Idle issues after AC removal - Coincidental??

[ghamilton]

so; I pulled my non operating AC compressor & deck lid condenser about 2 weeks ago. I have not removed the hoses, but I did tuck the one on the left side in along the back of the firewall and wire tied it to a hose/harness so that it stays out of the way. Same with hose by oil tank.

No changes done to electrical system because the compressor clutch was not hooked up anyway.

Car ran fine after that; but a day or too later went for ice cream and the idle kept dropping down at stop signs & lights, so much that it would stall out, or almost stall the whole way home.

You could hear the idle hunting from 1100 to 3-400 as it searched for my set idle of 900; which has always been rock steady.

Got home and wiggled any hose I could see on the left side and it seemed to be back to normal.

BTW the idle did not drop appreciably if I removed the oil cap. (vacuum leak?).

So; I drove a few times since and no issues; probably 30-40 miles or so.

Tonight I took a ride to marine store and about 20 minutes after driving it just suddenly did it again at the traffic lights & stops. I did notice that on decell in neutral that the idle was slow to drop down to normal maybe 5-10 seconds.

It stalled twice on me and was a little tough from a start sometimes as I had to feather the throttle.

Car was running great as always, from 30-65 mph. Temp was normal. Got to store, shut off, started right back up and idled fine. Pulled out of the parking lot & at first light did it again. Car still warm.

Got home, issues continued at most stops.

Again, no change in idle with oil cap off.

pulled vac advance on distributor & it reved up. retard side removed made no diff.

As I started to wiggle hoses/wires on left side I noticed that the connector on the back of firewall if I wiggled it a bit the car would stumble. It's a rectangular connector with a couple of brown wires that I think are grounds on the engine. Hard to see with heater fan in place. I am attaching pic.

Seemed as though if I wiggled the connector it would stumble, but then I tried to isolate the 2-3 brown wires at engine and it still acted up. Not sure if I was wiggling the connector?

I also might add that when I did the AC I noticed the O2 sensor wire connector was brittle and broken where it connects to the harness.

I stripped the ends of the wire and put on a bullet connector on either end. I did notice it was shielded? But the orig connector was just a single wire.

When I unplugged the 02 sensor tonight it made no difference.

Even when the car is not hunting for idle sometimes it is running around 1000-1100 rpm, sometimes it seems to settle down to 900.

If I blip the throttle to 2500 or so and let go, it idles down very slowly, 2-3 seconds and then drops really low as if it's going to stall.

So, do I have 2 issues? an electrical and vacuum?

Car has always run great & it sure seems like this all started after I did the AC work.

Not easy to see vacuum hoses behind engine...

Ideas??

Thanks:

[Bob Kontak]

Originally Posted by ghamilton

As I started to wiggle hoses/wires on left side I noticed that the connector on the back of firewall if I wiggled it a bit the car would stumble. It's a rectangular connector with a couple of brown wires that I think are grounds on the engine.

That is the 12 pin connector. 10 more than two.

I be drinking the finest beer - Keystone Light - so bear with if I am a touch of a choad.

The 12 pin is the little sister of the 14 pin.

14 pin is in the rear most driver's side cubby of the engine. It is like the T-Rex of connectors. The 12 pin is maybe like a Velociraptor. Your O2 sensor and frequency valve flow through the 12 pin.

When you wiggle the 12 pin and the car coughs up a little hair ball it is probably the frequency valve circuit being interrupted.

The frequency valve connection is on the right side closest to the rear bumper based on your picture orientation.

I see a smidgeon green in the pic. Oxidation?

Pull the blower and get on in there. Split the connection. Look if there is crud. Do what needs to be done to clean the crap off. Others will know better than me the tricks how to clean. But I betcha just disconnecting and re-connecting with a little bit of knocking of crap off will work wonders.

Advise as to results.

[ghamilton]

Bob, once again thank you for your insightful advise.

My hopes are when I get home the car is still doing it and I will then immediately
Pull the connector and clean it up.

Hopefully that is it.

I was banging around in that corner, too, hopefully that was it.

I will keep all aprised.

I was hoping to go to the Thompson speedway vintage races tomorrow.

[Ronnie's.930]

Originally Posted by Bob Kontak

. . . I am a touch of a choad.

Talk about yer classic under-exaggeration right thar !!!

[Bob Kontak]

Originally Posted by ghamilton

My hopes are when I get home the car is still doing it and I will then immediately
Pull the connector and clean it up.

You have to split the connector. Take you time and be gentle. It's way in the back, you can't get a good look at it as to how it comes off the metal flange thingie that is part of the big support rail between the two shocks.

I think you may be able to just split the clam-shell carefully. It's old school. Soldered pins on one side. Soldered female receptacles on the other.

Look for corrosion. Make sure the pins are full seated when reassembled.

[Bob Kontak]

Originally Posted by Ronnie's.930

Talk about yer classic under-exaggeration right thar !!!

+1

Why even push back?

[Reiver]

Originally Posted by Bob Kontak

+1

Why even push back?

Lol....

[ghamilton]

Tonight I got back into my hot idle issue. I did replace the orig cloth covered vac hose to the the Aux Air Valve, it was pretty dry.

Also cut the ends of the disto vac lines to get a tight fit.

Then I pulled the 12 pin pug apart and cleaned with contact cleaner. I no longer had the little cough when I wiggled the plug when the car was running.

Car started fine as usual. Ran 1000-1100 for about 10 minutes , then idled down to 950.

Took it for a ride, when car was not near warmed up it seemed fine. As soon as it got just below the first mark on the gauge it started to have a slight idle issue. As it got warmer it got worse.

Had it running in driveway for 10-15 minutes full hot & it was running up and down between 500 & 1000, almost stalling. Same thing as before, when I blipped the throttle it would come back down and almost stall.

