nine tenths

[Kubelwagen]

So, I feel like I'm *almost* there. Got the '81 Adventurewagen (Vanagon) purring at warm idle, just a little sleepy sounding on cold start and moving much better.

Situation:

As-new Philbin rebuilt dizzy went in this evening, timed to the best of my abilities per my battered old Bentley manual and my shiny new timing light. Clear increase in the power curve, third gear is now a real zoom.

Remaining issues:

There's a new? vacuum leak someplace - will work on fixing that tomorrow when the sun comes back.

Pop-pop-pop on decel remains - perhaps from the leak above?

Still lacking some on the top end. She'll get on up to 65, but should it really take so long from 60? No room to try to go faster tonight. Wondering if I should plumb the mysteries of my air fuel mixture next? Gypsie, still got that fancy meter?

Michael

[germansupplyscott]

Pop-pop-pop on decel remains - perhaps from the leak above?

pop on decel is usually exhaust leak. probably close to the exhaust port, ie heat exchanger flanges may not be sealing well.

[Kubelwagen]

Thanks - I know the exhaust is less than...pristine.

What do folks think about the top end? Am I expecting too much?

[Gypsie]

Yes I have the LM1, but.....



I recommend it's use as a testing and diagnostic to confirm adjustments.

resolve all the possibilities first then use it to check the end result.


Look for the exhaust leaks.... find any stray vac leaks.... Dial in using yer best wrenchin' and Bentley specs....,

P'raps a 'baseline reading' with what you have now to see yer starting point. Then give the once over. dial in using the Colin AFM adjust method (after the above issues are resolved) Then a follow up reading.

I found that focusing on the LM1 readings makes it too easy to overlook the other items.

2cents.

[Kubelwagen]

Sounds like wise words. I know I've got previous-owner syndrome with my exhaust. It seems to have that certain cobbled together look.
Thanks!

[Kubelwagen]

Gypsie was kind enough to share his Saturday morning with me and we found some things out.

Firstly, Clan Gypsie is both generous of time, coffee and expertise (not to mention I owe him a coil). They also have found themselves a great house in a picturesque neighborhood.

But, VWs. The symptom was lack of power, most noticeable in 4th gear. On the way up to Chez Gypsie I was luck to get 60 and couldn't hold it on any sort of incline. This is after the dizzy refurb (which did solve one problem), new cap, rotors, plugs and wires.

So, we double checked the timing - fine. Moves good on revving, etc.

Hunted vacuum leaks, fixed those we found.

Other findings:

ARM intake air sensor resistance check - is out of spec (550-600+) on both 6 & 7 and 7 & 8. Max is supposed to by 500, so it out but not an order of magnitude out. Cleaning the connections didn't change our results.

Question: what symptoms would this cause? Is there a way to test if this is causing a problem?

Decel valve has been disconnected since I bought the van. When we hooked it up the engine would stay at high revs, never quite coming down. Fixing the vacuum leaks seemed to help this....but more on this valve in a minute.

At this point we had some coffee and looked at a frog for awhile.

Upon hooking the LM1 up we found extreme lean - 23-25 which did not get much better upon revving the engine. We did some poking around and eventually disconnected the decel valve again. This had no real impact on the idle readings, still 23-25. But, revving values dropped down to around 15-17. We (OK, Gypsie) did three clicks richer on the "spring" high rev adjustment. This made the rev numbers better, but I didn't write them down.

Question: what are the symptoms of a bad decel valve?

Took it on the road at this point, driving LM1 reading were better, but still lean 15-16 or so. Low power symptoms were the same.

Coming back, we tested the coil which was out of spec. Gypsie produced one (for which I owe beer, food and thanks) from one of his workshops and we installed it.

LM1 reading at idle was the same*. Gypsie moved the overall richness up one click, dropping the idle level to about 22. We're both out of time with our spouse at this point so we button up and I head home.

Hit the freeway, I'm focused on not getting run down by a semi with a death wish (other peoples), look down when I'm in the clear and I'm doing 65. Power problems largely gone, still perhaps a little less go than 6 months ago but it is hard to tell.

* Another factor in play is the exhaust system. It is clearly subpar and we may be artificially inflating the idle LM1 readings. This concern led us to minimize our fiddling till I can get a tight pipe on there.

So, my plan at this point:

See if I get some wisdom from you all.
Source a stock muffler, etc. and install it before/as I have Halsey do a once over?

Or - other things I should check?

Mike

[Lanval]

Question: what are the symptoms of a bad decel valve?

As far as I know, the only direct effect of a bad deceleration valve is that when you take your foot off the gas, the engine doesn't return to idle.

I couldn't say if it has other effects, but it's pretty easily fixed, expensive or cheap.

Expensive = buy a new one
cheap = plug the line that goes to the T fitting (I cut mine, and put one screw each in both sides of the cut).

Didn't seem to affect getting smogged, so I can't see it having much effect on engine power.

