Solid State Glow Plug Relay In Place Of Old Style?

ChristopherH · November 12, 2008

One of my parts guys asked today about a 7.3 modification he has heard of and that is to install the solid state glow plug relay found on California emission 7.3s on a truck that uses the conventional style round relay. I have never heard of this and honestly am not sure if it is possible. I can think that the PCM, engine harness, and relay may need to be changed so it begs the question of if its really worth it. Has anybody else every heard of this or seen it?

Bruce Amacker · November 12, 2008

I think you're getting IDI and PSD confused. It is common to replace the early (1984-1987) 6.9/7.3 IDI glow plug system with the late IDI solid state system used from 87ish to '94 which is much more reliable. This would involve replacing a round relay with the solid state style and I've done a bunch of them in years past. There would be no reason to do this on a PSD that I can think of.

Good Luck!

/forums/images/%%GRAEMLIN_URL%%/grin.gif

Mekanik · November 13, 2008

What year is the truck. These were on California Emission trucks and Excursions from around 1999-2000 and newer. Nothing is impossible, just a question of how much money, time, and agrivation.

BrunoWilimek · November 13, 2008

To get an idea of what is involved in this swap, I went to the 2000 Excursion wiring diagrams and compared the California emissions schematic to the non-California schematic. The wiring from the top of the page to either the glow plug relay or the Califoria style Glow Plug Control Module is similar, so that should not present a problem. However, The PCM and wiring harness between the PCM and GPCM and to the glow plugs, as well as the GPCM would have to be available, say from a donor truck. I don't know if the glow plugs themselves are the same, and other things not readily obvious might be required as well. What would be the benefit if any of performing this operation, I would have to ask? The only thing that comes to mind is the ability to determine from DTC's which, if any glow plugs were dead. Maybe more reliable also, but at what price? /forums/images/%%GRAEMLIN_URL%%/2cents.gif

ChristopherH · November 14, 2008

Thanks Bruno, that confirms the opinion that I already gave our parts guy on this question. Sometimes its nice to just throw one of these off the wall questions out there and see if anyone has ever done it before. (Not to mention getting a qualified second opinion from you gentlemen) I think the benefit he was after was increased reliablility, but after explaining all the needed parts (PCM, harness, GPCM, etc.) to him, I think common sense has now settled in. Just for the info, the truck in question is a 2001 and he also has an 01 Excursion 7.3 that gave him the idea. Thanks guys for your prompt replies.