3.0 running horribly after messing with mixture
 

I've hard either cold start or cold running issues since I rebuilt my CIS this winter. Every once in a while it starts cold as it should, but most of the time it's sluggish to kick over, and takes about 20 seconds or so to rev up to where it should be. I've been living with it. It always seemed to me like it's just too rich when starting, but there's no science to that evaluation.

A few days ago I replaced my original, 34 year-old spark plug wires with new Clewett wires. It started up as usual after the switch (sluggish). I ran it around town for a bit, it felt a wee bit peppier. But I noticed that after warm-up the idle was now running around 1300 rpm. When I got home, I left the car running, lowered the idle to 950, checked the timing (dead on), and decided that while I'm at it I'll see if ,y cold start issues are being caused by the fact that it might be running just a bit rich. So I shut off the engine, and I lowered the mixture by about half a turn on the screw, and let it sit a while. After several hours I gave it a crank and start up was horrible. It would not stay running without me giving a little gas. When I let it go on its own it revs up a bit, drops to almost 0, revs back up and keeps bouncing up and down and stalls.

I turned it off and reset the mixture to where I thought it was originally. I let it sit overnight and cranked it over today, it kicked in eventually but idle is still just as horrible, even after holding it at around 1800 rpm for a few minutes to get it warm.

I've double checked and all the wires are tight. Could this have anything to do with the new wires? Did I mess up the mixture so much that it's totally out of whack? Where to start?

No. Especially since you did not mention you were missing at higher rpm which could indicate the wrong order.

Your car should start every time with a working cold start valve. If I read your post it may be starting ok but does not grab a decent idle. Is that what is happening?

I have Clewett wires and have no issues with them at all.

Hey Groovy 1/2 a turn is a huge adjustment. Normally you would be doing adjustments in 1/8 turns. I think 1/2 a turn is actually considered the max range of adjustment after the base setting i.e. CW until the injectors just start to eject then back 1/2 a turn.

I just put new Clewetts, rotor, cap and plugs in mine and it runs really sweet. Still got that low cold idle that I'm chasing (need to do another pressure test) but when it's warm runs sweeter than ever. I had to adjust my idle speed with all the new gear installed once it warmed up. When you adjust the idle you usually have to adjust the mixture too. If you reduced the air by a large margin then you have to reduce the fuel to match I think. Messing with the mixture will change the starting plate height when it's cold. If you lift the plate slightly when it's cold does it run better? What's your cold control fuel pressure?

I would have first had the CO2 checked before adjusting mixture - I have John Walker do this at least once a year to his recommended setting of 3.5% (richer side).

Also, do I remember that the adjusting screw is sprung or under movement when in use - sorry, others will be of more help. Here, the physical adjustment may not yet have taken and maybe a drive would help you "get back" at least.

Good luck!

No. If fuel is set correctly and all else is ok, you will simply impact RPM. (I think :D - not getting too cocky)

One trick to check for vacuum leaks is to turn the idle air bypass screw all the way in. If it still runs half way decently, you have air leaks.

Need to get more feedback from OP on how it starts. Some days my 81 will start just fine across the whole nine yards Always starts though, it's that minute afterwards that can vary. Depends on temperature and battery strength based on my observations.

OK, so I'm guessing I messed up the mixture enough to throw the whole thing out of whack. The good news is that after cleaning out my screen in my WUR I may have fixed the cold start problem. I can't seem to find a thread saying how to get a base mixture without a CO meter, is there a way? Then I can take it to Mr Walker for a fine adjustment.

My woes all started when I replaced my wires with Clewetts recently. Here are 2 things to check:

1) did your plugs have terminal nuts on them? The Clewetts need terminal nuts, the Berus snapped onto the threaded post so the terminal nuts had to be removed.

2) the Clewett coil wire does not have a sliding hood on the coil side so you have to be damned sure that it is seated properly

Both of these bit me and caused all sorts of angst. Coupled with changing the plugs once I realize #1 and one of the plugs turned out to be bad! just a slippery bad slope.

What are terminal nuts?

I've got the mixture back to where it should be (roughly), using the sensor lift technique (lift sensor at idle slightly, if it revs up it's too lean, revs down too rich). I was way too rich.

Back to the wires, what are terminal nuts? I noticed that the distributor ends do look a bit different than the stock Bosch units. The car seems to be driving much smoother than before, but the idle and decel seem off.

The little nipple things at the top of spark plugs. They can be removed on some plugs (like the Bosch plugs recommended for SCs).

