Hoppps
Reader
9/12/25 2:48 p.m.
I'm about to go crazy! Diagnosing a Cranks but won't Start/No Fuel Pressure issue on my 94 Miata.
Background: Miata ran on track for 2 days. Came in from my last 30min session, cooled down 10 min, before trying to start again. Car has not run since.
No Fuel pressure is verified by fuel pressure guage on the fuel rail.
Car also ran very rich for 2 days.
Things I've done to try and fix no start:
1) Tried the jumper trick with FP to GND jumper.
2) New main Relay
3) New Fuel Pump
4) Blew out fuel lines and fuel filter (which was new before race weekend)
5) Fuel injectors rebuilt before race weekend (Could clogged fuel injectors be issue???)
6) Verified power to FP at connector with test light - weak signal but still showed power
Not sure what else to test. Is there a relay under the dash maybe?
Car has a healthy sounding crank, but no FP anywhere. When I disconnected the fuel lines to blow them out there was just a couple drops in the lines.
Hoppps
Reader
9/12/25 2:57 p.m.
I found an exposed ground wire on the fuel pump connector so I spliced it, and now I have a very strong signal with test light.
The connector looks like on of the terminals is damaged, so going to cut the connector and wire directly to it as a test.
Was just going to recommend hotwiring the pump directly to check for the possibility of a pump failure (or confirm that it's a wiring/electronic issue).
Does this car have an AFM? If so, is it plugged in?
Just hot wire 12v straight to the pump and see if the new pump works.
On 2nd gen rx7s and rx8s, there IS a big relay under the dash. On rx7s, it's a blue wire with white stripe that goes from relay to fuel pump+. The relay on rx7s and rx8s is almost directly under the steering column (just to the right of it actually).
I'd assume miatas are similar. Though the color may be different. Or placement. Or everything.
OP, how did this end? Did you fix it or did you set it on fire?
