GP(R) Testing
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Posting Guru
Joined: Apr 2010
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From: South Shore, MA
GP(R) Testing
Been hard-starting and romping this winter with some black smoke.
An ohm test from the GPR to Ground measured 7.11. I think a healthy system should measure between 8-9, right?
What's my next step? Ohm test at the valve cover harness?
An ohm test from the GPR to Ground measured 7.11. I think a healthy system should measure between 8-9, right?
What's my next step? Ohm test at the valve cover harness?
Elder User
Joined: Jun 2007
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From: Sandia Park, NM
I would check for 12v going to the GPs rather than ringing the GPR out. Bad GPs and/or GPR usually results in white smoke. I replaced all my GPs, UVCH, and GPR with the Stancor from Mouser. I still get the romp romp if I don't plug in and it's in the teens.
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From: South Shore, MA
If I'm plugged in, everything's smooth - no issues.
If I'm not, and it's below 25-30, I get the Romp Romp, white smoke - white smoke - white smoke - grey smoke - grey smoke - black smoke - black smoke - black smoke - smooth idle, no smoke.
140k on the clock, maybe a few GP's are toast and some injector o-rings are worn?
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Post Fiend
Joined: Nov 2007
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From: Payson, AZ
I'm pretty sure the GPR works, I can see the voltage drop when it's energized.
If I'm plugged in, everything's smooth - no issues.
If I'm not, and it's below 25-30, I get the Romp Romp, white smoke - white smoke - white smoke - grey smoke - grey smoke - black smoke - black smoke - black smoke - smooth idle, no smoke.
140k on the clock, maybe a few GP's are toast and some injector o-rings are worn?
If I'm plugged in, everything's smooth - no issues.
If I'm not, and it's below 25-30, I get the Romp Romp, white smoke - white smoke - white smoke - grey smoke - grey smoke - black smoke - black smoke - black smoke - smooth idle, no smoke.
140k on the clock, maybe a few GP's are toast and some injector o-rings are worn?
How long are you letting the GPs heat up before you try to start?
Once it gets down to freezing temps I wait between 20 and 40 seconds before starting. The caolder it is the longer I wait, but never have waited longer than 60 seconds even in the single digit temps.
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From: South Shore, MA
I'm certainly waiting long enough - maybe 30-40 seconds. If it's really cold, I'll wait 30-40 then cycle the key and wait another 10-20. Usually on those days, it'll try to romp, but I can stop it with a (very) little pedal manipulation.
How do I check for proper voltage transmission?
(I'm very electrically and mechanically inclined)
How do I check for proper voltage transmission?
(I'm very electrically and mechanically inclined)
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Post Fiend
Joined: Nov 2007
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From: Payson, AZ
My GPR would operate but not pass voltage because the contacts looked like this.
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Posting Guru
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From: South Shore, MA
Sounds good. I'll report back with the results.
So, while the GPR can draw voltage from the battery, it still may not be passing current to the GPs? I guess I thought that if the voltage dropped while the GPR is energized, it was passing current.
Thanks
So, while the GPR can draw voltage from the battery, it still may not be passing current to the GPs? I guess I thought that if the voltage dropped while the GPR is energized, it was passing current.
Thanks
Post Fiend
Joined: Nov 2007
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From: Payson, AZ
Assumptions could have you chasing your tail.
still plays with trucks
Joined: Mar 2004
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From: Twin Falls Idaho
best way to check GP function is with an AMP guage. If you have access to an inductive AMP meter simply clamp around the wires coming off the output terminal. On a cold engine you will see 192 Amps if all the GP are working correctly. The Amp draw will taper off the longer you leave the key on. you can then check individual sides by clamping around only one output wire. this can help decide which side the bad ones are on.
12v may be passing through the relay but if it won't handle the amps, its not going to work correctly.
Barney
12v may be passing through the relay but if it won't handle the amps, its not going to work correctly.
Barney
Elder User
Joined: Jun 2007
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From: Sandia Park, NM
I'm certainly waiting long enough - maybe 30-40 seconds. If it's really cold, I'll wait 30-40 then cycle the key and wait another 10-20. Usually on those days, it'll try to romp, but I can stop it with a (very) little pedal manipulation.
How do I check for proper voltage transmission?
(I'm very electrically and mechanically inclined)
How do I check for proper voltage transmission?
(I'm very electrically and mechanically inclined)
Hotshot
Joined: Nov 2006
Posts: 11,288
Likes: 269
From: North of Greenville
One other option you may want to consider, if you're not already doing it, is to change from 15w40 to a full synthetic 5w40 for winter driving. That has resolved cold start romps for many others in the past.