whiteboyslo
FNG
I replaced the GPs (thankfully they were the original Motorcrafts) soon after buying the truck almost 2 years ago. Now, less than 15K miles later, I think my GP system is indicating I have a bad GP or two.
When I first bought it, the GPs wouldn't even cycle for 5 seconds. The controller would click rapidly and cold starts usually took a couple of cycles of the GPs and quite a bit of cranking. I installed new ZD9s and repaired the harness where needed (plenty of the plastic ends crumbled apart while replacing the GPs). Afterwards, the system would cycle for 10-15 seconds with only one solid click of the relay when I first turned the key, then silence. Assuming I let the GPs do their thing, the truck would fire almost immediately every time.
As of two days ago, the system is now somewhere in between where it was when I bought it and where it was when I fixed it. The WTS light will stay on nearly as long as it did after I replaced the GPs (maybe a bit shorter), but then the whole system goes nutty with the clicks. EVERYTHING electrical in the truck dims with the clicks; both the tach and the voltmeter in the dash jump with the clicks as well. The truck still fires, but cold fires take a couple extra seconds of cranking when cold. I had this happen once before and it turned out one of the 'fixed' plugs on the GP harness had managed to back itself off the GP. I checked last night, and they all seem fine.
Assuming it is a bad GP, is it normal for Motorcrafts to die this quick? I'm still somewhat of a diesel newb, so I honestly don't know. I've read that having the timing too far advanced can cause them to wear prematurely, but my timing is set at a reasonable 8° (per the Kent Moore meters icanfixall rents out) and had been much more retarded prior to that (like ~4°). Also, does the amount of time the GP controller runs normally before it begins to click correlate to the number of GPs that are bad? In other words, if I had 1 bad GP, would the system wait longer before clicking than if 4 were bad?
Lastly, is there any chance all of this is having an ill effect on my charging system? I have a handy little voltmeter that plugs into the cigarette lighter. It normally reads in the low 14s when the truck is running (high 13s if the lights are on), but has seemed to drop a couple decimals in the last few days (correlates to when the system started going weird). Only other electrical work I've done lately is to add an oil pressure gauge using the stereo's constant and switched power sources to light it. It's an Autometer digital gauge that requires power to operate and uses the switched source to know when to dim. It should be pulling a very negligible amount of juice, though.
I ordered a new set of ZD9s just in case. Seems like having a few in the glovebox wouldn't be a bad idea. I plan to test the GPs using a test light once I have the new ones.
Mike
When I first bought it, the GPs wouldn't even cycle for 5 seconds. The controller would click rapidly and cold starts usually took a couple of cycles of the GPs and quite a bit of cranking. I installed new ZD9s and repaired the harness where needed (plenty of the plastic ends crumbled apart while replacing the GPs). Afterwards, the system would cycle for 10-15 seconds with only one solid click of the relay when I first turned the key, then silence. Assuming I let the GPs do their thing, the truck would fire almost immediately every time.
As of two days ago, the system is now somewhere in between where it was when I bought it and where it was when I fixed it. The WTS light will stay on nearly as long as it did after I replaced the GPs (maybe a bit shorter), but then the whole system goes nutty with the clicks. EVERYTHING electrical in the truck dims with the clicks; both the tach and the voltmeter in the dash jump with the clicks as well. The truck still fires, but cold fires take a couple extra seconds of cranking when cold. I had this happen once before and it turned out one of the 'fixed' plugs on the GP harness had managed to back itself off the GP. I checked last night, and they all seem fine.
Assuming it is a bad GP, is it normal for Motorcrafts to die this quick? I'm still somewhat of a diesel newb, so I honestly don't know. I've read that having the timing too far advanced can cause them to wear prematurely, but my timing is set at a reasonable 8° (per the Kent Moore meters icanfixall rents out) and had been much more retarded prior to that (like ~4°). Also, does the amount of time the GP controller runs normally before it begins to click correlate to the number of GPs that are bad? In other words, if I had 1 bad GP, would the system wait longer before clicking than if 4 were bad?
Lastly, is there any chance all of this is having an ill effect on my charging system? I have a handy little voltmeter that plugs into the cigarette lighter. It normally reads in the low 14s when the truck is running (high 13s if the lights are on), but has seemed to drop a couple decimals in the last few days (correlates to when the system started going weird). Only other electrical work I've done lately is to add an oil pressure gauge using the stereo's constant and switched power sources to light it. It's an Autometer digital gauge that requires power to operate and uses the switched source to know when to dim. It should be pulling a very negligible amount of juice, though.
I ordered a new set of ZD9s just in case. Seems like having a few in the glovebox wouldn't be a bad idea. I plan to test the GPs using a test light once I have the new ones.
Mike
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