I have other issues which I should be looking at first, well maybe, lately my car is been acting really funny. laggy power when flooring it, running crappy at certin rpms, giving it gas, like maybe tps/throttle switch.

anyway, i'm looking at info on adjusting it and it's just checking that it clicks and it doesn't seem like the test is accurate. I looking in the bently where it's having you ohm the wires untill conituity or lack of a WOT, etc. which seems like a better way to adjust it. but I only have the 240 manual at my shop, the 740 appears to only have 2 wires or wires in only 2 of the 3 pin locations on the connector.

does anyone have the bently test for 740's???

thanks.

 

Your car being a 1988 740 turbo has LH2.2 FI. So there are only two wires that go to the Throttle Position Switch. If you car is equipped with a "turbo plus" kit, there would be a third wire. The first two leads are connnected to each other via a micro switch. It makes a distinctive click when it changes form open to closed and vice-versa. That switch has one job: when the throttle plate is closed, the switch closes and you have continuity between those contacts (contacts 1 and 2, written on the switch in small print). Contact 1 is the signal to the computer, and contact 2 is a ground. So you can set it up to make contact when the throttle is closed. Contact 3 closes a switch that connects 2 to 3 when the throttle plate is around the fully open piston, but LH2.2 does not use that signal unless your car has the "Turbo Plus" accessory.

So you can use that information to test it to your satisfaction. The Volvo Green Book in this car just says to check for it to click when the throttle plate closes and adjust it so it functions like that. With the car off, it's pretty easy to hear, but a continuity test should dispel all doubt.

Good luck.

 

my 740 is a turbo, is the turbo plus something rare that I probably don't have even though it is a turbo?

 

Yeah, turbo plus is rare. I found one on davebarton.com for $40 for my year car and figured I should give it a try. It was about a $1000 Volvo mod you could get at the dealer. It came standard in the later 780s that came with the turbo 4 instead of the PRV v6.

 

I'll have to check that out.


Well my issue was that I retarded the ignition timing 4-6 degrees when adjusting it. it's at 12-13 now and it runs way better. now when I pinch off the line from the iac to the intake the idle drops. it does do anything when you disconnect it ( the connector to the iac).

anybody with a known good iac, car runs well at idle at 750rpm, etc. I need one.