The 90-93 have a AFM and it does stop the FP from running if it is no good or if the connection is no good. It really isn't looking for the engine turning, it's looking for airflow through the meter.
Larry Alster 91 Miata White Knight 92 Miata Silver Bullet 92 Miata Honey B 04 MSM MX-5 Whooosh 06 WRX STi Subie From: [email protected] [mailto:[email protected]] On Behalf Of Ken Bogart Sent: Thursday, April 22, 2010 11:56 AM To: Mark Phillips Cc: MiataPower Subject: Re: no start 1990.. When you first turn the ignition on, the fuel pump runs for 10 seconds or so to pressurize the system. I think it then shuts off until it sees the engine turning. Ken On Thu, Apr 22, 2010 at 11:40 AM, Mark Phillips <[email protected]> wrote: Hi Stephen, The airflow sensor on a '90 will prevent the fuel pump from running. There is a switch inside that opens when the flapper door is closed (fuel shut off). You might also check the fuel pump relay/replace under the dash that is operated by the air flow switch. It has a yellow connector IIRC. This is a timed circuit on start-up and may allow the car to fire but not run. Mark _____ From: [email protected] [mailto:[email protected]] On Behalf Of Stephen Rigley Sent: Thursday, April 22, 2010 10:55 AM To: Ken Bogart Cc: MiataPower Subject: Re: no start 1990.. Thanks Ken! On Thu, Apr 22, 2010 at 3:53 PM, Ken Bogart <[email protected]> wrote: My random thoughts.... Sounds like a broken timing belt except that you say the cams are turning. A failed MAF won't stop spark and fuel. If CAS is rotating, you should see spark and fuel. If CAS is bad, no spark, no fuel. Just because the plugs are "dry" does not mean you are not getting fuel. Can you smell fuel at the exhaust? Check to see if injectors are firing. Use a stethoscope on the injectors (rod to the ear). you should hear them clicking when cranking. The only explanations for both no spark and no fuel is timing belt, CAS or ECU. I would verify that the injectors are NOT firing. If they are not and the CAS is rotating, it has to be related to bad CAS/wiring or ECU. Good luck! Ken Bogart ----------------------------------------------------- 96 Montego Blue FFS Coldside (His) 97 Black & Tan (Hers) 90 Crystal White (sons) ------------------------------------------------------ http://www.miatacare.com http://www.cincimiata.com http://www.miatagathering.com http://www.bcchallenger.org MiataMail.com list owner On Thu, Apr 22, 2010 at 10:39 AM, Stephen Rigley <[email protected]> wrote: Hi, Having a problem starting getting a stock '90 started, it died a few weeks ago, replaced coil, nothing.. no spark, unplugged and replugged in ECU, it started (!?). A day later, it died in traffic.. no spark, no fuel (plugs are dry), fuel pump runs w/key on crank, power at coil, power in and out of ECU, have tried a good ECU (at least it was good when I took it out.. ) from a '91, tried the CAS from my car, cams are turning, wiggled wires near rear of intake manifold, wiggled key in ignition, tried another coil.. still nothing.. Might see if we can source/try a different MAF, although if thats bad it stops fuel pump from running.. true? Fuses + relays checked (need to double check EFI fuse and relay to be sure though) Anything else we've forgotten? Thanks Steve _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
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