newbie hi/props & another idle prob. '94 850 w/340,000mi

Post by **Wagonizer** » 28 Jun 2007, 15:21

Hi,

First, hello and I'm happy this site exists. I'm new to new Volvos (I had two 122s a 15 years ago). I've learned a lot about my new car in the past week. THANKS (also I donated). I just got a '94 850 wagon with 340k miles on it a couple weeks ago. It was dealer maintained. Its a 5 speed, is in beautiful shape and was cheap. The car feels great (especially after the torture chamber on wheels I used to drive (an '87 ford Bronco II). It has a few little mileage plaques on the grille. Using this site I was able to confirm and fix my first crippling problem (a bad cam position sensor), re-cap my fuel pump relay (I thought this was the problem before I got the CPS code and had intermittent stalls) and wired my i pod into the stereo. ROCKIN'!

I've been having pretty constant idle speed oscillations from 500-1500 rpm in 15-30 second cycles when it warms up, it sometimes stalls when first warmed up then starts after 30 secs. No problems driving. The idle until being warmed up is very smooth and when I put the AC on the idle is basically stable around 850. Unplugging the MAF sensor causes the motor to race. Unplugging the idle valve cause the idle oscillations to happen faster. My generally awesome (non-volvo) mechanic seemed to be pretty sure it was the Idle control valve.

I did a search on the forum and came across the nice idle valve cleaning thread:

https://www.matthewsvolvosite.com/chat/p ... highlight=

I gave the valve a good cleaning as suggested but the same problem persists. I'm hesitant to buy a new idle control valve because they're so f&*&king expensive. I've read a lot of posts and this usually doesn't seem to fix things. I've also tried to follow all the vacuum lines (including the elusive elbows in back of the steering pump) to search for a leak and haven't found any glaring problems. Though I do notice what seems like a small suction hiss in the vicinity of the serpentine belt (not sure if this is normal).

Summary of symptoms:

stable Idle when cold

idle sometimes slows to stall when warming up without responding to accelerator as it slows, then starts after 30-60 secs

idle oscillates when warmed up

idle with AC great (stable) when warmed up

no problems driving after the initial warm up stall

So far I've:
checked for vacuum leaks, replaced cam and crank sensors (as per codes), cap, rotor, plugs and given the idle valve a CRC enema

ECU clear with no codes at present .

I'm contemplating MAF and idle air valve swaps with junkyard components, and maybe a throttle body cleaning or a new flame stopper but don't really want to waste time or money. Maybe I should wait for a code to show up.

So does anyone have any ideas or tips? If it was a little less pronounced I'd forget about it. Maybe I'll do that anyway.

Thanks so much in advance and sorry for the long post.

Bradford

Post by **Ozark Lee** » 28 Jun 2007, 20:20

an '87 ford Bronco II

Had one. The handling was like driving a phone booth.

re-cap my fuel pump relay

Did it work for you? It sure worked for me and I think it will fix any relay out there. I'm proud of that one.

As far as the rest of the stuff goes, you are on the right track for sure and kudos to you for getting this far. Double (no, triple) check the vac lines and also check the throttle body. Just a little crud in the throttle body can cause the grief you describe. Also make sure that the crank position and cam position sensor wires are well clear of the coil wire or any plug wires.

You are 90% there and you will do fine.

...Lee

Free2drive! · Post by **Free2drive!** » 29 Jun 2007, 14:20

Hello

Could it be the engine coolant temperature sensor? If the car idles steady when cold but not when warm perhaps the ect is sending irratic signals to the ecu causing the idle to fluctuate, not sure but when the a/c is on then the fan runs continuously bypassing the ect signal?

Are there any codes from A7?
Matt

Post by **Wagonizer** » 29 Jun 2007, 18:33

Hi Guys,

Thanks a lot for the responses and encouragement.

Had one. The handling was like driving a phone booth.

ha ha ha
Driving a phone booth can be thrilling but it gets old fast and then I kept driving 'em for 8 more years. Cheap parts , could haul lots of stuff and chicks dig em. One thing I've noticed since driving the Volvo is that people don't give me breaks as much (changing lanes, merging, etc.) and cut me off more. Also the oil change place I went to for years asked me for the first time if I wanted to pay a few bucks more for "bottled" oil that the oil that came out of the hoses was recycled. This really pissed me off. Now everyone thinks I'm a yuppie. Oh well. Now I'm a comfortable whatever in my fancy wagon.

