4.2 problems
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Tuned
Joined: Mar 2001
Posts: 491
Likes: 2
From: MS.
4.2 problems
I have a 98 with the 4.2.The troubles started with popping a little through the exhaust ,bogging down and bucking,rough idle and had the two codes together that deal with having bad intake gaskets don't remember the codes offhand.
I also noticed every plug in the truck was wet and black however it didn't appear oil wet.I have changed the fuel filter,spark plugs,lower intake gaskets,plenum gasket ,injector o rings,checked injector ohms all were 16.5,new EGR gaskets,all bolts are torqued to specs
Now I have a no run condition,it will crank but not run.i heard a pop in the engine one time.i cranked till the battery went dead.I also noticed as I was calling it a day last night the radiator resovior was empty. I don't know if somehow I got a hydro lock even though I put new intake gaskets in it or i have some other issue like timing or something.I don't know where to look next
I also noticed every plug in the truck was wet and black however it didn't appear oil wet.I have changed the fuel filter,spark plugs,lower intake gaskets,plenum gasket ,injector o rings,checked injector ohms all were 16.5,new EGR gaskets,all bolts are torqued to specs
Now I have a no run condition,it will crank but not run.i heard a pop in the engine one time.i cranked till the battery went dead.I also noticed as I was calling it a day last night the radiator resovior was empty. I don't know if somehow I got a hydro lock even though I put new intake gaskets in it or i have some other issue like timing or something.I don't know where to look next
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
The mistake you made was diving in and replacing parts before diagnosing the problems.
Now, you don't know if you created more problems on top of what you had.
The empty coolant is the first thing to solve for or all the rest is moot.
Is there coolant in the crankcase oil?
Is there any signs in any cylinder etc.?
Pressure test the cooling system to see where the leak is.
At the point your at, we don't know any more than you until you begin to sort it all out.
Good luck.
Now, you don't know if you created more problems on top of what you had.
The empty coolant is the first thing to solve for or all the rest is moot.
Is there coolant in the crankcase oil?
Is there any signs in any cylinder etc.?
Pressure test the cooling system to see where the leak is.
At the point your at, we don't know any more than you until you begin to sort it all out.
Good luck.
Thread Starter
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Tuned
Joined: Mar 2001
Posts: 491
Likes: 2
From: MS.
No water in the oil.I pulled the brand new plugs out and all of them were wet.the wettest one was the driver side forward cylinder.I spun the engine over and no fluid came out the cylinders except for a very small amount on that drivers side cylinder.that may have just been fuel cause the plug did smell like gas.I seen nothing to indicate hydrolock.How do i pressure up the cooling system the 4.2 dosen't have a radiator cap as an entry point
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
If there are no water beads on the plug straps but yet look wet, it's gas.
The motor must fire when cranked or fuel will keep being injected and flood the motor.
There is no way for the system to stop fuel injection at that time.
Also be very careful about cranking the motor with the spark plugs out and live ignition wires close to the plug holes.
It can start a fire from the gas being pumped out of the cylinders.
To do cranking for a reason trying to look for a problem, disconnect the coils so they can't spark the wires.
Good luck.
The motor must fire when cranked or fuel will keep being injected and flood the motor.
There is no way for the system to stop fuel injection at that time.
Also be very careful about cranking the motor with the spark plugs out and live ignition wires close to the plug holes.
It can start a fire from the gas being pumped out of the cylinders.
To do cranking for a reason trying to look for a problem, disconnect the coils so they can't spark the wires.
Good luck.
Thread Starter
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Tuned
Joined: Mar 2001
Posts: 491
Likes: 2
From: MS.
I put the spark plugs back in and tried to start the truck.It did not start,i pulled the plugs back out and they were all gas fouled.I have confirmed there is fire to the plugs a strong white spark.I took the coil pack off and tested it with an ohm meter and the coil is good.the engine has compression I did a redneck compression test though stuck my finger in the plug hole and cranked,it blew my finger out with plenty force.I haven't a clue what the problem is
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
Time to test fuel pressure.
If it's way too high it will foul the plugs.
Put pressure gauge on test port and cycle ignition to Run and off several times.
Do not crank engine.
Look at pressure.
Double check the coil to plug fire order for being correct.
You may have introduced another issue from the work already done..
Good luck.
If it's way too high it will foul the plugs.
Put pressure gauge on test port and cycle ignition to Run and off several times.
Do not crank engine.
Look at pressure.
Double check the coil to plug fire order for being correct.
You may have introduced another issue from the work already done..
Good luck.
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jroehl
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