308QV ingnition problem

Since it's intermittent, it would probably be an electrical ignition problem, and on one side of the engine, then it must be due to one distributor, or one coil, or one ignition module. Do you know if its' the front or rear bank of cylinders that is faulting.

Check all the wires for tight connections, check the resistance of the coils, take off the high voltage lead that goes from the coil to the distributor, and check it for any intermittent breaks or loss of continuity.

Check the coil low voltage wires. If you have a wiring diagram, see what wires or devices feed the coils, and check those devices (relays, fuses, etc).

Also, could be a faulty Digiplex ignition module, or fault in the digiplex wiring harness. I have no clue how to dianose or fix those, and they are hard to find used. Worst case you can replace the digiplex modules with one of the many after-market ignitions discussed in this forum and eliminate the obsolescence problem there.

 

Simple system. Sensors > Module > Coil for each bank

When one bank goes non-functioning, reversing components to see if systems also reverse.

Reverse module connector to rule out the Ignition Module.
Reverse coils to rule them out.

Check sensors for resistance. Of 3 sensors the 2 TDC should
indicate about 700ohms and the tach sensor about 750 ohms.

 

Forget checking the coils, wires and caps, etc and go straight to the crank position sensors. There are three and I'll almost bet the bank this is your problem. Happened to me back in 06. One is dried up and cracked just like mine was. VERY common problem

 

I second what Tommy says. I had one good bad while it was being test driven by the new owner. I knew exactly what it was. I checked mine with an ohm meter and the one that showed infinite ohms was the culprit. Pulled it out and sure enough it had cracked from age/heat. We replaced it, he bought the car and it ran great the entire trip home for him. It isn't an uncommon problem. I think they are $100 each now. I would replace all 3 just to be safe but if you don't want to do that at least replace both TDC sensors.

 

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