Cold hard start, low idle

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Kubelwagen
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Location: Portland, OR
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Cold hard start, low idle

Post by Kubelwagen » Wed Mar 06, 2013 8:57 pm

So, I think I'm on the trail of this one but I'd like some confirmation.

Situation:

1981 Vanagon is running fine when warm. On "warm" Oregon winter days (over 50) it starts on one turn without touching the gas. On "cold" Oregon mornings (below 40) I have to give it a few tries and hit the gas to start and the idle is down around 800 on starting, slowly to go up to normal as it warms up. It does, however, idle and is drivable cold, it just takes a little longer than I'd like to get to normal. While this isn't a huge issue I'm concerned about possible impact of altitude and colder weather. Also, on startup and while cold it "smells rich".

Note: Gypsie and I just eliminated some vacuum leaks over the weekend and rechecked the AFM settings. It is currently probably just a touch rich at highway speeds but within acceptable limits.

Thoughts:

I have a cold start injector that is probably full of gunk. Tank was full of rust and the other injectors were not in good shape but I neglected to get this one seen to when I had the other fixed at Dr. Injector. I'm going to pop it out and take it in.

Auxillary Air Regulator - status unknown. From what I have read this is a likely culprit and I'll investigate per the guide posted on this subforum. Anybody in PDX been down this road already? A copilot would be welcome.

Anything else I should be checking?

Thanks,

Mike
Patience the 81 Adventurewagen

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Amskeptic
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Re: Cold hard start, low idle

Post by Amskeptic » Sat Mar 09, 2013 12:24 pm

Kubelwagen wrote:So, I think I'm on the trail of this one but I'd like some confirmation.

Situation:

1981 Vanagon is running fine when warm. On "warm" Oregon winter days (over 50) it starts on one turn without touching the gas. On "cold" Oregon mornings (below 40) I have to give it a few tries and hit the gas to start and the idle is down around 800 on starting, slowly to go up to normal as it warms up. It does, however, idle and is drivable cold, it just takes a little longer than I'd like to get to normal. While this isn't a huge issue I'm concerned about possible impact of altitude and colder weather. Also, on startup and while cold it "smells rich".

Note: Gypsie and I just eliminated some vacuum leaks over the weekend and rechecked the AFM settings. It is currently probably just a touch rich at highway speeds but within acceptable limits.

Thoughts:

I have a cold start injector that is probably full of gunk. Tank was full of rust and the other injectors were not in good shape but I neglected to get this one seen to when I had the other fixed at Dr. Injector. I'm going to pop it out and take it in.

Auxillary Air Regulator - status unknown. From what I have read this is a likely culprit and I'll investigate per the guide posted on this subforum. Anybody in PDX been down this road already? A copilot would be welcome.

Anything else I should be checking?

Thanks,

Mike
Cold start valve only works when starter is energized.

A too-rich mixture will degrade cold idle.

AAR may need an adjustment to get your idle speed up to 1,100-1,200 rpm at first light-off.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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Kubelwagen
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Re: Cold hard start, low idle

Post by Kubelwagen » Tue Apr 02, 2013 8:21 pm

Have had basically zero time to investigate this. Did a slight (two clicks) adjustment last night at the Lab to the leaner to see what happened. Started better that it had been when it was time to go. However cold start this evening it was worse, if anything. Could hardly start it at all. IF I can manage to escape work long enough I'll remove the AAR and go through that test procedure.

Any other thoughts?
Patience the 81 Adventurewagen

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Amskeptic
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Re: Cold hard start, low idle

Post by Amskeptic » Wed Apr 03, 2013 8:33 am

Kubelwagen wrote:Have had basically zero time to investigate this. Did a slight (two clicks) adjustment last night at the Lab to the leaner to see what happened. Started better that it had been when it was time to go. However cold start this evening it was worse, if anything. Could hardly start it at all. IF I can manage to escape work long enough I'll remove the AAR and go through that test procedure.

Any other thoughts?
Do not hit - n - miss guess with this one. The best foundation to your inquiry is to have it running well when warm, then you can focus on Cold Start Componentry.
TS II
TS I

TTS ___ these guys only work during cranking
CSV

AAR ___ needed for decent cold idle for the first five minutes

Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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Kubelwagen
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Re: Cold hard start, low idle

Post by Kubelwagen » Wed Apr 03, 2013 6:59 pm

Good points. It is running great once warm. Smooth and responsive across RPM, good power, etc.


Had some time this evening:

Reset the AFM back to where it was Sunday. Monday's change didn't impact the problem, so went back to baseline.

Took the AAR off. Found that the hose from the AAR up the boot had a significant "kink" in it that may be impacting air flow.

With the AAR hose off, but electrical still on, tried to start the bus. Fired right up as it should, but would not idle. - Tentative thought: likes the air, but too much of a vacuum leak to idle?

Inspected AAR: Very dirty. Cleaned as per the instructions here. Observed open at ambient temp of 65. Ohm reading 29.5. Closed up tight after a brief stint in the oven at 250 degrees.

Conclusion: AAR seems to be in spec.

On to reading up on TS I and II.
Patience the 81 Adventurewagen

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Kubelwagen
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Re: Cold hard start, low idle

Post by Kubelwagen » Wed Apr 03, 2013 7:17 pm

Three more observations.

