328 - Ignition Loss on One Bank

The only challenging part of replacing the rotor (if this is the problem) is the cost. Rotors and distributor caps are outrageously priced on these cars.

 

This sounds similar to a problem I had with my 328 a few years ago. The dealership took a couple days to diagnosis the problem. End result was a short in the wire harness going to the crankshaft postion sensor. During the problem solving, it appeared at one point one bank wasn't firing and the problem eventually toasted a coil. I would recommend pulling out the rather short sensor harness and check it's continuity. The harness is about 1 foot long, white, and located at the driver's side of the engine, next to the oil cooler.

 

Did you try swapping the coils over to see if the non-firing bank switches ?

 

When you swap coils, you must swap all the wires attached to it. Otherwise, you have it firing as if it were still attached to the other bank, hence timing no where near correct. This problem is likely related to a flywheel sensor or associated wiring as noted above.

Dave

 

I experienced the same thing with an '85 308. It turned out to be one of the flywheel sensors.

Hardtop is absolutely right--don't just switch the coil wires from coil to coil . Essentially, you're throwning the timing out about 180 degrees in doing that! If you want to see if it's the coil wires, you need to disconnect them from their respective dist caps and the coils. To test the coils , they must be completely switched, including their respective input wires.

Another thing to check is the bulkhead connectior which connects the wires from the Digiplex to the engine wiring harness. On 308's they can become dirty and corroded, making for poor electrical flow to the engine ignition wiring. I'm not sure where that's located on a 328. On my old 308, it was under the expansion tank and next to the oil cooler .


In correcting the problem, be sure to replace the plugs. The old ones are likey glazed and won't fire well--if at all. So, you might correct the spark issue, but with the damaged plugs, you'll never know as they would fire anyway!

Good luck.

 

I had the same problem with my 85 Mondial QV this past fall, same bank and it died in the same manor. I swapped coils, wires, Crank sensors, Digiplex units and dist caps trying to get the problem to follow the part. As it turns out it was a bad rotor (not that bad in price when you look at the cost of a cap), It ohm'ed out fine but it was arching the spark to the distributor base, you could hear it if you listened closely. If you are checking the sensor you can test them without taking them out just follow the cables back to the connector, both banks will be in a bundle on the left of the bellhousing. If it is the front bank you are in luck as that is the easiest to get to and replace. After you trace it down do not forget to dry out the plugs and change the motor oil and filter as the front bank is fuel washed as well as the oil. Good luck!


All the best,


Chris

 

It could be a rotor/cap issue but I think you would have had some warning with poor running before complete failure.

Good luck,
Dave

 

It cannot be a crank sensor issue because the 3.2 motor has microplex ignition whitch utilizes a single ECU with a single TDC and RPM sensor. If either sensor packs it in, game over.

Ignition rotor is a possibility but the design was changed to rectify that problem. Coil wire is a possibility. To test remove coil wires from caps and switch coil wires only, bank to bank.

But if you want to save time, swap coils and see what happens. 99 times out of a hundred it is a transistor module on the coil.

On the microplex system one coil sends a signal to the fuel pump circut to run the pump. If you install the bad coil on that bank the motor will not run.

 

Same probem a few years back on my 84 Mondial, Flywheel sensor for the front bank failed, took me ages to find it, the problem that is, changing the sensor can be a bit of a pain. As I recall, the replacement came off a Lancia !

 

Hi Kevin,

After reading who already answered above, not sure I can add much to this discussion except:

1. Have you actually removed the distributor cap & inspected the cap/rotor assemblies? The seal can leak oil & cap can fracture, but otherwise likely will find a bit of corrosion.

2. You can remove & test the ignition module (black rectangle on top of coil) at Autozone; make sure they connect the proper tester harness. It's held in place by screws & a dab of dielectric grease underneath. New replacements are about $80-100.

Best,

Carl

 

Read Brians post..this is the most common reason for a bank failure on a 328.

 

Since no fire on coil wire, before thinking it's a bad distributor, rotor, etc., get a spark gap ignition tester, or just connect the coil wire directly to a spark plug & ground the case.

Should be firing the gap/plug if not, then the coil isn't getting fired. Make sure you're getting both power & a good ground to the front bank coils & ECUs.

If the plug is firing, look for distributor, etc. problems as you mentioned.

 

Yes, it sounds electrical, but are you sure you're getting gas to the bank that's failing?

Ken

 

I had the same problem. It was intermittent power to the front bank coil. Once I verified that all components were working by swapping from bank to bank (coils, caps and rotors), it was a matter of squeezing the connectors inside the molded rubber connectors that power the coil. Contact cleaner is not enough...and the more I pulled those wires off for testing, the worse the connection became. Hope it works for you.

 

I had the same problem as Canh in my 328 and it was connectors to the modules on top of the coils. You can try moving the harness around while the car is running, but be very careful to stay away from any high voltage components. The harnesses are stiff and partially held in place by the plugs.

You can also, test circuits with test plug--see attached diagram.

Good luck,

Mark
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My 1989 328 right after passing it's smog check (yay!), started doing exactly this (boo). I am happy to see I don't need to go fishing for crank sensors, but @kgoy how did this sort out for you?

 

I had this and it was caused by the coils being upside down meant water had run down into the rubber caps on the connections on the bottom (normally top) of the coils and caused corrosion of the blade connectors. Cleaned contacts then was OK.

 

Would anyone know what the ohm reading should be on 86 328 coils ?