I am looking for a good source to buy a new or used IAC valve for a 1990 Volvo 740GL. [P/N 1389557] The only place I could find it was at fcpgroton.com and they want $202 for it. I was hoping to spend a little less than that seeing as how I only paid $200 for the car.
What is the best way to test an IAC valve to see if it is faulty. I took mine off and noticed that the plastic electrical connector area will rotate. When it does, there is a crunching noise inside the part. I assume that this connector should not be able to rotate unless all of the electical connections are also rotating with it inside the body. Is there a way to put power to the valve to see if it will actuate? If I hook a multimeter to the two terminals, what resistance should it read?
There isn't any easy way to test an idle valve except by substitution. And a valve that works fine on one car may work poorly on another, and vice versa. It sure does sound like yours won't work properly on any car, it shouldn't rotate like that. However, that may make it easy to take apart and clean.
As far as the type, I think it is a regina, based on the part number for the IAC. I only make this assumption because on one of the part sites I was at, there is a different part number than what is on my IAC, and the site said it was for Bosch systems.
It's kind of a long story. I tried to keep it as brief as I can, but I thought some points may be relevant to the overall problem.
When I got the car, it had been sitting derelict for 16 months. It had 176000 miles on it.
The only problem that I was told it had was that the catylitic converter was missing. It had about 1/3 of a tank of old gasoline in it, so I put in a couple of bottles of fuel injector cleaner. I removed the spark plugs and sprayed some anti- seize cleaner down in the spark plug cavities. I then jump started the car. I got it to start by spraying carb cleaner and starting fluid directly into the throttle body. At this time, It was idling at about 1500 rpm, but it was running pretty rough, and loud because of the missing cat. I pulled it into my garage, and went to work on temporarily fixing the exaust. I bougt a cheap exhaust repair pipe and clamped it in place where the cat was. The cat had been cut off just above the flange. Actualy, The flange was still there, but it was cut about half way through. I had to cut it the rest of the way, but I saved it just in case it is needed in fhe future.
With the exhaust patched, I was able to get it started again, but it would only start by spraying the starting fluid and carb cleaner directly into the throttle body. It was still idling at about 1500 rpm, and when I put it into gear, (automatic trans) it would lurch pretty good. I took it for a spin around the neighborhood. It seemed to run OK. It had good acceleration, and the engine seemed to run well. I drove it about 6 miles and stopped at a carwash. I had to start it again by spraying starting fluid and carb cleaner into the throttle body again. I then got it onto the higway and it made it up to about 90 MPH. Everything seemed fine. The only problem I saw was that the overdrive switch on the trans seemed not to be working and it seemed to hang out in 2nd gear a little to long. I drove it about 9 miles on the highway and then exited to take it back home. This is where it all started to go downhill.
At the exit, I stopped at a gas station. Since it still had about 1/4 of a tank of bad gas, i figured that I would fill it up with premium to try to flush it out. I filled the tank with 92 octane and then tried to start the car. I again had to spray carb cleaner and starting fluid in the throttle body to get it started. This time, however, the idle had jumped to about 3000 RPM. I couldn't even get under the hood to try to adjust it, because of the wind coming from the fan. I stopped and started it several times the same way, and each time it idled at 3000. I was about 7 miles from home. It was about 10 PM and the road I was on led straight to my house. It is a country road and was pretty deserted at this time. I dropped the car into gear and began the journey home. About halfway there, I noticed that I forgot the latch the hood. I pulled over to close it, and when I put the car in park, the idle was surging up and down between 1500 and 3000 RPM. I closed the hood, got back in and limped the rest of the way home. I could not take my foot off of the throttle. It seemed like it wanted to stall if I did that. I got it back home and into the garage. Where it stayed for a few weeks, untouched.
