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nabilc
nabilc,
Category: Car
Satisfied Customers: 3498
Experience:  Manager/co-owner at Autotronic
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2004 ISUZU Axiom: used engine..random misfire & po306..compression

Customer Question

i am working on a 2004 ISUZU Axiom 3.5L.The vehicle came to me after a used engine was installed.the vehicle has a dead skip on #6 cyinder setting code po300 random misfire & po306 cylinder 6 misfire.checked compression on all cylinders 185lbs to 200lbs on all cylinders.check to be sure coil packs were in right position.The slightly shorter one was on #6 cylinder.checked ignition fire on all cylinders. each cylinder seemed to be getting good spark.Insalled correct plugs part #sxu16hpr9 DENSO & made sure we had no intake leaks or vacum leacks(ok).same problem.verafied fuel pressure(good).check for injector signal all cylinders seemed to match.Suspected faulty or clogged ijector.removed fuel rail & check all injector screens.all were clean in including fuel rail.diagnosed,faulty #6 injector.made the repair w/oem injector from isuzu.still same codes & still skipping on # XXXXX cylinder.swapped plugs around,rechecked all of the above to make sure that i did not miss diagnose.same problem.also disconnected checked & reconnected every connector going to engine,o/2s,pcm & all sensors found nothing obvious.still dead skip on #6 cylinder.THANKS TIM
Submitted: 6 years ago.
Category: Car
Expert:  nabilc replied 6 years ago.

Billy :

Hello Tim, I'm Billy and i will assist you with your problem

Billy :

You seem to have checked everything, i need you to confirm the following:

Billy :

have tried swapping coils?

Billy :

and when you delete codes, do they come back at once or when engine gets warm?

Customer :

Yes to both questions

Billy :

Hard one;)...........So i suggest you proceed as following:

Billy :

- do a wiggle test on coil wiring (wiring from coil to ECM) try and wiggle every wire on it's own while engine on, and listen to changes. Then check continuity, on each wire (aslo coil to ECM)

Billy :

- flush engine oil (with a good flushing product), and put new oil and filter (as problem might be a faulty hydraulic valve)

Billy :

- flush coolant, then put some block solder in it, run engine till cooling system cycles, and then leave to cool off overnight, and the next couple of days, flush again and put back coolant. (as the problem might be a compression leak; i know you perfomed a compression test, but the leak might only show when engine warms up).

Billy :

Having done all of the above, i think we will have covered mostly everything (you covered most before coming here...), but there might be one more thing: you may try reprogramming or even changing ECM.

Billy :

A confusing problem indeed, so Good luck!