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GhostlyHalo
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Joined: December 22, 2020
Posts: 68
Location: Dallas TX
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 Posted: Sun Apr 25, 2021 12:32 am Post subject: 82 Aircooled With Some Odd Problems |
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I’ve run into an issue that just doesn’t make sense. Well, 3 issues combined to be honest.
First 2 problems are that I have low compression on two cylinders. Compression readings are:
1: 65-70 psi
2: 135 psi
3: 130-135 psi
4: 90 psi
Adjusted valves on both low cylinders with less pre load than before to see if maybe the valves were just open too long. 1 full turn of pre load now.
Let the van idle for 30 minutes to fill lifters with oil. Removed plugs, rechecked compression. Same exact compression. No change whatsoever. Put a couple drops of oil in cyl 1 to see if that helps, no change. What could this be? Why wouldn’t it change when I adjusted valves?
3rd problem is the cyl 3 seems to not be receiving spark. Something sounded a bit off, so I was checking spark. Pulling wires effected idle for 1,2, and 4, but didn’t change anything for 3. Brand new wires and new plugs. When I pulled plug for compression test, 1,2, and 4 all look normally slightly discolored. Number 3 looked to be fresh out of the box. Will check spark on plug tomorrow.
The great conundrum is this:
How is it that this engine has 2 cylinders with low compression, one cylinder not receiving spark, and one cylinder functioning properly, but still running?
Does anyone have any other ideas on what may be going on? |
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djkeev
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Joined: September 30, 2007
Posts: 32584
Location: Reading Pennsylvania
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MarkWard
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Joined: February 09, 2005
Posts: 17114
Location: Retired South Florida
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| Posted: Sun Apr 25, 2021 7:20 am Post subject: Re: 82 Aircooled With Some Odd Problems |
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New parts can be defective. You can check a plug wire with an ohm meter. Swapping spark plugs, swapping injector leads can sometimes help pinpoint a flat miss. If you can get the miss to move.
A cylinder leak down test will tell you why your low pressure cylinders aren’t sealing.
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jlrftype7
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Joined: July 24, 2018
Posts: 3576
Location: Chicago
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| Posted: Sun Apr 25, 2021 7:43 am Post subject: Re: 82 Aircooled With Some Odd Problems |
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You could have a burned valve or eroded valve for those cyls. that didn’t respond to a bit of oil being added on the 2nd go around with compression testing.
Valve clearance can be set to spec, but your actual sealing is not happening due to issue between valve and its’ seat.
As Mark noted, next step is renting or borrowing a Leak Down Tester. Do you have access to compressed air or compressor. A small unit is all that’s needed since you are only filling the tiny combustion chamber on your engine.
With the valves closed on the cylinder you’re testing, you fill the cyl. with compressed air via removed spark plug hole, adjust the gauges and follow the tester instructions , and listen for air escaping if the leak rate is high on your gauges.
Intake valve leaking will hiss air out of your intake manifold/throttle.
Exhaust will be heard out of the tailpipe.
A piston ring leak can be heard through the engine with removal of the oil filler cap.
You can leak through both a valve(s) and worn cyl/rings at the same time on an older engine. Broken rings are also possible .
_________________
'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto |
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GhostlyHalo
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Joined: December 22, 2020
Posts: 68
Location: Dallas TX
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| Posted: Sun Apr 25, 2021 8:42 am Post subject: Re: 82 Aircooled With Some Odd Problems |
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I understand that it will still fire, but won’t it sound very weak at idle? Won’t it be rather rough with 2 cyl low compression and something TBD happening in a 3rd cyl? Just my thought.
Plan today was to check wire and change plug out. So that will surely be done. I will also switch injector with another cylinder and see how it runs then.
