GP Issue after replacing it all

[84TD]

Ever since it dropped into the 20's around here my truck will not start w/out ether under 40*. I replaced all 8 GP with beru's, the solinoid, the controller, the fusible links and nothing has changed, if anything its harder to start now.

All thats left is the wiring. I do not want to go to a push button, especially since I just replaced the controller.

I thought I remember a post about combining some wires at the controller or somewhere that would give more amps to the GP's. I feel like thats the problem because I am getting a good 10-12 sec glow and after glow and I got batt voltage at the plugs. My volt gauge only drops about half a volt during glow and I remember it dropping to almost 10 when the truck used to start.

Please Help, I hate using the spray.

 

[SparkandFire]

On my white truck I took and ran 4 AWG wire to the controller and eliminated the two yellow wires that meltdown in the harness.

Brown truck had the same treatment, but was on a pushbutton.


I loved the pushbutton GP control, but it's not everyone's style (I figured it almost as an extra bit of anti-theft insurance... If someone tried to hotwire the thing, and it just cranked and cranked, I would hope they'd give up and move on to the other cars in the parking lot...)

Are you still on the original 6.9 style GP control (the thread in controller at the back of the block with a separate relay on the fender well?)

Those are known to have many issues...

If you don't want to spend the bucks on a 7.3 solid state system, definitely re-consider the pushbutton.

 

[84TD]

Yup, its the original system. I really want to get it working especially after spending $70 on a new controller.

Is the two yellow wires the ones with the fusible links coming off the relay?

Does the power have to go through the controller? Is there any way to let the controller do the timing and run some fat wires from the soliniod to the GP harness?

 

[SparkandFire]

The yellow wires run from the relay on the fender well to the GP harness on the passenger valve cover.

The terminals inside the connector block get corroded and melt-down.

All the controller does is send 12v to the coil on the relay, no GP current runs through the controller (that's the relay's job)

If you've got good GP time (10-12 seconds) when its cold, and all your GP's have good voltage, then you might have another hard-start issue (such as air, weak starter, weak batteries, etc.)

 

[84TD]

Justin I have a 6.9 so nothing is on the valve cover.

I replaced my starter with a new gear reduction unit to get it to turn over faster but it didnt change the hard start.

is there anyway to see how much amperage a GP is pulling to know if its the wiring?

could this be a timing issue? I have a spare IP maybe I should try it.

I might just park it until spring this is so frustrating, its so cold out there! I lost the feeling in my fingers changing that starter.

 

[EMD_DRIVER]

Before you give up on it, consider changing to the 4ga wire. It will go from the fender mounted relay, to the GP solenoid. It really sounds as if they aren't getting enough amperage. When I changed the GP's on my 93, the truck started like nobody's business!

If you want to, you could also check each yellow wire separately and see that both wires have full voltage. I would also highly recommend cleaning all the terminals in the GP system. A little corrosion can kill a lot of voltage!

 

[MR.T]

Clamp-on meter

I'd use a clamp-on ammeter (AC/DC) too troubleshoot it. Measure current at a single plug, both fuse links together, one fuse link, etc. Here's a link to one of the ones I have. Works for troubleshooting the AC stuff like the water heater or a heat pump too. Here's a link to some 7.3 IDI amperage data.

EDIT: Just noticed you have an '84 where it's easier to get a volt meter at the plug connector with that style plug. Do you have similar voltage (of about 5-7 volts) at the plugs when initially turned on -- if so, the GP's are probably working OK. Higher voltage at the plug terminal means a plug is drawing less current, and the voltage should be rising as it heats. I still like the clamp-on meter method best.

 

[f-two-fiddy]

What brand of GP's did You put in it?

 

[84TD]

Motocraft Beru plugs.

I have batt voltage the entire time at the plugs. I think thats how the 6.9 system works. It starts at 12.2 and goes down to 11.9 with the gp's on.

 

[OLDBULL8]

Something is strange here.
Your getting 10-12 seconds glow. Then controller is off/on
That is a normal GP cycling.

Your getting 12.2 then drop to 11.7 volts at the GP's.
Normal drop in voltage should be around 10.5 at the GP's

Try this: With some help to start, Use a jumper cable from the GP relay (GP side) direct to the B+ on the battery for 10 seconds, then key on to start. If it starts, then bad wiring or GP relay. No start then fueling issue.

 

[SparkandFire]

You can test the voltage drop across a relay by putting one of the leads on your meter on the battery side of the relay, and the other lead on the output side, the lead going to the GP's.

When the relay is on you should see very low voltage (less than a volt) and when it is off you should see battery voltage.

If you have an voltage across the relay when it's engaged, then the contacts inside are dead...

 

[icanfixall]

Those two yellow wires go thru the main engine wire harness plug. Pull open the plug and look for corrosion. The plug pins are way too small for the amps required and any mes in there will reduce volts and amps to the controller. Sometimes the plug melts.... Mine did one morning. Try to start the truck and then feel the plug. If its hot you have issues. A 4 gauge speaker wire going directly from the fender solenoid to the controller will fix the problem. Get rid of those two tiny yellow wires.. Thats just another bad idea from ford...