Bad idle, stumbling - out of ideas!!!!!

[sdg3205]

I've tried everything i could find on here.

I had a beautiful idle and it ran beautifully, then I had to go and mess up a good thing.

After changing the fuel filter, it ran fine, but i figured i should re-set my baseline mixture.

Pulled injectors, did bottle trick. Ran like poop.

Pulled injectors again, check spray, back left dumped twice as much fuel. Ordered new injector and tried again in the mean time. Ran like poop.

Pulled injectors again to put in new one, but all sprayed well, even the one that was bad before. All sprayed same amount of fuel this time. Decided to avoid new injector this time and see if situation resolved itself. Ran like poop.

I've tried:

- new plugs
- checking spray pattern 3 times
- unplugging vacuum line to spark advance
- FV is buzzing
- ground on passenger side intake re-cleaned and checked.
- removed K-jet unit to ensure all caps were tight on distributor
- traced all vacuum lines back to thermistor under intake and all were on and routed properly
- cleaned and checked ALL bulk head connectors
- idle speed motor working
- checked ALL fuses
- if I lean out the mixture it stalls
- if I richen the mixture it starts popping and banging more
- dwell meter not swinging, stays around 30, approx 40 with WOT pushed in
- installed new coil

Symptoms:

Bad, rough idle - sounds like one cylinder is dead at idle
really bad exhaust - burns my eyes and sticks to clothes, makes people run away
banging and popping sounds at idle
hard starts
slow, poor acceleration if using hand on spool (i avoid driving it like this)
stalls if i lean it out
pops and bangs more if i richen it
Dwell meter sits at 30, but I'm afraid to let it warm up to operating temperature because I dont want to damage the cat or O2 sensor.



I'm completely out of ideas. Short of putting in the new injector, which seems unnecessary now because it sprayed well on the 2nd test.

I've tried all the ideas suggested in similar threads here for the past 5 days.

Please chime in if you have any ideas, my Dad's in town and I really want to have the car running for him.

[Spittybug]

You didn't say so, but did you by any chance remove distributor cap? Could it be on backwards or not seated properly? Did you remove plug wires? Are they all secure? Could be sticky fuel distributor plunger. Do you run long enough to see if the cat glows?

[sdg3205]

You didn't say so, but did you by any chance remove distributor cap? Could it be on backwards or not seated properly? Did you remove plug wires? Are they all secure? Could be sticky fuel distributor plunger. Do you run long enough to see if the cat glows?

I replaced the cap, rotor, wires and plugs in april and it ran perfectly until last week, but no, i have not touched the distributor otherwise. I did check all the wires were on tight.

The plunger seems fine, but im not sure how to test it. moves freely with no rest pressure, moves with resistance with rest pressure, BUT i thought when you press it down after the car was off, you should loose ALL pressure and it should move freely again. My is hard to push even after multiple pushes with the car off (and injectors in bottles) for at least 5 hours.

[sdg3205]

I replaced both TABS last week if that matters at all.

[sdg3205]

I replaced the cap, rotor, wires and plugs in april and it ran perfectly until last week, but no, i have not touched the distributor otherwise. I did check all the wires were on tight.

The plunger seems fine, but im not sure how to test it. moves freely with no rest pressure, moves with resistance with rest pressure, BUT i thought when you press it down after the car was off, you should loose ALL pressure and it should move freely again. My is hard to push even after multiple pushes with the car off (and injectors in bottles) for at least 5 hours.

this leads me to believe it could be the plunger. If i press is all the way down, even after multiple pushes a full hour after the car is off, it takes a while for the plunger to move back down (the flap will spring back but if you gently hold it down, you can feel where the plunger is moving slowly back to first position).

[DMC5180]

- dwell meter not swinging, stays around 30, approx 40 with WOT pushed in
- installed new coil

Symptoms:

Bad, rough idle - sounds like one cylinder is dead at idle
really bad exhaust - burns my eyes and sticks to clothes, makes people run away
banging and popping sounds at idle
hard starts
slow, poor acceleration if using hand on spool (i avoid driving it like this)
stalls if i lean it out
pops and bangs more if i richen it
Dwell meter sits at 30, but I'm afraid to let it warm up to operating temperature because I dont want to damage the cat or O2 sensor.



Your dwell meter should reading 30-50 with 40 average. WOT should read 55.
How long are you letting the car warm up? I should run at least a minute to get the O2 sensor working. Speaking of which have you verified the O2 sensor is working/connected. How about the Vacuum Advance Solenoid. Messing with stuff on the back wall can inadvertently knock loose vacuum lines also.

Dwell should 45 under normal set up If the O2 was disconnected. Since you have already played with it from the Original position. This may be why it's stuck at 30 and moves to 40 WOT. increase of 10.

Normal 45 WOT 55 Increase 10

HMMM, what setting CYL setting are you running the dwell on? It should be 4.

[DMC5180]

this leads me to believe it could be the plunger. If i press is all the way down, even after multiple pushes a full hour after the car is off, it takes a while for the plunger to move back down (the flap will spring back but if you gently hold it down, you can feel where the plunger is moving slowly back to first position).

I don't know how long it would take to bleed of Accumulator pressure. But I would suspect the more it bleeds off, that lower pressure may effect the return rate of the plunger. Does the plunger return quickly if you turn the key to run position or jumper the FP at the RPM relay connector.

[Bitsyncmaster]

Your dwell will read constant during warmup since the O2 has not warmed up and gone into closed loop control.

Normally I would say check the PPR o-ring but I think I sent you the one that should not fail.

The other thing that can suddenly change mixture is the WUR getting plugged in the inlet screen. That's something you can do for no cost. Just pull it out of the can and look in the inlet with a flashlight. If it's dirty, use compressed air (or that air in a can) to blow the sh** out of it.

