Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) Plus Six, hot start problems

We are away in the Dales and had a hot start issue twice now,
The engine is reluctant to turn over and the stop light flashes up on the dash give it a few minutes and it turns over and starts anybody else experienced this?

I had an issue where the engine would occasionally cut out as it warmed up, it would start again but not running on all cylinders. Give it a few minutes and all would be OK. Took it to MMC and they looked at the fuel and earthing. Now solved, with the most likely cause one of the earthing points on the basis that (a) nothing was found wrong on the fuel and, (b) earthing faults were a known issue on the Plus Six.

Why that would only be when it was warming up is a mystery to me, but it could be related to your problem I guess.

Is your battery fully charged? If you have one of those L-Ion booster pack thingies it might be worth trying it as an assister if by 'reluctant to turn over' you mean the engine isn't cranking at its normal speed.

Many modern car systems are quite sensitive to battery voltage and if your battery is maybe a bit tired and not delivering the full 13V or whatever it might throw a MIL.

Battery is new, 096/100 type , I did measure the rest voltage at 12
4v, starts cold no problem.

When you start the car a high amperage and quite a lot of stored charge is used, then during the first few minutes the alternator kicks out max charge to try and replenish the battery - this could show up in the faulty earth, and I suspect complex Mogs like a CX may well have a dedicated alternator earth connection

12.4 v is roughly 70% efficient.

Sorry to read of your hot start issue but it seems much is the dependence on critical voltages within modern vehicles and the difficulty even dealerships in tracking them down, all of which is a real pity.

For sure a resistance in a joint, or connection point in so many sensors may create issues to the extent that simple stuff can be overlooked, in one non Mog vehicle it is seemingly possible for a the heavy cable which connects both the starter motor and I think alternator to have a "T" joint in it, whether it is the joint that fails or the crimps which create the points of connection to the starter motor that may alter at the engine gains temperature I do not know, but the resultant issue is a very slow/sluggish starter speed when the engine is hot. Fitting a new original equipment cable from the manufacturer seems to resolve the issue on these particular cars...?

Also left of field, dependant on battery location and how happy it might be when hot as opposed to cold, might be an idea to check the voltage out after a run...?

One might hope attaching a code reader when the engine is hot might show up a sensor read back issue that may not readily appear when cold, though one would hope the ECU would capture and store any such data... BUT..?

Best of luck in resolving such a frustrating issue.

Does anyone know where the OBD2 socket is located on a Plus Six?

Drivers side under the dash mounted in the alloy under tray, if I remember correctly..

Correct