I then discovered the brickboard and read many of the postings there. It was there that I realized that spraying carb cleaner into a fuel injected engine may not have been wise. I also learned that my problem nay have been a dirty throttle body. I went to eeuroparts on the web and bought a new TB gasket and new plugs and wires. I removed the throttle body and TPS and cleaned the throttle body. I adjusted the throttle position screw and the TPS lilke the instructions on the brickboard FAQ said. I then replaced the throttle body and started the car. It started ok, but it idled at about 2500 RPM. I loosened the TPS and clicked it back and forth to make sure it was in the right position. In the idle position, it would go up to 2500. When I clicked it into the open throttle position, the idle would surge between 1500 and 3000 rpm in about 1 second intervals. I readjusted the TPS, and it was still idling at 2500 conistently.
At this point, the boneheaded mistakes were many. I went to do more research. I turned off the engine, but left the key in the on positon. When I got back to the car, several days later, the battery was dead. It was an old battery and didn't hold a charge well. I tried to jump it, but couldn't get enough juice. I then took the battery out of my Ford Ranger. I was anxious to get the car running again. In my haste, I hooked the battery up backwards. There was a horrible hissing noise as white smoke came from the ground cable on the alternator to the engine block. I quickly disconnected the battery. The only visible damage was that the insulation had melted off of the ground cable. At this point, I thought that the car was fried. I removed the ground wire, and inspected it. The only problem was the insulation. I wrapped it heavily with electrical tape, replaced it, and put the battery in the right way. I was able to start the car one more time. It still idled at 2500 RPM. It ran for about 5 minutes. When I put it into gear. the idle would drop down to about 1100 rpm. In neutral or park, it was at 2500. I shut the car off, removed the truck battery and left.
I then learned about the IAC valve from Mike F. This sounded like it might be a winner. I bought a new battery and installed it. Unfortunately, I could not get the car started to thest the valve by restricting the hose. I pulled the vavle off the car, and inspected it. I sprayed WD40 into it to clean it. Not much dirt came out. It is the type of valve that cannot be dissassembled. When I was wiping it off, I was holding it by the plastic connector end and twisting a towel around it with my hand to dry off the rest of thw WD 40. This is when I noticed that the connector was twisting in the valve body. When this happened, there was a grinding noise in the valve. I figured that it was the electrical connections tearing loose. Since there is no way to dissassemble the valve, I have no idea what's happening inside. I reinstalled the valve, but the car still won't start. At this point, I have no idea what the problem is. If I spray starting fluid into the manifold, It will turn over and run until the fluid is burned off. It seems now that there is no fuel going to the engine. I don't know if this is a clogged fuel line, a bad fuel pump relay, or a bad ECU. All of the fuses are fine. It's a bugger getting to the relays. I haven't checked them yet. How do you test them?
Could I have done more damage than I thought by putting the battery in backwards? I was able to get the car running one more time after doing that. The only other thing that I noticed since then is that the radio speakers don't work. The radio powers up and receives stations, but no sound comes from the speakers, even at max volume. What is the radio noise suppression relay, and could it be affecting this? If the connectors are bad in the IAC, could this keep the fuel pump from turning on?
If you read this entire post, thank you for your patience. I hope I didn't piss anyone off. I am not ready to give up on this car yet.
I can email pictures of the engine, If this will help.
That was a good post.. the more information the better. That way, someone can ask more useful questions of you. Expect a more complete followup later on this evening.
I had a lot of luck today. I played around with the IAC some more. I looked in my Haynes manual and it had a cross-section view of the valve. It looks like maybye the whole inner assembly may rotate inside a solenoid. I sprayed some lubricant inside the valve to make it easier to rotate. This made the "grinding" stop when it rotated. I did notice a click about every 180 degrees of rotation. The manual said that the resistance betweent the two terminals of the valve should be 4 ohms. I rotated the connector until it clicked. I checked the resistance and got no reading. I rotated it agan until it clicked. When I checked the resistance, I got around 4.1 ohms. This was close enough for me. I reinstalled the valve.