Lanval

[airkooledchris]

are you CERTAIN that you have no exhaust leaks anywhere in the system?

otherwise all of the AFM fiddling needs to be done all over again. be sure to mark where you start with that stuff, it's painful trying to get it back when you realize you've adjusted the wrong way (if you end up having found an exhaust leak.)

your power issn't shouldn't have jack to do with the decel valve.

how is the compression?

[Kubelwagen]

We didn't get around to checking the compression, but since the power was (mostly) back after the new coil I'm thinking that the problem was elsewhere, or at least think I have reason to hope so :) . I don't have the stuff to test it, but will look into that as well.

I did some more looking today and it seems that I do have an exhaust leak. Black soot, poor condition, etc.

The whole system is hokey, so I'm on the lookout for a decent OEM type exhaust. Given everything else that's going on I'm looking at used first. Though, Bus Depot got a set up for a bit over $200 so I've got that as a reference point.

I also have some vacuum lines that I'm just going to replace because they are a) old and b) ugly. I should replace the whole S boot, but will have to do some looking.

I'm still unsure if I have a problem with my AFM or not, the resistance check certainly did fail.

[Gypsie]

Sorry it's taken me so long to look here.

I will preface this by saying that when Michael showed up at our agreed upon time of "early or around 8ish" I was nursing a bad hangover that had me worshipping at the porcelein altar...

20 minutes with exhaust and things got better, surprisingly.

We did the Colin AFM testing to see what the engine wanted, the LM1 was used for reference later and was always questioned because of the exhaust concerns. Colin's method told us that the engine wanted more fuel. More at high rpm than at low rpm. 3 clicks ccw.

More colin method and LM1 referencing indicated that an allover enrichment was called for. (one cog of the static adj, ccw)

The road test (pre coil swap) with LM1 reference gave me grave concerns about blowtorching valves (steady low to mid 20's with a rare dip into the high teens) but this concern was tempered with the exhaust leak potentials.
We relied more on the engine's feedback via the Colin method than the LM1.

We did find some noted vacuum leaks (carb spray at the usual suspects) though nothing 'really' responded). Even when pulling the dizzy advance line and squirting directly into it there was only a 'slight' response.

the s-boot has been 'repaired' by wrapping the entire length with elect. tape. as are several of the other vacuum lines. (the big ones with braided exterior.

The decel valve connection to s-boot (the metal flange that goes into the s-boot was very loose and pulled out with little coaxing. we dabbed some rtv to secure it in place on the s-boot side.

My spidey sense makes me think that there is either a substantial vacuum leak somewhere...
or
the AFM is not sending the right signals for the injectors. The 500-600 ohms mentioned was while sweeping the afm across the range and wasn't at each point but a few points along the arc. Bentley says it should not ever go over 500. Tested the meter for accuracy as well.

Michael,
I recommend that you monitor your exhaust pipe color. deep black would indicate a rich condition and ashy white a lean condition.

The popping on deceleration you have mentioned before could also have been a rich condiiton combined with exhaust leaks that allowed the fuel to burn in the exhaust system (or so I'm told). Makes sense so is worth pursuing the exhaust repair.

I also recommend that you go through and replace each and every vacuum line (big,little and in between), to eliminate vacuum leak possibilities.
Also look into doing a better s-boot repair. (pull it off and look for cracking around the lips. and give a thorough look see inside to see if you can see why they taped it up (before attempting to remove any of the tape). You may find a biga$$ tear inside that made the PO want to seal it up. There may also just be plain ol' funky mechanican goin' on (not just mine...) As in...I think I have a vacuum leak...I know, I will tape all these vacuum lines to eliminate them as a culprit...(there was a lot of elect tape in there) It may have been one vacuum leak or something else and they were just going overboard...Hard to say.

If you do decide to remove the tape from the s-boot, be gentle and try not to work the sboot rubber too much (use wd 40 on the tape adhesive to make it easier to let go (peel, rub at adhesive seam, peel rub repeat). Someone posted a while back about 'painting' black rtv over the entire surface to resurface and seal the cracks. This could be an economical solution but replacement would be better.

Also check to see if your brake booster connection isn't leaking. You will have to...ahem... suck the pipe to see if there is a leak or a good seal. Someone let us know if there should be a point at which the brake booster will stop allowing vacuum draw. I think there is. Not sure at this moment...

Perhaps another visit when I get ready to drop the engine and tranny on mine and I will be in better shape to go through the other items we didn't do (compression, fuel pressure, and I didn't even remember that I have a new vac pressure guage...Doh!). Timing seemed alright though the marks were stamped on withg a center punch and were not confirmed with a TDC check.

I think you can do many of the things needed before taking it in to someone.

I also seem to recall that you said you hadn't checked valve adjustment in a while.

Maybe we can plan an engine/tranny extraction for another weekend morning and I will do a valve adjustment on mine prior for some pre-
extraction recon. This can give you some practice and observin' time.