[Slowpc]

Hey all... well ... i have just started to run into some trouble with the viggen (other than a little thing i will add to this post)

As the summer goes on ... it is starting to heat up here on the cape. A few weeks ago i filled up the a/c and now that is working great. Nice to have good cool air in the car when it is 96F out. Now... lately when i pull up to a light and put it into neutral, idle can be rough sometimes. Before (a month ago) it would drop a little bit, from its normal 900'ish rpm to 750ish and the computer would bring it back up with no problems. This never threw a CEL or anything too and i was like.. well ... it could just be the compressor kicking in now that it has freon in the system. The other day comming back from work, it was very warm and on the way home the ac was on and i hit around .. 400rpm at one point. This did throw me a CEL and i have not checked it yet.

Plugs are pretty new and gapped to spec (but going to be doing fuel filter, plugs and some other things soon anyway so those will be replaced) and the computer is doing its job at bring the idle back up to the 900rpm mark, but it is just rough to see the viggen not running in tip-top shape.

I can feel a little bit of a "buck" when i gas it too sometimes. I can be running at a constant 45mph and every once in a while feel the engine kick over a little with the ac on or off. Anyone have any ideas for me?

I believe the DI is orginal too (89,000 miles right now) so could a replacement be in order? If so... anyone got a spare?

Off to get some stuff done (so nice having the ipod setup in there now too) I will be back later to hear what you guys and gals have to say.


Also... I have to work on the 13th of aug... but ... i can get the 11/12 off for the meet ... maybe ... just maybe ....

 

[Fast_Ed]

Well, Slowpc,

This sounds VERY familiar to my recent problem. I had my DI cassette fail at 75kmi; and had been getting a horrible clacking sound from teh AC compressor. Found out that had to be replaced, so drove home from VT (where the DI had so conveniently failed) with the AC off. First time 'getting on' the car out of the dealer it hesitated in 2nd gear. Unsettling.

Then it started sometimes idling roughly at lights (AC compressor was on back order, so I've been driving with it off for a week) Down to ~500 rpm or so and surging. Most times it idles fine, but once or twice each 15 minute trip it does this. One day, I was coasting and turning, and the car stalled. It started right back up and ran fine after that. Still seems to pull normal too. I'll be getting mine checked out next week (this comes after AC compressor) sometime, bit it would be interesting to know what this could be..

 

[Slowpc]

Keep me up to date too. If/when i go to my dealership for my parts (i get them at about the same as eeuroparts here) i will ask about it too.

Anyone else have any ideas on this for us?

 

[Tarpot]

1. Do a search for "rough idle".

2. Clean idle air control module and throttle body with carb cleaner

3. Check all your vacuum hoses for cracks.

Good luck!

 

[Fast_Ed]

For my part, I'm pretty sure it's jsut teh AC clutch failing. As I'll be getting this fixed next week, I'll just live with the weird idle till then.

 

[Slowpc]

Well... i do have an exhaust leak i got to fix too... i dont think that is helping things out also...

Hopfully i will be a good state of mind sunday and i will have to get my hands dirty and see what is going on with the viggen.

 

[Slowpc]

Well... i was in a pretty good state of mind to be able to work on the problem at hand today for a little bit. We cleaned out teh T.Body (which was pretty bad) and after that we ran into some new problems.

Now... i am getting what sounds to be a relay clicking in on/around the T.body. Also my rpm at idle is now around 1150rpm (warm idle) and there is a few other litlte things like that. I am going to call my local shop tomorrow at work to get this thing looked at and see what is up with it. Can get my tires balanced/rotated and check on my exhaust.

Guess i will bite the bullet.

 

[Fast_Ed]

Yeah, I'm no longer confident this is caused by the AC clutch failing. The Vig threw a check engine code yesterday, and when I had it read at autozone, they said it was a misfire on cyl #4 and an air/fuel metering system fault (which apparently can be anything...)


This morning it idled high with some weird roughness... very strange. Flattened out when the car warmed up, but then idled low occasionally like it was doing... This car drives me nuts sometimes.

