Car #: 113
Year : 1990 Posts: 145
Several off season upgrades in, head, ART tuned AFM, fat cat bumps stops and a little dyno time. As race day approaches, the gremlins have reared their ugly heads.
Mystery radiator leak - fixed, replacement on order.
After installing the repaired radiator, suddenly a check engine light, turned off the ignition, restarted no check engine light.
Ran to temp, no leaks, turned it off, cooled it down, turned on the ignition, and the fuel pump suddenly sounds like it could supply a small city with high water pressure, its working that hard - ignition on, not started. When started the idle is a tad variable.
Forum search revealed only a single thread that related to "tuned AFMs" and "open flappers" causing a fault whose only symptom is a constantly running fuel pump. But why so loud?
MY thought is blocked fuel filter, which admittedly is older than is probably wise.
Do I change the filter? Do I install a new fuel pump? Do I just ignore it and see how she runs?
Thanks for any and all helpful suggestions.
Andy (Increasingly wound up, because non of this has any track time yet. I'm not sure if its too much caffeine or too little sleep, or both)
Region: NWR / Oregon
Car #: 88
Year : 95 Posts: 2000
Andy, This may sound dumb but you didn't leave a jumper in your diagnostic box between FP and GND did you? Been there on the track and it will cause both an intermittant check engine light at temp and the fuel pump to run constantly. Not enought sleep and too much caffine can easily cause that one.
I also had it run constantly with the ignition on but no jumper when my battery died and I had the car hooked up to the charger. Two easy problems but admittedly long shots.
-------------------- Keith Novak (Will work for tires)
Car #: 72 and ?
Year : 90 and 90 Posts: 1051
Your problem is in the air flow meter. When the wiper arm is adjusted for better performance it no longer swings back far enough to turn the fuel pump off. The cover needs to come off so you can bend the tab that opens the contact points for the fuel pump circuit.
-------------------- Advanced Autosports, The Midwests leader in Spec Miata Service, Parts and Rentals 608-313-1230 Authorised Spec Miata service center www.advanced-autosports.com
Car #: 68
Year : 91 Posts: 2359
Andy just open the top and you'll figure it out pretty quickly. When you turn the flapper mechanism back and foth with the key on, you will see and hear where the contacts are, and it should be fairly easy to figure out how to bend the tab so that when the flapper comes to rest, the concats are no longer touching.
-------------------- Bruce Wilson 2010 Oregon Region Champ 2010 Monte Shelton Driver of the Year 2010 25 Hours of Thunderhill E3 and Under 2 liter Overall Champion Oregon Region SM Class Advisor