wait dave, only the starter relay has the i and s?

 

dave my truck is 92 ford 450 i bought it in 2000 never had to change any thing with the glow plugs other than that the harness and controller has never been touched except the glow plugs

 

branden only the starter relay has the I and S by the small terminals.

towpro, if you bought a 92 truck in 2000, that means someone else had 8 years to change things.

If you read this forum long enough, it is amazing what some people do to vehicle wiring.

I wish I could help more, but trying to figure out a truck problem by typing back and forth sometimes gets to be very frustrating for everyone.

Do you have a volt meter?

Let's try again with a different approach.
First unplug the front electrical connector on the drivers side of the IP.
That is the fuel shut off solenoid, so the engine will not start and the solenoid will not burn up while testing the glow plugs.

Also for these tests, leave the negative lead on the volt meter on the battery negative terminal for all readings.



Key off.
How many volts across the battery?
Now how many volts at the battery terminal of the glow plug relay?

Now key to on.
How many volts across tha battery?
How many volts at the battery terminal?
How many volts at the ignition terminal?

Now make up a short jumper wire.
You are going to check the voltage at the glow plug terminal.
Clips on the volt meter lead may make it easier if you have them.
10 seconds max time for the jumper to be installed on the white wire terminal and a ground connection.

When you have the key on, and ground the white wire terminal, the relay will close.
How many volts on the glow plug terminal?

Jumper wire off the white wire terminal.

Now pull a couple connectors off the glow plugs, one at a time.
Check the voltage at each of the connectors by closing the relay with the jumper wire.
What are those voltages?

 

i was told by an ex mechanic at napa that these relays that he sells do a dual purpose for these year trucks, this isnt my area of expertise but can he be correct?

 

The internal electrical connections are different.

Starter relay coil grounds through the mounting bracket, and I don't remember what the gasser motor used the I terminal for, diesels have nothing on that terminal.

The glow plug relay coil is grounded through the second small terminal, not the mounting bracket.

With a wire reconfigure you can make the starter relay work, but it will not work if you just swap them out.

An 86 glow plug relay will swap right on to an 87 or newer controller, repair for 18 dollars versus 150 for a new controller/relay they list for the 7.3 engine.

 

I'll say it again! Use AC 12Gs or Autolite 1109s and you won't have to worry about melting your GPs down. You'll have to change the terminals but it's worth the effort. Don't believe me? Try it before you install them. You should preheat you GPs before installing them anyway. You'll see I know what I'm talking about. If anyone knows a BERU dealer that is willing to search for parts, have them look for a set that is designed for the military HUMVEE. The GPs for the HUMVEE will fit our IH engines.

 

Low voltage means higher current only works for electric motors. GPs are pure resistance. Lower voltage means lower current which means slower heating.

 

What ever you say Marianna.
You can post that as much as you want, I will never recommend anyone use them.

Autolite and AC glow plugs are garbage.

Amps = volts / ohms

So if you have a 12 volt system and .5 ohms resistance the glow plug draws 24 amps.
Four of them draw 96 amps.
192 amps for all 8 glow plugs fed with two 10 AWG wires.

If the voltage drop laws don't hold true for glow plugs, can you tell me why you have 12 volts going into the glow plug circuit and only 7 volts at the glow plugs?

My guess is, 96 amps should be running through a #3 wire instead of a #10 wire to deliver the amperage the glow plugs draw.
But I don't know much, I am only a master electrician.

 

No need to be sarcastic! The Master Electrician didn’t pick up on the statement posted by 16Vjohn “the lower the voltage the higher are the required amps to perform the same work” !!! This statement is true except it does not apply in any way to GPs as I tried to point out. GPs are pure resistance. You are right E(voltage)=I(current)times R(resistance). And we all know ‘You can’t fool Mother Nature’. Lower voltage means slower heating. I wonder if the engineers intentionally used the wires to drop the voltage to the GPs.

 

That is exactly what I have always said.

Small wires with a big load to drop the voltage to the plugs.
Otherwise with the correct wire size, like if I was wiring something in a house with that many amps it would be at least an AWG 3 copper wire and probably a AWG 2 because of distance.

