Idle variation, unknown cause
Elder User
Joined: Sep 2011
Posts: 979
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From: Vancouver
On multiple vehicles including my 7.3 I have solved drivability or strange symptoms when no obvious cause was apparent by changing a seeming ok battery. I had the luxury with my 7.3 of swapping a set of batteries to test my theory.
For this reason I think that batteries can cause electrical noise in a vehicle. In the old days of mechanical injection pumps, this was not a problem. The more computerized vehicles get, the more easily they can be affected by electrical problems.
Obviously corroded cables and clamps can cause problems also.
All that said, if the IPR has not been changed in 200Kmiles, I would do that for overall drivability reasons. If the IPR is delayed in its action that could be the cause. The IPR works as hard as any device on these trucks.
Larry
For this reason I think that batteries can cause electrical noise in a vehicle. In the old days of mechanical injection pumps, this was not a problem. The more computerized vehicles get, the more easily they can be affected by electrical problems.
Obviously corroded cables and clamps can cause problems also.
All that said, if the IPR has not been changed in 200Kmiles, I would do that for overall drivability reasons. If the IPR is delayed in its action that could be the cause. The IPR works as hard as any device on these trucks.
Larry
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From: Blairsville, Pennsylvania
Hotshot
Joined: Jan 2011
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From: Puget Sound
I'm not so sure that's the correct course of action. You have some tired injectors, and firing off Buck$Zooka rounds at sensors may do little more than deplete your armory inventory. I would get my mitts on the information needed to test each sensor thoroughly before spelunking in my pockets. I would also get some Deoxit and start cleaning all my connectors. You might look into products like Stabilant 22 - Tim Hodgson is your source of information on this [LINK].
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Joined: Mar 2007
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Alright, this is long but I am trying to give all the details, not sure if some of these things relate. But I will say all of it and we can go from there.
Had a Outlet fitting on the HPOP leaking. The night I found the leak I was trying to see if the cut out between the two fittings was actually a hole that had gotten punched in the pump. So I grab a long screwdriver to probe(no jokes here
) the spot to see how deep it is. While I was doing this I accidently rubbed the screwdriver on the cable going to the alternator. As I am sure you already guessed it a large amount of sparks insude. Enough that it caught me off guard. I dropped the screwdriver which wedged itself in place and starts to glow cherry red. I tried to get it out but no luck. Next thing I know if there are flames from under the hood. I grab the fire extinguisher I keep under my seat and get the fire knocked out quickly. Thankfully the screwdriver actually melted in half and fell away from the cable. So after blowing 2 pounds worth of dry powder off the engine I survey the damage. I think I got really lucky and only saw a small section of wire loom burnt. I inspected the wires and didn't see any damage. So I replaced the loom. The next day I go to the dealership and get the parts needed for the HPOP fitting leak. The fix goes well and am back together in just a couple hours. Drive the truck to work and it seems fine. I drive it today and have noticed that it seems to be struggling a lot at first to turn over. Like weak battery's or something. But it always starts. Also when I stopped at a stop light I have an idle variation. It is going up and down around 75-100 rpms. I have looked under the hook for any loose wires. I am at a loss.
What is causing the rpm to go up and down?
Why does it seem like the truck is hard to start all the sudden? (Temps have been in the 50's at night)
Batteries are two year old INTERSTATES, glowplugs and injector o rings next week.
Any ideas?
Had a Outlet fitting on the HPOP leaking. The night I found the leak I was trying to see if the cut out between the two fittings was actually a hole that had gotten punched in the pump. So I grab a long screwdriver to probe(no jokes here
) the spot to see how deep it is. While I was doing this I accidently rubbed the screwdriver on the cable going to the alternator. As I am sure you already guessed it a large amount of sparks insude. Enough that it caught me off guard. I dropped the screwdriver which wedged itself in place and starts to glow cherry red. I tried to get it out but no luck. Next thing I know if there are flames from under the hood. I grab the fire extinguisher I keep under my seat and get the fire knocked out quickly. Thankfully the screwdriver actually melted in half and fell away from the cable. So after blowing 2 pounds worth of dry powder off the engine I survey the damage. I think I got really lucky and only saw a small section of wire loom burnt. I inspected the wires and didn't see any damage. So I replaced the loom. The next day I go to the dealership and get the parts needed for the HPOP fitting leak. The fix goes well and am back together in just a couple hours. Drive the truck to work and it seems fine. I drive it today and have noticed that it seems to be struggling a lot at first to turn over. Like weak battery's or something. But it always starts. Also when I stopped at a stop light I have an idle variation. It is going up and down around 75-100 rpms. I have looked under the hook for any loose wires. I am at a loss.What is causing the rpm to go up and down?
Why does it seem like the truck is hard to start all the sudden? (Temps have been in the 50's at night)
Batteries are two year old INTERSTATES, glowplugs and injector o rings next week.
Any ideas?
Thread Starter
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Lead Driver
Joined: Mar 2004
Posts: 5,372
Likes: 108
From: Northern Indiana
Nope. I don't think it's as bad as it was originally. But still there for sure. Debating on trying to drop in some sensors or what. It always does it whenever I came to a stoplight. Have not idea.
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On Edit, I've read all of this thread as well as others and my brain is hurting trying to keep all of this info in relation to this thread, as well as other info to it's own pertaining threads, so I'll post it here. This one is a good read, with some great info. This guy didn't get his solved either but as I said, it does have some great info in it. Might find something you haven't tried yet. http://powerstrokearmy.com/forums/sh...t=Erratic+idle
Thread Starter
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Lead Driver
Joined: Mar 2004
Posts: 5,372
Likes: 108
From: Northern Indiana
Very good read. I feel bad for the original poster as he did a lot of work trying to trace the problem. I am thinking about replacing the alternator with the spare I have just for the heck of it and see if that does anything.
Posting Guru
Joined: Mar 2007
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Over charging, under charging, but again how does no power to the electrical system and or the rest of the components stop this issue? *Did you try removing the belt as well to see if the condition changes?
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Lead Driver
Joined: Mar 2004
Posts: 5,372
Likes: 108
From: Northern Indiana
I want had a chance to do that yet. I was at the station. For 24 yesterday and had a Sidejob today. I am hopeing on trying to get to this Sunday morning. Will try the belt first, then the alternator. I have to be honest it is really annoying. Espically when I have owned the truck for 9 years and have never had an issue before this.
Elder User
Joined: Sep 2011
Posts: 979
Likes: 4
From: Vancouver
Seth, I have re-read the all these posts. I noticed that you have a 6637 with a sock. The socks will get clogged with dirt, because they are quite fine and have very little area compared with the filter area (the filter is corrugated and has a complex construction). After trying to keep up with my sock, I threw mine away.
Why not remove the sock and see if the idle improves?
That said, this symptom did not happen until the alternator cable was shorted, so the problem has to be electrical in nature.
Larry
Why not remove the sock and see if the idle improves?
That said, this symptom did not happen until the alternator cable was shorted, so the problem has to be electrical in nature.
Larry
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Lead Driver
Joined: Mar 2004
Posts: 5,372
Likes: 108
From: Northern Indiana
I was my filter sock out with degreaser when I change the filter. So it should be clean. But I can get it a shot. I really do think it electrical. But automotive electrical can be a real bear sometimes.