[sdg3205]

Your dwell meter should reading 30-50 with 40 average. WOT should read 55.
How long are you letting the car warm up? I should run at least a minute to get the O2 sensor working. Speaking of which have you verified the O2 sensor is working/connected. How about the Vacuum Advance Solenoid. Messing with stuff on the back wall can inadvertently knock loose vacuum lines also.

Dwell should 45 under normal set up If the O2 was disconnected. Since you have already played with it from the Original position. This may be why it's stuck at 30 and moves to 40 WOT. increase of 10.

Normal 45 WOT 55 Increase 10

HMMM, what setting CYL setting are you running the dwell on? It should be 4.

the car has run for several minutes while working on the mixture but i havent seen the needle swing like it did back in the spring. Hopefully this doesn't mean its connected and fried.

How do i verify the O2 sensor is good again?

as for the cyl setting, my meter shows dwell for 6 and 8 cyl engines, so i made a mistake earlier, the dwell sits at 20 on the 6 cyl scale.

[sdg3205]

Your dwell will read constant during warmup since the O2 has not warmed up and gone into closed loop control.

Normally I would say check the PPR o-ring but I think I sent you the one that should not fail.

The other thing that can suddenly change mixture is the WUR getting plugged in the inlet screen. That's something you can do for no cost. Just pull it out of the can and look in the inlet with a flashlight. If it's dirty, use compressed air (or that air in a can) to blow the sh** out of it.

Hey dave

I dont think you sent me any PPR o-rings. I only have your RPM relay - it's fused too.

Took the WUR apart, no clogs and the wires inside are in great shape.

[Ron]

$.02

Use the 8 cylinder scale then double the reading for 4 cylinder.

(your dwell = "20 on 6 the cyl scale" = 15 on 8 cyl scale = 30 on 4 cyl scale)

[sdg3205]

$.02

Use the 8 cylinder scale then double the reading for 4 cylinder.

(your dwell = "20 on 6 the cyl scale" = 15 on 8 cyl scale = 30 on 4 cyl scale)

totally, thats where I got 30 before, I was just going with that scale based on what i had read before.

I feel like this is beyond mixture though

[Bitsyncmaster]

Hey dave

I dont think you sent me any PPR o-rings. I only have your RPM relay - it's fused too.

Took the WUR apart, no clogs and the wires inside are in great shape.

I thought it was you. At the last minuet you asked if I could send the o-ring with the RPM relay and I did put it in the box.

[Ron]

totally, thats where I got 30 before,...
I feel like this is beyond mixture thoughI don't know...30 sounds like you need to bump it up the 10 Dennis was speaking about ...plus 5 to 45 if its cold (open loop) for now....then go find the swapped wire or loose vacuum line ;)

[sdg3205]

Thanks for all the help folks!

Bottom line - I'm an idiot. I had two plug wires backwards. I replaced the suspect injector while I was in there.

The mixture fell into place nicely afterwards.

Now I have this shrill wine/scream at idle, around 6 kHz. It sounds like a vacuum leak, but not that I can see. It disappears when you hit the gas. Thoughts?

[Bitsyncmaster]

Thanks for all the help folks!

Bottom line - I'm an idiot. I had two plug wires backwards. I replaced the suspect injector while I was in there.

The mixture fell into place nicely afterwards.

Now I have this shrill wine/scream at idle, around 6 kHz. It sounds like a vacuum leak, but not that I can see. It disappears when you hit the gas. Thoughts?

Common whine at idle is the seal of the W pipe gasket. I ended up making a thicker gasket for mine but if you do that you need to make some minor adjustments.

[Spittybug]

Thanks for all the help folks!

Bottom line - I'm an idiot. I had two plug wires backwards. I replaced the suspect injector while I was in there.

The mixture fell into place nicely afterwards.

Now I have this shrill wine/scream at idle, around 6 kHz. It sounds like a vacuum leak, but not that I can see. It disappears when you hit the gas. Thoughts?

I love the easy ones.

[DMCMW Dave]

Common whine at idle is the seal of the W pipe gasket. I ended up making a thicker gasket for mine but if you do that you need to make some minor adjustments.

A very thin application of "sensor safe" RTV is a help here too. Just about any gasket sealer will work. Over time the "ears" on the W pipe deform a bit and it's hard to get a good seal with just the paper gasket.

[sdg3205]

A very thin application of "sensor safe" RTV is a help here too. Just about any gasket sealer will work. Over time the "ears" on the W pipe deform a bit and it's hard to get a good seal with just the paper gasket.

I bet that's it Dave. I've had that W-Pipe off about 8 times in the last week which I'm sure has exhausted those little paper gaskets.

Here is a video for reference. Let me know what you think.

Thanks so much.


http://www.youtube.com/watch?v=UP-z1Xm9deo

[Ron]

If I didn't mind getting that pretty engine wet, I'd try cracking the hose faucet and using my thumb to spray around and find it. Works fairly well for rubber mounts, belts, pulleys, and of coarse vacuum leaks ;-)

[DMC5180]

That whine seems pretty typical to my ear. If it was leaking at the W pipe You could spray some carb cleaner/staring fluid by the gaskets and listen for an increase in RPM. The other thing is that you should be running lean since the leak would be downstream of the Air-meter plate.

[sdg3205]

all fixed.

thanks everyone!

[Ron]

Soooooo,...W pipe?

[Spittybug]

He's keeping us in suspense.

[sdg3205]

TOTAL SUSPENSE!!!

Yes, there was a lot of air moving past the paper gaskets on the W-pipe.

After some sensor safe gasket sealant the whistle is gone.

I'll have to readjust the mixture as you suggest. My idle has moved up to about 1000 RPM as well, so perhaps I've had a slowly increasing leak of a while.