 

[Slowpc]

Well. my viggen is going in on wednesday morning to get it looked at. Any info i recieve i will forward back to here. after cleaning the T. Body it is running great .. but no ac and the idle is higher so ... only 2 days til i find out what is going on.

No A/c in this VERY humid weather is not fun..

 

[Slowpc]

Ok... got the viggen back... and running great!
GOt a new..... Thottle body... I will say the viggen is really moving now too, and it really responsive now.

well , that was the main thing and they replaced it and did some others things that i needed to get done.

Now... time to work on the ac again. It was running "ok" and it is now back to where it was a little cold but now after trying to rechange it today... back to warm/hot air.

We have tested it and found connectivity between the ac clutch and the temp switch. The ac relay and fuses are all good. We have recharged the ac with freon and if we "eject" some freon off out the high pressure port and it does come out. It does seem to work better on a cold engine start, once the engine gets warm it does not work very well. We think it is the clutch itself is not kicking in when it is warm due to expantation of the magnetic disk. Hey... anyone got an idea on what is going on with it????

Going to give the dealership a call to see if they can look at it (they dont charge for looking at stuff... which is nice)

 

[PMI]

...It does seem to work better on a cold engine start, once the engine gets warm it does not work very well. We think it is the clutch itself is not kicking in when it is warm due to expantation of the magnetic disk. Hey... anyone got an idea on what is going on with it????

The clutch may well not be engaging, but probably not because of thermal expansion. That is a tiny amount compared to the play in the clutch, and the designers would have taken it into account. I would check the pressure, and recharge if low. Then see if the air stays cool, and for how long before the refrigerant leaks out again. You may have more than one leak, I have found three small ones so far this summer.

If you tested the AC overtemp cut-off switch when the engine is off or just idling, continuity only tells you that it is working, it does NOT tell you if the compressor is overheating when the engine rpm goes up, and the switch is opening like it should.

If more oil than refrigerant leaks out, depending on where the leak is located, or if the system is recharged with refrigerant but not enough oil after a leak, the compressor runs low on lubrication, and overheats. It overheats more at higher rpm and hot weather. The overtemp switch opens (that's why it is there), The clutch disengages, and the AC stops cooling.

Btw, if you happen to think of bypassing the switch, don't. If it is opening at high temp, the compressor is just this side of failing, probably due to poor lubrication, and sending bits of itself into the condenser and the drier (a.k.a reservoir/accumulator), and if you get really lucky , into the evaporator as well...

 

[Slowpc]

We filled it to the recciemnded PSI and it worked off and on. I just got it back and after my 20 minute highway drive , got home and tested it... 140psi of hot air, no freon in it at all. We charged it and still nothing. Freon is in there since we can see the "bubbles" in the little reservoir. It just seems that the compressor just does not want to kick in at all when the engine is warm. Would hope it would be something that would not cost a large amount (like 1k after labor and recharge....)

 

[PMI]

Did you add any oil with the R134a recharge?

 

[Slowpc]

yep. The latest refill was with freon , oil , and a little leak stop.

 

[PMI]

Sounds like you have to find the leaks and make sure the system holds pressure, I can't think of anything else.

 

[Slowpc]

would a leak increase pressure and if not... what is the best way to find leaks?

 

[PMI]

would a leak increase pressure and if not... what is the best way to find leaks?

Not normally. A leak means less refrigerant in the system, so assuming the compressor is working, the pressure at the low-pressure as well as the high-pressure port would go down as the gas leaks out.

You can put some dye in the system (that is what I did), or a mechanic with the right tool can "sniff" for R134a escaping into the air. It really does sound like you will have to take this in.

 

[Slowpc]

I do have some green dye in there that i have not been able to see myself but will check it again soon.

 

[Slowpc]

Well ... yea it might have cost me some cash for the new T. Body... but an extra 5mpg more ... it will pay out in the long run! woohoo! From around 20ish mpg to around 25-26 in my everyday stop and go driving.