With wires that size, the glow plugs would be hot in 3 seconds.

As for the Autolite plugs here is a post copied from another thread posted today.

i put 8 new autolite glow plugs in my 93f350 to avoid winter problems. 3 weeks later
3 were already burned out. i had a problem getting one out because it swelled up
in the hole and was stuck. i used pb blaster and 3 hours of patience. i switched all
to motor craft and repaired 2 injection lines leaking fuel sometimes,which means
could pull in air and lose prime. now it starts in about 2 seconds at 34degrees
good luck p.s i learned the hard way

Again, I will never recommend Autolite glow plugs and will recommend they not be used.
Post 18 in this thread,
https://www.ford-trucks.com/forums/9...ml#post8204050

I don't have the opinion I do about Autolite glow plugs for no reason.
I read it constantly right here in this forum.
With winter here, many of the people in this forum will not be starting their engines if the glow plugs are dead.
And many of them may be out on temps at or below zero for three hours trying to get one stuck Autolite glow plug out of their head that they installed three weeks ago when it was warmer thinking thay would be good to go all winter after they read your post.
And do believe me, you are the only person posting how great Autolite glow plugs are.
Not sure what the temp is outside right now, but it is below freezing, so I do know where the northern people are coming from when they can't get the engine started and are out in the driveway working on their truck.
So I will still say the same thing to every post you make recommending Autolite glow plugs.
They may be OK in Florida, but most of us are not there.

 

Interesting discussion. I had nothing but trouble with the glow system in my old 6.2L and about 18 years of no trouble in my '86 Ford, which has a nearly identical system. I replaced the ORIGINAL glow plugs after 18 years in 04. Four had gone but came out OK. I replaced the controller just because.

I won't tell you how many times I replaced controller and glow plugs on the 6.2L (I'm sure I put someone's kid thru college) until I built my own manual system. Kennedy Diesel had some glow plugs that you could hook up to a battery with jumper cables and it would just sit there and glow until the battery was dead. Tried that with some ACs and they could go about 10-15 seconds. Even with the whiz-bang glow plugs, the 6.2L never started as good in cold weather as the Ford. On both trucks, though, just a few seconds of extra glow time really helps a lot... if you have a glow plug that will take it. I'm not actually sure what I put into the Ford in '04. Likely Autolite, but I guess I'll look

 

I got a quick question guys can I use a later model relay on a 1994 F-250 7.3 IDI TURBO i got the price for a new GP controller from ford it was like $190????

 

I think all the idi glow plug modules are the same from 1987-1994. dave s listed the part # for the relay that needs to be used or just ask for a GP relay for a 1986 6.9 truck.

 

Here's a few places to check. Others have recommended but I have no first hand experience with them.

Diesel performance parts and accessories. Diesel injectors, pumps, filters, kits, additive, gauges and apparel.

Pensacola Fuel Injection | Worlds #1 Diesel Rebuilder - Cart contents

 

Autolite themselves rated the 1107s (which cross for ZD1-A's) at 6v and 53W. Go to the website and see for yourself. click parts catalog and type in 1107. look at the specs.

According to the catalog I can use 1115's too. they are 11v 80w (unregulated also)

I'd like to know why you say the 1109's vs the 1110's vs 1106's...... Specs from autolite below.

1109's 5MM Probe Diameter, 11.5V 60W, .250" Spade Terminal Connector, Sheathed Coil

1110's 5MM Probe Diameter, 10V 70W, .250" Spade Terminal Connector, Sheathed Coil

1106's 5MM Probe Diameter, 11V 75W, .250" Spade Terminal Connector, Sheathed Coil

1112's 5MM Probe Diameter, 10.5V 90W, .250" Spade Terminal Connector, Sheathed Coil

just for reference.. Both cross ref for Motorcraft ZD1-A
1107's 5MM Probe Diameter, 6V 53W, .324" Spade Terminal Connector, Sheathed Coil, Uses a voltage controller
1115's .192" Probe Diameter, 11V 80W, .328" Spade Terminal Connector, Sheathed Coil, Uses a voltage controller