RoadWarrior Reader
May 20, 2013 1:45 p.m.

So, my loud, lowered, race-seated '94 miata mostly survived it's ~ 3500mile trip from Boston to California. But now it seems to be having some issues with hard starting and lack of power. I noticed it a little bit when I hit altitude crossing the rockies, and thought I chalk it up to that. But it seems to still be there in some shape.

So before I left I gave it basic tuneup, fresh oil change, new fuel filter, regapped the plugs, new plug wires, new denso o2 sensor, new ecu coolant temp sensor, etc etc..the poor car is progressively having a harder time starting (especially in the morning or sitting after a long period of time)and a definite lack of power at the higher rpm ranges. Checked the plugs, they look decent, and the gap is about right, air filter isn't clogged, and no CEL's are stored in the ecu. Tried different grades of fuel and it makes 0 change.

Soo...I'm not sure where to start on this one,I only have a few of my tools unpacked, so trying to figure out the easier ones to check before I start tearing into it. Any good idea to test the pump sans a fuel testing gauge? If not , I might need to find a local harbor freight and make that happen. Could a failing ignition coil be another possible suspect?

What are your thoughts?

mistanfo SuperDork
May 20, 2013 3:29 p.m.

My experience with Miata fuel pumps is that they either work, or they don't. No real in between (not saying that it can't happen). Coil is possible, know anyone with a similar model that you could do a quick swap to see if it solves the issue?

amg_rx7 Dork
May 20, 2013 7:52 p.m.

2 ways I know how to check for a weak fuel pump. 1. monitor fuel pressure. As the pump wears, it is not able to pump at higher pressures and fuel pressure decreases as revs / fuel deliver rises. 2. check spark plugs to see if they look like they are running lean.

Before doing that, I'd check voltage on the alternator.

what year miata?

You'll need to log in to post.

Also on Grassroots Motorsports

How Ben_Modified Wows the Crowd: 1 Part Imagination, 2 Parts Fabrication

1 hour ago in News

Ben_Modified's build combines some of our favorite things.

Modern Day Track Junkie

1 day ago in Articles

Christina Lam went from the sidelines to full-on track enthusiast in 8 simple steps.

2017 Audi A8 L

1 day ago in New Car Reviews

When it comes to luxury sedans, Audis are usually front-runners. The A8 L is the biggest and maybe most comfortable ...

Slight Project Pause for Our BMW M3

1 day ago in Project Cars

Few things slow down our project car progress more effectively than a broken arm.

Grassroots Motorsports Experience Ticket Renewals Have Been Sent

1 day ago in News

Check your inbox for our Grassroots Motorsports Experience renewals.

First Drive: Turbo ND MX-5

2 days ago in News

We hit the track with Flyin' Miata's latest power adder.

Project Turbo Miata: Fire Fighting

2 days ago in Project Cars

We transfer the fire system to our new Miata.

Vintage Views: GMC Syclone and Typhoon

3 days ago in Articles

All-wheel drive, turbo power and a Q-ship’s stealth.

Classic Motorsports Mitty Presented by Hagerty Celebrates Porsche

4 days ago in News

Gearhead heaven? We think it looks something like this.

Meet the Rebels Who Started the Cannonball Run

4 days ago in News

Relive those desperado days through movie excerpts, and hear the real facts and wild stories from the legends themselves.

This Weekend at the Mitty: The Ultimate Auto Festival

1 week ago in News

Gates open this Friday for the Classic Motorsports Mitty at Road Atlanta.

ND Miata Turbo Kits Now Available!

1 week ago in News

Add 70 horsepower and 70 ft.-lbs!



Grassroots Motorsports Magazine

Subscribe Today

Also get your instant access to the digital edition of Grassroots Motorsports Magazine!

Learn More