I have a multitude of qs for anyone who can help: Firstly I have 91 740 b230f, with 226K.
1. I've read just about all the faqs on idle problems but didn't find just the right one. I'm not kidding, but I must have spent at least an hour and a half looking at my haynes and just staring, only to find there is no damn way to adjust that idle speed!!! My warm idle in drive gear is about 600rpm and causes the car to shake. Once the idle reaches about 800rpm, in neutral, the shaking is gone and otherwise car runs fine. What should I do?

2. I've just spent alot of money on complete mobil 1 line up of fluids: 10w-30oil; atf trans fluid; and gear oil. What has your experience been. I'm a huge fan of mobil 1 products and when it comes to oil, undoubtedly they are the best. My present and past porsches will vouch for that and I've used other synthetics too, eg, torco, castrol, redline, etc. (15w-50 mostly).

3. My radio has stopped working. The 5amp fuse seems fine. The cd security light flashes, but no lights, no sound, deadom only. Any tips.

4. Has anyone done a r12 to 134a conversion. Is the conversion kit (no compressor) enuf, to do the complete conversion? My system works but there is a leak bc it eventually leaks out in about 2 months. Ouch.

Thanks a bunch anyone.

I'll offer my advice on your idle problem since I've dealt with a lot of idle issues in the past.

First, verify that you have ZERO vacuum leaks. Everything downstream of your Air Mass Meter should be inspected. Pull your accordian tube and bend/flex it to find any holes or cracks. Trace every vacuum line that goes to the throttle body (there's not that many of them) and make sure they're in good shape. Replace them if you find cracks, crumbling, or the ends are getting hard/stiff. Small splits in an accordian tube can be temporarily fixed with tightly wound electrical tape with a high temperature rating. I just did this on my car about 2 weeks ago and I'm awaiting a new accordian tube to replace my slightly cracked one.

Second. Pull your IAC Valve and clean it. If this is clogged or stuck, you will not be able to adjust your idle at all. The Idle Air Control Valve is a cylindrical silver motor with a 3-wire connector attached to it and two 1" tubes entering/exiting from the top. On most cars, it sits just below the throttle body and is bolted to the side of a brace that runs from the engine mount to the underside of the intake manifold. The IAC Valve allows the computer to regulate the airflow at idle speed when your foot is off the gas pedal. They are made by Bosch and the label on the unit should have a part number that ends in 501, 520, or 516. Clean your flame trap and asscoiated tubing at this time also, since a clogged flame trap can increase oil accumulation in the IAC valve and hamper it's operation. Note: Some people may refer to the IAC Valve as a "Constant Idle Speed Motor." I believe that the term carried over from the days of CIS Injection, but rest assured, you do not have CIS Injection in your car.

Third. Verify proper operation of the Throttle Switch. Turn the large throttle cable disc/wheel and you should hear the switch 'click' just as it begins to move. Most 200/700 Volvos use a 3-position throttle switch that tells the computer when your foot is completely off the gas pedal, wide open throttle, and the area in between. Later models use a variable resistor to determine the exact throttle position when traveling through the 'in between area,' but don't worry about that unless you have to replace the unit.

Fourth. Set your idle speed (with a warm engine). I'm not sure which fuel injection system you have on your 91, but on my 87, 88, and 89 Volvos, the test connector is along side of the fender by the strut tower on the Left side of the car (US market vehicles). There are two terminals present, and you ground one of them (use the info in your service manual and don't ground the wrong one). When the terminal is grounded, the car closes the IAC valve and it allows you to set the base idle speed via the throttle body thumb wheel screw. This is located on the bottom-front of the throttle body and has a Black thumb wheel that points towards the Left side of the car. Using your tach, set your idle speed. Remember, you must have the test terminal grounded, or the car will try to automatically compensate for the changes you are making by opening and closing the IAC Valve. You may need to clean the throttle body to acheive stable results. This can be done with a strong aerosol carb cleaner and removing the thumbwheel completely and spraying the passegeways clean. Also be sure to clean the areas around and on the throttle plate itself to prevent binding or restricted operation. Ideally, this can best be accomplished by removing the throttle body from the intake manifold (3 easy bolts), but reattachment requires a replacement gasket and possibly re-calibrating your Throttle Switch position.

