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Old 07-27-2013, 12:37 PM   #5
BostonGreen318

Name: BostonGreen318
Title: United Newb
Status: Offline
Join Date: Nov 2009
Location: Raleigh, NC
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Your Ride: 1994 318is & 1999 318ti
Engine Driveability Troubleshooting - Phase 1

Thanks for the replies. At this point, the plan is to systematically troubleshoot and report the findings. Since I'm not altogether familiar w/ electrical systems, it is my hope that someone can provide a brief education on the subject.

According to Bentley's "Engine Driveability Troubleshooting" checklist under the general symptom of "engine fails to start," the first step is to test fuel pump and fuel pump relay.

Using a digital multimeter and under the DC Volts setting (20V range), the battery voltage was tested at 12.19 V at the time of this fuel pump testing procedure. I realize this is rather low but should still indicate if there is a problem, right?

At the fuel pump, the top white terminal measured 11.60 (+/-) while the bottom black terminal measured .13/.14.

As far as the fuel pump relay goes, it's more complicated. After removing the relay at the fuse box, what is visible are nine slots. The relay has a set of four prongs that fit into terminal 30 (top middle), terminal 85 (bottom middle), terminal 86 (middle right), and terminal 87 (middle left).

Using the multimeter, the following measurements were made:

Terminals 85 and 87 = 12.16/.17
Terminals 85 and 86 = .03
Terminals 85 and 30 = 12.08
Terminals 86 and 30 = 12.01/.02
Terminals 86 and 87 = 12.09

Since I haven't a basic understanding of what this might mean, I am wondering if anyone could shed some light on these figures?

Last edited by BostonGreen318; 07-27-2013 at 02:59 PM.. Reason: Clarification
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