rough idle when WARM
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Postmaster
Joined: Nov 2008
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From: Buckley, WA
rough idle when WARM
I've spent all day and I cannot figure it out. Here is what she does: shakes my seats, feels like a little miss. Exhaust shounds like it has a little miss. Rpms bounce a tiny bit. Idles at around 700. Put it in drive or reverse and the rough idle becomes more pronounced.
It doesn't smoke, it doesn't leak any fuel, new ip, new injectors and return lines. I've tried advancing and retarding the pump. I've tried increasing and decreasing idle. I can't figure out what else to check? Lift pump maybe? When I put any throttle to it it smoothes right out and also runs very smooth on cold starts!! Also shifts kinda funny sometimes.
Im out of ideas, and could use some help. Any thoughts?
91 7.3l e4od trans
It doesn't smoke, it doesn't leak any fuel, new ip, new injectors and return lines. I've tried advancing and retarding the pump. I've tried increasing and decreasing idle. I can't figure out what else to check? Lift pump maybe? When I put any throttle to it it smoothes right out and also runs very smooth on cold starts!! Also shifts kinda funny sometimes.
Im out of ideas, and could use some help. Any thoughts?
91 7.3l e4od trans
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From: Massachusetts
It's smooth during a cold start because the cold advance is advancing the timing a bit and the high idle will raise your RPM's.
Are you sure that none of your injector lines are leaking? Are they all nice and tight?
Are you sure that none of your injector lines are leaking? Are they all nice and tight?
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Postmaster
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From: Buckley, WA
I've inspected every one, all are completely dry. Including the return caps. Could air be finding its way into one? I've tried cracking all the injectors to see what one makes the least amout of difference and it was all pretty close. Each one when cracked sounded similar
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From: Buckley, WA
Its about 2months old. Uhaul special and Pensacola injectors. Yours sounds like its missing and shakes the cab? Once it was shaking so bad the Exhaust tip almost fell off haha and yes the pipes do have hangers lol only been that bad once, after puttin new fuel filter on
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From: Massachusetts
Has it been shaking the whole time since the IP install? Could be a stuck metering valve in the IP...easily fixed with a couple doses with fuel cleaner.
When i had a hard injector line break, the engine shook so bad I coud watch my shifter move. I thought I was gonna shear a motor mount.... I had to drive that way to college and back (20 miles each way) for a week before a new line came in.
I'm trying to remember the patterns now...crap I'm having trouble remembering...
It seems like it would idle OK, not great. But it would run OK under slight acceleration. Hard acceleration was pretty rough. I seem to remember trying to maintain a specific RPM on my highway section of the commute...I don't have a tach, so I don't know what RPM that was. Putting the engine under load would make it worse...
It would be the equivalent of running on 7 cylinders. Just take off one of your steel injector lines all the way and imagine running like that.
This experience is kinda why I was thinking of a busted injector line...
Seems like when you put the truck in Drive or Reverse, you're placing the engine under "load" and that's when it gets rough.
When i had a hard injector line break, the engine shook so bad I coud watch my shifter move. I thought I was gonna shear a motor mount.... I had to drive that way to college and back (20 miles each way) for a week before a new line came in.
I'm trying to remember the patterns now...crap I'm having trouble remembering...
It seems like it would idle OK, not great. But it would run OK under slight acceleration. Hard acceleration was pretty rough. I seem to remember trying to maintain a specific RPM on my highway section of the commute...I don't have a tach, so I don't know what RPM that was. Putting the engine under load would make it worse...
It would be the equivalent of running on 7 cylinders. Just take off one of your steel injector lines all the way and imagine running like that.
This experience is kinda why I was thinking of a busted injector line...
Seems like when you put the truck in Drive or Reverse, you're placing the engine under "load" and that's when it gets rough.
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From: Buckley, WA
I think it has been running rough since then. But I can maintain high rpms pretty smooth. Just straight diesel kleen in the filter to clean it? Or whole bottle in one tank?
The other lever on driverside wouldn't cause this right? Maybe that might just be the odd shifting problem
The other lever on driverside wouldn't cause this right? Maybe that might just be the odd shifting problem
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From: Massachusetts
Sorry, I don't know squat about Auto's and their relation with the IP...
As for the cleaner. I always just get the engine nice and warm, then pull the fuel filter, dump the diesel out, and fill it up with cheap ATF...and then run it as usual. Always works for me.
But, I get in trouble for that recommendation sometimes
When my Dad's 03 F350 7.3 feels doggy, he runs a double dose of Power Service (white or grey bottle, never can remember...probably doesn't matter.) thru the fuel tank and it always does the trick.
Of course, that's a TOTALLY different animal.
I say try a double dose of Power Service and see what that does.
If not, you can try pulling the fuel filter off. Dump the diesel out, then fill it with seafoam, run it for about 15 seconds until the Seafoam gets into the IP. Then shut it off, let it sit overnight and let the Seafoam go to work inside your IP.
As for the cleaner. I always just get the engine nice and warm, then pull the fuel filter, dump the diesel out, and fill it up with cheap ATF...and then run it as usual. Always works for me.
But, I get in trouble for that recommendation sometimes
When my Dad's 03 F350 7.3 feels doggy, he runs a double dose of Power Service (white or grey bottle, never can remember...probably doesn't matter.) thru the fuel tank and it always does the trick.
Of course, that's a TOTALLY different animal.
I say try a double dose of Power Service and see what that does.
If not, you can try pulling the fuel filter off. Dump the diesel out, then fill it with seafoam, run it for about 15 seconds until the Seafoam gets into the IP. Then shut it off, let it sit overnight and let the Seafoam go to work inside your IP.
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Postmaster
Joined: Nov 2008
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From: Buckley, WA
Let's hope not, just spent 400$ on them about 2 months ago. I have 3 sets of injectors and 3 ip so if it gets worse ill through one in and see what it does
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From: Agawam MA
Mine did this, same Uhaul IP and same Pensacola injectors...
I took the injectors all out and pop tested them, and I found that 2 had carbon build up not letting the copper washers seat properly, so I cleaned out the injector bores in the heads, reinstalled the injectors, and she idles smooth like a gasser at 675 rpm now.... so if you didn't clean the bores before you installed your new injectors, maybe that could be it... also, one or more may be a bit loose...
I took the injectors all out and pop tested them, and I found that 2 had carbon build up not letting the copper washers seat properly, so I cleaned out the injector bores in the heads, reinstalled the injectors, and she idles smooth like a gasser at 675 rpm now.... so if you didn't clean the bores before you installed your new injectors, maybe that could be it... also, one or more may be a bit loose...
Thread Starter
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Postmaster
Joined: Nov 2008
Posts: 2,851
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From: Buckley, WA
Mine did this, same Uhaul IP and same Pensacola injectors...
I took the injectors all out and pop tested them, and I found that 2 had carbon build up not letting the copper washers seat properly, so I cleaned out the injector bores in the heads, reinstalled the injectors, and she idles smooth like a gasser at 675 rpm now.... so if you didn't clean the bores before you installed your new injectors, maybe that could be it... also, one or more may be a bit loose...
I took the injectors all out and pop tested them, and I found that 2 had carbon build up not letting the copper washers seat properly, so I cleaned out the injector bores in the heads, reinstalled the injectors, and she idles smooth like a gasser at 675 rpm now.... so if you didn't clean the bores before you installed your new injectors, maybe that could be it... also, one or more may be a bit loose...
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Joined: Aug 2010
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From: Agawam MA
675 is at idle with my foot on the brake at a stoplight.