Ignition Mismatch

[roady94]

- I bought my 2001 Avalon with 80,000 miles, and it has 130,000 now. I picked up plugs, wires this week with plans to do some maintenance.

When I popped the plastic shroud, I noticed there were no plug wires running from the front coils to the rear three plugs. In fact, there were no connectors on the front three coils that would attach these rear plug wires. Just the standard signal wire connection.

The rear three plugs had coils mounted with signal wires attached, exactly like the front. My Haynes allowed for no such iteration of this ignition system. When I looked on the RockAuto site, I found my engine called for coils only in front, and plug wires to the rear.

Then I checked the parts for the 2002 model year, and there are no plug wires available, and the parts list shows coils on each of the six plugs - just like my car.

So it looks like I got a 2002 engine, or at least ignition system, in my 2001 car. No signs of original engine being replaced or front end damage or repair. I'm figuring my car was a very late 2001 editon and somehow got some 2002 pieces under the hood.

I'm wondering what else is different. Anyone else seen this before?

[toyomoho]

One cylinder bank may use a combo coil spark plug tube/wire that plugs into the spark plug tube and spark plug.

A high voltage spark plug wire runs from each coil to a spark plug on the other cylinder bank.

In this system each coil fires 2 plugs at the same time. However only one cylinder ignites, the other cylinder does not (not at TDC on compression stroke).

[roady94]

Originally Posted by toyomoho

One cylinder bank may use a combo coil spark plug tube/wire that plugs into the spark plug tube and spark plug.

A high voltage spark plug wire runs from each coil to a spark plug on the other cylinder bank.

In this system each coil fires 2 plugs at the same time. However only one cylinder ignites, the other cylinder does not (not at TDC on compression stroke).

-Thanks for responding toyomoho. You offer an explanation of the standard ignition setup common to these engines from at least 1997 on up through 2001, and maybe later. I know this system well, because I own a 97 Camry V6 that has it. My Haynes manual says my 2001 Avalon should have the same ignition system, ie. coil on the front 3 cyls with leads to the back. This is not the case.

My 2001 Avalon has a coil on each of the six plugs. No high tension wire runs from the front plugs to the back. Maybe I could have made this more clear.

I posted wondering if anyone else had this arrangement on a 2001 Avalon. Still hoping someone will turn up.

[toyomoho]

The Rockauto parts site lists 1 coil per each cylinder on the 2001.

Would assume the Haynes manual has incorrect info.

[roady94]

- Good catch, toyomoho, the plot thickens. I guess we both found what we were looking for.

You went looking for a 6 coil setup, and found it. I went to Rockauto and looked for Sparkplug Wire Set before opening this thread. Sure enough, they offer the three wire set (POWERMAX Part # 70001) that includes 3 rear tubes, boots, and high tension wires that connect to the front 3 coil-on-plug arrangements with the special connector for that attachment. This is the same - different mfgr. - assembly my local NAPA gave me for the car (parts going back today)

It is clear that this wire set can't be used with a 6 coil-on-plug ignition.

Indications are that two systems were used on this model year.

I must go back to the diagnostic exercises.

Thanks for taking the time to share your opinions.

[aznstylez]

Originally Posted by roady94

-Thanks for responding toyomoho. You offer an explanation of the standard ignition setup common to these engines from at least 1997 on up through 2001, and maybe later. I know this system well, because I own a 97 Camry V6 that has it. My Haynes manual says my 2001 Avalon should have the same ignition system, ie. coil on the front 3 cyls with leads to the back. This is not the case.

My 2001 Avalon has a coil on each of the six plugs. No high tension wire runs from the front plugs to the back. Maybe I could have made this more clear.

I posted wondering if anyone else had this arrangement on a 2001 Avalon. Still hoping someone will turn up.

94-99 Camrys and Avalons used the same engine but with no VVt-i. 2000 and up had VVt-i.

[roady94]

Originally Posted by aznstylez

94-99 Camrys and Avalons used the same engine but with no VVt-i. 2000 and up had VVt-i.

- No disagreement here aznstylez, but does this relate to the discussion about the 2001 Avalon coming with either of two ignition systems: One with 6 coil-on-plug, the other with 3 coil-on plug?

If so, thanks for contributing, and please clarify your point.