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My friends truck is having some sort of issue where the idle increases 100 to 200 RPMs he said most noticeably when at stop lights. I’ve been asking him to get a video he said he can’t get it though. Told him I will give him a courtesy post over here. He has been driving the truck daily.
I'll be watching this because I've been seeing the same thing now for about a year. My idle variability seems to be not as great as your friends (mine only being about 70-100 rpm), but it is definitely there and most noticeable when sitting at a traffic sign or traffic light (or otherwise idling anywhere else).
Mine does it . Around 50 to 100 rpm. Moreso when it's at operating temp. New ICP and pigtail. Tried other CPS, didn't change. Does it in any tune I have. My injectors are worn so I have just put it down to that. Fuel pressure is decent everything else checks out fine.
Have heard it can be caused or influenced by the torque convertor . Not sure how true this is or not.
Recently, FTE'r @RyeThomas shared a similar experience he is seeing from his RPM. I posted the following information in order to give him a baseline or another FTE'rs observations when considering the RPM.
Originally Posted by Sous
RyeThomas , you say the "RPM is doesn't change but it's a constant shake". Are you looking at the gauge in the cluster or using an OBDII scan tool?
If you are using a scan tool, I have provided a couple of "good running conditions" from my archived data logs for you to compare to. I have provided two snips as you can see. One is the engine warming up to operating temperature and the other is at operating temperature.
On an unrelated thread about RPM, stalling and surging, I posted this as a summary of some actions another FTE'r took which seems to have affected his running/idle condition.
Originally Posted by Sous
Recently an FTE'r was having some stumbling and stalling issues when the truck was coming to stop. While replacing his IPR and ICP again, he noticed the EOT sensor harness side was broken. He ziptied it together and all has been well since.
Another FTE'r had a stumble at idle only when warm. His BIL bought the truck and found one of the injector cups was leaking and possibly causing the ignition sequence to be interrupted by the coolant. Also, his EOT was providing erroneous readings via FORScan and was replaced.
I am not saying your issue is any of these noted above, but just some details observed over the past few months from other FTE'rs.
I am hopeful some of the information and the collective power of the FTE brings y'all to a fix action or at least a reason why. Perhaps AuF250 is on to something regarding the TC.
I’m seeing about a 20-25 rpm fluctuation on a warm engine and trying to find a new repeated shimmy/shake at idle. I need more Data logging time.
im hoping to get some seat time and logs next week.
I wouldn’t really care about it but I see some have near zero change in rpm…. Odd
I mean Sous has 3, lol so I want 3. 649-652 must feel great. Show off, haha
My friends truck is having some sort of issue where the idle increases 100 to 200 RPMs he said most noticeably when at stop lights. I’ve been asking him to get a video he said he can’t get it though. Told him I will give him a courtesy post over here. He has been driving the truck daily.
Is his IPR nut tight?
Does it do it when driving with the ICP unplugged?
A cleaning/reseal of the IPR might be helpful as well. I'm considering this as I sometimes get a slight rough idle I can feel at stoplights.
Worn injectors might very well be a contributor though.
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