And from the sound of it, a leak down test is my next course of action after all that. When I get that done, I will report back with my findings! Thank you for the run down of how to use and assess findings from it. |
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dobryan
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Joined: March 24, 2006
Posts: 16501
Location: Brookeville, MD
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brickster
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Joined: January 05, 2004
Posts: 512
Location: CO, USA
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| Posted: Sun Apr 25, 2021 10:18 am Post subject: Re: 82 Aircooled With Some Odd Problems |
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| Also test series resistance (24.6 in Bentley). |
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GhostlyHalo
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Joined: December 22, 2020
Posts: 68
Location: Dallas TX
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| Posted: Sun Apr 25, 2021 1:31 pm Post subject: Re: 82 Aircooled With Some Odd Problems |
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Harness is brand new from kyle automotive, but will check it out if switching injectors doesn’t do anything. As previously mentioned, can’t rule out something just because it’s new.
Will check series resistance too!
Got a full rest of the day with the van ahead of me! Should be a grand ole time! |
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GhostlyHalo
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Joined: December 22, 2020
Posts: 68
Location: Dallas TX
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| Posted: Sun Apr 25, 2021 2:38 pm Post subject: Re: 82 Aircooled With Some Odd Problems |
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An update so far
Whipped out the multimeter to test a few things before swapping spark plug for a different one or swapping injectors.
Series resistance:
6.0 both sides (5.5-6.5 Bentley 24.6)
Fuel injector resistance:
(between 2-3 ohms)
1 : good
2 : good
3 : good
4 : good
Ignition wires:
(1000 ohms +/- 200)
1 : 2000 ohms
2 : 0 ohms
3 : 2000 ohms
4 : 2000 ohms
Cyl 2 is where I thought I had no issues. Looks like something is up with that wire though.
On to continue the rest of the hunt.
I also bought an air compressor and leak down test kit to check this all out. Should be getting to that this evening. Allowing time to be sure I’m doing this right before I give it a go.
Edit: spark plug changed to a known working plug. No difference. Changing injector now. |
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jlrftype7
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Joined: July 24, 2018
Posts: 3576
Location: Chicago
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| Posted: Sun Apr 25, 2021 7:57 pm Post subject: Re: 82 Aircooled With Some Odd Problems |
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| GhostlyHalo wrote: |
An update so far
Whipped out the multimeter to test a few things before swapping spark plug for a different one or swapping injectors.
Series resistance:
6.0 both sides (5.5-6.5 Bentley 24.6)
Fuel injector resistance:
(between 2-3 ohms)
1 : good
2 : good
3 : good
4 : good
Ignition wires:
(1000 ohms +/- 200)
1 : 2000 ohms
2 : 0 ohms
3 : 2000 ohms
4 : 2000 ohms
Cyl 2 is where I thought I had no issues. Looks like something is up with that wire though.
On to continue the rest of the hunt.
I also bought an air compressor and leak down test kit to check this all out. Should be getting to that this evening. Allowing time to be sure I’m doing this right before I give it a go.
Edit: spark plug changed to a known working plug. No difference. Changing injector now. |
Thanks for the update- 
_________________
'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto |
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GhostlyHalo
Samba Member
Joined: December 22, 2020
Posts: 68
Location: Dallas TX
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| Posted: Sun Apr 25, 2021 8:26 pm Post subject: Re: 82 Aircooled With Some Odd Problems |
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So swapping the injectors made a huge difference. Good injector on good cyl now and faulty injector on low compression cyl. Ran MUCH better that way. Gonna order injectors tonight. Any suggestions on brand? Or should I have mine rebuilt by fuel injection Corp? My problem one is a little burnt from a fire the previous owner had. Don’t know if they will rebuild that one.
Didn’t have time to do leak down test today, but I’m happy with the progress I did make. I’ll do the leak down sometime this week. |
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djkeev
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Joined: September 30, 2007
Posts: 32584
Location: Reading Pennsylvania
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GhostlyHalo
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Joined: December 22, 2020
Posts: 68
Location: Dallas TX
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| Posted: Mon Apr 26, 2021 11:42 am Post subject: Re: 82 Aircooled With Some Odd Problems |
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Thank you!
That’s exactly the type of thing I was looking for! Thanks! I’ll be sending them off to mr injector!
