Long start-up / warm-up

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fancy pants
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Long start-up / warm-up

Post by fancy pants » Fri Aug 01, 2014 11:01 am

My late-1976 bus is running fantastic. Idles great, runs smoothly, stays cool, is happy as can be :cheers:

BUT, start-up is a bear. Engine fires right up whether it's hot or cold outside, but after about 30 seconds of nice smooth idling, it begins to cough and sputter. The only way to keep it from dying is to keep my foot in it for almost 10 minutes (!) - if I remove my foot from the throttle during those 10 minutes it dies and it is difficult to restart. However, if I leave my foot in it for the warm-up period (~ about 10 min), all is well and she will run without complaint.

note: I cannot drive during this warm-up period. If I put it in gear it will cough and sputter, even with the throttle open.

I've read about a spacer for the ts II sensor that is intended for vehicles that run well at start up and operating temp, but not warm-up. That would seem to describe my problem. But, where do I get this spacer? It is part # 022 133 079

http://www.ratwell.com/technical/TempSensorII.html

Any thoughts? Am I thinking correctly? Or am I missing something obvious?
:salute:
John
76 Bus - Riviera
81 Mercedes 300TD
05 Golf TDI

Gone but not forgotten:
1972 Bus
1973 Squareback


We are not going to stick anything that dirty down in your hole - Colin, 6/30/2010

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airkooledchris
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Re: Long start-up / warm-up

Post by airkooledchris » Fri Aug 01, 2014 11:12 am

fancy pants wrote:My late-1976 bus is running fantastic. Idles great, runs smoothly, stays cool, is happy as can be :cheers:

BUT, start-up is a bear. Engine fires right up whether it's hot or cold outside, but after about 30 seconds of nice smooth idling, it begins to cough and sputter. The only way to keep it from dying is to keep my foot in it for almost 10 minutes (!) - if I remove my foot from the throttle during those 10 minutes it dies and it is difficult to restart. However, if I leave my foot in it for the warm-up period (~ about 10 min), all is well and she will run without complaint.

note: I cannot drive during this warm-up period. If I put it in gear it will cough and sputter, even with the throttle open.

I've read about a spacer for the ts II sensor that is intended for vehicles that run well at start up and operating temp, but not warm-up. That would seem to describe my problem. But, where do I get this spacer? It is part # 022 133 079

http://www.ratwell.com/technical/TempSensorII.html

Any thoughts? Am I thinking correctly? Or am I missing something obvious?
:salute:

I have 4 or 5 of those spacers stashed away in my garage. From what I understand the bus shouldn't need them unless it's to mask a different problem (like vacuum leaks) - but if you rule out everything else and want to try it - shoot me a PM with your address.
1979 California Transporter

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airkooledchris
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Re: Long start-up / warm-up

Post by airkooledchris » Fri Aug 01, 2014 11:30 am

did this same engine run without this issue previously?
when the problem started, was it gradual and then got worse and worse or was it out of the blue?

for a build where this has always been an issue, id say try the sensor extension and see if it helps. if something changed, especially a sudden change, id keep pushing forward with troubleshooting everything else.
1979 California Transporter

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fancy pants
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Re: Long start-up / warm-up

Post by fancy pants » Fri Aug 01, 2014 11:48 am

I rebuilt the engine 4 years ago and the start issue has been present the whole time. It has definitely worsened, but not suddenly. Initially the bus had a lopey idle after the build, but with some time spent dialing int he mixture, that is no longer an issue. However, now that the idle is cured, the startup issue has worsened.

I should also say that even though it has been 4 years since the engine has been rebuilt, there are less than 5000 miles on the rebuilt engine. Up until this summer, over the past 2 years I've put on less than 100 miles, but I have been determined to get her out this summer - and I have. Taken a few long trips with great results (with the exception of the warmup), and am heading to Orcas island on Wednesday. It'll be the longest trip i've taken since the rebuild. (One reason that I bring this up now is that I am dreading starting/warming the bus up while on the Ferry. I'd hate to hold up a whole line of people trying to get off the boat while I rev the engine for 10 minutes!)
John
76 Bus - Riviera
81 Mercedes 300TD
05 Golf TDI

Gone but not forgotten:
1972 Bus
1973 Squareback


We are not going to stick anything that dirty down in your hole - Colin, 6/30/2010

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SlowLane
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Re: Long start-up / warm-up

Post by SlowLane » Fri Aug 01, 2014 12:17 pm

Two things to check: the Auxiliary Air Regulator (AAR) and the thermostat. Both are in effect during the warmup period.

Colin has a comprehensive writeup on the AAR somewhere in here. While you have the AAR out, be sure to inspect the AAR rubber elbow carefully under good light to make sure it doesn't have any vacuum-inducing cracks or splits. I've found it prudent to carry around a couple of spare AAR elbows, because the ones available from the aftermarket are pure c**p.

