5.9L jerks randomly at ~1500RPM
#1
5.9L jerks randomly at ~1500RPM
My Magnum 5.9L started jerking randomly at idle and up to 1500RPM. It gets worse on hot (actually, regular - 180-190 degrees) engine. Spark plugs and wires have been replaced already - no change.
Run with another PCM/ECU - still jerks.
Engine jerk followed by a more intense exhaust. No stalling so far
What's going on?
Run with another PCM/ECU - still jerks.
Engine jerk followed by a more intense exhaust. No stalling so far
What's going on?
#3
Don't have a manometer to measure an exact pressure. But
a) I moved/shook all vacuum hoses on hot engine to replicate those jerks - no success.
b) Disconnected a vacuum hose to check the air flow - it sucks
c) also the engine idle RPM increases from 600 to 1000 and jerks became more visible.
I would say that jerks become more frequent and occur at lower engine temperatures as it was before (but the weather gets warmer as well).
a) I moved/shook all vacuum hoses on hot engine to replicate those jerks - no success.
b) Disconnected a vacuum hose to check the air flow - it sucks
c) also the engine idle RPM increases from 600 to 1000 and jerks became more visible.
I would say that jerks become more frequent and occur at lower engine temperatures as it was before (but the weather gets warmer as well).
#5
Cleaned the throttle body (is wasn't bad, actually). Found 2 gaskets cracked: between the throttle body and engine and the throttle body and air intake. Are they critical?
Also found that a hose fitting adapter, (the hose from an air intake to the left cylinder head cover) is a little bit loose, but wiggling of this adapter does not change anything.
Overall - the problem still exists, no changes at all.
Also found that a hose fitting adapter, (the hose from an air intake to the left cylinder head cover) is a little bit loose, but wiggling of this adapter does not change anything.
Overall - the problem still exists, no changes at all.
#6
Check for vacuum leaks.
http://www.hughesengines.com/Index/p...p?partid=27091
#7
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#8
I was in mountains this weekend and noticed very frequent missfire when the engine temperature hits 210 degrees. Even on idle. Says once per 1-2 seconds.
Also noticed, if I turn a steering wheel to the very end position, the idle RPM drops from ~600 to 450-500 (on the hot engine) and from ~600 to 550 (on warm).
#10
Brought the truck to mechanic. He has found 3 problems, but I'm not sure how 2nd and 3rd could be related to the engine temperature.
1. He has found a manifold intake leak. He sprayed propane(!) in the engine compartment and observed a huge change in the engine behavior. - I would agree, that this leak could depend on temperature.
2. He also found that distributor cap should be replaced. - no doubts, it could cause missfire but the engine temperature should not affect on it. I guess.....
3. He also told me that the distributor shaft is loose and suggested to replace a bushing.
How bad is a first problem, could it be fixed "externally" without a removing of manifold?
For sure, I'm going to replace the distributor cap and rotor, which is easy fix and see how it helps...
1. He has found a manifold intake leak. He sprayed propane(!) in the engine compartment and observed a huge change in the engine behavior. - I would agree, that this leak could depend on temperature.
2. He also found that distributor cap should be replaced. - no doubts, it could cause missfire but the engine temperature should not affect on it. I guess.....
3. He also told me that the distributor shaft is loose and suggested to replace a bushing.
How bad is a first problem, could it be fixed "externally" without a removing of manifold?
For sure, I'm going to replace the distributor cap and rotor, which is easy fix and see how it helps...