Troubleshooting request for rough cold idle

[Van Gooo]

Hello Folks:
I am the proud owner of a new to me ‘77 Westy. It is FI, pertronix, hydraulic lifter original type 4.

I scour this site and others and really value the community here. I am hoping to get some advice from some of you seasoned vets for trouble shooting.

I have had the bus for about a month now, and have had my first side of the road breakdown experience today.
I have noticed over the the last two weeks that the bus when cold, will not idle. I have to have my foot on the accelerator for about 4-6 mins until the motor is warm, for it to idle properly. If I don’t let it warm, it will stall.
And then today, it was 90+ degrees here in central Indiana and I was just about home after a two hour trip home, and at a red light, the bus stalled out. After waiting for 15 mins or so, it fired up and then it did it again. Stalled at a stop sign.
So I waited and took it to get gas.
I only run Shell premium gas in it.
I also got a can of Sea Foam and mixed it in. I again had to wait 15 mins at the gas station for it to start.
When trying to start it, it turns over great, but then acts as though it isn’t getting enough gas, as I can have the accelerator 3/4 of way pressed and the engine struggles to run and will not power up into gear.
Then I wait a few minutes more and it runs fine.
Any trouble shooting suggestions would be most welcome.

Thanks in advance,

Jamie.
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VanGooo
77 Westy
DOB 9-2-76
CA bus 2.0 FI

"It is what it is or else it would be weird."

[busdaddy]

Start here: https://www.thesamba.com/vw/forum/viewtopic.php?t=620083&highlight=smoke+tester
Then move on to here: http://www.ratwell.com/technical/TempSensorII.html
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Слава Україні!

[SGKent]

change the fuel filter and do a smoke test for vacuum leaks. Check your fuel pressure too.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Van Gooo]

Thanks Gents! I will do and report back afterward...
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VanGooo
77 Westy
DOB 9-2-76
CA bus 2.0 FI

"It is what it is or else it would be weird."

[airschooled]

How far do you have to depress the accelerator pedal to get it to idle cold? If you have to floor it, you have a significant issue that must be addressed. If you only have to give it 1/4 throttle or less, I would suggest reading up about Auxiliary Air Regulators (AAR) and their function.

http://www.itinerant-air-cooled.com/viewtopic.php?t=7834

The photos are gone, but it might make sense anyway…

Here is another car's site with good details. The engine is a different block, but the principles and valve are all the same:

http://www.firstfives.org/faq/aux_air_valve/aux_air_valve.html

Good luck!
Robbie
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[Van Gooo]

As an update, I replaced the fuel filter the other evening. I have noticed an improvement in the engine starting and running.
I hope to perform the smoke test to see if there are any leaks.

Thanks Robbie for the info regarding the AAR. I will say that I am having a difficult time finding this on my engine. Any help in that regard would be most welcome.

Best,

Jamie
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VanGooo
77 Westy
DOB 9-2-76
CA bus 2.0 FI

"It is what it is or else it would be weird."

[ivwshane]

[Van Gooo]

Thanks so much Ivwshane! Really appreciate the good photos.
I have found it now.

Best,

J
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VanGooo
77 Westy
DOB 9-2-76
CA bus 2.0 FI

"It is what it is or else it would be weird."

[Van Gooo]

Evening Gents:

I have completed the smoke test and found that one hose (top hose) going into decel valve was leaking. I fixed that leak.
It also appears that the throttle valve housing has a leak too.
I haven’t been able to fix that one yet.
I will say that after fixing decel valve leak, engine ran noticeably smoother. It still want to stall out while warming up, but it’s definitely running smoother.
I will try to fix throttle valve housing tonight.

I will look at temp sensor, AAR, and fuel pressure in the next few days.
Also, my new Bentley came yesterday and has already been a huge help!

Any other thoughts or snares with regard to the throttle valve housing, please advise!

Best,
J
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VanGooo
77 Westy
DOB 9-2-76
CA bus 2.0 FI

"It is what it is or else it would be weird."

