Auxiliary Air Valve...

[dfeghali]

Hi all,
I have a 1983 Volvo 360 GLT with a B19E LE-Jetronic fuel injection system (BOSCH)
It has an "erratic" running on cold-idle (20 minutes after ignition)
First, I cleaned up the injectors and replaced all the air tubes (from and to the AAV) so I have a good spray pattern and no air leakage.
But the problem persists !
Then, I have partially checked the electrical system of the injection and noticed that there is a constant 14 V on the AAV even when the engine is hot !
So the "order" is getting to the ECU which is transmiting this voltage to the AAV (I think the continuous voltage for a long time (years) has damaged the AAV)
What Sensor gives this order to the ECU (Coolant temperature sensor or thermal time switch) ?

If anyone has an idea about this problem...keep me posted
Thanks a lot for your helpful advices,
Cheers,
David.

[SteveP]

This is very interesting... many, many GLT's suffer from poor running from cold and excessive fuel consumption. Although they do usually clear within the first few seconds. I can't offer any clues but the findings so far are good! Where are you based out of interest? An 83 GLT in black must look rather nice (pics!)

[volvodspec]

sounds like a faulty thermal time switch; this is what swithes the 14v on the 5th cold start injector

[dfeghali]

@ Steve
I'm based in Lebanon (Middle East). My father got this car from the Volvo Company Beirut in 1983 (he had before a 1973 MGB Roadster...that is till now in the underground parking ) and in 1994 he got a Range Rover so he parked it for about 15 years...and then I took it to go to the university in 2008...
It's a very good car so far ! I have no pics of it right know...but I will post some in this few days
@ volvodspec
If it's the thermal time switch...what is the volvo part number so that I can get it from my Volvo dealer (I don't know if they have one left...if not is it from Bosch or on another car ?)
So this thermal time switch operates on the cold start injector and the AAV ?
Cheers,
David.

[Chris_C]

I'd agree with Anjo, the thermal time switch is a bi metallic strip that seizes up over time. I had a bit of a fight with one on my GLT last year.

I havn't got a GLT at the mo to be able to help with numbers though I'm afraid.

[dfeghali]

Thanks a lot Chris
So I have to replace the thermal time switch...
Can anyone of you help me with the volvo part number ? Or tell me if the same switch is fitted on another car...because I'm affraid that the Volvo dealer does not have one...it's a very rare car in here...

Cheers,
David.

[volvodspec]

hmm can't help you with the partnumber.

but; if you take the electric plug of the fifth injector, you're done for now. that will atleast make driving better; i believe you don't even need this at all since the thermal switch operates at 20°C and it's above that practically all the time in the middle east??

[dfeghali]

In Lebanon we have 5 degree celcius in winter (and 34 in summer )...so it's difficult to drive it in the early morning and in the late night...
Are you sure that the coolant temperature sensor does not have any effects on the AAV ???

Anyone has the Volvo part number or an equivalent ???
Anyway thank you very much for your help

Cheers,
David

[Fuse]

Auxiliary air valve is supposed to have a constant voltage when the engine is running! It shares the + feed with the fuel pump. It should close completely though 5 minutes after being powered up when temperature is ~20C. When the valve is not powered it should be half open when temp is ~20C, fully open when temp is -30C and completely closed when temp is +70C.

Like others said above, this sounds more like a cold start circuit problem. It's also easy to check if this is the problem. When the engine is running rough take out the power connector of the cold start injector. If problem goes away, your thermo time switch is faulty. If it doesn't go away the injector it self is leaking or the problem is somewhere else.

Cold start circuit is luckily a separate system from the ECU. Thermo time switch controls the cold start injection directly so like said it's easy to fix.

Volvo part number for the thermo time switch is 1219731. I hope it is still available! Many parts are NLA (no longer available) but it's a Bosch part so maybe they still have those. Same switch is used in many other cars also, like 200-series Volvos with K-Jetronic injection. Also many other vehicles which have either K- or L/LE/LU-jetronic have had the same switch.

About the coolant temp sensor, there are actually two of them in injection models. One for gauge (only 1 wire going) and one for Le-Jet (sensor has two wires). Neither of those have any control over the cold start circuit because like said above the cold start circuit is a separate circuit. Faulty LE-Jet temp sensor can cause bad running also though if the ECU gets wrong info about the temperature of the engine. Condition of the ECU's temp sensor is also easy to check, the resistance between the two pins on the sensor should be about 2 or 3 kilo ohms when temperature is ~20C.