Unfortunately, the Haynes book does not cover US market cars past 1988, and I wish you the best in accomplishing the task of setting the idle speed on your '91 (hopefully it's the same procedure as the earlier vehicles). You may want to consider investing in a few of the Volvo Green factory service manuals to complement your Haynes manual. I've bought several from eBay and Skip Albright is a great seller (and a board member). Also, I've found the 240 Haynes book to be much better than the 740 book and it might be a worthwhile investment. Yes, there are differences, but many similarities also exist.

Also, to answer your Question #3. I'm assuming that you have some sort of aftermarket stereo installed. Take a Volt Meter and check the voltage on your Constant Power Line and your Switched Ignition Line. Look for an in-line fuse installed on one or both of them that may be burned out. If no fuses are present and power is not available, trace the wiring back on the dead line until you find the problem. Remember, always replace fuses with their proper sizes. Don't put bigger fuses in places that were intended for a smaller fuse unless you enjoy dealing with electrical fires.

Lastly, if you still have a quivering engine after getting the idle properly set (and your mixture is correct and not missing, etc), look into changing your engine mounts and the transmission mount as prevously mentioned. My engine quivers a bit more than I'd like it to and a new set of mounts will be installed soon. Also, if you're running Platinum plugs, swap them for either the OEM Volvo plugs, NGKs, or Bosch standard plugs (although, based on reports from others, Bosch plug quality seems to be going downhill after the move to India). Platinum plugs have a higher resistance than what the ignition system is designed for and you will have poor results with them.

God bless,
Fitz Fitzgerald.
--
'87 Blue 245, NA 228K
'88 and '89 780 project cars.

The shaking will probably be corrected w/ new (use only thehydraulic, like OEM were) motor mounts.

Make sure the micro switch on the throttle body clicks when you go just off idle. You can hear this with the engine off and by moving the pulley on the throttle body. This can be adjusted w/ the allen screws in the side. This switch evens out the idle by signalling the computer.

I also had a bone shaking idle on my 90 turbo wagon. I replaced both engine mounts, and the transmission mount,as they were sagging badly. I was amazed at the difference; at idle, and at highway speeds. Check the faq's, about determining if your mounts are worn, & if so consider replacement.

My 1990 134 conversion went great with the volvo kit.

My friend had a 1991 940 with a terrible idle. Turns out it was a bad transmission mount that caused the vibration to be pad the idle was actually ok.

hope that helps.

hawkeye

I have not had to reset the idle speed on my 89 745 TIC yet but have done so many times on my 84 245 TIC. The proceedure was to disable the CIS system by grounding the connection by the fender (see a wiring diagram or spec sheet), adjusting the idle with a GOOD tach and the idle speed control adjustment at the throttle plate area, and ungrounding the CIS connection. The CIS would then pickup the new idle setting and keep the idle just a bit higher (about 50 rpm) than what was set. The sensing of the new idle speed was automatically done by the CIS when the ground was removed and the engine was running at the new idle speed. I would imagine that the 740 system is set the same.

Answering backwards ...

4. I've done a R134 conversion on my '86, and yes, a conversion kit is more than sufficient. Most likely cause of leaks are old o-rings anyways. IMHO, replacing the receiver/drier is a must for good performance.

3. Sounds like there's no voltage on the ACC circuit. If it's an aftermaket stereo, usually there's an inline fuse in the back. Pull the unit out and check if that's blown.

2. Mobil 1 is good. I use it in my '91 ... 203k+, still original turbo.

1. Vibration is not just a consideration of idle speed. Something must be mismatched for such to happen ... usually, it's in the form of a small air leak. Check for cracked vacuum and intake lines.

-- Kane ... not all the solutions, but some, at least.
--
Blossom II - '91 745Ti/M46 ... Bubbles - '74 144GL/BW35 ... Buttercup - '86 245GL/AW70 ... The Wayback Machine - '64 P220/M40

For the A/C conversion ,make sure you also get a variable orifice expansion tube. It will improve the cooling by about 5 degrees.