1990 740 Turbo Idle setting

n1cjs · Post by **n1cjs** » 18 Aug 2011, 08:33

I'm new to this group and this is my first question, so bear with me...

I have a (new to me) 1990 740 Turbo wagon that seems to have a very low idle. It shows about 600-700 on the tach. I have done a search (the best I could) to try and find out what the correct idle speed should be. What is the correct idle and how do you adjust it if need be??

Thanks, Chris

Post by **billofdurham** » 18 Aug 2011, 12:07

Welcome to Matthew's Volvo Site.

The idle speed for the turbo should be about 750rpm. Idle problems on these cars are often down to a dirty throttle body.

To clean the throttle body you need to remove it, spray it with a fuel injection cleaner, not a carburettor cleaner, and brush off any stubborn deposits with an old tooth brush. Refit with a new paper gasket, inexpensive even from a Volvo dealer, and see if it makes a difference.

Bill.

n1cjs · Post by **n1cjs** » 19 Aug 2011, 10:46

Thanks Bill. I'm picking up a can and gasket this weekend and going to start there.

Chris

kingsorder · Post by **kingsorder** » 20 Aug 2011, 17:53

i have the same car , just wondering if this solvo your problem ?

n1cjs · Post by **n1cjs** » 22 Aug 2011, 16:43

UPDATE!

I did not have time this weekend to do the fuel inj. cleaner cleaning job, but did however (i think) fixed the low idle I thought I was having.

This morning on my drive to work, I heard something under the car making a slapping noise. Ended up being a loose plastic shield. Got that tied up and alls well there. So while I was tinkering around, I thought I would look at the throtle body and see just what I'm in for. Well low and behold, there is a little screw on the front tward the bottom that looks like it has something to do with the throtle linkage. Well after freeing up the jam nut and about a half turn of the screw the idle went right up to about 750 and sounded much better.

What started this whole question for me is when I was at a light last week, the clutch fan kicked in and just about killed the engine. Now with the idle up a bit, where it should be, it will be interesting to see what happens when the fan kicks in next time.

I'll keep you posted.....

Thanks