strange misfire problem
strange misfire problem Hi
i´m trying to figure out some strange misfire problem in myn Corvette C5 404ci cam 248/254 615/622 114lsa
it´s brand new rebuilt motor in it only 150miles on it and i´m logging the car whith HPT and it it throwing p0300 code first after startup and then in driving it´s current misfiring on both #2 and #3 and sometimes it flashes the check light, but the funny thing the car doesn´t feel all that bad.
it seems to misfire only under little load on around 1800-2500 rpms but nothing 0 whith a bit of throttle
misfire current on #3 is showing much 10-50 and sometimes all the way up to 110-120
but
misfire current on #2 shows less from 10 to 30-40
and all the others cyl. are normal
Things i´ve checked so far
plugs OK
Wires OK
Coils OK
Swapped Coil-bracked OK
Exhaust leak OK
Injectors OK
so i´m gona do a compression test
but this sounds more like some electric/ground issue to me and others here....
What could this be ? has any one else had similuar problem
Baezi
i´m trying to figure out some strange misfire problem in myn Corvette C5 404ci cam 248/254 615/622 114lsa
it´s brand new rebuilt motor in it only 150miles on it and i´m logging the car whith HPT and it it throwing p0300 code first after startup and then in driving it´s current misfiring on both #2 and #3 and sometimes it flashes the check light, but the funny thing the car doesn´t feel all that bad.
it seems to misfire only under little load on around 1800-2500 rpms but nothing 0 whith a bit of throttle
misfire current on #3 is showing much 10-50 and sometimes all the way up to 110-120
but
misfire current on #2 shows less from 10 to 30-40
and all the others cyl. are normal
Things i´ve checked so far
plugs OK
Wires OK
Coils OK
Swapped Coil-bracked OK
Exhaust leak OK
Injectors OK
so i´m gona do a compression test
but this sounds more like some electric/ground issue to me and others here.... What could this be ? has any one else had similuar problem
Baezi
If that was the case, why would it only do this misfires on only these two cyl and not the other ones ???
Baezi
Misfire tables are very sensative in factory tune. I usually raise those values a good bit. Hi stall converters will cause it to do that too. I see u have a 6 speed so id just have ur tuner bump up the misfire tables if they havent been.
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could it lie in the wires (loom) bad ground or something like that....
Baezi
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Verdad Gallardo i´ve been searchin on the forum, and on the hptuners forum and i´ve runned into few threads about case relearn , if it´s needed it can throw p0300 codes and show as misfire on some cyl.
I have changed from LS6 engine to LS2 stroker engine whith out doing case relearn
and then again i just changed the crank , new 4" in the new block when i rebuilt it
but i´ve never done case relearn.
Can this be my problem
Baezi
I have changed from LS6 engine to LS2 stroker engine whith out doing case relearn
and then again i just changed the crank , new 4" in the new block when i rebuilt it
but i´ve never done case relearn.
Can this be my problem
Baezi
First thing I think of is to make sure the Cam sensor wires are correct.The car will run but misfire if the cam sensor wires are switched around. On the vette it will still read the tach unlike the f-body.
A good way to tell is that is starts fine a few times then has a problem starting.Also idle can vary and be a bitch to tune in.
A good way to tell is that is starts fine a few times then has a problem starting.Also idle can vary and be a bitch to tune in.
First thing I think of is to make sure the Cam sensor wires are correct.The car will run but misfire if the cam sensor wires are switched around. On the vette it will still read the tach unlike the f-body.
A good way to tell is that is starts fine a few times then has a problem starting.Also idle can vary and be a bitch to tune in.
A good way to tell is that is starts fine a few times then has a problem starting.Also idle can vary and be a bitch to tune in.
the cam wires/sensor is ok, and the car idels fine, just this bit misfire reading on cyl 3# and 2#
i´m gona try this crank relearn see if it does something for me
wil poste it up
Baezi
