[10f250/6.4]

I've got a 2010 6.4 thats got a small idle surge. Its about 30 rpm it idles down mainly notice it after it warms up. It acts like somethings turning on and it causes it to idle down. I'm deleted with egr disabled egr is still plugged in. About 8k miles on current fuel filter drained water separator about a week ago. Changed the fuel rail sensor under valve cover Saturday its still surging. Any help is appreciated. Doesn't surge while driving just enough to notice at idle.

 

[Roccafellas]

I've got a 2010 6.4 thats got a small idle surge. Its about 30 rpm it idles down mainly notice it after it warms up. It acts like somethings turning on and it causes it to idle down. I'm deleted with egr disabled egr is still plugged in. About 8k miles on current fuel filter drained water separator about a week ago. Changed the fuel rail sensor under valve cover Saturday its still surging. Any help is appreciated. Doesn't surge while driving just enough to notice at idle.

Any codes? Sounds like either a plugged up intake/throttle body where the egr is (you have the factory intake elbow correct? There is actually a throttle body flap in there that can seize up and cause it to choke under idle.

That or you have a sticking turbo/leaky injectors.. any smoke?

Can you monitor contribution balance to see if any cylinders are contributing to the cause.
If not the frp sensor then maybe a lpfp issue with a restriction or such.

Is the ac cycling on and off? Is the clutch stuck engaged? Is the clutch fan turning on?

Also what tune are you running?


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[10f250/6.4]

Dpf removed and tuned everything else is stock. H&s mild street with low boost fueling at 1 default is 3. smokes at wot off boost and slight smoke at full throttle run haven't noticed any more than usual. I do have a vacuum leak, vacuum pump does kick on occasionally hasn't since I unplugged batteries Saturday to change fuel rail sensor auto hubs don't work. The idle rpms don't change with the vacuum pump it kicked on a few times the truck does it regardless. I'll check ac clutch tomorrow. It has been in the low 20s to low 30s the last few weeks surely it couldn't be the fuel gelling.

 

[10f250/6.4]

No codes haven't checked with the tuner

 

[Roccafellas]

Dpf removed and tuned everything else is stock. H&s mild street with low boost fueling at 1 default is 3. smokes at wot off boost and slight smoke at full throttle run haven't noticed any more than usual. I do have a vacuum leak, vacuum pump does kick on occasionally hasn't since I unplugged batteries Saturday to change fuel rail sensor auto hubs don't work. The idle rpms don't change with the vacuum pump it kicked on a few times the truck does it regardless. I'll check ac clutch tomorrow. It has been in the low 20s to low 30s the last few weeks surely it couldn't be the fuel gelling.

It’s a diesel you don’t have ANY vacuum.. the only thing that vacuum pump does is run your 4x4 THATS IT. So this vacuum leak you speak of is non existent lol. Diesels don’t have regular throttle bodies to make vacuum there’s a valve in the egr valve that diverts the gas flow but that’s it. It will not make vacuum at idle.

What does your FRP do while it’s surging
And go get a good scanner and see if you can pull any codes most won’t cause a C.E.L


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[10f250/6.4]

Is there not an electric vacuum pump on drivers side by firewall? I didn't mean there was vacuum leak like on a carbed gasser. The cheapest scanner to read fuel rail pressure etc is around 250 right? I might try to see if the dealer can hook there's up when I get my oil change assuming it does it while its there.

 

[Roccafellas]

Is there not an electric vacuum pump on drivers side by firewall? I didn't mean there was vacuum leak like on a carbed gasser. The cheapest scanner to read fuel rail pressure etc is around 250 right? I might try to see if the dealer can hook there's up when I get my oil change assuming it does it while its there.

Oh I thought you were referring too engine vacuum haha. Resulting in the idle surge.

Yes that is your vacuum pump. Best solution is to put in a smoke test you can use a cigar or a smoke machine unplug the lines from the vacuum pump on the firewall and at the actuator on the passenger side rad support cover probably a crack or leak in the lines very common or maybe a bad hub seal.


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[Roccafellas]

Is there not an electric vacuum pump on drivers side by firewall? I didn't mean there was vacuum leak like on a carbed gasser. The cheapest scanner to read fuel rail pressure etc is around 250 right? I might try to see if the dealer can hook there's up when I get my oil change assuming it does it while its there.

And not only carbed gassers have vacuum leaks, any car efi gdi etc can have a vacuum leak, any gas engine with a throttle body really. Electric or not.

And scanners vary, just go to a mechanic shop around you pay em $40-50 bucks or aome guys are nice and be like hey can you just plug in and read my frp for 5 minutes I just want to see, also while they are there get them to do a power balance/contribution balance test. See if you got any leaky injectors etc..


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[10f250/6.4]

whats the throttle blade by the egr you were talking about? Would i need to completely remove egr to fix it ? Assuming its not fuel related.

 

[Roccafellas]

whats the throttle blade by the egr you were talking about? Would i need to completely remove egr to fix it ? Assuming its not fuel related.

It’s in the intake elbow i’d suggest if you have a egr delete tune just unplugging it remove the 4 bolts and remove that whole ugly elbow and replace it with an egr delete elbow there so cheap and improve flow
Along with that get yourself a cold side pipe you’ll gain a seat of the pants increase in performance and WAY better flow to the engine.


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[10f250/6.4]

Ya I'm wanting to fully delete the truck just have about 20k or 30k miles worth of warranty left just in case. I let the truck idle after I got back from work about 5 minutes it never idled down, wonder if its me turning the steering wheel slightly and not noticing it. The ford dealers wanting to charge me 125 just for diagnostics as they worded it. Is there any way to tell if that throttle blade is actuating just in case it starts again?

 

[Roccafellas]

Ya I'm wanting to fully delete the truck just have about 20k or 30k miles worth of warranty left just in case. I let the truck idle after I got back from work about 5 minutes it never idled down, wonder if its me turning the steering wheel slightly and not noticing it. The ford dealers wanting to charge me 125 just for diagnostics as they worded it. Is there any way to tell if that throttle blade is actuating just in case it starts again?

Did you do any work before it started happening like lets say fuel filters were changed then it started happening etc? Or IC Piping or boots changed. Honestly at this point without plugging it in and watching PIDS I have no idea if you can’t pull any codes up (check engine light or not) then it needs a diag, to watch FRP watch maf g/s and fuel supply and power balance to see if its a fuelling issue a air restriction or something else. Take off your intake elbow and inspect it try and move the egr valve by hand it should move freely as well as the throttle blade.


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[10f250/6.4]

No I haven't changed anything. I'm getting the oil changed tomorrow. I'm changing the fuel filter and air filter this weekend. If that doesn't fix it I'm gonna go to a diesel shop and have them monitor the truck while I drive it. I let the truck idle again when I got to work it was fine this morning.