Only the blue part is a little crispy, but resistance was still dead accurate. If resistance was off, then it would definitely be a no brained for me! Think it’s still better to replace it to be on the safe side? |
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MarkWard
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Joined: February 09, 2005
Posts: 17114
Location: Retired South Florida
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| Posted: Mon Apr 26, 2021 11:51 am Post subject: Re: 82 Aircooled With Some Odd Problems |
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You’d want to change injectors in sets. They need to be equal in flow and characteristics.
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GhostlyHalo
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Joined: December 22, 2020
Posts: 68
Location: Dallas TX
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| Posted: Mon Apr 26, 2021 12:08 pm Post subject: Re: 82 Aircooled With Some Odd Problems |
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| MarkWard wrote: |
| You’d want to change injectors in sets. They need to be equal in flow and characteristics. |
A little confused by this. Are you saying to buy 2? And send those in with 2 of mine? Instead of just sending 3 of mine with 1 that I buy used? |
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djkeev
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Joined: September 30, 2007
Posts: 32584
Location: Reading Pennsylvania
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GhostlyHalo
Samba Member
Joined: December 22, 2020
Posts: 68
Location: Dallas TX
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| Posted: Mon Apr 26, 2021 1:42 pm Post subject: Re: 82 Aircooled With Some Odd Problems |
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| djkeev wrote: |
Send the four you have. He will test initially.
He will then clean retest and make sure they are all good as a set.
If something is amiss, he will let you know.
Honest outfit.
IdahoDoug keeps an eye on them ..... 
Dave |
Works for me! Thank you.
Now the choice is, do I send them off next week after I run my leak down test? Since I will need to warm up the engine before testing. Or should I just send them off tomorrow and do leak down when they get back? I guess either works huh? |
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MarkWard
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Joined: February 09, 2005
Posts: 17114
Location: Retired South Florida
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| Posted: Mon Apr 26, 2021 3:15 pm Post subject: Re: 82 Aircooled With Some Odd Problems |
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I wouldn't bother trying to run the engine any more. Gas will soak down the rings if it's not atomizing properly. It can also overheat a cylinder if it's not spraying enough.
Set of 4 if you purchase new ones. Send 4 to have yours renovated.
If you need to rebuild the engine for a compression issue, you'd be doing the injectors anyhow. Might as well get that out of the way. Also make sure your tank is clean. Remove the fuel filter and see what is in it. You don't want to be running water into your renovated injectors.
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GhostlyHalo
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Joined: December 22, 2020
Posts: 68
Location: Dallas TX
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| Posted: Mon Apr 26, 2021 6:08 pm Post subject: Re: 82 Aircooled With Some Odd Problems |
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| MarkWard wrote: |
I wouldn't bother trying to run the engine any more. Gas will soak down the rings if it's not atomizing properly. It can also overheat a cylinder if it's not spraying enough.
Set of 4 if you purchase new ones. Send 4 to have yours renovated.
If you need to rebuild the engine for a compression issue, you'd be doing the injectors anyhow. Might as well get that out of the way. Also make sure your tank is clean. Remove the fuel filter and see what is in it. You don't want to be running water into your renovated injectors. |
Will do! Thanks for the input!
Fuel filter is new. I changed it right after I bought the van. And I drove 400+ miles to get it home, so any bad gas in the tank was more than likely gone before I changed filter. |
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4Gears4Tires
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Joined: October 08, 2018
Posts: 3019
Location: MD
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| Posted: Mon Apr 26, 2021 9:41 pm Post subject: Re: 82 Aircooled With Some Odd Problems |
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Whatever you do, don't buy ebay injectors. They aren't the right size and they come pre corroded! What a waste of money! They are too short and will wobble around, not making a great seal and potentially leaking gas out and setting your van on fire. I cut the old rubber bushings in half to create 1 1/2 rubber bushing space and now they fit tight, but I don't trust them now. What are the chances the fuel flow rate is correct? 
I am sending my old injectors off and will be throwing these in the garbage when my originals are back.
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