Amazon: Misfiring B18

[arcturus]

Ron,Long time no hear!Hope all OK with you.PV at 12 volts behaving faultlessly.Stay safe

[Derek UK]

Originally Posted by Bob Meadows

For quality components like condensers- rotor arms & many more try Distributor Doctor.
Link:~ http://www.distributordoctor.com/

They have developed part of their trade by solving the inferior rubbish being offered to classic car owners.
Regards Bob.

You can ask but he seems to be Lucas only. A friend with AC Delco on his Vauxhall had no luck.

If you have twin SU's wind the jets back up, count the flats and note that down. With the air filters off make sure that the jet tops look to be in the same position, just below the carb bridge. If not equal recheck that the nuts are fully up. If that seems to be the case. carefully lower the high jet to match the low one. That might be less than a flat. Wind them down 12-13 flats and test drive. If OK you can make small adjustments to the jet nuts but usually they are within 1 - 1 1/2 flat s of each other. Rarely less than 11 flats down unless you have the wrong needles. If you have access to a carb suction tool. loosen the shaft nuts and adjust until equal using the tick over screws. That should really be done first as long as the engine is running. Don't forget to tighten the clamp screw afterwards!

[blueosprey90]

A comment from the peanut gallery.

"It can start fine and run for a short period and then, not always, misfire. It does not want to accelerate and is very hesitant and kangeroos down the road.

Plugs changed so far. Cap looks quite new and can't see any issues with it. I have also cleaned out the fuel filter."

So if we can assume that the car has recently been tuned up and has relatively new ignition components, and that the distributor points are clean and properly gapped, then to me, "kangeroos down the road" suggests condenser.

I have absolutely no experience with the B18 engine and can't even remember if the condenser on my B16 is internal or external. But I've had many a misfire, and a condenser failure can be a "spitting misfire", kind of like an angry cat, with the car bucking down the road.

If you have an inductive timing light, set it up as if you intend to time the car. Start the car and one by one attach the inductive pick up to each plug wire. Simply look at the light. If it is flashing evenly and smoothly on all 4 wires, then it is not the condenser. If it is flashing poorly on just one wire, then that is where you have the misfire. If it is flashing erratically on all four wires, then it most likely the condenser.

You can confirm without removing the existing condenser by attaching a second condenser to the connecting post and grounding it against the body of the distributor. Just lay it there, trying to insure a good ground. If the car then runs smoothly, you have your diagnosis.

Insofar as the coil is concerned, I agree with Arcturus that a failing coil can sometimes be diagnosed by touching it after it has run for a bit. If it is getting very hot, it is likely failing. A defective coil can also manifest itself as an intermittent failure, manifesting itself once the engine is hot, but running smoothly wnen the engine is cold.

Good luck.


Edit: I don't know if this will be relevant to your long term plans or if it will help, but I swapped out my coil for other reasons in post #235 here. 6 volt system. https://www.volvoforums.org.uk/showt...279014&page=24

[arcturus]

Just to be clear a hot coil indicates an ignition problem,not necessarily a faulty coil. I experienced this with a broken center contact in the dizy cap.

[Clan]

Originally Posted by 80Sprint

I am a first time owner of an Amazon B18 (66) but finding it frustrating as it has already developed a misfiring fault.

It can start fine and run for a short period and then, not always, misfire. It does not want to accelerate and is very hesitant and kangeroos down the road.

Plugs changed so far. Cap looks quite new and can't see any issues with it. I have also cleaned out the fuel filter.

I sense it may be electric rather than fuel. Maybe coil ? It is running the original coil. Can i test this and what is involved in upgrading to a Bosch blue coil as i plan to use this daily ?

thanks



Mike

Its unlikely to be the coil , or at least eliminate the rest first .
Make sure you have genuine volvo distributor cap , rotor arm and Spark Plugs and Contact points ... they can be guaranteed to be ok , other's can't ... condensers are high quality from new , if someone has fitted a cheap general one it might not be .

[HRA]

For what it's worth, the symptoms sound very similar to a problem I had many years ago with an MGB. It had been serviced a day or two before and it had been running well until I'd driven somewhere and it was time to go home. It started fine and idled well but any attempt at acceleration led to spitting, mis-fires and the kangaroo-effect. I was lucky enough to be within walking-distance of a little car-spares place. I bought a new condenser, fitted it at the roadside and everything was fine again.

A week or so later I mentioned it to the mechanic who had serviced the car for me. He apologised. I wasn't the ony person with problems - he'd had a bad batch of condensers.