So I decided to start a new post just for the smaller issues with my Volvo.

1. Surging Idle:
Idle surges from 1500rpms-2100rpms in a rhythm, it gets worse after the car has warmed up. If I don't touch the gas pedal it doesn't surge but if the car is starting to warm up and I touch the gas pedal it starts surging and does it a couple of times the returns back to normal idle. If the car is completely warmed up and I touch the gas pedal it surges and doesn't stop until I do one of these 3 things, turn car off and restart it, unplug the IAC and plug it back in, or if I cover the hose coming from the air box to the IAC(this doesn't make my car die or almost die either). When I do any of these things, it idles fine until I touch the pedal and then it's back to surging again! What could this be? I hooked the valve to the 12v battery and could hear a distinct clicking when I hooked it up and unhooked it, I did it several times in a row and it worked every time.

2. Bogging In Gear:
When I put the car into gear(R, D, 1, 2) the car bogs down and begins to vibrate/shake like its going to die(but it never does), rpms are at about 500 or so. When I put it into park the idle increase about 300 rpms and the returns to regular idle, isn't that what it should do when I put it into gear too? Or am I wrong?

3. Mystery Thud:
When I am cruising and the car starts to coast or when it starts to accel there is a loud "thud" type of noise, I can't tell if its coming from the front or the rear end, may be worn anti-sway bar bushings up front but like I said it kind of sounds like something from the rear end, but I'm not sure, sorry for being vague on this part, I'll try to listen for it better tomorrow to pin-point it.

4. Slow Power Windows:
When I roll the front drivers side or passenger side window down it goes strong and steady until about halfway down and then they start to go really slow and bog down, like they are binding but they aren't(drivers side is worse and takes forever to go completely down). The rear windows roll down just fine.

5. Wipers stay on:
If I have the wiper intermittent relay in the wipers stay on slow if the switch is on start II, if I take the relay out the wipers work except in intermittent position(of course) but the wipers won't go back to rest position when I turn them off(I've tried a couple "known good" wiper relays and the wipers still do the same thing).

I think that's all of my annoying little quirks with the car as of right now, thanks for any of the help/advice/comments I get!!

-Dillon

 

1 and 2 are probably related, it sounds like your idle is bunged up.

when you touch the gas pedal, you are no longer idling, so I'm a bit confused with your description of 1.. its running WAY too high if its at 1500-2000 rpm with no gas pedal.. check the throttle mechanism and cable, make sure its fully returning home and closing the throttle idle switch. check the switch with a ohm meter (0 ohms closed at idle, infinite ohms off idle) its very possible your throttle body is gummed up and not closing fully. you can remove and clean it with throttle body cleaner spray and a small brush...

ideally, it should idle at a rock steady 750 rpm. if you put it in gear, or the AC compressor kicks on, it might dip a bit, but it should come right back to 750 rpm. when the engine is cold, its more like 900-1200 rpm.

warm up the car, in park with everything shut off (no lights, stereo, ventilation fan and AC off), then shut the car off, unplug the IAC and turn the car back on. now, it should settle in on an idle around 500-600. if it doesn't, you make darn sure everything is good, no air leaks, no broken vacuum hoses, and if its all good, you adjust the idle per the factory procedure. remove and clean the idle air control valve with throttle body/fuel injection cleaner spray... replace both its hoses unless they are already brand brand new. reinstall it all, hook it back up, and it should idle properly.

 

your power windows probably need new regulators. you might be able to repair your old ones via new plastic slider pieces, cleaning and lubricating the tracks, and cleaning/lubing the motor gears, but its really easier to just replace them and get another 20 years.

the thud/clunk could be bushings in the rear, or a broken shock... it could be the driveshaft center bearing and its rubber mount (but that usually goes rumble/thudthud), it could be signs of a worn transmission or differential.

it would take me awhile with the wiper wiring diagram to figure out what sort of failure mode would match your symptoms. the wiper motor assembly has a 'I'm not home yet' switch contact in it which is powered all the time, so when they are shut off in the middle of a cycle they keep running til they get home.

 

Sorry, I could understand how its confusing after I re-read it. When I say I "touch the gas pedal" I mean I rev it up to 3000 rpms or so and then it starts idling crazy, going from 1500 rpms to 2100 rpms.

I cleaned the throttle body when I installed a new intake manifold gasket the other day because that's where my vacuum leak was coming from. It would be very smart if I would re-adjust the idle though, because the last time I did it by the manual was when I had the bad intake gasket on it, so that may be why its idling so high, it idles about 01300 when cold, and 900-1000 when warmed up(I think). So it pretty high, I didn't think anything about having to re-adjust it though, thanks for that!

I'll also check the throttle switch, its good to know how to test it, thanks again! haha

And when you say the IAC hoses be "brand brand new" does that really mean they should be that new? What I mean by that is the ones that are on it are(I'm guessing) the original ones, but they look really good and I haven't seen any signs of rot or cracks or any leaks from them, but should I still replace them anyway?

And again thanks Pierce, your the man!

-Dillon

 

well, if they are still elastic and go on and off the fittings without cracking, then I guess they are OK. but my experience is, 20 year old rubber should be replaced.

