GP Circuit Low Input

[ward cleaver]

I'm thinking this has something to do with the glow plugs right?
What? The relays?

P1391
GP Circuit Low Input Bank No. 1 (RH)

P1393
GP Circuit Low Input Bank No. 2 (LH)

 

[Crumm]

Sounds like it might be time for a new GPR (Glow Plug Relay).

(Allied Electronics) 576-1078 (Stancor Heavy Duty 586-902) -Best One!!!!!
(AutoZone) MR99
(Ford) F7TZ-12B533-CA (94-96 with pigtail)
(Ford) F81Z-12B533-AC (96-early 2000 w/o pigtail)
(International) 1807230C2
(International) 1826634C94
(Napa) GPR-109

 

[BJS]

Crumm is right.

 

[Patrick Feeley]

I haven't messed with my Cali 1997 enough, but I don't think you can use the Stancor (and some of the other aftermarket units) on a truck with the GPR shunt on it as it won't fit. You may have to go with stock as I'm not sure any of the Cali guys have found one that will work with the shunt. Cheers!

 

[ward cleaver]

The Stancor won't fit? I was going to buy one online.
I'll check my GPR when I get home, but I think the '97s are still the old ones (4 posts).
Also someone told me to check my valve cover connections.

 

[DaveBen]

I haven't messed with my Cali 1997 enough, but I don't think you can use the Stancor (and some of the other aftermarket units) on a truck with the GPR shunt on it as it won't fit. You may have to go with stock as I'm not sure any of the Cali guys have found one that will work with the shunt. Cheers!

Why would the GPR have any effect on what the CARB guys think? Why is it different fron a Non-California truck? I don't get it!

Dave

 

[Patrick Feeley]

Obviously, CARB issues would have nothing to do with the GPR (wasn't speaking to that) . The California 1997 models have a big shunt on the relay for the glowplug monitoring circuits (49-state trucks do not). The shunt (supposedly) will not work on the Stancor relay. Trouble codes will be set if the shunt is not used. After going out and looking at the GPR and shunt on my 1997 and looking at the Stancor off my 1994, I'm inclined to agree (just by visual inspection), especially with the orientation of the Stancor (it sits with the posts pointing towards the driver's side vice pointing upward for the factory unit). I'll see if I can find the posts discussing this further. Hope that makes more sense.

Added in edit: Take a look at the pic at the bottom of this page: Welcome to guzzle's Stancor GPR replacement Mod Web Page
It shows the shunt (possibly bent to make it fit) so maybe it will work, but the decorative engine cover may not fit ... I still have my doubts

Cheers!

 

[Crumm]

Also someone told me to check my valve cover connections.

Could be the connections but since you are getting low voltage on both sides I would lean towards GPR. Check voltage on both big GPR terminals when the glow plugs are on and see what the voltage drop is.

 

[ward cleaver]

I went to Guzzle's site and found out how to do it. Here's his last note about the shunt style (Mine). I think I'll make a bracket so it sits upright like the oem. Thanks guys.

NOTE FOR TRUCKS WITH A GPR SHUNT:

It is possible to replace the factory GPR on trucks with the shunt on the outlet power terminal. It will be necessary to bend the outer terminals of the shunt to fit the larger Stancor relay but it will not damage the shunt to do this.

WIRING:
If you remove the wiring on the shunt, make sure that you wire the shunt back up properly.

There are three smaller blue wires going to the shunt. One of the blue wires is connected to a fusable link and then to a white/green trace wire. This wire must be connected to the large center post (relay outlet) where the shunt connects to the GPR.

The larger brown GP wire and the blue wire that is connected to a fusable link and then to a white/purple trace is connected to one side of the shunt.

The remaining blue wire and Yellow GP wire is connected to the other side of the shunt. It does not matter which side is connected to the shunt as long as you match the correct blue wire with the GP wire.

 

[Patrick Feeley]

Let us know how it works out! If you have the large decorative cover, there's not that much room between the GPR and cover in stock form. Cheers!