If they are missing from your plugs, the Clewetts won't snap on properly.

Dear Groovy (great handle by the way!),

Lots that could be said here, about reading all the CIS threads and buying a set of gauges to check your pressures. But I believe I have THE BEST advice for you: get the car straight into your local guru (Seattle! Ergo John Walker!) and let him, at a minimum, if you are a hell-bent DIY'r or necessarily careful with your nickels and dimes, point you in the right direction. Maybe..it's possible...that with some knowing twiddling, carressing and fettling, he can get you sorted without any components even being replaced.

I too like figuring out my own issues, but learned (from years as a service manager, working with some Grade A+ techs) that there is not only no shame from asking a real, proper mechanic for help but that often it is completely wasteful and foolhardy not to. They have so much good stuff stored in their noggins that paying them can often yield the cheapest and most elegant and permanent repair.

I'd also hate to see this turn into one of those "I already replaced the X, then the Y and after that the million dollar Z, but the car still runs like dog scat" threads.

If you don't agree with my "wisdom", no worries. The truly amazing, generous and selflessly patient CIS gurus here can walk you through the it.

Best of luck, John in CT....also an 82SC owner.

Yeah i just chucked that thought out there. I'm not sure either.

Lately it's been really hot here in GA ~100 F and my AAR closes too quickly, chokes off the air and it runs like crap until it warms up. I figure that's probably expected.

You know when the Clewetts are properly seated. They make a really nice "click" when they seat :).

Did you ever check the frequency valve was working?

Ah, thanks! The wires snapped into the plugs nicely, so I don't think there's any problem there. The FV is clicking away, so it sounds good.

Gazzer - I can relate to your summer issues, even here in the PNW! I think if/when (lol) I'm confronted with spending more money on the CIS I'll switch to EFI.

I had John set my fuel mixture after I rebuilt my CIS last winter. Since then I've adjusted the timing, which was pretty far off, and now replaced the wires. I think it's possible that the old wires were weak, and the bad timing were creating a need for a richer mix at idle. I always felt it was too rich (even John says that some people say he sets his too rich). This would explain the cold start issues, which as I said just felt like it was getting too much gas. I've got it dialed in with the sensor plate technique to just a hair rich, so we'll see. If the rpm issue persists I'll probably start a new thread, since it probably isn't mixture at this point.

I'll let it sit and see about the cold start tomorrow. I'm also wondering... every time I mess around near the idle screw I have to work around the cruise control cable. I noticed that a tug on the cable causes the engine to rev, so if it got tugged and didn't snap back all the way it could effect idle rpm.

Who uses CC on these cars anyway?! I'll search and see if there's a simple delete. The fewer variables that I have the better!

Yeah I pulled my CC cable. There's some horror stories about over revs at stop lights. You can adjust the cable at the mounting bracket near the big throttle body spring to slack it off.

Very interested to see if your cold idle issues have cleared up tomorrow.

you HAVE to know what your control pressures are doing.
you need to make sure the following are all working before doing anything else.
the CSV system
frequency valve
aux air regulator
temp sensor
no air leaks.

the system starts in open loop mode, no O2 sensor. its strictly based on control pressure.
the aux air reg (AAR) raises the idle when cold
the warm up reg (WUR) drops the control pressure to make it richer when cold for starting, then raises it to lean it out for warm running.
the frequency valve controls the control pressure once warm to maintain mixture below 3500

Top advice......
 

Groovy,

I seldom agree 100% with TY's advices, but not this one. You need to try the suggested tests before bringing the car to JW. Some critical information I don't find in your posts are fuel pressure readings to evaluate (WUR and FD) and vacuum leak test. Why are you tinkering the mixture setting all the time to troubleshoot without verifying your fuel pressures and air leaks? Keep us posted.

Tony

I'm going to mke a suggestion. Maybe not popular, but it's based on experience.

Load the car up on a trailer and haul it to John Walker. Ask him to sort it out and pick it up when he's done.

Nothing personal, but judging from what you have done, you don't know enough about CIS to mess with it and you probably have none of the special tools needed, anyway.

We can spend the next two weeks figuring out how much of your original CIS system is remaining and still functional and give you enough knowledge to poke around a little. Go this route and you'll miss the summer, then you'll have to get it to the shop anyway.

Spend a few bucks now, drive it all summer. Then, leave it alone.

JR

^^^ +1

Last I checked JohnW likes Ninkasi Total Domination IPA.