backpressure test is what determines it ultimately, on mine it should have 2.5psi max but was reading 5psi at idle and 10psi when throttled up
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- Thread starter Dan2002
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TollKeeper
Full Access Member
My last car that made the converters glow red, it was not the converters, but the ECM Driver was double pulsing the injectors, once when it was supposed to, and once 180* out, so it was dumping raw fuel into the exhaust.
Replaced the ECM, and that solved the problem... And increased my fuel mileage!
Replaced the ECM, and that solved the problem... And increased my fuel mileage!
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well, after new converters , it is still giving me code p0300.
any ideas whats the next step i should take?
new plugs and wires
new coils.
new fuel injectors
new cats
new all 02 sensors
Did I miss what the short- and long-term fuel trims look like?
rockola1971
Full Access Member
Did you clear all codes after installing cats?well, after new converters , it is still giving me code p0300.
any ideas whats the next step i should take?
new plugs and wires
new coils.
new fuel injectors
new cats
new all 02 sensors
yes all codes cleared before starting the vehicle, then i started the vehicle and no lights were on but it wasnt running smooth, so when i attempted to acelerate the check engine light cames on flashing, and gives out code p0300 only code.
rockola1971
Full Access Member
Flashing check engine light means active spark knock. You need to get a scanner on that top see which cylinder(s) are knocking. Could be bad knock sensors or their harness or a bunch of other things. Need to see if we can get it narrowed down to certain cylinders only or all cylinders.
yes, i have already seen with my scanner and live data.
i see number 7 cylinder misfiring the most
drdave81
Full Access Member
No a flashing check engine light means you have a catalyst damaging misfire. Basically you are sending raw fuel right into the cats. That's why the one was glowing. OP fixed a symptom, not a cause.
You need to figure out why you have no spark, or not adequate enough spark to properly light the air/fuel mixture in the cylinder.
rockola1971
Full Access Member
How much of a difference between #7 and others that are showing misfires? You may have narrowed it down to #7 and that would be a big help in figuring out what is going on. First I would suspect the wire. Swap with another and see if the misfire moves too. Then if that doesnt change anything, put it all back original and swap coils and see if that moves the problem to another cylinder. If no change after wire and coil change then you are down to the spark plug, coil wiring harness, output of PCM to fire coils and then the valvetrain and rings of the #7 cylinder. That would need a compression check to see where you are at there and at that time all 8 cylinders would need to be checked to see how #7 looks in comparison.
Ive chased my rear many times over a bad spark plug wire that visibly looks fine but in the dark you can usually see the lightning jump from them to ground depending on where the flaw in the wire is. So at night start it up and with hood raised have a look at #7 to see if you see a light show, also listen closely for a snapping sound. Keep your hands in your pockets so you dont get in the fan or find the lightning the hard way....with your hand. A coil with a cracked housing can do the same and the lightning will jump out to ground (metal) and it will make a snapping sound also. Ignition voltage is over 20kv so dont find out the hard way! Itll make you pee yourself!
