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Old 11-06-2010, 08:03 PM   #11 (permalink)
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Default Re: Is it time to pull the head off ?

Quote:
Originally Posted by Vigman
The miss sounds... bad.. maybe bad wire ( yes I know you ohmed them all out ) is the inside of the cap still clean ( no carbon or other dust in there. or on top? )

If it was me ( since I think you have multiple air leaks ) ...
That in & out diaphram ( next to vac gauge ) ... did you plug 1 side and do the vac test on the other?
( still waiting on this answer
On all your mighty vac tests, you pulled a vac.. and the vac held for a minute or better on all the vac operated devices ( eg Vac advance for Dizzy? ) )

I would plug EVERYTHING POSSIBLE on the manifold, short of the bare minimum to run... no brake booster, no advance, no PVC, bare bones...again.

I know this is frustrating.. and you WILL shoot yourself when you find it... I do not believe it's an internal engine thing.

OR

Confirm first, take it to a emissions station and have the tail pipe sniffed... that will tell you EXACTLY what's coming out the backside..

Cap is still perfectly clean. Runs the same on the cheap advance auto cap that I drilled a hole in the top of to phase the ignition.

Wires are new. I suppose it could be a bad one, but would it miss random like that ? Yes, I did ohm them all out. They are autolite wires from the local parts store. If it is recommended and you think it will help, I'll try something else.

On the vac advance, it will hold a vacuum forever. It doesn't even get any vacuum at idle though.

The in and out diaphram is the bcp. It controls when the EGR opens up. It doesn't have any vacuum on it until you deccelerate from 3000 rpm I think. I've pulled the lines off of it before, at idle it's doing nothing and has no vacuum.

If it's something simple that I've continued to overlook for a month, I wont' shoot myself. I will be ecstatic that it's fixed and I didn't have to put a new motor in it.

Don't forget that it really runs worse than it is now, the video is with the AFM richened up by loosening the spring 6 teeth, and the timing is on 13 degrees now.

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Old 11-06-2010, 08:06 PM   #12 (permalink)
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Default Re: Is it time to pull the head off ?

Quote:
Originally Posted by Tony
I'm just going to ask some stupid questions:

How much did your vacuum gauge cost, and when was the last time it was calibrated?

This reading is consistent no matter what vacuum gauge you put on it, right?

You have tried more than one gauge on it to verify the readings, right?
It's a cheap vacuum gauge, probably about $30. It is new. I checked it against the vacuum gauge on the hand held mighty vac I have. They agree. Even if the vacuum gauge was off, the car still runs poor. In the video I've got it richened up with the AFM and the timing advanced just to make it somewhat drivable. If i put the AFM back to stock setting, it will pop through the intake, miss, and stumble bad at lower rpm.
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Old 11-06-2010, 09:32 PM   #13 (permalink)
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Default Re: Is it time to pull the head off ?

You HAVE to do a leak down test. Bad news is I do not think AZ nor Oreilly has one to rent. You can find it at Harbor freight for about $30-40. Basically you freeze it on the compression stroke, inject compressed air, and measure how long it takes to bleed out....I don't know how you could simulate it otherwise, but it will tell you how well your valves are seating. Then I'd worry about removing the head after I found this out. BTW, I found an air leak around my CSV. Also, I've been told that back in the day there were cars that leaked fuel thru the CSV. Take needlenose and crimp off the fuel line to the CSV and see if it smooths out.
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Old 11-06-2010, 10:20 PM   #14 (permalink)
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Default Re: Is it time to pull the head off ?

How much initial lead do you have dialed into the motor? Are you sure the reading on the balancer/pointer/timing light is correct?
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Old 11-06-2010, 10:28 PM   #15 (permalink)
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Default Re: Is it time to pull the head off ?

