Rear spark plug bank is fouled. The 3 in front are fine. What cold be the problem?

Sounds like a bad distributor. Had you pulled a spark plug out you may have found them wet with gas after cranking. If they are wet the crank sensor is working since both injector pulse and coil pulse rely on crank signal.

The distributors are known week points in the ignition system and used to be common when theses cars where still on the road. A reman will run you $250 U.S.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

P1316 ACURA Spark Plug Voltage Detection Circuit Malfunction (Front Bank 2)

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http://engine-codes.com/ just for future references

Ford numbers the cylinders on the V6 as follows: The right hand bank [or bank of cylinders closest to the firewall] are numbered front to rear as 1, 2, & 3, The left hand bank of cylinders [closest to the radiator] are numbered front-to-rear as 4, 5, & 6.

The firing order on a 318 is 1 8 4 3 6 5 7 2, the drivers side bank is 1 3 5 7 front to rear and the passenger side bank is 2 4 6 8 front to rear.

The front bank of plug wire is easy just remove them one at a time and trace them back to the coil pack. making sure you put them back in there clip harness. The rear bank of plug wire is much harder In the shop we have a tool the titls the engine a little foward and allows you to reach in over or around the engine to gain access to the rear bank of spark plug wire . this tool is sold by OTC , Snap on , Matco , Mac or you might try your local parts store to see if they have one for loan or rent . the firing order on your buick is coil nearest the drive side is 1/4 middle coil is 3/6 and the end coil nearest the passanger side is 2/5

passanger side l----l l----l l----l drivers side
2 5 3 6 4 1


front of truck
this is the firing order for a 3.4 v6 vin e

ignition coil is x 6 plugs back

x 3 2 4 6
x 2

x 5 1 3 5
x 4
front
x 1


hope this helps let me know

the firing order should be - 1-6-5-4-3-2 , Front Bank 1-3-5, Rear Bank 2-4-6. Hope this helps.

carsandcomps,

Guru, Premium Expert @ Fixya.com

TIP: When replacing spark plugs and wires, do one at a time to ensure each is placed back in it's original position and place.

Are you trying to route the wires and need to know where the cylinders are. The numbers are on the coil pack. The 3 short wire are for the rear bank and the 3 longer wires are for the front bank. Number 1, 3 and 5 are in the rear with one being closest to the altenator. 2, 4 and 6 in the front with 2 being closest to altenator.

1 6 5 4 3 2
Front bank 1 3 5
rear bank 2 4 6