 

And I just seen your other reply, I may just try cleaning all of the window mechanism parts until I can get 2 new regulator or mechanisms, have to do some price searching any everything, but it isn't a major problem yet.

Ohh ok, is there anyway to diagnose the transmission and diff to make sure their fine just so I can get the biggest worries out of the way? Or do I just need to take it to a transmission shop and get them to check it out? To add with this problem, when I'm driving(w/o cruise) and let off the gas completely it does the "thud" and when I hit the gas again it does the thud and if I'm not mistaken the front kind of raises(when I hit the gas) and lowers(when I let of the gas), I'll pay better attention tomorrow and let you know for sure.

Could the "I'm not home yet" switch be somehow shorted out with something in the intermittent circuit causing them to stay on only when that relay is in?

Ohh and also to add to the idle issues, its my understanding that when the throttle blade is closed that the IAC should have 12v and when the throttle blade is open that all power should be cut to the IAC right? Well when I tried this test with the key on start II, the IAC plug seen a constant voltage whether the blade was opened or closed. Maybe that will add a little more information on it.

Edit: Ok, I didn't know if there was just something I didn't know about those hoses or something is why I asked, and yes it would still be a very good idle to replace them honestly. I just haven't put it on my list of things to do yet haha.

Thanks!

 

careful with that price searching, its pretty easy to end up with chinese junk parts. not saying everything made in china is junk, but they sho' do see to make a lot of it.

the front going up and down with the throttle is pretty normal automobile. but, you should check your front strut towers... pop the hood, on each fender, the big nut thats sticking through the center of the hump on the fender with the big rubber washer under it? thats the top of your McPherson Strut, and that big rubber piece wears out and tears, then the strut can flail through your hood. if its got bad cracking and the strut is flexing around, the strut mounts should be replaced immediately. this requires removing the struts, so its smart to use new ones as yours are undoubtably worn out. for the stock ride, get Boge/Sachs, for a sporty stiff ride go Bilstein HD.

 

Re the slow windows, no need to replace the regulators unless they leave air gaps when closed. All a regulator is, is a scissor type thing and it's only failed when the hole gets enlarged... Just open them up and lube them, clean them, etc....

 

Well I say goes up and down, but it isn't a smooth up and down like most vehicles I've driven, it like a pop or plop up and a pop/plop down and there's also a slight vibration maybe a rumble when accelerating so its possible that the center support bearing is on its way out, any reliable way to check this? Should I just grab the driveshaft and see if theres any play in or will that test work for this car? And I checked and one of the strut tower bolts was loose, maybe 1/16 or 1/8 of an inch so I tightened it down, but it still didn't make a difference, or none that I could feel. I didn't see any tears or rips in the rubber mounts but they seem awfully soft and I could see them move up and down excessively when I bounced on the bumper, so that and the struts are some of the next things on my list. Have yall heard anything about Sensen parts? They have the strut mounts for $16 each(which is by far the cheapest) but I'm not going to buy them if I have to replace them in a month...haha

And thanks lev, I really didn't want to have to go threw the trouble of replacing the regulators, I didn't have time to do much today, but tomorrow I'll get to cleaning and greasing them. That also goes for adjusting my idle, which is veryyyyy desperately needed!!

I let yall know what happens tomorrow, thanks for the help!

Ohhhh before I forget, is there any way to make or rig up some kind of shift linkage bushings until I order mine? Maybe using a tire side wall or something like that? Remember I'm in Alabama and redneckery runs in my blood, so I'm all about a cheap fix hahaha.

 

Alright, so I got around to some things today, I'm pretty sure the driveshaft center support is shot, if I grab it I can move it 1/2 inch in every way, and can see that the rubber is clearly gone and if I move it hard enough I can hear a "thud" sound.

I didn't get around to looking at the window regulators though, the food got finished quicker than I thought it would haha.

Now for the most frustrating, the idle adjustment. I set everything according to the manual. While it feels like it revs and drives better, there's still some issues that are making me want to just scrap the car haha. When its idling at about 700-750, its slightly fluctuating maybe 50-100 rpms up and down when its warm, it seems little worse when its cold though, its just enough to be able to hear it and its annoying. When its warm and I do a quick rev the idle still surges like it was doing it before but now its a slower type of rev, still goes from 1500-2100 in a rhythm. Needless to say I'm frustrated... If it was the IAC wouldn't it surge like that all the time? What would make it surge only after I rev it up when its warm? Thinking about taking it to the Euro mechanic after work tomorrow since I'll be up that way and get his opinion. But right now, its off to searching the old internet for any possible theories or solutions!

Edit: Could it be the O2 sensor? I guess I should ohm it out tomorrow and see what readings I get, since its temp related and only does it after I rev it up...Makes a little bit of sense

Anyway, Happy Thanksgiving y'all, hope it was a good one! I know mine sure was!

