For some reason my truck keeps shorting out the glow plug relay. Happend 4 times. The very first time was right after i got all my motor work done. Sounded like loud static in the speakers and smoke coming from under hood. After that truck would not turn off with the key. Sent it back to shop that did the work and the fixed some wiring and replaced GPR. Shortly after getting it back it did it again. This time i killed truck and cranked it back and never had another issue until a week later when truck died. Figured out it was gpr and replaced it. No more problems. Last week i was getting fuel and it did it as i was leaving fuel pump. Then today in the drive thru line it did it again.

Same scenario everytime. After idling for a period of time usually 5 minutes or longer, very loud "static sound"(best way i can describe it), followed by smoke from under hood.

Been thru 3-4 gpr in the last 4-5 weeks.

Also truck doesnt want to start very well first thing in the morning. Usually wont crank the first try, then gpr will start clicking and smoking. Second crank its usually fine.

Lastly, just recently truck will crank, immediately start running rough and then die. Then crank right back up after like it never happened. Dont know if thats at all related.

PLEASE HELP!! TIRED OF FIGHTING THIS TRUCK

 

Is it possible they are selling you wrong relay to use for GPR?

The GPR and the ford starter relay look identical.

However, there is one major difference.

Starter relays ground thru the base. GPRs are grounded by pcm.

When you turn the truck key on, one small terminal gets 12v keyed voltage. The other receives a ground signal from pcm to energize relay.

If you have a starter relay in the gpr location, it will stay energized anytime the key is on and eventually blow out/melt down.

Most likely, the reason your truck did not shut down is the relay fused internally and you were back feeding 12 v down the small wire. That wire also provides 12v to IPR and some other things that make it run.

Another possiblitly is if somehow an external ground is attached to small terminal of relay and keeping it energized.

I guess if you replace relay again and both large terminals are still energized after 5 mins of running you have the answer. It should show in volt gauge on dash as well.

 

The last one i got was the BWD GPR 11. Best one oreillys had. Before that was a cheaper brand that the diesel shop had put on

 

The voltage gauge on dash has never worked right. Sometimes its reading the top end of normal, sometimes its barely registering. Unless somehow its getting sent those readings

 

Try a Western Plow GPR and yes, check the voltage across the big wires five minutes after its been running, good advise!

 

I have been trying to research. BWD does not provide internal schematic for relay but many folks have complained about it, some similar issues to yours.

I have a 2000. My son has a 95. His volt gauge will be at the lower end of the NORMAL bracket when the gpr is energized and around the R when de-energized. That is with new batteries and new cables all around.

The only way i can think to check it is to use an ohm meter and check for continuity between the mounting base and each small terminal. Of course, if yours is melted, its a waste of time. On a non melted one, there should not be continuity between the mounting base and either small terminal. If there is, its a starter solenoid and will stay energized until it melts.

Out of curiosity, what kind of motor work did you have? Was it removed?

 

it was removed. Headstuds pushrods, resealed whole enging, upgraded turbo, uppipes, plenums, downpipe, intercooler, efuel etc etc

 

I don't think a shop capable of doing that kind of work would mistake a starter relay for a GPR but stranger things have happened.

If i were you i'd go disconnect all of the wires that hook onto the GPR and test them individually to make everything is normal.

 

What do the two small wires do? Im wandering of they got crossed somehow because looks like they were twisted so maybe they got put on the wrong side. How would i know if they were wrong?

 

Also what exactly are the big wires for? I know the one with the cover on it stays hot cuz i dang near started welding when i changed it last time

 

Big post - 12v supply from battery. Always hot.
Other big post - should only have 12v when the GPR is activated.
Small post - switched 12v from ignition.
Other small post - ground. The ecm controls the ground. It takes input from the oil temperature sensor and the air intake sensor and if it sees certain critiera it grounds the small wire and energizes your glow plugs.

I've had to disconnect that last wire on a few trucks because it either stopped working or would randomly ground it causing issues. In that case I just run that post to a push button and then you can manually control the glow plugs.

 

Small wires can go to either terminal, it makes no difference. You can disconnect either small wire and GPR should never come on. Sounds like you have a short in the wiring to PCM to ground or the PCM is itself bad.