Volvo 480 Club Europe

My B18E (with the stupid sensors) seems to have became very difficult to start when cold. It runs perfectly when up to temperature.

When cold and finally coaxed to life after about 3-4 awful starts and stalls, it doesn’t do the fast idle thing at all.

As far as I can see, the trigger for cold idle is the coolant temperature sensor to the engine ECU. Fast cold idle is achieved by longer injection pulses and more air in at the idle control valve.

I’ve tested this at cold temperature and the resistance is correct. I’ve boiled it and the temperature and resistance behave correctly.

I tried a spare idle control valve from Jeff with no improvement.

Does anyone have any ideas as it’s made me stop driving the 480 and I miss the old girl now summer is here!

(I have a brand new unobtainium temperature sensor coming from Europe (plus one for Dave Kit!) as a bit of a stab in the dark just in case the original is a little off.

The ignition parts have just been renewed— except the ignition coil and it’s amplifier.

Hi James,

Did you have any luck on this matter?
I seem to have the same issue, long starter cranking to start the engine, usually 2-3 attempts. Also, sometimes takes 2 tries to start when the engine is warm. Once started it runs nicely.
I have renewed the coolant temperature sensor and idle control valve, but the problem is still there.
As a workaround, someone in the Facebook group offered to disconnect the temperature coolant temperature sensor (for ECU) for a cold start only, which seems to help, but I would be looking for a long-term solution.

Any advice is highly appreciated.

Thank you.

kaups wrote: ↑

Mon Sep 04, 2023 1:42 pm

I have renewed the coolant temperature sensor and idle control valve, but the problem is still there.

So, some questions from me.
1. Is it a b18e engine?
2. Do you know if you've PTC or NTC sensors (or tell us the last 6 digits of the chassis number)
3. Have you got an additional electric pump on the chassis leg?

The reason for asking, is that in my many dealings on the R1 rescue car (oh its notforgotten!), which is also plagued with odd running problems, I've made a recent discovery.

There are 3 types of coolant temp senders. I'm not talking about the one that feeds the gauge, I'm talking about the 2 terminal connector at the front of the engine.



As you can see, the first is the PTC type for chassis up to 520280. The second is the NTC type, for everything else. Then there's a third....

On vehicles without the auxilary pump, both the air temp and water temp (B6/B5) share a common earth back to the ECU

Not so on the B18e - B16 is the Coolant temp sensor.



As you can see, the sensor is actually two sensors in 1. One half controls the pump, the other is the ecu signal. You know what else has an auxilary pump? the turbo models. Guess what the third sensor in the parts book is for?

Thank you for your reply and support!
I try answering the best I can:

1. It is a B18FT engine

2. I am not quite sure which type it is, the last 6 digits of the chassis number are 539663.
I have this one currently installed:
https://www.skandix.de/de/fahrzeug-teil ... z/1037368/
Man, it would be funny if I had the wrong type installed but
Skandix showed this part is applicable to my VIN and the old part has the same P/N on it. However, this could all be wrong as I don't know what the previous owner did...

3. Yes, there is an additional electric pump for coolant installed.

I guess the third PN is for the turbo models then?
Or is there an additional temperature sensor (in the turbo area) installed, compared to the non-turbo versions?
Must be the temperature sensor for the auxiliary water pump? Do you think if this one is bad it could affect the cold start ability?
info: My 480 also has the injector's cooling fan.