81 Vanagon, signs of running lean at ~3100-3500 rpm

[RSorak 71Westy]

The valves are under the valve covers, The covers are on both sides of the engine. They are held one by a wire bale on air cooled buss'.

[Gypsie]

Hey Mike, Are you working on this today. I could cruise by during my lunch break to point and give tips, and make inappropriate comments... but I am in work clothes so no climbin around under the rig...

[dtrumbo]

I'm assuming you have hydraulic lifters since I'm assuming your vehicle is the '81 Adventurewagon listed in your signature. If my assumptions are correct, be careful with your Google/TheSamba searchin' as the valve adjustment procedure is different depending on whether you have hydraulic lifters or solid lifters.

I wish I knew of a "with-pictures" link to which to point you. Unfortunate that Colin just left town. A half-day would give you the basic care and feeding.

[airkooledchris]

this page has an excellent writeup on how to adjust yer valves: http://www.benplace.com/1700valves.htm

with pics.

[Kubelwagen]

Thanks all! Sorry if I sounded an ass. This has been a looooong week at the office.

Gypsie didn't do it today, thought I might this evening but the kids have got me. Just got your pm - will give you a ring this weekend. I have hopes of getting in there early on Sunday.

Thanks again,

Mike

[Kubelwagen]

Update. Gypsie and Frank, a fellow aircooled Vanagon driver, did some looking today.

First, cold compression test. #3 and #1 were about 100, #4 and #2 around 110.

Adjusted the valves. Number 3 exhaust was set at about 2 3/4 turns, quite a bit more than the others. After the valve adjustment and some general messing around (those beers don't drink themselves). We did another compression check, which I apparently didn't write down (see comment above).

All cylinders were over 100 and most clustered around 110. Exhaust "pressure" was much better. We did the "Colin check" on the AFM and did a very minor adjustment.

We also did the pull each plug wire in turn test and #3 seemed to be pulling a more equal weight after the adjustment. A test drive showed smooth power across the rpm range and good power up to and including freeway speeds (over 60). There was one backfire on decel, but we were not able to replicate it. Note: decel valve is still disconnected awaiting new vac lines etc.

Next steps. I plan, in the next couple of days, to do a more prolonged freeway test run. Also, I have a AFM "boot" on order to replace mine which is all taped up and presumably not so very good. Plug leaks associated with decel valve and see if I can get it working.

All in all it was a positive day. I'm still kind of confused about Gypsie's "ritual of removal of the valve covers" and the "blessing of the adjustment" - did we *really* need all that lube? Why did I have to wear that ceremonial outfit?

[Gypsie]

after adjustement compression:
#1 100
#2: 110
#3:108ish
#4: 110
As I recall #2 also had an exhaust that was above 2 turns in.

I am attributing the extra turns from 'first contact' (FC) to being a 'reduced gap' ie if these were solids, then they would be getting a tighter clearance. Cause: either valve seats recessing or valve stems stretching. Now please step in here and correct if this is heading down the wrong path.

Remember that this is the first adjustment since Mike has had the rig. We assessed its current setting only as an exploratory exercise. Most of the valves were at 1.5 turns in from FC but a few were at more than 2 and at least one was at only 1 turn.

This engine made a desert run to Maupin, loaded with family and camp gear, with what is presumed to be a very lean condition and some vacuum leaks. Could this have contributed to seat recession or stem stretching?.....

At this point, I think that the vacuum leak elimination process is close to complete and will help. As well, we have confirmed that the engine likes it's current mix adjustments via the Colin method (as yet no LM1). Good power and runs strong up to and beyond 4k under load. The initial 'backfire' was in 2nd gear after a hard increase to almost 5k (or close to) and wasn't very strong. I am attributing it to a hard push and release.

Our adjustment to the afm was a static enrichment adjustment (app a half step), this in addition to the 8 clicks dynamic enrichment from last week, seems to be helping. so much so that we turned the idle mix screw out one full turn to lean it out a bit at idle since it was loving the mix at medium and high rpm.

As far as the lube and the outfit....remember that you must not remove either for at least three days....


Otherwise we'll have to do it again....

[Amskeptic]

this is the first adjustment since Mike has had the rig.

This engine made a desert run to Maupin, loaded with family and camp gear, with what is presumed to be a very lean condition and some vacuum leaks. Could this have contributed to seat recession or stem stretching?.....

There are absolutely no conclusions to be made until *after* your first adjustment.
Who knows?? how carefully they were adjusted by prior hominid.

Thou Shalt Not Catastrophically Speculate Here . . .

[Kubelwagen]

But, given the (at least for now??) improvement in #3's contributions and improvement in overall running. Can we make any conclusions?

