It doesn't start when warm

[Baxter]

After bought it, I left the 480 turbo with the B18FT '95 and the battery unplugged for more than one month. The car was running correctly and with a perfect idle and perform correctly. Only a bit long craking to start the engine. But maybe this is normal on 480

Now it starts on cold after a bit long craking as usual and the idle is ok at the beginning but little by little starts to be a bit variable.
When the water temperature arrives to 60 celsius degrees the idle is not good, no big variations but up and down constantly. As temperature arise idle gets worse.
At a point the engine stops and it is impossible to start again. During the cracking, from time to time very little explosions on exhaust.
The test is performed with the car stopped.

I unplugged the air meter hoping than limp mode would appear and solve the problem but no luck. No change.
The same with the automatic idle valve unplugging and no change.

When cold it start again at first.

Any idea where to have a look? coolant temp sensor?

Thanks

[brinkie]

I would suspect the ignition coil.

[doingitsideways]

Either that or the coolant temp sensor, like you say. The one around the front of the engine, in the cylinder head, near the distributor with two wires coming from it.
The other one with one wire is for the guage/info centre.

Had similar symptoms to you, and when I came to change the sensor I found one of the wires had pulled out of the plug, as it's quite taught from the lead to where it joins the rest of the loom.

[Baxter]

Thanks for your answer. I took the car today from the mechanic. New oil, filter, oil for the gearbox, air filter and spark plags.

The problem of not starting seems to be solved.
The spark plags were very worn. The gap was very big, more than 1mm, so probably the spark plag got wet after a while at idle. I don't see another explanation.
They are volvo spark plags.

Yes, the wiring is very tight on the temp sensor. It needs some fix.