Is this a automatic transmission? Term put it in gear makes me think that. Adding load at idle to adding more with the foot.

First of all the Electronic Control Unit needs to know it is in idle mode. The throttle position Switch has to be clicked closed.

This allows the Idle Air Control motor to work. It has to be set in middle range according to the manual. Adjusting basic idle. Very important that this switch works for smooth transitions! I set the idle stop screw only about a 1/4 turn up against the closed throttle body butterfly plate. Resting but switch not open. All things being clean per instructions!

Then when you step on the gas a click occurs to open the circuit of the IAC-Valve.

At this point you are on the Air Mass Meter, Rpm/crank timing sensor, coolant sensor and o-2 sensor. Above idle mode ,in run mode. Totally, closed Loop operations with engine and the o-2 sensor hot.

These are controlling mixture through the mentioned pluse width from the ECU, you read about.

The ECU parameters are set in both modes but it needs to know when, you the driver are changing them. I think there is another click at the wide open position, full load. That shifts the computer into another program. Again the switch!

Hope this sheds light on the workings for you. I like to help when people demostrate they are willing to use a manual. Good Luck

- Is the vacuum line going to the fuel regulator functional and with a leak in vaccum?

- What about AMM: This can point to the fact that it does not run warm; where it needs a leaner mixture. You can only test that by swapping it out.

Greg Mustang
Montreal - Canada
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Greg Mustang - www.volvoclassic.bravehost.com

Today im going to check the fuel pressure on my 240. She is still dying under load only after she warms up. Im looking in my Haynes manual right now and see that the system has a fuel system control unit that controls load signal.I have no idea where this piece is located. One listing that I read also stated that the...........


For an engine with fuel injection, a control unit will determine the quantity of fuel to inject based on a number of parameters. If the throttle pedal is pressed further down, this will open the throttle body and allow more air to be pulled into the engine. The ECU will inject more fuel according to how much air is passing into the engine. If the engine has not warmed up yet, more fuel will be injected (causing the engine to run slightly 'rich' until the engine warms up).

I would think that with the vise grips in place you would be effectively raising the fuel pressure at the rail

If it were mine I would be wondering what the pressure at the rail was; both with the clamp in place and with it off.

If you are near a pick and pull or have a parts car available you can make your own fuel pressure gauge with the fuel rail connector and a trip to the hardware store.

In your image I have circled the piece you need from the fuel rail; cut a couple of inches back on the hose side and enough of the solid line to get a nice straight portion to make the compression connection on.



The next image shows the way it all goes together and what you need:



Then you simply disconnect that attachment to the fuel rail and make the connections to your test gauge. This is for testing purposes only. It would be a good idea to work outside and have a fire extinguisher at the ready. Once you start the car the gauge will read the pressure at the rail

I would hate to suggest that you replace the main fuel pump without having some pressure readings to think about.

Randy