how reliable is gp test?
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Senior User
Joined: Feb 2007
Posts: 180
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From: Maple Ridge, Canada
how reliable is gp test?
I'm having hard start issues. I checked gpr and its good. I took the wiring harness out of each side of the valve covers. Then tested the 2 outside pins on each valve cover. One side all had .8 ohms and the other side all had 1.5 ohms. This seems good to me as I read that if gp's are bad they will be 100 ohms and up.
the starting issues are romp, rough idle when cold, at temp of 20deg. This morning was the worst. It took 5 tries to get her to run. It would romp then stall.
the starting issues are romp, rough idle when cold, at temp of 20deg. This morning was the worst. It took 5 tries to get her to run. It would romp then stall.
Post Fiend
Joined: Mar 2007
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From: Texas
You need to ohm the outside 4 pins (2 in front and 2 in back) for each side so that you test all 8. Good readings should be between 0.6 and 2 ohms.
What kind of oil are you using, what weight, and how old is it? Bad glow plugs make it hard for the truck to start the first time, and are coupled with white smoke out the tail pipe. If you think it may be glow plug related in 20 deg weather, turn the key to the on position and leave it there for 60 seconds before you try to start. The glow plugs stay on after the wait to start light goes out.
Many times the romps are cured if you switch to a synthetic oil. If the oil is old, or past due for a change, you're not helping the issue since the injectors fire off of engine oil.
What kind of oil are you using, what weight, and how old is it? Bad glow plugs make it hard for the truck to start the first time, and are coupled with white smoke out the tail pipe. If you think it may be glow plug related in 20 deg weather, turn the key to the on position and leave it there for 60 seconds before you try to start. The glow plugs stay on after the wait to start light goes out.
Many times the romps are cured if you switch to a synthetic oil. If the oil is old, or past due for a change, you're not helping the issue since the injectors fire off of engine oil.
Senior User
Joined: Feb 2008
Posts: 107
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From: Virginia
I am having the same issue, I was told to open the IPR valve reservoir and see if there was oil, about a half inch from the top. What I was told was this, the IPR valve o-ring may need to be replaced. I am not a diesel Mech, but that is what I have found out so far.
You will get many more responses soon, the people on here are the best
You will get many more responses soon, the people on here are the best
Thread Starter
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Senior User
Joined: Feb 2007
Posts: 180
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From: Maple Ridge, Canada
In cold weather, I usually cycle the wait light a couple times and that makes it start better. I do have white smoke, too. The oil is ok, maybe need changing in a month or so, I only drive the truck 2 or 3 times a week. The oil is 15-40 rottella t, so I could go with 5-40 for the winter.
I checked all 4 pins on each side, 8 total. the okm .8 for all on one side, and 1.5 for all on hte other side. They are just a little heater, so with those readings there must be a good connection and working. Its jus twierd that I have al the symptoms of them not working. There is nothing else in the gp system? a fuse or something?
I checked all 4 pins on each side, 8 total. the okm .8 for all on one side, and 1.5 for all on hte other side. They are just a little heater, so with those readings there must be a good connection and working. Its jus twierd that I have al the symptoms of them not working. There is nothing else in the gp system? a fuse or something?
Post Fiend
Joined: Mar 2007
Posts: 26,966
Likes: 50
From: Texas
There's nothing between the GPR and the glow plugs except the wires & plug connectors. If too many glow plugs are bad, the truck won't start at all. Try taking your multi meter and checking voltage on the 2nd large post after the key has been turned on. See how long your relay is staying on. Maybe the relay isn't staying on long enough?
Post Fiend
Joined: Mar 2007
Posts: 26,966
Likes: 50
From: Texas
Yep. It will only hurt your wallet with the electricity usage. Anything over 3 - 4 hours won't do you much good. Most of us just buy a timer and set it to come on a few hours before we plan on leaving.
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My truck was doing the same thing checked the relay and it seemed good then about a week ago the relay gave up I installed a new relay and all is well. Make sure the relay is staying on it can stay on up to 2 1/2 minutes I believe. I had just checked to make sure it had voltage after the key was turned on and did not check to make sure that it was running long enough I don't think it was do to the fact that with the new relay it starts right up and has taken care of the problem it still smokes out the stacks for a little bit when it is real cold but it has always done that.
