No fuel pump after reflash. - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 03-11-2011, 10:26 PM   #21
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Funny, I have a similar problem.
  • the fuel pump turns on when jumped at the pump with power using factory gnd.
  • the FP relay works in my daily driver
  • the FP does not turn on when jumped at the diagnostic box

Am I chasing wires at this point or a bad GND? I really hope I make it to the track tomorrow. How do I check to see which side of the relay is working properly?

http://www.y8spec.com/miata_tech/wiring%20all.pdf
P12

Last edited by hustler; 03-11-2011 at 11:02 PM.
hustler is offline   Reply With Quote
Old 03-12-2011, 12:05 AM   #22
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by Braineack View Post
the ECU grounds the Fuel pump relay, instead of the AFM doing it.
So if I jump power, and the fuel pump turns on, then MS is working properly (GND to fuel pump)?

Both relays appear to be working. I can hear the relay click under the dash and I can run the relay under the hood in my daily with success. All fuses are good.
hustler is offline   Reply With Quote
Old 03-12-2011, 12:54 AM   #23
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

I'm starting to question the computer. I have continuity on all wires, and this is the last thing I have not checked. The violet wire coming out of the plug should switch to GND, right?
hustler is offline   Reply With Quote
Old 03-16-2011, 12:32 PM   #24
Supporting Vendor
 
Matt Cramer's Avatar
 
Join Date: Sep 2006
Posts: 2,266
Total Cats: 51
Default

The ECU violet wire should supply 12 volts when the fuel pump is on. The coil this activates on the circuit opening relay grounds via a black wire.

The light green wire should turn the relay on when grounded, but the MSPNP does not control this wire. The wire this circuit would get 12 volts from is white with a red stripe and gets power from the main relay. This is the setup that is tested at the diagnostic box.
Matt Cramer is offline   Reply With Quote
Old 03-29-2011, 08:06 PM   #25
Junior Member
 
Join Date: Jul 2010
Posts: 89
Total Cats: 0
Default

I have a DIYPNP and I'm concerned that if for any reason anyone was to replace the ST SIG fuse I'd have a dead ECU.

What's the best method of providing some protection here? install a relay or diode inside the DIYPPNP on the 1C pin?

Btw, where is the Section B-2 diagram in the mazda manual? I can't find it.
giblets is offline   Reply With Quote
Old 07-15-2011, 03:25 PM   #26
Junior Member
 
Join Date: Oct 2009
Posts: 89
Total Cats: 0
Default

Bummer about this design. Just fell prey to it when the guys in the shop replaced the ST Sign fuse while tracking the fuel pump not working. I should've remembered and told them, or taped over it.

Convinced me to go back to stock, which I dd, in Iowa (I'm from SF, CA). Not that the MSPnP isn't a good product, but when traveling cross-country it's just something else I had to worry about. And to be honest, I don't like to play around as much as required. It was fun and educational, just not for me.
jonljacobi is offline   Reply With Quote
Old 07-15-2011, 03:50 PM   #27
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,892
Total Cats: 1,792
Default

cool story bro. it's a .20c part you need to replace.

The ST_SIGN fuse sends power to the fuel pump relay to activate it for ~2seconds with key ON. The MSPNP acitavates the pump in the same way. The problem is when the fuse stays in place, it overloads the driver in the MSPNP, heats up, and burns out.

There are other methods in order to activate the 90-93 fuel pump (I've used 4 different way myself) but this method is the most PNP way.

there's nothing inheretly dangerous about their method, you just need to make sure the fuse stays out. the car will run without that fuse when the stock ecu is also in place. even if you blow the component inside the MS, jumping FP an dGND in the diagnositics box will have you running again.
Braineack is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 Yesterday 09:00 PM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 10:17 AM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM
why is my car running like pewp? (tune/datalog) itsMikey MSPNP 3 09-28-2015 07:40 AM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 05:23 AM.