Help!! #7 not firing
Thread Starter
Joined: Nov 2001
Posts: 818
Likes: 1
From: Hamilton/Ontario
Help!! #7 not firing Hi there. I just finished swapping.a 6.0 LS from whipple to turbo. I changed cam, timing chain, fuel system to e85 friendly, move computer into cabin meaning in cut every wire, soldered and installed.
new intake, exhaust, injectors, relocated coil packs to fenders
We checked all injectors and coil outputs. All good.
Swapped spark plugs all were black #7 looked like new.
Swapped coil
Verified spark at the plug a couple different ways.
Swapped plug wires
Checked pushrod length
Flow checked injectors
Did a Compression test
Swapped a different computer
double checked cam and crank sensor wiring
Double checked (just finished) to make sure the cam install was straight up.
Tomorrow morning I'm getting new cam and crank sensors.
Anyone have any ideas what else I could check?
Thanks in advance.
new intake, exhaust, injectors, relocated coil packs to fenders
We checked all injectors and coil outputs. All good.
Swapped spark plugs all were black #7 looked like new.
Swapped coil
Verified spark at the plug a couple different ways.
Swapped plug wires
Checked pushrod length
Flow checked injectors
Did a Compression test
Swapped a different computer
double checked cam and crank sensor wiring
Double checked (just finished) to make sure the cam install was straight up.
Tomorrow morning I'm getting new cam and crank sensors.
Anyone have any ideas what else I could check?
Thanks in advance.
Last edited by romanss; May 29, 2025 at 07:59 AM.
On The Tree
Joined: Nov 2015
Posts: 132
Likes: 17
Didn't read what factor indicates no firing on number 7, aside from the new looking plug; codes??? Did you check for spark on the plug wire at the plug end?
Compression?
My experience with oddball analysis like this one is that more than one thing is contributing...
Nick
Compression?
My experience with oddball analysis like this one is that more than one thing is contributing...
Nick
Thread Starter
Joined: Nov 2001
Posts: 818
Likes: 1
From: Hamilton/Ontario
Thanks
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
How did you check the injector output? Scope it with the injector connected and supposedly running? I'm wondering if a bad electrical connection shows continuity but cannot handle the 1 Amp of current needed to ground the injector.
Have a tried a new spark plug?
How was the removed sparkplug which looked new, dry or wet with fuel?
And the dumbest question (sorry) are you really sure that #7 is not firing? Assuming you have headers, have you used an IR thermometer to confirm that header pipe is cold? Again sorry, but you sure seem to have tried everything.
Have a tried a new spark plug?
How was the removed sparkplug which looked new, dry or wet with fuel?
And the dumbest question (sorry) are you really sure that #7 is not firing? Assuming you have headers, have you used an IR thermometer to confirm that header pipe is cold? Again sorry, but you sure seem to have tried everything.