I still could not get the car started. I did some more reading in the Haynes manual. I thought that the trouble might be the fuel pump. I took out the fuel pump relay and jumpered the connectors that start the fuel pump. I could hear it running. I replaced the relay and tried to start the car. To my amazement, it started, but stalled right away. I started it again and kept it running by giving it some throttle. I was able to keep it running, but now, the idle is at about 500-600. I like this better than 2500, but it seems to be on the verge of stalling. I'm not sure whether or not I fixed the IAC. I don't know if it is funcitioning, or if it went from being stuck open to stuck in a more closed position. When I remove the hose from the IAC at the manifold, the idle jumps back up to 2500 RPM.
One thing I did notice: When I remove the vaccuum hose from the pressure regulator on the top of the manifold (I think it is the pressure regulator) I get a better idle. It goes up to about 700 RPM and the engine runs smoother. Is it possible that the pressure regulator is faulty, or does it need cleaning? How is it disassembled?
Not suggesting this is your problem, but don't always be fooled by hearing the pump running, the fuel pump failed in my 240 Turbo a few months ago and the pump sounded just fine, just that internally the impeller had broken off the nubs on the motor shaft that engage it so the motor was buzzing away but no fuel was being pumped.
The pressure regulator is one of those things that is cheaper and quicker to replace than it is to test. Based on your report, if this was my car, I'd put in a new regulator, then (assuming it's clean) set the throttle plate and throttle switch, which I'm not 100% sure how to do on a Regina equipped car, although I think it's the same as on the LH2.4 models as explained at:
The first step is to make entirely sure what type of fuel injection you've got. If it's a Bosch setup, you'll have a cylindrical coil, and an air mass meter (a large cylinder in the air intake path with a big flat electrical connector). If it's a Regina setup, you'll have a weird (square I think) looking coil and a MAP. I believe that the MAP will either be in the passenger compartment with a vacuum hose going from the air intake path, or the sensor will be in the intake ducting itself and will have a smaller electrical connector.
Yes. It sounds like you're not getting fuel at all. If it's the Regina, I really have no idea about the specifics.
With the relays (on the Bosch FI 240s at least) you can just jump the appropriate fuses to bypass the fuel pump relay (or get a test relay for the earlier 240s). Not sure with the Regina setup. Also, once you get the fuel pumps running, you can check for fuel flow. On the 240s it's simply a matter of jumping the two fuses.. or you could just convince the relay to do its thing with a toothpick or something.
If there's a radio suppression relay, perhaps that has gone bad?
The brickboard's 700/900 FAQ's fuel injection section has a few other good ideas (including a clogged fuel rail or fuel pressure regulator) worth checking.
It's definitely a Regina system. This really stinks because all of the regina parts are more twice as expensive, if not more, than the Bosch parts. For example, the fuel pressure regulator on FCPGroton is $37.03 for Bosch and $105.00 for Regina. Maybe its because they only have genuine Volvo parts for the Regina.
I think the problem is with the IAC. I disassembled it last night, even though it was made not to be disassembled. I ground off the rolled over end that held the connector in place. This allowed the connector to slide out. Both connections were twisted and broken. I soldered them back together and covered the exposed wire connectors and solder with a urethane epoxy. This will keep them insulated so they don't touch the sides of the valve body. I reassembled the unit and cemented it together. I took a 12V power supply and touched the tow terminals. The solenoid actuated the valve, which it never did when I tried this before. I am currently waiting for all the adhesives to cure. I will then put it in the car and test it. If if works, I saved $200 for the new valve.
Actually, I don't think it is the fuel pressure regulator. From what I've read elsewhere, if the diaphram goes bad, I should be seeing fuel coming through it. This is not the case. I think the idle is poor because the IAC is completely shut and the engine is starved for air. It runs fine when I give it some throttle.
I will keep you posted. I think I am getting close!
Yeah, I would be curious to see what's so special about the Regina FPR. If it's merely a different fitting or a different pressure, you would be able to use some sort of generic FPR quite easily.
Supposedly the FPR can fail in a way that would either completely inhibit gas from getting to the engine, or completely inhibit gas from returning to the fuel tank. Neither result would yeild reasonable running.
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