Quote:
Originally Posted by palladin
You HAVE to do a leak down test. Bad news is I do not think AZ nor Oreilly has one to rent. You can find it at Harbor freight for about $30-40. Basically you freeze it on the compression stroke, inject compressed air, and measure how long it takes to bleed out....I don't know how you could simulate it otherwise, but it will tell you how well your valves are seating. Then I'd worry about removing the head after I found this out. BTW, I found an air leak around my CSV. Also, I've been told that back in the day there were cars that leaked fuel thru the CSV. Take needlenose and crimp off the fuel line to the CSV and see if it smooths out.
I blocked off the CSV, and started the car with it in a jar to observe it's operation. the CSV gave a quick squirt of fuel then shut off as normal. Also CSV leaking would make car run rich, and it's running lean. The more fuel I give it the better. Also CSV has had healthy dose of carb spray and propane around the mounting surface. It isn't leaking.

I've thought about the harbour freight leak down tester, many reviews say that the gauges are way off on it though.
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Old 11-06-2010, 10:29 PM   #16 (permalink)
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Default Re: Is it time to pull the head off ?

Quote:
Originally Posted by Powerglide
How much initial lead do you have dialed into the motor? Are you sure the reading on the balancer/pointer/timing light is correct?
It's correct. Details in the 30 page thread. It's not ignition or valve timing.
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Old 11-06-2010, 11:02 PM   #17 (permalink)
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Default Re: Is it time to pull the head off ?

Or leaking injectors, or fuel pump system.
The chain was a hair old and moved it to position 2 and the mark is bang on ( leading by a hair ) .
Timing is at 15btdc
Compression 150 +/- 5 a hole
EGR changed
TPS checked 3X
New rubber in out of AFM
Fuel pressure in spec
No " light show " when running in the dark ( spark cross fire )
New plugs
Runs & drives
Makes good power
balance check confirms each hole is firing
Voltage / charging system good
ECM wiring all cleaned.
Sensors all within spec.
Exhaust not plugged
No cat
( and about 10 other things )

PO stated the car always had this problem and it was way worse before

Vac still low

I'm stumped
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Old 11-06-2010, 11:19 PM   #18 (permalink)
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Default Re: Is it time to pull the head off ?

I'll add to the fix list just for anyone else who hasn't read the other thread.

new cap and rotor
ignition system replaced with crane xr700
water temp sensor replaced
intake/exhaust manifold gasket replaced
fuel filter replaced, and g3 pre filter installed (no dirt was in fuel pump inlet screen)
spare ecu tried
spare afm tried
new pvc valve and hose
new injector connectors
injectors cleaned and flow tested

And as far as the exhaust not being plugged, not completely sure on that but it appears to be working ok. I did try taking a rag while running and stuffing it some more to watch what it did. I had to cover it up pretty good before the vacuum started to drop further. Also, the 2500rpm vacuum test according to blues tech tips should see the vacuum gradually drop while holding rpm steady and it didn't. Car still has original resonator and there area couple of dents in the exhaust tube way back by the half shafts, but it doesn't appear to be significant. I posted pics in the other thread.

I'm beyond stumped. I'm praying someone will chime in and make sense of it for me. I reckon I'll see if I can't round up a leak down tester from harbour freight and see what that shows.
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Old 11-07-2010, 12:18 AM   #19 (permalink)
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Default Re: Is it time to pull the head off ?

Best check yet... drop the manifold to headpipe juction. It's easy as brass nuts are usually involved.. Abit noisy, but if your vacuum jumps up , you've got your answer!
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Old 11-07-2010, 03:10 AM   #20 (permalink)
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Default Re: Is it time to pull the head off ?

Going off the edge....
( just to rule it out ) measure cam height...and verify no worn lobes.....
Look at EC-10 ( figure 14 )
Cap the line that's feeding your thermal vac valve (9)
AND
Check the bottom diaphram of (5) BPT valve ( or just get out of circuit for now )
EC-11 If the BPT valve is ginked it will let air OR exhaust get into the intake...

As stated before having your tailpipe sniffed will tell you ALOT about how the engine's burning ( rich / lean ) .

DO you have smog inspection in your state?

In the AFM is the overall condition clean? Is there a bunch of goo on the air temp sender ( EF-14 ) ?
And in the lower right corner of the AFM there is a set screw adjustment ( page 10 of the OLD EFI bible ) ....

Your lean idle misfire could be just that....
( and I see you posting elsewhere....)

Again, you & I both know till the vac issue is sloved ( or at least @ 17.5hg ) everything else is a bandaid...
You don't live at a high altitude right??

Mike

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