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JK McDonald JK McDonald is offline
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Join Date: Oct 2003
Location: Texas
Posts: 1,067
Garage
Fuse/Relay Panel Grounds -

Hey John - Have you seen the car run previously or is this a new project to you ? Although the computer can fail - they are pretty tough. Make sure to check and clean all the critical fuel computer ground terminals just above your fuse/relay panel, inspect the computer connector plug and the injector harness for damage.

Since it sounds like you have a reasonable spark and the signal from the distributor (green wire) to the ignition unit is good - If you have the cold start injector wired and plumbed correctly - as the starter turns the motor over it should try to run for a short period on the cold start injector.

Next - make sure the distributor (green wire) or "Engine Speed Pulse Signal" is also reaching the computer connector - Pin #1. This signal is used to tell the computer to alternately apply the fuel injector grounds in pairs. If the computer is correctly receiving the "Engine Speed Signal" a NOID LIGHT can be used to see a flash at each fuel injector connector.

One other point - make sure you have a good hot battery. If there is any question as to your battery status - add a second battery at the jumper post up front. There have been several instances where an owner has been chasing a "No Start" condition only to find out that it was a questionable battery or it's ground straps. If there isn't enough of the +12 volts remaining while the battery is being loaded by the starter - the fuel computer will not wake up.

Keep us posted - Michael
__________________
1984 928S - "Miss Purdy"
1987 911SC - "Frau Helga"
1986 930 - "Well Hung"
1975 911 Targa "Blue"

Last edited by JK McDonald; 08-30-2016 at 05:11 PM..
Old 08-30-2016, 04:43 PM
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