CIS Idle Issues - stumped

[schleven]

CIS gurus, I can't seem to get my car running properly. Any insight? Here's what we're dealing with:

WUR is making good pressure at control, cold and warm
AAV is bench testing fine
AAR is bench testing fine
Decel Valve no leaing and actually working.
New vaccum advance can.
New accumulator
CSV is working
No vacuum leaks - can soak the upper half of the engine in carb cleaner and no idle change.
New injectors
Fuel Dist arm not sticking
Air flow plate not sticking
New airbox, intake runner seals, o rings north of the block,
New O2 sensor
CO set to 1.5% when warm.

If I lean down the mix when cold its too lean warm. If I fatten it up its WAY too rich cold (idle bounces and surges).

Basically the cold start is too rich and we aren't getting a warm up high idle and settling down, could be that aux air coming in at idle is not occurring correctly, that the mix is too fat at idle and we have the right air and we are compensating that with the idle screw, but if we settle in the idle mix to be stock then our warm idle is junk.

Some of the small exhaust leaks could be interjecting air in the upstream exhaust and causing O2 misreadings too, but Im not sure they are large enough to do so. Plus I would have seen a jump in the smog test, which I passed fine.

[jason2guy]

i have an 81 rosewood as well, so i have to at least try to help. what are the actual SP, CCP and WCP readings?
im not clear as to the actual problem, idle- ok. will it idle? is it missing?
as for the mixture setting, i just looked at the bentley and it says, .04-.08
o2 disconnected. post your readings
and how did you get a hold of a new vacuum advance?

[tirwin]

I read your post and I've been thinking about it while having my morning coffee. You've done a lot and i think you've covered a lot of the most common problem areas. This is starting to feel like it's going to be something simple that has been overlooked or it's going to be esoteric.

With that in mind, please don't take offense at any of my suggestions. I'm going from the blindingly simple that might be a simple oversight to the complex here, ok?

- Could you just confirm that if you take the oil fill cap off with the engine warmed up and idling that the RPMs, do in fact change?

- Some amount of hunting at idle is supposedly normal for these cars. Maybe posting a video would help us see what you mean?

- Have you checked the fuel injectors for flow? I'm thinking about uneven fuel delivery or maybe the pressure is off (like leaking vs fine mist)

- How does the car seem to drive other than the idle?

- Have you checked the timing at idle and full advance?

- How long since changing the plugs, wires, rotor and cap? I'm just thinking about spark quality here...

- There are a couple of inputs the ECU relies on and the tests are pretty simple. Might not fix the problem but it may be worth some peace of mind. I'm thinkng specifically about the 15°C switch and the OXS relay. You've also got a couple of plugs on the back side of the engine. Just maybe use a mirror or reach back there and verify that they are not loose or disconnected.

- Another idea is to check the 12-pin ECU connector at the firewall. That one is going to be really hard to get to. I would look for corrosion, loose connections and broken pin wires.

That's probably enough to start with...

Keep us posted!

[tirwin]

Another thought occurred to me. Let me see if I can find the post but I think Jim Williams posted it somewhere in one of the CIS threads. It may have been mine! Basically the idea is that you want to check the plunger adjustment. With the car idling, gently reach in and pull the plunger arm down and note what happens. Then do the same thing by gently pushing up on the plunger arm.

[kodioneill]

You state the wur pressures are fine. List the readings and temperatures when they were taken. What's the overall fuel pressure?

[schleven]

Took the car out for a drive yesterday. Car ran as normal (idle issues when cold) but then great. After a 30 minute drive, the car died at idle (at a stop sign) and then failed to start. Got it home and it looks like it's the ignition CD - as the motor isn't getting spark and the CD box is getting voltage into it but nothing out. Will have to fix this issue and then will dive into cold start/idle issues. Will post numbers in here when I get it back running... Thanks for all of the feedback.

[boyt911sc]

What is your cold control fuel pressure? What is the resistance (Ohms) reading of the WUR (cold state)? Do you have a Bosch CDI or a Permatune? Keep us posted. Thanks.

Tony

[T77911S]

could be coil, could also be dist are wire from dist to CD.

set every thing up warm. mixture, idle, check and post WCP and duty cycle of FV.
then work on cold issues.
is the AAR opening and closeing. air leaks. CCP. post it.

make sure timing is set, advance is working, you have new plugs cap and rotor and no air leaks. make sure you have power to the WUR and AAR.
what about injectors?

[Paulporsche]

Sounds like CDI at this point.

Check your O2 sensor relay. Is your dome light working?

As Tony mentioned, what type of CD box do you have? There are quite a few examples on this BB about people who have had a certain generation of Permatune give out when hot. Even if it's a Bosch, it could still be what, 35 years old?