No change.

I'm gonna check all the underhood fuses since I have spares, it was been jumped off a bunch of times and one or more could be blown, that's the next logical thing that might explain it.

Mikel

Replaced main EFI relay with known good, still no start but I did manage to lose some weight off my thumb extracting the relay, so that's a plus.

sharkythesharkdogg

What year Miata is this?

Had a similar issue with an old NA6 and it turned out to be an internal ground failure in the AFM flapper. Would ground so it wouldn't prime the pump, power the pump, or send spark signal. (As I recall)

Onyxyth

iTrader: (2)

I had a somewhat similar issue with no fuel/spark that turned out to be a broken timing belt. Test the CAS while you crank and see if you get pulse. If you don't, remove the CAS and do the test again, this time spinning the CAS with your hand, slowly. See if you get 5v pulses during either test.

edit: Oh I see you said you replaced the CAS already. Oh well, have you had the valve cover off yet? Pull that **** off and see if the cams are spinning when you crank it.

Mikel

I looked through the oil filler cap and the cam was spinning when it's cranking, I'll test the CAS if I run out of other ideas but I doubt I have two bad ones.

Mikel

96, so no flapper. I did try cranking it with the MAF unplugged and that didn't change anything, on a lot of cars if the MAF is bad, unplugging it will let it crank in limp mode. I can try the MAF off the parts car though.

Rafa

iTrader: (22)

You say you have another 96 as a parts car.

Change the coil pack.

I have a 96 and faced a similar issue sometime ago. We changed the pack and everything was good from then on.

Mikel

Coil pack and Cam sensor off the parts car were the first things I did. No change. When I left last night I was still not getting fuel or fire.

Now I'm really confused. I've done absolutely nothing since yesterday in terms of "fixing" anything. I got in today, found the OBD2 connector hidden in the center stack and hooked up my scan tool. I went into data stream KOEO looking for clues like a lack of signal for a cam or crank sensor or no communication to ECU or something that might point me in the right direction.

Everything seemed to be working, so I kicked the key over. Now it's firing both fuel and spark.

I verified less than 24 hours ago it was getting neither. I pulled every plug wire and got no spark while cranking on any of them. I pulled every plug and they were all bone dry after literally a full minute of cranking.

Now i have fuel on the plugs and every plug wire firing. I have literally no idea why.

It still won't run, though it gets really close and even pops over a few revolutions after I release the key. I'm thinking I need to set my timing, as I swapped out the cam sensor, but I have no idea how to do so since the normal procedure involves a running engine.

Onyxyth

iTrader: (2)

Sounds like magic.

Have you made any adjustments to where the CAS sits? Try to start it with the cas in a few different positions.

Have you you verified mechanical timing is OK, and not skipped a tooth?