LH2.4 240 no start.

Spac

1991 244GLE, auto.

Would alternate between starting and running fine, starting and running badly until it warmed up, and not wanting to start at all.

When it ran badly, it was running rich - black smoke out the exhaust and the smell of unburned fuel.
When it didn’t start, the spark plugs would be wet.

I assumed a bad air flow meter, but a new one made no difference and the old AFM works perfectly in the other car. The new Chinabay AFM works fine in the other car too.

Now is consistently refusing to start and has no visible/audible spark out of the ignition coil.
The positive side of the coil has +12V with the ignition on.

Any suggestions?
I don’t have the time or brain space to dig into the wiring diagram at this point, and am hoping this might be a known issue???

familyman

Spac consistently refusing to start and has no visibl

You have some faults common to my drama a while back. It took a lot of time, much frustration testing a bunch of things, and a lot of help from the guys here who didn't abandon me until it was finally FIXED. Is the sticker on your ECU pink? If yes type "pink ECU" into the search field /\. I bought another ECU from a guy in the USA but it still wouldn't start. A mechanic I knew looked at the spark plugs and said buy new ones - and it roared to life. There's a lot of great info from all the guys in that thread covering common faults that prevent starting and tests to do: https://ozvolvo.org/d/7351-7351/57.

ramrod

No spark, first items to check:

RPM sensor resistance
Power stage unit (front left inner fender)
Spark plugs, leads, distributor cap and rotor
EZK ignition ECU
Wiring and connections

Good luck

jamesinc

You can test the coil itself (and distributor/leads) by powering it up, setting engine to #1 TDC, then disconnect the negative lead, which will fire spark plug #1.

Major Ledfoot

Given all the wet weather lately, it might also be worth checking out the distributor cap for corrosion in the terminals.

I had an 89 LH2.4 240 once which would run rough at startup and wouldn't start in wet weather, until the dizzy cap was cleaned of the blue-coloured corrosion inside the lead terminals.

dmc

Sounds like a coolant temp sensor. @carnut222 has some experience troubleshooting and replacing these. They are simple to try, just make sure it is earthed and plug it in. For the first minute, while the coolant is still at room/outside temperature, then you will have a good test for the cold running. After that it really needs to be in the engine, which is more involved. Testing them is moderately simple, they are in a tough spot for a multimeter probe though it is just 2 pins and read the voltage.

Ramrodfunk

When the car warms up and dies, does it start again when cooled down?

Ingnition amplifier/power stage(USA).

On the fire wall near the battery.

My car, started and ran, warmed up and died. With the intervals between running and dieing becoming shorter and shorter untill it refused to start altogether.