Don't have a working thermostat? The unit from Clark Callis at Awesome Powdercoat is the cat's meow. Better than OEM. It's a bit pricey at $120, but that's the way of things nowadays.
'81 Canadian Westfalia (2.0L, manual), now Californiated

"Wisdom comes from experience. Experience is often a result of lack of wisdom."
- Terry Pratchett

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Amskeptic
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Re: Long start-up / warm-up

Post by Amskeptic » Sat Aug 02, 2014 8:16 am

fancy pants wrote:I rebuilt the engine 4 years ago and the start issue has been present the whole time. It has definitely worsened, but not suddenly. Initially the bus had a lopey idle after the build, but with some time spent dialing int he mixture, that is no longer an issue. However, now that the idle is cured, the startup issue has worsened.

I should also say that even though it has been 4 years since the engine has been rebuilt, there are less than 5000 miles on the rebuilt engine. Up until this summer, over the past 2 years I've put on less than 100 miles, but I have been determined to get her out this summer - and I have. Taken a few long trips with great results (with the exception of the warmup), and am heading to Orcas island on Wednesday. It'll be the longest trip i've taken since the rebuild. (One reason that I bring this up now is that I am dreading starting/warming the bus up while on the Ferry. I'd hate to hold up a whole line of people trying to get off the boat while I rev the engine for 10 minutes!)
Hello John,
Seeing as I haven't heard from you in ages, I would exPECT that your VW MUST be running excelLENTLY.

Now then, do you have a "performance" cam, a "mild performance" cam, a "lightly massaged" cam, a "designed specifically for the fuel injected bus but a little better power" cam? Tee a vacuum gauge on the manifold nipple and give us a number on a warm engine. I do forsee an adjustment to improve aux air regulator opening.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 93,996 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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fancy pants
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Re: Long start-up / warm-up

Post by fancy pants » Sat Aug 02, 2014 4:30 pm

Yep - I do have what Hall's Machine Shop called the "bus grind" on the cam. Word is that it is a pretty mild alteration, but it's non-stock just the same. Hambone is a-gonna swing by this week and we are going to look at the AAR together. I unfortunately don't have a vacuum gauge though. Will try to wrangle one. (Hey, anyone in PDX have a vacuum gauge I can borrow? :bounce: )
John
76 Bus - Riviera
81 Mercedes 300TD
05 Golf TDI

Gone but not forgotten:
1972 Bus
1973 Squareback


We are not going to stick anything that dirty down in your hole - Colin, 6/30/2010

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Amskeptic
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Re: Long start-up / warm-up

Post by Amskeptic » Sun Aug 03, 2014 9:10 am

fancy pants wrote:Yep - I do have what Hall's Machine Shop called the "bus grind" on the cam. Word is that it is a pretty mild alteration, but it's non-stock just the same. Hambone is a-gonna swing by this week and we are going to look at the AAR together. I unfortunately don't have a vacuum gauge though. Will try to wrangle one. (Hey, anyone in PDX have a vacuum gauge I can borrow? :bounce: )
Bone-stock 2.0 pulls 13.7-14 inches vacuum at warm idle.
Performance cams will knock that down closer to 10.
Engines runs poorly under 10, AFM just can't get enough air flow signal with all that exhaust dilution at overlap.

As your guides open up due to normal wear over time, the vacuum at idle drops. Open up the AAR by loosening the 7mm pivot screw and sliding it in the "open" direction as far as it will go.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 93,996 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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fancy pants
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Re: Long start-up / warm-up

Post by fancy pants » Sun Aug 03, 2014 10:43 am

Thanks Colin. That sounds like something to look into for sure. Just to be clear though, the idle is beautiful once it warms up, and upon immediate startup. After starting, it idles well for about 30 seconds, then the idle dives and sputters and I need to keep my foot on the accelerator for about 10 minutes. After that, the idle is great.
John
76 Bus - Riviera
81 Mercedes 300TD
05 Golf TDI

Gone but not forgotten:
1972 Bus
1973 Squareback


We are not going to stick anything that dirty down in your hole - Colin, 6/30/2010

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Xelmon
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Re: Long start-up / warm-up

Post by Xelmon » Sun Aug 03, 2014 1:29 pm

Fancay, great to see that you're still around - and that you still have the bus!

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tristessa
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Re: Long start-up / warm-up

Post by tristessa » Sun Aug 03, 2014 6:31 pm

fancy pants wrote: I unfortunately don't have a vacuum gauge though. Will try to wrangle one. (Hey, anyone in PDX have a vacuum gauge I can borrow? :bounce: )
I don't have a gauge to loan you, but this one is available close to your house, gets good reviews and doesn't cost much:
http://www.harborfreight.com/fuel-pump- ... 93547.html
Remember, only YOU can prevent narcissism!

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Amskeptic
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Re: Long start-up / warm-up

Post by Amskeptic » Sun Aug 10, 2014 7:50 am

fancy pants wrote:Thanks Colin. That sounds like something to look into for sure. Just to be clear though, the idle is beautiful once it warms up, and upon immediate startup. After starting, it idles well for about 30 seconds, then the idle dives and sputters and I need to keep my foot on the accelerator for about 10 minutes. After that, the idle is great.
Classic auxiliary air regulator behavior with a "performancy" cam . . . or even a "RV' cam, right mtcamper?
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 93,996 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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