code 0302
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From: forsyth
code 0302
which is misfire cyl 2..
Anyhow, my B2500 (2000) was having a rough idle for a little while and threw code 0302. Changed plugs, wires, fuel injectors, cleaned throttle body, and then the ignition coils.
Still rough idle, still throwing code 0302
I did check the compression of cyl 2 when I changed plugs, didn't bother to compare to other cylinders as I got 152 and figured "how far off could that be?" That may have been wrong thinking...
while I was doing the injectors I did change the egr, Idle control valve as well since they were literally in hand and cheap enough...
The engine is a ATK reman with approx 120,000 miles on it, the truck has 285,000. It is the second ATK reman, the first I had to get at 125,000 miles when it blew a cylinder and head (again #2) however the first reman started to leak oil badly before the warranty ran out so ATK was awesome and replcaed it.
I am a fanatic on oil changes every 3k, and all routine maint. Just haven't gotten great engine life out of this truck. Had since new.
Anyhow...any ideas?
Anyhow, my B2500 (2000) was having a rough idle for a little while and threw code 0302. Changed plugs, wires, fuel injectors, cleaned throttle body, and then the ignition coils.
Still rough idle, still throwing code 0302
I did check the compression of cyl 2 when I changed plugs, didn't bother to compare to other cylinders as I got 152 and figured "how far off could that be?" That may have been wrong thinking...
while I was doing the injectors I did change the egr, Idle control valve as well since they were literally in hand and cheap enough...
The engine is a ATK reman with approx 120,000 miles on it, the truck has 285,000. It is the second ATK reman, the first I had to get at 125,000 miles when it blew a cylinder and head (again #2) however the first reman started to leak oil badly before the warranty ran out so ATK was awesome and replcaed it.
I am a fanatic on oil changes every 3k, and all routine maint. Just haven't gotten great engine life out of this truck. Had since new.
Anyhow...any ideas?
Yes, checking at least one other cylinder when doing a compression test is a must.
Reason being is to test gauge as well as cylinder comparison, other cylinder may have tested at 190psi, yes gauge is off but you would also know #2 is lower than it should be.
On the Dual spark plug 2.3l/2.5l both spark plugs fire on compression stroke and exhaust stroke, they don't alternate.
So misfire from spark would mean BOTH spark plugs and BOTH coil packs would have to be an issue, so long shot.
One heads up on spark on these engines, only the exhaust side Coil and spark plugs work when starting the engine, starter motor engaged.
When Engine RPMs reach 400 the computer will start Intake side coil and spark plugs.
This can cause some confusion if testing for spark while cranking engine.
To check fuel injectors
Cold engine
Unplug Coil Packs 3 wire connectors, you want No Spark
Crank engine over a couple of times
Pull out #2 spark plug and at least one other spark plug from another cylinder
Both should be wet with fuel
If #2 is dry then test that injector
Key on should shows 12volts at Red wire on injector
OHM Meter should show 11-18ohms when put on the 2 injector pins
Reason being is to test gauge as well as cylinder comparison, other cylinder may have tested at 190psi, yes gauge is off but you would also know #2 is lower than it should be.
On the Dual spark plug 2.3l/2.5l both spark plugs fire on compression stroke and exhaust stroke, they don't alternate.
So misfire from spark would mean BOTH spark plugs and BOTH coil packs would have to be an issue, so long shot.
One heads up on spark on these engines, only the exhaust side Coil and spark plugs work when starting the engine, starter motor engaged.
When Engine RPMs reach 400 the computer will start Intake side coil and spark plugs.
This can cause some confusion if testing for spark while cranking engine.
To check fuel injectors
Cold engine
Unplug Coil Packs 3 wire connectors, you want No Spark
Crank engine over a couple of times
Pull out #2 spark plug and at least one other spark plug from another cylinder
Both should be wet with fuel
If #2 is dry then test that injector
Key on should shows 12volts at Red wire on injector
OHM Meter should show 11-18ohms when put on the 2 injector pins
Last edited by RonD; Nov 22, 2016 at 09:32 AM.
Thread Starter
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From: forsyth
well, did all 4 cylinders for compression...all within 6psi... (148-154) with cyl 2 sitting at 151.
The injector was wet when testing per your instructions...which wasn't a surprise as a new injector.
To recap, this was showing code 0302 before I changed the wires, coils, plugs, injectors, ICV, pcv,
So...what on earth could be causing this?
The injector was wet when testing per your instructions...which wasn't a surprise as a new injector.
To recap, this was showing code 0302 before I changed the wires, coils, plugs, injectors, ICV, pcv,
So...what on earth could be causing this?
Yes, checking at least one other cylinder when doing a compression test is a must.
Reason being is to test gauge as well as cylinder comparison, other cylinder may have tested at 190psi, yes gauge is off but you would also know #2 is lower than it should be.
On the Dual spark plug 2.3l/2.5l both spark plugs fire on compression stroke and exhaust stroke, they don't alternate.
So misfire from spark would mean BOTH spark plugs and BOTH coil packs would have to be an issue, so long shot.
One heads up on spark on these engines, only the exhaust side Coil and spark plugs work when starting the engine, starter motor engaged.
When Engine RPMs reach 400 the computer will start Intake side coil and spark plugs.
This can cause some confusion if testing for spark while cranking engine.
To check fuel injectors
Cold engine
Unplug Coil Packs 3 wire connectors, you want No Spark
Crank engine over a couple of times
Pull out #2 spark plug and at least one other spark plug from another cylinder
Both should be wet with fuel
If #2 is dry then test that injector
Key on should shows 12volts at Red wire on injector
OHM Meter should show 11-18ohms when put on the 2 injector pins
Reason being is to test gauge as well as cylinder comparison, other cylinder may have tested at 190psi, yes gauge is off but you would also know #2 is lower than it should be.
On the Dual spark plug 2.3l/2.5l both spark plugs fire on compression stroke and exhaust stroke, they don't alternate.
So misfire from spark would mean BOTH spark plugs and BOTH coil packs would have to be an issue, so long shot.
One heads up on spark on these engines, only the exhaust side Coil and spark plugs work when starting the engine, starter motor engaged.
When Engine RPMs reach 400 the computer will start Intake side coil and spark plugs.
This can cause some confusion if testing for spark while cranking engine.
To check fuel injectors
Cold engine
Unplug Coil Packs 3 wire connectors, you want No Spark
Crank engine over a couple of times
Pull out #2 spark plug and at least one other spark plug from another cylinder
Both should be wet with fuel
If #2 is dry then test that injector
Key on should shows 12volts at Red wire on injector
OHM Meter should show 11-18ohms when put on the 2 injector pins
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