Subject: Re: Hmmm, need some troubleshooting help (a little long) Author: maun : member since October, 2004 : 226 posts Posted on: 2009-10-15 20:43:34

Gearhed,
I am getting the following from my engine performance book. If these do not work, please call me or e-mail, I have some other procedures which are too long to type. Phone 301 332 7554.

Your question:

Anyone know how to check "fuel trim"? How can I check for a sticking injector? Wouldn't the code reader have turned up a bad injector, bad coil, or at least a mis-firing cylinder?

Fuel trim applys to the O2 sensor and here is the check with multimeter:

Make sure the ground for O2 sensor is connecting good first.

Using volts attach positive to sensor wires and ground out the common with the engine off.

Wait for the engine to warm up to close loop. Then O2 sensor should fluctuate between 800mV and 200mV. If it reads above 550 all the time the fuel mixture is rich hence you are smelling gasoline. If below 350 all the time fuel mixture is lean which is not your symptom as you described.

Two ways to check for intermitten problems:

If you have propane (lighter fluid will also do) shoot a little around the uspected leak areas to see for the engine rev up a little and your leak should be nearby the sprayed area.

For electrical shoot some water with a little salt solution near the wires to determine any engine rev difference. You can also wiggle wires, connectors or hoses to determine if engine difference results. And check electrical connectors for rust.

For sticking fuel injector, place a long screw drive or stethescope on the injector and listen for the clicking noise and then test on another one to determine if the same freqency.

I can look up the codes on the All Data next week if you still need to know.

hope this helps,

Norman

Norman
93 740I
Nov 92

• Hmmm, need some troubleshooting help (a little long) - geerhed 2009-09-30 21:34:50 (152 views)
  • SOLVED? $8.19 - geerhed 2009-10-26 21:31:48 (3 views)
  • Re: Hmmm, need some troubleshooting help (a little long) - maun 2009-10-15 20:43:34 (14 views)
    • Thanks, Maun - geerhed 2009-10-24 09:10:00 (3 views)
  • Re: Hmmm, need some troubleshooting help (a little long) - maun 2009-10-10 21:52:38 (27 views)
    • OEM - geerhed 2009-10-15 19:17:20 (9 views)
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    • Re: Checked MAF, changed O2 Sensors; no change - paulmer 2009-10-10 00:07:51 (32 views)
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  • Re: Hmmm, need some troubleshooting help (a little long) - skucera 2009-10-01 00:45:13 (76 views)
  • Re: Hmmm, need some troubleshooting help (a little long) - paulmer 2009-09-30 23:08:01 (81 views)
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