Pennock's Fiero Forum
  Technical Discussion & Questions
  Fuel Pump - ECM to Relay

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version

next newest topic | next oldest topic
Fuel Pump - ECM to Relay by AaronM
Started on: 08-20-2014 09:54 PM
Replies: 1 (196 views)
Last post by: phonedawgz on 08-20-2014 11:11 PM
Posts: 15
From: Bellevue, NE, US
Registered: Aug 2014

Feedback score: N/A
Leave feedback

Rate this member

Report this Post08-20-2014 09:54 PM Click Here to See the Profile for AaronMClick Here to Email AaronMSend a Private Message to AaronMEdit/Delete MessageReply w/QuoteDirect Link to This Post
When I turn the key to "ON", the fuel pump does not kick in.
If I remove the relay, and jumper the pins, the fuel pump works.
When the car is running, and I turn it off, the fuel pump runs a few seconds then turns off (from the oil pressure bypass).
Relay tests good, and I have tried a second relay (new).
Ground and power to the relay test good.

There was an issue with interment power that was related to the connector below the ECM. The connector was replaced and at least this one issue was resolved.

When I remove the relay and measure the voltage from the ECM (dark green / white), turn the key on, I get 12v for a few seconds, then it drops... this is expected.
Connect the relay and do the same test, all I get is about 0.7 volts?

Thoughts on what may be wrong or next troubleshooting steps?
Can I verify the ECM is working correctly?

IP: Logged
System Bot
Posts: 17011
From: Green Bay, WI USA
Registered: Dec 2009

Feedback score:    (23)
Leave feedback

Total ratings: 290
Rate this member

Report this Post08-20-2014 11:11 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Take the console off and preform the same test at the Dk. Green/Whitew wire at the ECM. Do this with the relay disconnected first to make sure you are on the right wire. Again look for the +12v when it kicks on an then for it to drop 2 sec later. Depending on if you have a 4 cyl or V6 the wire will be in a different place but I think there is only one or two Dk/Green/White wires on the ECM so it shouldn't be hard to figure out which one has the +12v for two seconds.

Anyways once you figure out which one, then plug the relay back in and try it again. At the ECMs connector does the voltage level also drop to almost zero? If so then you are looking at a bad ECM. If the voltage stays high there but only drops at the relay socket(with the relay installed) then the problem is in the wiring or relay socket. Suspect corrosion on the relay socket first. Suspect the first 2 inches leading from the relay socket next. Wires rarely do not fail in the middle of the run unless damaged.
IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay

Copyright (c) 1999, C. Pennock