ive been ignoring the problem but now its a problem starting in the cooler fall tmeperatures.
Lately ive had to cylce the plugs twice in a row before I start it or it flat out wont fire. In cool temperatures they cycle 9 seconds but no luck firing up. On the cooler mornings (40F) it takes 5-7 seconds of cranking to fire even after 2 GP cycles in a row.
I replaced all the plugs with Motorcraft GPs and they are all good, ive also replace some harness ends. The relay is new and seems to cycle correctly. The timing advance and high idle turn on when it gets cool out. Two cycles means I turn the key on, the light goes out, I turn the key off and back on immediately and wait till the light goes out and crank. It will usually fire up in the afternoon after sitting all day but it takes lots of cranking firts thing in the morning.

Any help would be appreciated. I fail to see how such a simple system NEVER works on my truck. Maybe its just the guy fixing it.

 

Do you depress the fuel pedal and hold it at 1/2 pedal for the start.....release after start.

 

I think its a problem with the controller or a bad connection somewere,i go through the same sullation it seams to hapen more when its damp out and temps are less than 60

 

Could be a slow starter,it should be over 200rpm while cranking.

 

Howdy,

I had a similar problem with my 86 6.9. It was fairly new when this happened.(I bought it new).

All the plugs were good but they weren't getting any power at all. I discovered that the relay providing power to the plugs gad burned contacts inside. I had to drill out the rivets and take it apart to see this. I lightly sanded the contacts and it worked fine after. I did replace it though and kept the "fixed" one as a spare.

Before the relay failed, it took longer and longer as the contacts burned more and more. I still have the relay. I sold the truck in 1993!


By the way the best way to check this is to put an accurate volt meter on one of the plugs to check the voltage when it cycles. The power relay is just a simple solenoid controlled by the glow plug control system. Each plug probably draws somewhere around 10+ amps so with 8 of them we're talking 80+ amps when the relay closes. Every time it closes and opens there's a little arc and it burns a little each time. If the contacts are burned very badly, the voltage at the plugs will drop considerably.


Regards,

Rick

 

when you turn on the key and the wait light comes on....wait for it to go off...then wait some more...until it starts clicking on-off (another 5 seconds or so)...THEN press the throttle 1/2 way ...when over 40 degrees and all the way when its colder.....turn to start and VIOLA!...probably will start. If not ....do like youre doing with repeat ...BUT WAIT....the extra 5 or so seconds...good luck...no more white clouds in the morning bring a smile....

 

I have cleaned all the contact socket things on the end of the harness wires many times and replaced some and recrimped some and I do floor it at every start up. The relay is brand new also.

 

Did you determine that you are in fact getting power to each plug and each plug is actually drawing current?



The other thing important to indirect injection diesels is the timing. The DB2 has an automatic advance device internally that will advance the timing a few degrees for cold starting. You can tell when it retards during warmup (at idle of course) when the rattle decreases. It should never be necessasary to depress the throttle when starting any diesel.

If the injection pump has been "played" with by someone and they did not get timing back where it should be (and it's retarded too far) it will be VERY hard to start when cold and might not start at all even if ALL the plugs are working. This is very common where someone has changed the pump and didn't have the luminicity probe required for setting the timing so they just put it back "matching up the marks".....Sometimes it works and sometimes not!

Timing is critical for cold starting a diesel, especially an indirectly injected one.

If all the plugs are good and are getting power (And you have adequate compression and cranking rpm), retarded injection timing is probably the problem.


Regards,

Rick

 

It states clearly on my sun visor of my 89 F250 7.3 to depress pedal 1/2 way when above 32*F and fully when below.

 

I believe my 86 might have indicated the same thing. I started mine regularly at temps in the teens and single digits... and never pressed the pedal at all during cranking. It always started on the first "turn"!

 

I believe when you press the throttle before start-up youre letting the fast idle solinoid pop up and give you fast idle as well as advancing the timing when its cold...probably why the instructions are as they are on the visor.....I follow the instructions and mine starts no problem....a ford update way back in 1989 or so changed how long to wait ...dictated additional time before turning the key to let glow plugs warm pre-combustion chamber more for easier cold start....

 

My injection pump has not been messed with at all. The cold timing advance circuit works because the high idle comes on and it is all the same circuit.
Why wouldnt giving it full throttle make it start easier? Last time I checked its kind of hard to flood a diesel and more fuel=more combustion.

 

I got out the tester this morning and found that my gps are only getting 8 volts to them. That sounds like a problem to me. The controller is new, the gps are new, so that widdles it down to the wires going from the controller to the gps. Right?
I tested the the controller and it is getting 12 volts in from the battery but only putting out 9 volts on the glow plug side. Am I correct when I assume the glow plugs use 12 volts?
This frustrates me because that is a new controller and I dont want to run another switch in my cab for manual plugs. Ive already figured ive ran over 100 feet of wire on my truck that wasnt there from the factory I dont want to make it 110.
I dont see how its even possible to run a switch when the controller isnt putting out 12 volts. The cycling part works fine.

 

What you are seeing is voltage drop due to the wire size and the amps being used.
That is about a normal reading for voltage at the glow plugs.

 

If 8 or 9 volts at the terminal for the gps is normal than I dont know what the problem is. So let me get this straight, the gps are made to work with just 8 or 9 volts?
When I plug the block heater in at night it fires right up the next morning so I know its not a fuel problem so it has to be the gp system. I remember cranking for maybe 5 seconds last year when it got down to 10-20 F but it would fire up like a cummins above 30F.
Now it gets below 50F and im out in the parking lot cranking like I drive a GM diesel.