The fuel pump relay re-cap seems to be fine. Great fix! I thought this was a good place to start as it seemed like a typical problem and an easy fix before I got hip to code reading.

Since my last post I quick cleaned the throttle body and MAF sensor with the appropriate chemicals and there was no difference at all. I also blew out the flame trap with compressed air. As I finished the job my mechanic stopped by on his was home from work and gave the motor a listen and seemed pretty sure the intake manifold gasket is the where the hissing I mentioned in my last post is coming from. He thought this would be a good place to start before buying a new idle valve. A leak at the intake manifold seems to make sense as most of my symptoms seem to be the same as those caused by a vacuum leak according to other posts I've read. So my Volvo adventure continues.

I guess the next step is a new intake manifold gasket and maybe some crucial PCV parts as well as a throttle body gasket while I'm at it. I do have to pull the throttle body right? Should I do the knock sensors as well, do those go often? Should I try and tighten the intake manifold bolts just for the hell of it?

Any comments? Am I barking up the right tree here? I've checked every possible place for vacuum leaks, even pulling hoses and blocking off branches of the system and it makes no difference.

Looks like I'm going to finally have to buy a torque wrench as well. I also have to do the heater core as its got the interior smell and rusty dampness at the bottom of the plastic box in the dash. I hope this car stabilizes soon.
[/i]

Post by **MadeInJapan** » 29 Jun 2007, 19:26

Hey! Sounds like you're actually doing pretty well with this high mileage Volvo...good going! I wouldn't just blindly replace knock sensors...now, if you're getting codes for them, yes! You really need to read or have them read. As far as the intake gasket is concerned, if it's never been replaced it could have deteriorated just enough to give you that leaking that is going to be the same as a vacuum leak as you suggested. Let me suggest a tank of high octane gas and bottle of Chevron Techron to make sure your injectors are good and clean too. Good luck and keep us informed. A PCV replacement will do your car a world of good! www.fcpgroton.com is your friend for this.

Post by **Ozark Lee** » 29 Jun 2007, 19:28

As I finished the job my mechanic stopped by on his was home from work and gave the motor a listen and seemed pretty sure the intake manifold gasket is the where the hissing I mentioned in my last post is coming from. He thought this would be a good place to start before buying a new idle valve. A leak at the intake manifold seems to make sense as most of my symptoms seem to be the same as those caused by a vacuum leak according to other posts I've read. So my Volvo adventure continues.

Grab a can of starter fluid and spray (small sprays cause I've had big sprays get away from me on my Chevy 350 boat motor) in the area you suspect the leak. If the engine goes nuts when you spray an area, you found the leak. The intake manifold gasket is cheap but might I suggest that you redo the PCV while you are there. Getting the intake manifold off is the hardest part of that job.

1/4" swivel sockets are your friend.

...Lee

Post by **HareBall** » 30 Jun 2007, 10:24

Not to be hijacking a thread, but what is the best way to know if your PCV is starting to clog or is clogged? I haven't had any problems that I know of, but would prefer to not have my rear seal blow out from this.

Post by **Ozark Lee** » 30 Jun 2007, 11:01

Not to be hijacking a thread, but what is the best way to know if your PCV is starting to clog or is clogged? I haven't had any problems that I know of, but would prefer to not have my rear seal blow out from this.

The quick and dirty check is to stick a balloon on your dipstick tube, if it inflates the balloon you need to do the PCV service.

...Lee

Post by **Wagonizer** » 30 Jun 2007, 14:05

Thanks once again for the great tips.

I sprayed starting fluid around the thermostat where I'm hearing the hiss and sure enough then engine revved so the intake manifold gasket has to be the source of my idling problems.

Lee, do I really need 1/4" swivels? 3/8" are easier to find...

also:

Can I leave the throttle body on or should I go for a new gasket and cleaning?

Looking at FCP I'm wondering what the minimum amount of PCV stuff I can buy is. I'm thinking just the elbows that are hard to get to. (I'd rather not have to buy a $45 plastic pipe and a $30 plastic box that I can clean.) Does that pipe fail a lot? Do I really need new clamps. Are the ones that are there hard to re-use? Sorry about my cheapskate questions.

Any more pre-manifold pulling words of wisdom?

thanks in advance
Bradford

Trilarry · Post by **Trilarry** » 30 Jun 2007, 14:12

You are right you can clean the "Black Box" you can't reuse the clamps because they are the crimp type but you can replace them with ADEL screw clamps. I believe the hose is very necessary, I wouldn't go cheap on it.
Tri