Mr. Kerry Chavez
#1
Mr. Kerry Chavez
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?
#2
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?
If you erase the code - does it come back?
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Check engine light
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?
If you erase the code - does it come back?
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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?
#7
Check engine light
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.
#8
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?
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?
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Check engine light
[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.
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.
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Check engine light
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.
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