-Dillon

 

the idle air valve is only used when the throttle is at idle as sensed by that idle position switch on the side of the throttle body. WHEN its at idle, then the ECU monitors the engine RPM via the timing pulses it gets from the ICU, and if the engine is too slow, it pulses the idle air control valve open. the IAC isn't opened up all the way steady, its pulsed open with a variable duty cycle. too fast idle == shorter pulses, too slow idle == longer pulses. with the IAC unplugged, a fully warmed up engine should idle at 500-600 rpm, with it plugged in, 750rpm. both the throttle body and IAC should be thoroughly cleaned and degummed for all this to work right.

 

Ok, I get what your saying, but it doesn't surge when the car is driving or during the rev cycle, it only does it after I let my foot off the gas and it tries to return to regular idle. I will say this though, if I unplug the IAC the idle doesn't surge when I rev it up, it maintains a steady 500 rpms. If I ever go on a drive, I usually just unplug the IAC after the car has warmed up, because it doesn't run good cold with it unplugged.

Edit: While I didn't find any suspected vacuum leaks at idle, could revving the car up create a leak somewhere that couldn't be found at idle? I'm going to get some injector seals tomorrow just for good measure, because mine looked pretty dried up last time I had the intake off.

Edit: Edit: I'll also go through cleaning the throttle body and IAC again after work tomorrow.

 

Also found this while searching around and the guy has the exact same issues as me, but his solution is different than mine is, because I just replaced my intake manifold gasket last week and my problem is still there... but this also would kind of make sense that maybe a fuel injector seal is leaking without me noticing it...

940 '93 940 Wagon Non Turbo - Another thread concerning Idle Woes (TL;DR WARNING) - Turbobricks Forums

 

Ok, so heres a small and quick update. I replaced the injector seals, and it idles much better when warmed up, but on cold starts the cars idle doesn't sound that great to me, it isn't smooth and just sounds rough. I went ahead and finally did the diagnostic test mode 3 which test all of my components(injectors, iac, coolant fan, fuel pump, etc.) Everything came on and worked like it was supposed to except for the fan. The fan doesn't act like it wants to turn on, I didn't hear the relay click or anything. I tested the relay and everything checked out fine there, the fan only turns on high for a few seconds during stop and go traffic. While it isn't a big problem because the car doesn't run hot at all, it just got me curious. Also as far as I can remember the fan doesn't turn on when I turn the a/c on either. What are some other things I can try, and are there any other ground points or anything I should check?

Edit: Also if the fan just happens to be running and I turn the car and ignition all the way off the ran continues to run for a few seconds, I was under the impression that when I turn the ignition off the fan should also turn off.

Another thing, I went to clean and lubricate the window regulator and while I had the door panel off I rolled the window down and about half way down the door metal on the inside buckles and I think somehow thats making the window go down slow the rest of the way? I didn't feel any looseness in the regulator anywhere but where its riveted to the door I could see it the rivet was loose. Would that make it go down slow?

If I confused anyone just let me know and I'll try to be more clear haha.

 

what do you mean by 'the door metal buckles' ?

slow regulators are usually due to both the sliders binding because the grease has dried out and the plastic sliders are worn, and the motor dragging because the gear mechanism grease has dried out. you pretty much have to take them out to service them, which means new rivets... by the time I do that, I'd as soon put a brand new one in, they aren't that expensive. I replaced my drivers window which had issues, and its 2X as fast as the other 3 now.

 

Well as far as that, the sliders are sliding just fine, none of the grease had dried up that I could tell, when it reaches the point where it slows down (about halfway down), the metal that the regulator bolts on to kind of pops out, it looks flimsy. It rolls up fast, and it rolls down fast half the way, but after that halfway(maybe a little more than halfway) its just really really slow.

 

Also would a bad ect/wiring be causing my fan not to come on during diagnostic test mode 3?

 

re your fan... unplug the fan relay. it has three connectors, A, B, C. find the 1A pin with the red wire, and jumper it to the 1C pin with the green wire, and the fan should come on slow. jumper 1A to 2C (also a red wire) and the fan should come on high.

if low doesn't work, follow that green wire to the fan, but I'm guessing the fan itself is DOA. If low DOES work, then the issue is probably with your fan relay.

the control signals to the relay are pin 1B (blue-black) is grounded for low speed, and 2B (white-black) is grounded for high speed. 1B (blue-black, low speed) comes from pressure sensor 7/38 and from LH2.4 ECU pin 10, either of these can ground it. 2B (white-black, high speed) comes from pressure sensor 7/40 and ECU pin 11.

the two pressure sensors are on the AC condensor manifold, 7/38 is the grey one on the end, 7/40 is the brown one in the middle.

and thats all folks! :-P

wait, one more. the fan relay pin 1A is the red wire to power, which somewhere splices to a grey wire which comes off a inline fusible link to the battery +

 

afaik, the ECT test 3 ignores sensors, the ECU directly controls the fan relay via the wires above.

 

edit; CRAP, I described LH 2.4, not regina

regina doesn't work quite the same way. the high speed is driven by a coolant temp sensor plugged into the upper right side of the radiator. low speed is controlled by the AC low pressurestat described above.

I'm not even sure if the regina ECU is connected to the fan, its not shown as such. since its not connected, ETM#3 can't do a fan test.