No spark on # 1 cylinder and weak spark on # 3 cylinder.

Here is the firing order and spark plug wire routing diagram for a 2006 Chevy Impala LT 3.9 V6:
Firing order: 1-2-3-4-5-6
Spark plug wire routing (starting from the driver's side):

• Cylinder 1: connect to the coil tower closest to the driver's side headlight
• Cylinder 3: connect to the coil tower next to cylinder 1
• Cylinder 5: connect to the coil tower next to cylinder 3
• Cylinder 2: connect to the coil tower closest to the passenger side headlight
• Cylinder 4: connect to the coil tower next to cylinder 2
• Cylinder 6: connect to the coil tower next to cylinder 4

Note: Make sure to route the wires properly to avoid cross-firing.

FIRST OFF LEARN THE RULES OF WASTED SPARK COIL PACKS
1-IF ONE WIRE OR PLUG GOES OPEN, YOU LOSE 2 PLUGS DEAD THAT IS BECAUSE 2 FIRE AT ONCE, AND IS WIRED IN SERIES
2-DO NOT MIX IF THE WIRES OR FIRING ORDER IS LOST (HORROR 1)

3- LEARN TO REPLACE HV WIRES 1 BY 1, NOT MIXING THEM UP EVER.
YOUR PACK IS 6 IN ONE, AND HAS 3 COILS INSIDE FIRING IN WASTED SPARK ORDER. IS THIS CLEAR? AND ANSWERS IT ALL.

4- WELL THE HV WIRES ARE FIRST TO CHANGED OUT WITH NEW SPARK PLUGS AS 17 OLD PLUGS AND HV WIRE SETS ARE NO GOOD UNLESS NGK MAG WIRE, NOW THAT IS A WINNER THOSE, NOT CARBON CORE OR SILCONE CORE JUNK WIRES EVER,SEE NOW MOTORCRAFT SAVED OUR BACON,

SEE PHOTO BELOW FOR FIRING ORDER.
ON TOP OF COIL CLEAR AS DAY 6" SEE 3 AND 4 THERE, THEY FIRE AT THE SAME TIME.
AS DOES 2/6 AND 1/5

5: CYLINDER #1 ON ALL V ENGINE IS THE ONE MOST FRONT
IT IS OFF SET TO THE FRONT MOST. BINGO #2
THEN WE GET ASKED THE FIRING ORDER.
6: THIS IS NOT GUESSING THIS IS SERVICE MANUAL FACTS .
BANK 1> 1,2,3
BANK 2> 4,5,6
VIN U) Firing order 1-4-2-5-3-6
SEE HOW ALL THIS MATTERS?

No cylinders fire at same time. 6 & 3 must be from same coil-ignition coil C-that is the one with the problem. And the secondary circuit- that is the spark firing portion of the coil. Coils have a primary winding circuit and a secondary wire winding circuit. The secondary comes out of coil as the tower, or the spark plug wire tower -the business end of the coil leading to the plug.

You could have a bad new coil (happens occasionally) or the connection to that coil may be the problem-the connection where the coil snaps onto the coil pack assembly. Try swapping that coil (coil C) with another one there and see if problem follows the coil. See? Keep your plug wires the same, just swap coils with another and see if the new position for suspect coil causes other cylinders to misfire. If a different coil in that "C" position causes same code, then it is not the coil itself, but probably the base assembly that the coil connects to.

These ignition systems use what is called a waste spark, or exhaust waste spark system. The coil will send spark to 6 & 3 simultaneously, but since one is always on the exhaust stroke while the other is on the compression (firing) stroke, the exhaust spark is very weak, and all the energy from coil is directed to the compression stroke cylinder. It sounds crazy but it works great.

Since you say it runs bad just as before, that indicates the coil is not the problem, but something wrong with the base of the coil pack . This is where the wiring is directed to the coils.

post 3, adds, no spark , 2/3 (and still no year, no country stated)
bad coil pack?
wired wrong, this pack.
no photo of the engine, nor real name of it, Petrol.
btw, we dont have "BAKKIE" here. not a single one.
nor KB trucks, either.
what spark system this car has, im clueless.
4 coils or 1 pack.? if one pack , replace all spark wires
if one pack system , if either 2/3 wire opens, both cylinders go dead. try new spark wires. high voltage,

or you measured spark wrong, on 1 pack car.
it takes 2 spark plugs do do that. 2 good plugs and 2 good wires,
#2 and #3, due to the fact they are wired, in SERIES.
see its called wasted spark system, with 1 coil pack and no distributor..
the testing is unique. on this, setup.
try new spark plugs, gapped correctly
and 4 new HV wires,
I bet its go. if not the coil pack is toasted.

