Spark question
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Spark question
This weekend we were tuning on the 406 and we noticed that when we pulled the plug wire off of the #! cylinder that there was almost NO change in the car idle,, spark was occuring. The resisitance check on the plug wires cheked out OK.
But when we pulled the #2 plug it ran noticeably rough.
We have 12 volts to the BRAND NEW injectors and all of the valves are opening and closing.
We checked the wires from the ecm connector to the injectors and the connections and wires proved to be OK too.
We teste the HEI and the coil and both were OK.
We changed plugs and it made no difference.
What do we check for next? Compression test?
:banghead: :banghead:
[Modified by ld85, 2:58 PM 9/10/2003]
But when we pulled the #2 plug it ran noticeably rough.
We have 12 volts to the BRAND NEW injectors and all of the valves are opening and closing.
We checked the wires from the ecm connector to the injectors and the connections and wires proved to be OK too.
We teste the HEI and the coil and both were OK.
We changed plugs and it made no difference.
What do we check for next? Compression test?
:banghead: :banghead:
[Modified by ld85, 2:58 PM 9/10/2003]
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: Spark question (ld85)
A compressiom test never hurts, but you have a new engine, don't you? I would verify that #1 isn't firing. Try wetting your fingers and touching the header tubes, or spray them with water to get an indication of relative heat from the other cylinders. Try subbing a plug, you MAY have a funky one. Connect a plug to ground, uninstalled, with the #1 wire attached and check for spark, while cranking. If the spark checks out, than it's on to fuel. Possibly a plugged or blocked injector? It's all just a process of elimination. Good luck, and...
RACE ON!!!
RACE ON!!!
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Re: Spark question (CFI-EFI)
Yes it is a new engine. We did spray the header tubes and there is a slight difference in temp with the # 1 being a little less hot than #3 tube.
Also we already swapped plugs but will try to spark one off of the engine.
Thanks for the suggestions, we'll keep "investigating"!
Also we already swapped plugs but will try to spark one off of the engine.
Thanks for the suggestions, we'll keep "investigating"!