Now don't get me wrong, I'm still basking in the fact that things *do* seem to be improved. I've not really done any deep thinking as to *why*.

[Gypsie]

There are absolutely no conclusions to be made until *after* your first adjustment.
Who knows?? how carefully they were adjusted by prior hominid.

Thou Shalt Not Catastrophically Speculate Here . . .

Agreed. We have reset to a known quantity and the engine tells us that it 'feels better'.

It was worth the 'exploratory exercise' to practice valve adjustment and do some thinkin' on cause and effect.

Please confirm or deny what is 'hypothetically' happening if the valve adjustment shows an increase in the number of turns back out to to FC. (ie does that mean that the 'gap' is shrinking? What would cause this? Stretching valves? receeding seats?)

Mike, after you have finished your vacuum leak eliminations there may be another mix adjustment needed.


Question for the experts:

RE: california model 1982, 2l vanagon with all the emissions bells and whistles (ie electronic ignition shtuff and the DVDA) seemingly intact. This is another IAC brethren lurker and fellow vanagoneer, OneWay.

The Colin method of mix assessment indicates a lean condition across the board.
When checking the high rpm mix zone, it appeared to indicate that it was very lean (i.e. the RPMs continued to climb with a manual manipulation to call for more fuel...??? Not just a little more fuel but seeming a lot more fuel...?? Then when I let go of the wiper (while continuing to hold the throttle open) the RPM.s dropped for a second and then climbed back to where we started...?
I am attributing this to the emissions devices stepping in to take control and do some adjusting to timing (the DVDA?) and such...
Cursory inspection found at least one vacuum leak when the vac line to fuel pressure and decel valve was moved around. There may be more as indicated by the old the vac hose connections and there is evidence of excess heat in the engine bay.

We made a mild static enrichment adjustment but I am thinking that the emissions devices (as well as vacuum leakage) may be interfering with a proper adjustment.

What say ye?....

[Amskeptic]

Please confirm or deny what is 'hypothetically' happening if the valve adjustment shows an increase in the number of turns back out to to FC. (ie does that mean that the 'gap' is shrinking? What would cause this? Stretching valves? receeding seats?)

Yes. Confirmed. IF it happens again at next valve adjustment, we are up to 2 out of 3 trend warnings. Next one would signal a cylinder head pull is in your future.

california model 1982, 2l vanagon
mix assessment indicates a lean condition across the board.
What say ye?....

I say, I say, do you have the oxygen sensor hooked up (green wire to the little flattish black plug)? It will demand 14.7 even if you compensate with manual manipulation of wiper in AFM. Then when you release the wiper, the ECU gets fooled for an instant. Read up on that infernally imprisoned engine to emissions requirements. Do think about plugging in the sensor again:
Rock: do you have a functional catalyst? It wants ox sensor.
Hard Place: do you like bleached white exhaust valves? they don't want ox sensor.
Colin

[Gypsie]

vunderbar. this is what i was looking for. A rabbit to chase down a hole.

I will look closer when next I meet with one way. He may join us on the Hambone trip this weekend. I will brush up before then...

[Kubelwagen]

So here we go again.

Took off camping last night and had to turn back. Once the engine was hot, that is 45 minutes from home, symptoms started.

1) First sign was we stopped at a light and I noticed the idle was wandering - little up, little down. But I still had good power pulling away from the light.

2) Couple miles down the road it was like she started running out of gas again at speed. Run, lose power, rev back up, lose power. Could hold speed, but not smoothly. Could not detect any unusual engine noises.

Pulled into a brewpub (what else is one to do) got the fam set up with food. Went straight back and felt oil dipstick, and around - engine did not seem super hot (I don't have a temp gauge.)

Played around with the fuel filter for awhile, could still blow through it, but it is time to replace it anyhow. Cancelled the trip and headed home after having been sitting there for 90 minutes or more.

Started fine, ran OK but not great in town. Still surged at 50 all the way to the freeway, but when we GET to the freeway.... it ran like a top all the rest of the way home, including through town and stop and go on side streets.

My thought is to look at the fuel pump, but with all the history on this engine I'm not sure if I'm not just grasping at straws.

[Amskeptic]

So here we go again.
Took off camping last night and had to turn back. Once the engine was hot, symptoms started.
Cancelled the trip ran like a top all the rest of the way home,

Dammit. You need a field technician. When it is hot and misbehaving is the exact time to perform crackerjack diagnostics.
Heat related:
Coil.
TS2
Valve Adjustments
etc ...
Colin

[Kubelwagen]

TS2?

Yes, I'm thinking to too regards the field tech. I just don't have enough experience to know what I'm looking at.