All spark is generated from the coil. You didn't state year make model. The vehicle may have only one coil and ignition wires or it could have a coil for each cylinder? Suspect a weak coil or high resistance in a plug wire causing this issue

wow, no engine option stated, and no DTCs.

4.0L I-6 or 4.7Liters?

WHY DO THAT FIRST. $$$$ parts first.

why not do a tune up first.

you swap in the most expensive parts first? ouch,

The PCM tells you when ckp or cmp fail, with DTC codes

so its not that. but you never posted ALL DTC errors. why not do that.?

do a real tuneup? heat (spark plugs, filters.)

if you have P030x errors,

eg: p0301 is cylinder #1 is misfiring (3 ways to do that not JUST spark)

eg: P0300, random on all cylinders. (fuel mix wrong) or never tuned up.



Misfire 101; (example P0301 DTC)

P030x codes, are all just about spark, misfire is caused by 3 things, (at least)

1: sure spark. weak. (tuneups work as does hV wires sets if no COPS) if 1 cop is bad move it to other location, does failure follow the move>???????? buy new cop boots if engine has cops.

COPS means coil over plug, so v6 has 6, v8 has 8.

coil packs have 3 coils inside for v6 and 4 for V8. called wasted spark to any tech.

2: low compression, think of your v6 (is it) as 6 engines, not 1.

3: wrong FUELING rates. including air leaks to 1 cylinder.

if engine has EGR that too, will cause gross misfiring.

so can an air leak near one intake runner, causing 1 cylinder to misfire.





why not scan it with a real scan tool that can see ALL jeep codes

then post all DTCs found. both idling and driving for 45mph or 1/2hr.

with these facts and what engine is there we can do the remaining tests.

free book



http://www.jeep4x4center.com/knowledge-base/index.htm?utm_source=cj#service







The tune up is this and filters.

do the tune up, new wires, and plugs using correct spark plugs not some bs, magic ones, use spec, plugs first. its in the manual.

then HV wire set on 4.0L,

if cops V8 , 4.7L try new boots on them. or swap them to find bad one.

the USA car V8 has coil on plugs





misfire means ONLY that this cylinder has weak COMBUSTION

its not weak spark only, that is only 1 cause of poor combustion.



post DTC\'s driving and we can fix it

the best tool is the

Innova 3160 scan tool, that is what I use on home cars.

it does all jeep codes, ALL.

i can drive , and scan and log DTCs.

and gather lots of facts on errors.

that is always the best way,

you can not fix cars today with out owning a scan tool.

unless , luckiest man on earth. (guessing)

Error Code: P0303
Description:
Cylinder 3 - Misfire Detected
Possible Cause:
Wiring harness, igniter and fuel injector connectors.
Ignition system. (Spark plugs gaps)
Fuel injector No. 3.
Fuel pressure.
Running out of fuel.
EVAP canister purge valve.
Evaporative emission system.
Low compression, cylinder No.3. (check valve clearance and throttle plate for excessive wear)
Engine control module (ECM).

Hello
Here is what to check let me know if you need help checking this out
most common misfire causes on the cars I've worked on have been:

1. Spark plugs
2. Spark plug wires
3. Ignition coil
4. Fuel injector
5. Wiring to fuel injector
6. Timing Belt
7. Vacuum leak or stuck open EGR
8. Contaminated fuel or bad fuel pump
9. Weak compression
10. Blown head gasket

On dis ignition systems if you have an open circuit plug wire you will lose spark on both cylinders of the coil. So however you are checking for spark,(screwdrivers or spark testers) Check cylinders 1 and 4 at the same time. A good way to eliminate the possibility of a bad plug wire is to take both wires off the coil and start the engine. Spark should jump from the coil tower to the coil mounting bolts. If it doesn't replace the ignition module.

Did you try swapping plugs & wire with another good cylinder. Maybe bad plug or wire, even though check says wire good.