I have a 1993 f250 7.3 idi 5 speed with 424k on the clock. A few months ago I replaced the glow plug controller and relay and now the wait to start light blinks off and and on once and the relay clicks not getting any power to the gps, any advice would be helpful.

 

could have some dead plugs........

 

I was thinking that a few plugs could be gone I'm gonna replace them all winter is comin soon.

 

you can test them with a test light and see if their dead or not. Glow plugs dont really wear out, so no need to replace plugs that are working fine.

 

I'm going to test them when I get too work tommorow thx, I was told if one plug was out too replace them all

 

nope, your fine just replacing one or two

 

Ok good thx

 

On the new style system, resistance feed back times the glow cycle.

So for the system to be in top notch shape, the resistance of each glow plug should be between .5 and 1 ohm.

Lower resistance draws to much power.
Higher resistance means shorter glow times and less heat produced.

Replace only with Motorcraft/Beru ZD 9 glow plugs.

The rest are junk, and could wind up costing you a lot of money.

 

i did hear that autolite champion glow plugs swell up and fall down into the motor and cause big problems. im going to replace all the gps hopefully today.

 

I changed out the glow plugs.......still nothing I'm now thinking the harness might have fried wires. What does a fusible link look like ?

 

You need to check the Engine Harness to Chassis Harness connector, they burn up ...
You need to check the Power Feed to the Starter Solenoid, goes from Positive Battery post to one large terminal on the starter relay, MINIMUM 8Ga wire ... Should be heavier!

And just in case...
*** Glow Plug Test:v2.0.1
Test light test of the glow plugs.

1. Unplug the Glow Plugs at the Glow Plugs.
2. Attach one lead of a test light to 12v+ battery.
3. Touch the other lead to the terminal on the end of the Glow Plug. (where you unplugged the harness)
   Does it light up?
   1. Yes, Chances are it's good.
   2. No, Replace with Motorcraft/Beru ZD1A for 83-86, ZD9 for 87-94.5.
4. Repeat step 3 for all Glow Plugs.
5. Reconnect Glow Plugs.

This test is susceptible to miss diagnoses and should only be used for a quick reference.
To do a positive test use a volt/ohm meter and test the ohms between the terminal and base. Should be .5 to 1 ohm resistance.

********************************************** Post '86 Glow System testing. (87-94)v2.0.1
***** The following assumes you have already checked cables, connections (chassis to engine connector), cab, chassis and engine grounds.
***** When testing energize briefly, long enough to get the answer, no need to overheat things and no more than 10 seconds.

Disconnect the forward most connector on the Injection pump (towards front of truck), this prevents overheating the FSS.

1. Turn Ignition on.
2. Does WTS come on at all?
   1. Yes, Test Glow Plugs.
   2. No, Test WTS Light.

*** WTS Light test:v2.0.1
Step 1

1. Disconnect WTS light at Controller connector.
2. Ground WTS wire on harness side. (not controller side)
3. Turn Ignition Switch on.
4. Does the WTS light come on?
   1. Yes, WTS light works.
   2. No, Check WTS wiring, Replace Bulb.

Step 2

1. Disconnect WTS light at Controller connector.
2. Turn Ignition Switch on.
3. Does the WTS light come on?
   1. Yes, Fix wiring.
   2. No, Replace Controller.

*** Test power to Glow Plugs:v2.0.1
Using a volt meter versus a test light and comparing battery voltage at the battery and glow plug connector gives a more difinitive answer on the condition of the harness, connectors and relay.

1. Unplug 1 glow plug on either the left or right bank.
2. Attach one lead of a test light to the glow plug wire ensuring a good connection.
3. Attach the other lead to ground.
4. Momentarily turn the key on while watching the test light. (No longer then 10 seconds)
   Does it light up?
   1. No, Inspect harness and connectors, test controller and relay.
   2. Yes, Test Glow Plugs.
5. Reconnect Glow Plug.
6. Repeat for other bank.

*** Controller test, Post '86 (87-94):v2.0.1
This is a solid state controller and works on a grounding system.

1. Attach one lead of a test light to the relay Ground Terminal. (white wire)
2. Attach the other lead to 12v+. (Input Terminal)
3. Turn the key on while watching the test light.
4. Does it light up?
   1. Yes, controller is good.
   2. No, controller is failed.

*** Relay test, Post '86 (87-94):v2.0.1
The relay is attached to the top of the controller and has 4 terminals. (same relay as the 83-86)

• 1 large terminal (Input or Battery Terminal) goes to full time 12v+. (battery)
• The other large terminal (Output or Glow Plug Terminal) goes to the glow plugs.
• 1 small terminal (Power Terminal) is Ignition Switched 12v+ relay power. (red wire)
• The other small terminal (Ground or Controller Terminal) goes to the controller and is a controlled ground. (white wire)
  The controller grounds the Ground Terminal to activate the relay turning on the glow plugs.

• Ensure there is 12v+ to the relay Input Terminal at all times. (yellow wire)
• Ensure there is keyon/keystart 12v+ to the relay Power terminal. (red wire)
• Ensure that the controller is well grounded. (black wire)

1. Attach one lead to the Output Terminal of the relay. (Glow Plug terminal)
2. Attach the other lead to ground.
3. Disconnect the small white wire from the relay Ground Terminal.
4. Turn key on.
5. With a jumper wire momentarily ground the Ground Terminal. (where the white wire was)
   Does it light up?
   1. No, relay is bad.
   2. Yes, relay MAY BE good.
      For a more difinitive answer use a volt meter and test the voltage at the battery positive post and the Output Terminal while energized (jumpered), BE QUICK 10 seconds or less.
      Are Voltages close to the same? (A couple volt drop is normal)
      1. Yes, Relay is good.
      2. No, relay is bad. (replace with one from a 83-86)
6. Reconnect the white wire.

Reconnect FSS. (forward most connector on the Injection pump (towards front of truck))

-Enjoy
fh : )_~

 

Thanks for all the info, one question though, I took a look at the power feed to the starter relay and it is in good shape but how do I tell if the fusible link is fried ?

 

Check it for continuity