Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

VS Caprice L67 - no spark

Flyingwide

New Member
Joined
Nov 7, 2021
Messages
21
Reaction score
7
Points
3
Age
44
Location
Brisbane
Members Ride
VS L67 Caprice
Hi Guys, I need some advice on this one. I’ve got an L67 Caprice, it started to miss, so I replaced the leads, this fixed the issue for a week, then it became worse. I replaced the plugs, helped at idle, but not under load. I bought a second hand dfi module and coil packs, but when I fitted it, the car would not start at all. I’ve had a closer look, and the one that was sold to me appears to be from a later model. I refitted the original module and coil packs and the car started and ran for 5 seconds, then cut out. It now won’t start. Below are the symptoms.
No spark
Has fuel pressure in the lines
I’ve checked the injectors with a multimeter, and the injectors increase in voltage as it cranks which sounds like they’re getting a signal, I’ll check further tomorrow with a noid light.
My questions are:
Can fitting the incorrect dfi module cause any damage?
Where do the injectors receive a signal from? Do they rely on the CAS?
Does spark and injector pulse rely on the same source?
Any help would be much appreciated.
 

_R_J_K_

Well-Known Member
Joined
Dec 20, 2008
Messages
6,723
Reaction score
1,856
Points
113
Members Ride
Zenki S14
No - AFIAK the DFI modules are pretty much the same VS-VY.
Yes.
Yes If you're asking about spark ignition and injector pulse signal.

Don't rely completely on rail pressure as an indicator as the ECU will tell the pump to prime whenever the key is turned, even if you don't start the car. Easy way to see if they're working is to crank the car for a while and see if the plugs become wet with fuel.

Try earthing out the block and see if that changes anything. Have you also checked your battery voltage?
 

Flyingwide

New Member
Joined
Nov 7, 2021
Messages
21
Reaction score
7
Points
3
Age
44
Location
Brisbane
Members Ride
VS L67 Caprice
Hi mate, thanks for that, the voltage at the injectors does change when cranking which I thought would indicate injector pulse? I’ll check tomorrow with a noid light.
The strange thing is it was starting easily prior to fitting the second hand DFI and coils, then it wouldn’t start with the original DFI and coils when I changed it back.
Battery voltage is good, it’s a brand new battery.
 

Lex

Well-Known Member
Joined
Sep 19, 2012
Messages
5,759
Reaction score
5,005
Points
113
Location
Geelong Victoria
Members Ride
VT Executive S1 V6 6 speed Auto Wagon
Hi mate, thanks for that, the voltage at the injectors does change when cranking which I thought would indicate injector pulse? I’ll check tomorrow with a noid light.
The strange thing is it was starting easily prior to fitting the second hand DFI and coils, then it wouldn’t start with the original DFI and coils when I changed it back.
Battery voltage is good, it’s a brand new battery.
Check your wiring at dfi plug. Also so undo some tape if neccessary, to see if there is any wire touching (plastic has rubbed through).
 

Flyingwide

New Member
Joined
Nov 7, 2021
Messages
21
Reaction score
7
Points
3
Age
44
Location
Brisbane
Members Ride
VS L67 Caprice
This is a strange one, I bought a noid light kit, and as soon as I plugged the noid light in and tried it, I got injector pulse, checked for spark, and now I’ve got spark. The car now starts, but runs like an absolute dog at idle and right through the rev range. I’ve disconnected one cylinder at a time, and each cylinder almost causes a stall, so it’s not any single cylinder that’s not firing.
 

Flyingwide

New Member
Joined
Nov 7, 2021
Messages
21
Reaction score
7
Points
3
Age
44
Location
Brisbane
Members Ride
VS L67 Caprice
I looked at just the one injector though, and I literally unclipped it and fitted the noid light. It had injector pulse and spark as soon as I looked at it today, so not sure what it could be.
 

Flyingwide

New Member
Joined
Nov 7, 2021
Messages
21
Reaction score
7
Points
3
Age
44
Location
Brisbane
Members Ride
VS L67 Caprice
It’s starting fine, idles nice for about two minutes, then starts to miss, does not rev nicely either.
 

_R_J_K_

Well-Known Member
Joined
Dec 20, 2008
Messages
6,723
Reaction score
1,856
Points
113
Members Ride
Zenki S14
Had a thought looking at another thread, how long has it been since you replaced the fuel filter? Maybe try pulling the TPS too,
 
Last edited:

Flyingwide

New Member
Joined
Nov 7, 2021
Messages
21
Reaction score
7
Points
3
Age
44
Location
Brisbane
Members Ride
VS L67 Caprice
I ended up replacing the DFI module with a new one, and it fixed it. I’m surprised because in my experience when the DFI is playing up it won’t start at all. Anyway, it’s running like a dream now.
 
Top