My friend with a 7.3 had rebuilt his motor about 20K ago. when he was rebuilding it, he opted not to go with Ford glowplugs and went with some plugs that were about $17 a piece from an auto part supplier.

His truck run's Great but the problem he is having is when starting up only on cold days.
He said it's throwing a glowplug or relay code, he can't remember.
I remember seeing a post on checking the glow plug relay. I think it said something about trying to jump it to see if that worked ?

only on very cold days his truck will start but smokes bad for a few minutes and clear up. he said the motor sounds like its missing till it clears.

I remember reading a post of this very thing but can't seem to find it.

he also said if it's plugged in over night it's fine, that's why im leaning to the relay going out..

if someone has the link or info I can tell him to try, we would appreciate it

He is two hours away and has no internet service where he is at to ask for him self..

thanks Phil

 

if it is throwing a code I am guessing it does not have a gpr it would have a gpcm. Glow plugs themselves can be ohmed out at the valve cover connection. Just do a search on checking glow plugs there is a ton of posts on it. The good thing about having the computer controlled gpr is it will throw codes and tell you exaclty which gp's are not working correclty. You will need a code reader for this. I was having the same problem with having to plug in my truck to get it to crank and run right, did he put in new injectors with the rebuild? My issue turned out to be injectors. hope this helps.

 

He said his builder put stage ones in.

 

hopefully that will rule out the injectors. I would pursue the gp's and gpcm as the culprits in that case. do you have a code reader? A buzz test while the truck is cold might be in order as well.

 

I have AE but am 2 hrs away. we were just looking to try something quick and jump it across to see if that works or not till I find the time to drive to Bakersfield.

 

I understand. If he has a gpr it can be done easy enough but not with a gpcm. Do a search for the gpcm and you will be able to see a pic of it and hopefully be able to tell what you have.

 

My truck was an E99 and had the same problem. When pluged in it started great but other wise not. My relay was clicking but was still bad. If you have the relay set up I would change it out. Let us know.

Chet

 

if he put autolites in there they may have blown out.

 

Glow Plug Relay is here. Glow Plug Relay 1999 - 2003 Non-California models
If it looks like this then you can short across the two large terminals with a screwdriver or similar thick metal object. Put it across the bolts and not on the threads. Hold it there at least 30 seconds before you start it to find out.
If it looks like this Glow Plug Module 1999-2003 Excursion and F-Series California Models
then you can't jumper it out that I know of.
If you unplug the connector going into the heads it is a 9 pin connector. The pinout is as follows.
G-G-I-I-C-I-I-G-G
G is glow plug
I is injector
C is common for the injectors.
Put a multimeter in ohms/resistance on the lowest scale and put one lead on the G pin and the other lead on metal from the head or ground. You should read less than 2 ohms for each glow plug.
He can check injectors with the leads between C and I and keep the one lead on C and change to all of the "I". His Under Valve Cover Harness may be loose but more than likely the GPR or GPCM. I don't know how you are going to convey this info to him over the phone but it is how you troubleshoot this problem.
Dwayne