Discussion:
Electrical short

Pops the 15 amp main power relay, ECU, 02 Sensor as soon as key turns on.
Here is the what I have dones. Checked and cleaned grounds and battery terminals. Checked harness for short to power or ground. Isolated it to the MPR1 relay circut. Pull mpr1 relay put in fuse pull up codes. 711 LSD_1 dither 1 open or short to ground blaa blaa. What and where is a dither?
431 EST1 open or shorted to power or ground or bad spark module. Again what and where is EST1?
Have color schematic and mpr1 is green n white for 02 sensor. Red battery, red n white x2. 1 red n white goes to ECU power, other red n white goes to optional connector. I still have to find the opt connector, if used and what it feeds.
Any thoughts?
  • Posted 16 May 2018 10:57
  • By Shadetree5080
  • joined 16 May'18 - 4 messages
  • Nevada, United States
Shade
Showing items 1 - 1 of 1 results.
Dither valves or also called FTV (fuel trim valve). can be found behind the vaporizer two black valves with vac lines and wiring attached. LSD refers to the style of Delco ignition system used. Check for shorts to and from the distributor, coil ect. Check also the harness which crossed over the transmission. Often this harness will wear through and short to trans.
  • Posted 18 May 2018 07:07
  • By tom_p
  • joined 21 Feb'11 - 198 messages
  • Alberta, Canada

Post your Reply

Forkliftaction accepts no responsibility for forum content and requires forum participants to adhere to our rules of conduct. Click here for more information.

If you are having trouble using the Discussion Forums, please contact us for help.

UN Forklift FBRS15KQZ2
HANGZHOU, Zhejiang, China
New - Sale
Taylor TX330S
Morgantown, Pennsylvania, United States
Used - Sale & Hire
USD159,500
Upcoming industry events …
October 15-17, 2025 - Bangkok, Thailand
October 21, 2025 - Atlanta, GA, United States
November 13-14, 2025 - Berlin, Germany
Latest job alerts …
Marietta, United States
Tampa, United States
Global Industry News
edition #1246 - 4 September 2025
Next Thursday is R U OK? Day in Australia , an important opportunity to bring conversations about mental health out into the open and a reminder to check in on those around us, including our colleagues... Continue reading
UN Forklift FBRS15KQZ2
HANGZHOU, Zhejiang, China
New - Sale
Taylor TX330S
Morgantown, Pennsylvania, United States
Used - Sale & Hire
USD159,500
Latest job alerts …
Marietta, United States
Tampa, United States
Fact of the week
The first practical visible-spectrum LEDs were red, not white. The red colour was the easiest to produce using the semiconductor materials available at the time (the 1960s). The alloy gallium arsenide phosphide (GaAsP) used emitted red light.