Progress Thread Let's try this again...

[gkomo]

Unfortunately there’s been little change even with the spout disconnected. Car is still idling at 1000 warmed up, although on startup it idles at 850-900, which I think is about where I want it.

Here’s a picture of my engine bay and egr spacer plus my vacuum tree.

Later today I’m going to check my base timing. I’m assuming advanced timing would raise the idle speed?

The B/R cap on your vacuum tree looks cracked and exposing the port. Or is it fine? If not definitely replace that.

 

[Noobz347]

My instinct is that you have a vacuum leak and/or a bad/leaking IAC.


Your idle in park/neutral should be 672 +/- 25 rpm.

 

[gkomo]

@Noobz347 can you see the port exposed on the B/R port on the vacuum tree? It’s tough to make out when zooming in on the photo on my phone

 

[Noobz347]

@Noobz347 can you see the port exposed on the B/R port on the vacuum tree? It’s tough to make out when zooming in on the photo on my phone

Definitely cracked

 

[Noobz347]

On a side note:

[All] of those rubber caps suck balls. They don't last. I've never found a brand that is the exception.

I keep replacements in bulk or have made my own plugs from capped off fuel line.

 

[Alldegree]

Definitely cracked

This is why I’m always glad we can post pictures, I didn’t notice that even when looking at it in person.

On a side note:

[All] of those rubber caps suck balls. They don't last. I've never found a brand that is the exception.

I keep replacements in bulk or have made my own plugs from capped off fuel line.

I’ll see if I can find some rubber caps at oreilleys if they’re open today, are there any alternatives to rubber caps that are better?

 

[Noobz347]

This is why I’m always glad we can post pictures, I didn’t notice that even when looking at it in person.


I’ll see if I can find some rubber caps at oreilleys if they’re open today, are there any alternatives to rubber caps that are better?

I have used fuel line and plugs before:

https://www.amazon.com/Podavelle-Connect-Adapter-Fitting-Aluminum/dp/B0DK6ZBDWF/ref=sr_1_2?sr=8-2

The fuel line lasts longer and the hard plastic plugs don't seem to deteriorate.

 

[Alldegree]

Replaced the B/R cap as well as the S/C cap just in case. Same thing happened, engine started at what I would consider somewhat normal idle, then crept up to 1000 rpm when it got to temperature.

When I unplugged the IAC and spout, it dropped to around 850.

Idle screw is all the way out.

Base timing is 12 degrees btdc.

I would think barring vacuum leaks and computer shenanigans, the only other possibility is I got a bad TB? I figure I could test that by putting the old one back, closing the adjustment screw and seeing what happens. The brass fitting for the pcv tube is missing, but that shouldn’t affect air past the blade since it’s upstream of it, right?

I figure if the engine chokes out with the IAC disconnected on the original TB, then the new one must be bad. Is that a valid experiment, or would I be wasting my time?

 

[KRUISR]

When I unplugged the IAC and spout, it dropped to around 850.

When you unplug these two you should be able to get idle down to 650 or less. It will run like a bag of , but it just needs to keep running. The lower the better because then the IAC has more range to adjust in.

If your throttle screw is fully backed out and still not going down to stalling, I would remove the IAC and see if there is any build up preventing the internal valve from fully closing and seating properly. Otherwise you definitely have a vacuum leak (or throttle blade not closing all the way) somewhere.

 

[Alldegree]

Ok, so I’ve gone down a bit of a rabbit hole.

While putting on the old TB, one of the nuts cross threaded on the stud, and while removing it I noticed they were different lengths, like a couple of them had been installed backwards.

I decided to just pull off the egr spacer to see exactly what I was dealing with, and while removing the spacer the gasket fell apart and I was greeted with this:

There’s a whole lot of shmoo and moisture (I’m assuming condensation) in and around the mating surface and the water jacket of the spacer, which makes me think that the gasket had been deteriorating over time, and may be where my leak is coming from. The small gaps in the paper gasket could have filtered the smoke during the smoke test and prevented me from seeing it.

I’m planning on ordering new studs and gaskets, I’ll probably put it all together and find that this wasn’t the problem at all, but it’s the theory I’m working under right now.

Would a solid egr spacer prevent this kind of moisture buildup and deterioration from happening?

I did look at the inside of the IAC:

I freely admit I’m not sure what I should be looking for, but it looks pretty clean.

 

[KRUISR]

With a small pick tool or screwdriver try manually moving the plunger open/closed (open toward the solenoid, closed away from it).

You could try spraying some brake cleaner on the left side (in your pic) and see if it flows to the right side. Its a tapered plunger so it should seat on the opening between the two sides. If you try spraying some cleaner first you can get an idea if (or how much) build up is there. Don't forget that the air that goes through the IAC can come from the breather tube from the valve cover/oil fill tube - hence could cause some oily sludge buildup over time - just like the throttle blade and get build up.

 

[Alldegree]

Unfortunately my gasket was not the issue. Problem persists even after replacement.

I put the old TB back on with the throttle adjustment screw backed all the way out, IAC and SPOUT plugged in, and the car wouldn’t idle.
So I think that confirms I have a problem with the new TB. I noticed during the earlier smoke test that a lot of smoke escaped from the TPS sensor, so I took it off to see if maybe a gasket was missing:

Once again, I don’t know exactly what it is I’m looking for, but it looks about as airtight as a rotating part could be.

I would imagine since the throttle opening is bigger, even a small leak would have a pretty significant effect on unmetered air getting past the blade. You guys let me know what you think, but I think my next step is contacting BBK to see if I’m doing something wrong.

 

[KRUISR]

I put the old TB back on with the throttle adjustment screw backed all the way out, IAC and SPOUT plugged in, and the car wouldn’t idle.

This is absolutely the wrong way to do the idle reset. Try it again. IAC and SPOUT unplugged. Turn the adjustment screw in enough to get the car running and then back it off until it will barely idle (lower the better). Then with the IAC and SPOUT plugged in it should idle better.


On the BBK TB, does the throttle blade fully close?

 

[Alldegree]

This is absolutely the wrong way to do the idle reset. Try it again. IAC and SPOUT unplugged. Turn the adjustment screw in enough to get the car running and then back it off until it will barely idle (lower the better). Then with the IAC and SPOUT plugged in it should idle better.


On the BBK TB, does the throttle blade fully close?

I actually wasn’t trying to reset the idle, this was merely a diagnostic test. I was trying to see if the car would have enough air from the factory TB to run even with it closed to rule out any leaks further downstream. And it didn’t, even with the IAC and SPOUT connected trying to keep the car running.

That tells me that even with all other things working properly, the car still shouldn’t be able to run with the throttle blade closed and my problem is therefore in the new TB itself.

As for the BBK TB, it looks like it closes all the way to me but I’ll throw some pictures on here.

 

[KRUISR]

The better test is can you get the car to idle and run right with the factory TB.