Multiple Cylinder misfire
Thread Starter
Instructor
Joined: Mar 2012
Posts: 188
Likes: 0
From: Cape Canaveral FL
Multiple Cylinder misfire
2005 LS2, Month ago all was well, then I got a CE lite and used my scantool to pull the code (lite went away by itself) it said Multiple cylinder misfire. So i looked it up says check wires plugs etc all wires are recent (2 year) delcos and plugs same.
Hd a buddy hook a tech II and candybar on it and we took for a ride under hard acceleration ALL of the cylinders are misfiring, so thought fuel issue fuel rail pressure is 62 and good.
So how can it be wires or coils if all cylinders are misfiring?
Am shaking head, very confused as to where to look now. Everything else is good even on the Tech II
Hd a buddy hook a tech II and candybar on it and we took for a ride under hard acceleration ALL of the cylinders are misfiring, so thought fuel issue fuel rail pressure is 62 and good.
So how can it be wires or coils if all cylinders are misfiring?
Am shaking head, very confused as to where to look now. Everything else is good even on the Tech II
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
Melting Slicks
Joined: Feb 2004
Posts: 3,307
Likes: 111
From: Tucson AZ
We have seen this before with folks using NGK spark plugs. Are you using NGK's?
Check the wiring to the alternator and make sure its all tight. Also check the wiring plugs going to each injector. Make sure none of the pins are recessed or bent.
Are the ground straps all intact?
Check the wiring to the alternator and make sure its all tight. Also check the wiring plugs going to each injector. Make sure none of the pins are recessed or bent.
Are the ground straps all intact?
Last edited by Vito.A; Apr 16, 2015 at 04:27 PM.
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Thread Starter
Instructor
Joined: Mar 2012
Posts: 188
Likes: 0
From: Cape Canaveral FL
I didnt make it by my battery guy today but I did check my battery with a fluke meter not the chepo one we used before sitting its 12.7 volts charging its a solid 13.8-14.2
I ran dashboard with my scantool and made a graph of battery voltage at the ECU under heavy acceleration it never went below 13.8 and stayed more around the 14V line.
I will make it to my battery guy tho he has some nice equipment.
I did check the alternator lugs battery lugs tightened each a little they were pretty snug.
I ran dashboard with my scantool and made a graph of battery voltage at the ECU under heavy acceleration it never went below 13.8 and stayed more around the 14V line.
I will make it to my battery guy tho he has some nice equipment.
I did check the alternator lugs battery lugs tightened each a little they were pretty snug.
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
I didnt make it by my battery guy today but I did check my battery with a fluke meter not the chepo one we used before sitting its 12.7 volts charging its a solid 13.8-14.2
I ran dashboard with my scantool and made a graph of battery voltage at the ECU under heavy acceleration it never went below 13.8 and stayed more around the 14V line.
I will make it to my battery guy tho he has some nice equipment.
I did check the alternator lugs battery lugs tightened each a little they were pretty snug.
I ran dashboard with my scantool and made a graph of battery voltage at the ECU under heavy acceleration it never went below 13.8 and stayed more around the 14V line.
I will make it to my battery guy tho he has some nice equipment.
I did check the alternator lugs battery lugs tightened each a little they were pretty snug.
Drifting
Joined: Sep 2009
Posts: 1,719
Likes: 4
From: cinnaminson n.j.
St. Jude Donor '14
Is the car running bad? I don't think you said it was, just that the light came on and the scanner showed all cylinders misfiring. Is your engine stock? Has the ECM been tuned/ reprogrammed?
Melting Slicks
Joined: Dec 2009
Posts: 3,411
Likes: 40
From: Smallingerland Friesland, Netherlands
We have seen this before with folks using NGK spark plugs. Are you using NGK's?
Check the wiring to the alternator and make sure its all tight. Also check the wiring plugs going to each injector. Make sure none of the pins are recessed or bent.
Are the ground straps all intact?
Check the wiring to the alternator and make sure its all tight. Also check the wiring plugs going to each injector. Make sure none of the pins are recessed or bent.
Are the ground straps all intact?
Limping across the line
Joined: Oct 2002
Posts: 5,299
Likes: 109
From: Peoria Az
One thing it helps to understand is how these engines determine a "misfire".
They do it by extrapolating data from the crank position sensor and other sensors.
You misfire may be nothing more than detonation. 1st I would try higher octane or different brand of fuel. it may even be caused by dirty injectors.
They do it by extrapolating data from the crank position sensor and other sensors.
You misfire may be nothing more than detonation. 1st I would try higher octane or different brand of fuel. it may even be caused by dirty injectors.