I have a 1993 Volvo 940 non turbo with rex regina ignition and the check engine light is on. The codes suggest that the idle air control valve is bad. The never really had a very smooth idle but I don't have any problems with stalling or difficulty starting. I've looked for an idle air control valve but they're not to be found. Is the valve really the problem or is it electrical?

 

The first step with a code is not to replace the part the code is pointing to - the first step is to diagnose whether there is actually a problem with the part - is it plugged in, are the connections good, is there power going to the right places, is it sticking, can you artificially make it work (say unplug an injector, does the idle speed drop down then the idle motor corrects the idle speed?)

If you erase the code - does it come back?

 

My friend Goldenblock here! If you do happen to need the part. I have over 30 regina iacs!!

Clear codes first see if it comes back.
then possibly clean valve
If they dont work out i got your back shipping nationwide!!

 

Thank you for the information. I'm at a friend's house today working on my car. He's really good with cars.

 

Hi Goldenblock. I'm SilverBox. Thank you so much for the reply. I will be testing and reading codes today with a friend. What is your location? Do have any other parts for my car?

 

I have everything for regina and most non regina cars.
except body. Engine and transmission.

 

So I've rechecked the codes and tried running the car with an injector disconnected. The car idled rough but the rpm didn't change. I also tested the air idle control valve. I tried testing the knock sensor but I had the meter set wrong so I need to retest it. I tested it because one of the codes suggested that there was a missing signal from the knock sensor. Also the car sometimes stalls.

 

If the idle speed stays the same with an injector disconnected, or drops slightly and immediately recovers - that means your idle valve is working normally, it is doing what it is supposed to do - keep the idle constant. Knock sensors will not make the car run bad -

For stalling I would make sure the throttle plate is clean, that the "base idle" is high enough that the engine stays running with no air going through the idle motor hoses, and electrically the fuel and noise suppression (if equipped) relays have no cracked solder joints. Also basic ignition stuff - what does the inside of the distributor cap look like? Plugs wires in excellent condition and not arcing?

 

So yes the ignition parts were replaced less than a year ago. The car also recently has developed a problem with starting. The basic electrical has been tested twice in the last week and the battery, alternator and starter are all working fine.

 

So any idea? I'm thinking of testing the ignition switch as well as checking the throttle plate as suggested and a friend recommended testing the fuel pump relay as that sometimes causes the engine to stall.

 

[QUOTE=SilverBox;497186]Hi Goldenblock. I'm SilverBox. Thank you so much for the reply. I will be testing and reading codes today with a friend. What is your location? Do have any other parts for my car?[/QUOTE
Hi again Goldenblock. SilverBox here again. If I order the parts from you how soon will they arrive? Other than engine parts I need other parts as well. Do you know any good resources? I need a grille, front seat belt buckles, an exhaust heat shield and possibly some lenses for the left front door and reading lights.

 

The car also does have a relatively rough idle that does not hold a very consistent rpm.

 

If you have "rough idle", it's probably an engine misfire which if not caused by an obvious tune up item you may want to do a compression test to eliminate bigger issues such as a head gasket, burned valve, etc.

 

[QUOTE=SilverBox;497402]Try Voluparts.com in Atlanta

404-352-3402

 

Yeah. I haven't done a compression test but I'm pretty sure after 28 years and 313,700 miles the compression has probably dropped somewhat. I've also been told by two mechanics that the engine has piston slap. One mechanic said it needs an overhaul and the other one said all cars like mine have piston slap. My car needed a smog check and because I haven't figured out why the check engine light came on I decided to follow the advice of one of the mechanics and disconnect the battery to make the check engine light turn off. Luckily the car passed the smog test but I'm still wondering what's going on. I'm sure by now the car needs everything but I'm not sure it's worth it to try to fix everything.

 

The compression may not be bad, miles notwithstanding. Piston slap is common, means that the engine has may be another 100-200K miles of life left, it will sound like a diesel, worse when cold. An occasional CEL means nothing, as long as it stays off, it's OK...

 

Yes i have grills heat shields injectors plug wires fuel pumps srarters iacs ecus alternators throttlebodys etc etc.

Voluparts are good but they are stuck in the 80s!!! Bad customer service.

We can ship as fast as you need it!
Just let me know brotha
Goldenblock!!!

 

Thanks Lev. Thanks Goldenblock. Do you think the starting problems are caused by a bad ignition switch? Can you send some prices and an ETA Goldenblock? I also need the driver's side sun visor including the attachment.

 

I have replaced hundreds of bad ignition switches, 240s,740s, 940s, 850s, - none of them for a starting problem - all of them were for problems with the accessory position. 960s, s90s used a different brand and did not fail the same way.

 

Hmmm. Bad wiring?