1) The reopening of the valve seems slower than you described Colin. But it is opening. Problem?

2) The rubber elbow is toast. Big crack in the bottom. I dont' think I did it taking it off, but of course it is possible.

3) I *need* a Beetle to drive to the parts store to get get parts for my Bus. We're talking a fundamental need here.
Patience the 81 Adventurewagen

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SlowLane
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Re: Cold hard start, low idle

Post by SlowLane » Wed Apr 03, 2013 10:16 pm

Kubelwagen wrote: 2) The rubber elbow is toast. Big crack in the bottom. I dont' think I did it taking it off, but of course it is possible.
Get yourself one of these in the 0.5" diameter size and never, ever have to worry about your AAR elbow and hose again.
'81 Canadian Westfalia (2.0L, manual), now Californiated

"Wisdom comes from experience. Experience is often a result of lack of wisdom."
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Amskeptic
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Re: Cold hard start, low idle

Post by Amskeptic » Thu Apr 04, 2013 6:14 pm

SlowLane wrote:
Kubelwagen wrote: 2) The rubber elbow is toast. Big crack in the bottom. I dont' think I did it taking it off, but of course it is possible.
Get yourself one of these in the 0.5" diameter size and never, ever have to worry about your AAR elbow and hose again.
$26.84 is a tad inexplicable to me.
With the AAR hose off, but electrical still on, tried to start the bus. Fired right up as it should, but would not idle. - Tentative thought: likes the air, but too much of a vacuum leak to idle?

Inspected AAR: Very dirty. Cleaned as per the instructions here. Observed open at ambient temp of 65. Ohm reading 29.5. Closed up tight after a brief stint in the oven at 250 degrees.

Conclusion: AAR seems to be in spec.

Kubelwagen, you may NOT run the AAR with a hose off, unless I did not understand how you did it.
You do know that it must take in CALIBRATED air properly READ by the AFM.

So, run a hose from the AAR supply nipple on the S-Boot directly to the intake plenum. Have a needlenose vise grip installed and ready! to clamp down on the hose to calibrate your idle speed. Can you find a cool 1,200 rpm? With the hose squished shut somewhat? Good! Make the damn AAR do that.

Tomorrow morning, leave the visegrips on the hose squished at the level that gave you 1,200 today, and see if the Vanagon starts BEAUTIFULLY> then let us know.

I have written everywhere on this Earth that a clean and fresh factory AAR still may not pass enough air to meet our more loosened up and leaky engines with the ovalized valve guides. I suggest to everyone to open the damn thing up as far as you possibly can, it still closes within the four minutes or so that its internal heater dictates.

Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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Kubelwagen
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Re: Cold hard start, low idle

Post by Kubelwagen » Thu Apr 04, 2013 7:22 pm

OK - so didn't see any of this before I headed out today. So here's where we are at.

Got a new little elbow from Halsey and buttoned everything back up, making sure that the line back up to the plenum (middle of engine) was not all torqued and pinched as it was before. Did a little walk around the engine making sure all the vacuum lines were tight.

Went forward, turned the key and she started right up. Idled fine. Turned her off, started back up. Stumbled slightly (I may have let go of the key a bit quick in my surprise) but the idle took off to normal with a vigor that had been sorely lacking.

Ran her for about 5 minutes and turned off the ignition to simulate stalling at the stop light. Took a hard crank to restart, but did. Turned off, restarted right off on the first try.

So, progress has been made. The primary symptom seems to be much reduced, possibly gone. My plan at this point is to drive for a couple of days and collect some more data. The "PDX Air-cooled Vanagon Club" is planning a work day soon so I'll use that time to complete the diagnostics on the TS I, TS II, etc. for completeness if nothing else. My suspicion at this point is that it is/was a series of things (pinched hose, leak) rather than a single system or sensor that is completely dead. We'll see.

Good exercise for me, I'm feeling more confident in my understanding of my engine having done this.
Patience the 81 Adventurewagen

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Kubelwagen
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Re: Cold hard start, low idle

Post by Kubelwagen » Mon Apr 15, 2013 8:16 am

Update:

I think it is fixed. Starts first try when cold in the morning, every time now.
Patience the 81 Adventurewagen

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Amskeptic
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Re: Cold hard start, low idle

Post by Amskeptic » Mon Apr 15, 2013 11:25 am

Kubelwagen wrote:Update:

I think it is fixed. Starts first try when cold in the morning, every time now.

Good. I wuz gunna say, do not idle your engine for five minutes to "simulate" cool driving, then expect it to start well.

We are NOT to idle our engines for any extended period. Says so in the owner's manual. Drive it right away gently. Afraid you will have a "no-start" that you are trying to replicate? Drive it around the block back to the driveway. Prolonged idling is bad for rings and causes oil contamination with combustion condensates.
Colin
(congratulations, by the way, doesn't a quick start change your attitude?)
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 94,615 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,990 miles

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hambone
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Location: Portland, Ore.
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Re: Cold hard start, low idle

Post by hambone » Mon Apr 15, 2013 12:27 pm

Great job! Nice to see you tackle this on your own, you've come a long way.
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