320i will not start - Bimmerfest - BMW Forums

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series & 4 Series > E21 (1975 - 1983)

E21 (1975 - 1983)

Thread Tools Display Modes
Old 03-28-2010, 06:57 AM
double L double L is offline
Registered User
Join Date: Jan 2010
Posts: 1
Mein Auto:
320i will not start

Have 1983 320i will not start. Was running fine tryed to start It would only run If key was In start position. Let off of key It would die. Now will not start at all and no fire at coil. Think mabe switch? Fuses ok.
Reply With Quote
Old 04-19-2010, 10:05 AM
galaxyflier galaxyflier is offline
Registered User
Location: Saratoga Springs, NY
Join Date: Apr 2010
Posts: 35
Mein Auto: 1981 320i (E21)
320i W/N Start

Check the fuel pump relay on the fusebox. It is the black plastic relay between the two mounting nuts for the air cleaner. This relay energizes the fuel pumps when it receives pulse signals from the distributor. The purpose of this relay is to cut off the fuel pressure in a major collision in which the engine stops. When the engine stops, the pulses from the distributor stop and the fuel pumps are both de-energized. The relay is by-passed when the key is in the START position.
This relay can be somewhat pricey, so do some troubleshooting before you buy a new relay. Here's how: Remove the relay and you will notice it has four prongs; three larger ones and one smaller one. Install a jumper wire between the two middle prongs which are perpendicular to one another. This would be the large prong toward the front of the car and the large prong closest to the engine. Turn the ignition on and the fuel pump will come as well. If the pump comes on, go ahead and start the engine. If it runs, the relay is defective and needs to be replaced. You can drive the car with the jumper wire in place of the relay, but if you're involved in a collision and a fuel line is ruptured, the fuel pumps could keep pumping fuel to a potential fire. That's a bad thing.

Last edited by galaxyflier; 04-19-2010 at 01:25 PM.
Reply With Quote

See More Related BMW Stories

Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series & 4 Series > E21 (1975 - 1983)
Today's Posts Search
Thread Tools
Display Modes

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 On

Forum Jump

All times are GMT -7. The time now is 12:19 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
© 2001- VerticalScope Inc. All rights reserved.