Missing valve seat and running rich

[oshima]

Could a missing intake valve seat cause a fuel injected 2.0L engine to run rich? I'm wondering because I've 100% thoroughly fixed all the vacuum leaks in my engine (smoke tested), but it is still running rich. I've used 2 different AFMs as well, both giving the exact same results.

The engine is out of the bus for new heads, but I'm wondering if this problem is going to rear its head again once I put it back in.
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1978 2.0L Fuel Injected

[KentABQ]

Have you tried Colin's AFM adjustment method?

https://itinerant-air-cooled.com/viewtopic.php?f=50&t=7761
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-Kent-
1976 Riviera, 1.8l FI chrome yellow VAN - "Chloe"

"I must say, how can you be in a bad mood driving this vehicle full of vibrant color.
Cars of today are so bland in comparison. It's like driving a celebration!" ---WildIdea

Bus ownership via emoticons:
---williamM

[skills@eurocarsplus]

if you had a missing valve seat you would have bigger problems. no, a valve seat will not cause an engine to run rich
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[kokanee]

To much fuel pressure will make it run rich

[airschooled]

A serious architectural issue can disrupt airflow enough to trick the AFM wiper into doing dirty things. I agree that I would be more concerned about the engine metallurgy than mixture…

Robbie
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Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com

[SGKent]

rich means too much fuel. The question is how did you determine it? Smog test? Smell? Color of plugs? Air to fuel meter?

The reason I say it let's say you used smell - a bad plug or wire causing a misfire might make the exhaust smell rich

Let's say a smog test showed high unburned HC - that could even be too lean and a lean misfire leaving unburned fuel.

A bad, corroded, or loose TSII could make a FI system run rich.

You need to tell us how you came to believe it is too rich.
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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

[oshima]

Plugs are totally fouled after maybe 100 miles. Extreme carbon buildup in muffler after the same 100 miles on a new muffler. Smells awful. Moving the wiper on the AFM to make it leaner increases idle speed.

I swapped plugs and wires without change, and put in a new TSII. I’ve replaced the entire fuel injection system one piece at a time with a friend of mine’s known good setup, and there was no change. Timing is on spec. Fuel pressure is between 30 and 32.

I’m stumped.
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1978 2.0L Fuel Injected

[airschooled]

So is the engine out for heads? Or is it currently driving? Do I need to stop in Tennessee on September 16th?

Robbie
_________________
Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com

[SGKent]

I did a write up on how to set the door flap up on the afm to factory tension. That is a good starting point.

Do you use an electronic ignition or points?
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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

[oshima]

Hmm, I'm wondering - would an incorrect computer from a wrong ECU year potentially cause a rich running issue? The computer in the bus says it's from a 1976, even though this is a 1978 bus. A kind stranger was nice enough to give me a 1978 known good computer this past weekend at Buses on the River, so once I get the rebuild completed I can stick that in.
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1978 2.0L Fuel Injected