[busdaddy]

Is the TB leaking from the flange where it meets the plenum?, or the cross shaft?

Sounds like you are making great progress so far!
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[Van Gooo]

I don’t know to be certain. However looking at TB, the smoke was coming from the right side of the TB. Sorry to be vague.
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VanGooo
77 Westy
DOB 9-2-76
CA bus 2.0 FI

"It is what it is or else it would be weird."

[SGKent]

don't adjust anything until the source of the leak is found. Then lets see where the bus performance is at. Do you have access to an air to fuel ratio meter to see what the idle CO is when the vacuum leaks are fixed? Once the leaks are fixed and the idle CO set, then you can adjust the aux air valve if needed. If you adjust it now and then fix a vacuum leak, you may have to put it back where it was. If the leak is the throttle shaft then there isn't a lot you can do unless you want to pull the throttle body shaft off and replace the seal. Sometimes the plastic gasket between the throttle body and plenum leaks. Sometimes the S-Boot has a crack and leaks.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Van Gooo]

Ok folks, I did another smoke test and found the the top of the throttle body, the brass coil area is the source of a leak.
Also PO had disconnected the egr works. They rigged it to seal it with a makeshift gasket. It failed. I pulled it and cleaned the EGR valve and made a gasket out of high temp rtv. Reinstalled it.
Also found an exhaust gasket is leaking. I got a new gasket for it and reinstall tonight.

My question surrounds the TB. What to do?
Can they be rebuilt?
Do I need a new one? If so, any good advice about where to find one?

Thanks in advance for your time and advice!

Best,

J
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VanGooo
77 Westy
DOB 9-2-76
CA bus 2.0 FI

"It is what it is or else it would be weird."

[Van Gooo]

Hi Gents,

Any suggestions on the Throttle body leak?

The leak appears to come from the brass coil itself.
Any help would be most welcomed!

Best,

J
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VanGooo
77 Westy
DOB 9-2-76
CA bus 2.0 FI

"It is what it is or else it would be weird."

[SGKent]

it comes from the seal around the shaft. Live with it unless the idle speed and CO cannot be adjusted because of it. You want to set the idle CO to the factory spec and see how it idles and performs with that. If afterwards it still stalls cold add a little more air thru the aux air valve.

If you have a catalytic converter it might have a port on the engine side you can sniff the idle CO. If it is a Federal bus with no catalytic then you can sniff it at the tail pipe. Most smog shops will have a CO sniffer (Air to fuel gauge). The screw that sets the CO is on top of the air to fuel meter. Then set the idle speed with the one on the throttle body. Set the base CO and idle speed with the engine up to temperature, and the oil at least 180F. (operating temp).
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[aerosurfer]

Where in Indy are you? I'm Southside of the city, I'm happy to help or at least give you a second set of eyes for anything? The air cooled crowd in town has been light too, so another bus to run around with would be great.

Plus I'm pretty fluent in late baby FI
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Rebuild your own FI Harness..My Harness

77 Westy 2.0L Rockin and Rolling Resto!

72 Sportsmobile (sold)
79 Tran$porter... Parts car money machine (gone)

[Van Gooo]

[busdaddy]

[Van Gooo]

TY Busdaddy. I thought so bud didn’t want to assume.
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VanGooo
77 Westy
DOB 9-2-76
CA bus 2.0 FI

"It is what it is or else it would be weird."

[SGKent]

the CO coming from the engine is a direct relationship to the amount of fuel and air going thru it. When it burns completely it makes CO2. When it burns part way it makes CO. So if the mixture has a little CO in it then it is just rich of a perfect mixture. Too much CO and it is too rich. Too little CO and it is too lean. Much more precise than by ear. Once it is set, and idle speed set then you can see how it runs cold. It may be perfect. Or it may still stall in which case you need to increase just the fast idle which is done thru the aux air valve on a FI bus. It acts as a bypass and adds more air like opening the throttle pedal a little without changing the mixture because it is metered air.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin