Air Temp Sensor, LH 2.4 & '90 745T[700/1990]

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Air Temp Sensor, LH 2.4 & '90 745T[700/1990] posted by Ed O'Briant on
Sunday, 1 August 1999, at 10:46 a.m.

The following is according to my Chilton's Volvo1990-93 Repair Manual...

Regina fuel injection system does not use an AMM but an air pressure sensor and an air temp sensor. On my '90 LH 2.4 745T, there appears to be such an air temp sensor plumbed into the rubber piping just downstream of the AMM (same rubber pipe which feeds the turbo). This sensor is then joined to the PCV system via a hose which runs over the valve cover to the oil separator fitting located between intake runners 3 and 4. Its electrical connection branches out from the wiring harness just upstream of the AMM's electrical connection.

I can find no reference to this sensor in relation to the LH Jetronic 2.4 fuel injection system anywhere. Is this just another Chilton mistake/oversight or have I got some kind of cobbled air metering system?

Thanks-
Ed O'Briant

P.S. Chilton's also mentions a "turbocharge control unit" or TCU. This appears to be another computer separate and distinct from the EZK and LH units. Where is this TCU located?

Re: Air Temp Sensor, LH 2.4 & '90 745T[700/1990] posted by abe crombie on
Sunday, 1 August 1999, at 7:17 p.m.

What you are seeing is the heated crankcase vent nipple (also referred to as the PTC heater nipple).
This is used on 90 and later where the air heater tube is deleted. Volvo decided that the preheat system which was thought would prevent throttle icing, would not due that on intercooled models due to cooling effect on air through intercooler before it goes to throttle. The heater is to vaporize the moist air that comes out of crankcase after start up and while driving in very cold weather.
Lh fuel inj system on that car doesn't use the IAT sensor.

Re: Air Temp Sensor, LH 2.4 & '90 745T[700/1990] posted by abe crombie on
Sunday, 1 August 1999, at 7:18 p.m.

Oops!
The tcu isn't used on US spec cars. It is used on 16 valve turbo 2 litre engines that were sold in some European markets.

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