I pulled the O2 relay while it was idling irregular & it smoothed out. After 3-4 minutes it got a little rough, think it started running rich.

As soon as I pull the relay it evens out for a few minutes. BTW, the relay was warm to the touch.

Did not get to check voltages on O2 sensor; but I have no record of it ever being replaced.

Good news is when I open the oil fill cap the idle speed changes by 150 or so rpm.

Should I just start by replacing O2 sensor? Maybe the relay too; always good to have a spare.

Very frustrating, not going to make it to Thompson for the vintage races...

Got to get this resolved.

[Bob Kontak]

Originally Posted by ghamilton

Should I just start by replacing O2 sensor? Maybe the relay too; always good to have a spare.

Absolutely not. You have an air sucker. Not too huge but in a critical spot. As the car warms it leans out. Then the leak rears it's head.

Go to the local auto parts store and buy brake cleaner (two tall cans) with the little stems on them. Carb cleaner is "better" but it is more volatile.

Spray into your injector sealing points and then at the base of the intake runners.

Around the air box, etc. All the points you are aware of the engine can suck false air. Pop-off valve? (Although, a leak there is usually pretty big.)

Get nasty on the intake runner to head mating.

RPM's will change when you hit the leak(s)

[ghamilton]

I thought if the idle speed changes when you remove the oil cap it was an indicator that you had no major vacum leaks?

I have a pop off valve and I did check that, it is tight as a drum, if there is a crack in the airbox; have never had a backfire since I owned it I can't see it.

It was getting late when I pulled out the cleaner to spray around the engine.

Tomorrows job.

[Bob Kontak]

Originally Posted by ghamilton

if there is a crack in the airbox; have never had a backfire since I owned it I can't see it.

I have never had an air box backfire since 96 except when I forgot to attach the fat hose to the aux air reg. Ka-boom. Infinite wisdom......I turned the key again. You guessed it.

Neighbors were staring and getting irritated. No crack, just BIG air leak.

You are nailing it and you are far beyond big air leak. but there is some sneaky leak that is causing grief.

This is my supposition. The closer to the heads, the more impact a smaller leak will have.

[Ronnie's.930]

^^^ Bob, my mom wants to know when you'll be back. And you know, there was a hint of a "leer" on her face when she asked!!!

[ghamilton]

Went through all my vac hoses, clamps I could see, no change in idle issue.

Started spraying start fluid with long ext nozzle on all runners, no change, then I went the the injectors. I found on 4 outta 6 the engine would stumble when I sprayed them. A few a pretty loose. On 3 of them I can push down and the idle drops way down.

Sounds like leaky seals. No history on replacing them.

Can I do a little sealent for now while I order a inkector seal kit?

Don't want to have to dig them out!

[ghamilton]

I zip tied the two loosest injector lines so the couldn't move. Car runs much better, still had a little searching of idle after 20 minutes (full warm) but I would say it's no where as bad as before.

Gonna order a set of injector seals. Do I need to order the larger rings for the sleeve?

I see Bentley shows a cable with a T handle tool.

Anyone know if that's avail, or worth it?

Thankd

[Bob Kontak]

Originally Posted by ghamilton

I zip tied the two loosest injector lines so the couldn't move. Car runs much better, still had a little searching of idle after 20 minutes (full warm) but I would say it's no where as bad as before.

Gonna order a set of injector seals. Do I need to order the larger rings for the sleeve?

I see Bentley shows a cable with a T handle tool.

Anyone know if that's avail, or worth it?

Thankd

Read post number 2. Yes on the larger seals based on this.

injector o-ring replacement?...again

[Bob Kontak]

Originally Posted by Ronnie's.930

^^^ Bob, my mom wants to know when you'll be back.

PO'd at yer Mom. I had eight Big Blues. Used three last weekend. Other five are missing.

She only does the nasty with one other person. So.....

Have fun, Woody.

[Bob Kontak]

Originally Posted by ghamilton

then I went the the injectors. I found on 4 outta 6 the engine would stumble when I sprayed them.

Odd factoid. When I found a leak at the bottom of #4 runner, rpm increased. Two injector seals leaking, rpm dropped/engine stumbled.

[ghamilton]

I think (hope) I have found my idle issue. This afternoon I replaced my O2 sensor (1 wire Bosch from Napa $20). One thing I noticed was the plug I had replaced at the O2 sensor on the harness had a shield. The harness wire has a center wire and another outerwire, both wrapped in typical insulation. It looks like part of the shield was touching the bullet connector.

Note, I replaced the connector back when I did the AC removal.

I redid both ends of the harness and made sure to isolate and heat shrink it.

Took the car for a good 20 minute ride and it ran great. No idle searching, even when fully warm.

So, was it my sensor, or a short in connector? .

I have also identified that I should be doing injector seals, hopefully I can wait til fall, so I can send them out for cleaning.

In the meantime can I use some RTV on the seals?

Will keep all posted.

[DaveMcKenz]

Shorting the O2 sensor would make it read 0 volts. When in closed loop that would be full rich (or lean, I forget), either way your running would suffer. Sounds like you found a problem, probably the problem with your issue. This is assuming you have an ecu that reads O2 sensor data to trim the FI.
Good luck,
Dave

[Bob Kontak]

Originally Posted by ghamilton

I have identified that I should be doing injector seals, hopefully I can wait til fall, so I can send them out for cleaning.

How did you figure out how to isolate the injector seals?

You have an air sucker but confirmed air sucking is not a problem based in your oversight.

Now you are into the O2 thing.

What is a rich reading when you put a multi-meter on the O2 output? What is lean? You know you can check it with a multi meter or a dwell meter and dial your car in real tight.