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69fordge · 04-03-2017, **(Subject: Rough idle )**

I have a 2001 ISX (pre EGR) that has a rough idle almost sounds like a miss. It had a miss for a long time when cold until blowby got really bad then last fall I did a complete inframe rebuild. Found several broken rings. Head was rebuilt, Injectors were tested and adjusted, upgraded to one piece pistons. Seamed good to start then the chuff came back(miss) plus surging while driven, replaced high pressure fuel pump and surge and chuff went away. But that only lasted about a month and now its back with a vengeance, seems to be worse. I don't have any way to hook up to ecm( cummins softwear). Tried swapping actuator positions no difference. Almost seems like a bad hole or injector. I tested injectors and no problem found. I reset all injectors and valves no difference. But the big problem is no bad blowby and clean exhaust (no smoke).
HELP!!

Kevin

gearhead · 04-03-2017, **(Subject: Rough idle )**

Take a infered thermometer and see if the front three are hotter than back three or vice verse.

69fordge · 04-03-2017, **(Subject: Rough idle )**

(04-03-2017 )gearhead Wrote: Take a infered thermometer and see if the front three are hotter than back three or vice verse.

Already did that and front 3 are lower than rear 3 but I tried swapping actuators front to back and the temps stayed in the same positions and #1 is lower than 2 and 3.

69fordge · 04-03-2017, **(Subject: Rough idle )**

Already did that and front 3 are lower than rear 3 but I tried swapping actuators front to back and the temps stayed in the same positions and #1 is lower than 2 and 3.

Rawze · 04-03-2017, **(Subject: Rough idle )**

You had the head and injectors rebuilt. What did you expect? - I am not a proponent of reworking an old head. they never last very long when someone does this. Injectors are not much better when re-worked by a local injector shop either.

Just my own thought on it anyways.

Signature620 · 04-04-2017, **(Subject: Rough idle )**

Clean out the check valve at the inlet to the IFSM & any others between there and the fuel tanks. They can get pieces of perished fuel lines and other debris stuck in them and cause surging.

gearhead · 04-04-2017, **(Subject: Rough idle )**

You need to check for with adaptor on front three sounds like you got compression going up through one of the tips i have seen this many of times and it causes the three cylinders to run colder because they are hooked together.