Testing injector Drivers
Thread Starter
On The Tree
Joined: Dec 2005
Posts: 160
Likes: 0
From: Cooper City, FL
Testing injector Drivers Anyone familiar with the process? Can it be done with a techII? I have three cylinders doing nothing,(3,5& 7).All have spark, and the plugs smell like fuel when I pull them. Can the drivers fail or be bad, yet still allow the injector to open?Or are they hanging open???? I hear no sound of obvious "noise", besides the fact that it idles like crap.(on 5 cyls...) This is driving me nuts... 
I did change the rails and injectors, nothing.
I did change the rails and injectors, nothing.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
The Service Manual has 2 test procedures, briefly they are:
1. connect pressure gauge, prime fuel pressure (ignition on/off several times), do not start engine, pressure should maintain pretty much constant for about 1 minute; if it's dropping, then 1 or more injectors are leaking;
2. connect pressure gauge, prime fuel pressure (ignition on/off several times), do not start engine, record pressure gauge, using Tech2 select an injector and fire it, observe gauge immediately on firing, should see a pressure drop followed by slight rise, record the initial dropped pressure, calculate the difference between the 2 readings, this is the "drop"; repeat this whole test on all 8 cyls, add all 8 "drops" and divide by 8 getting the average "drop"; see which cyls deviate from the average.
1. connect pressure gauge, prime fuel pressure (ignition on/off several times), do not start engine, pressure should maintain pretty much constant for about 1 minute; if it's dropping, then 1 or more injectors are leaking;
2. connect pressure gauge, prime fuel pressure (ignition on/off several times), do not start engine, record pressure gauge, using Tech2 select an injector and fire it, observe gauge immediately on firing, should see a pressure drop followed by slight rise, record the initial dropped pressure, calculate the difference between the 2 readings, this is the "drop"; repeat this whole test on all 8 cyls, add all 8 "drops" and divide by 8 getting the average "drop"; see which cyls deviate from the average.
