Click to view attachment
I broke the plug to my idle control valve. I bought a new plug housing. Easy. But I’ve had a devil of a time finding the right socket pins for the housing. Several weeks have been stalled waiting for 80 cents worth of pins that show up and are the wrong size.

So, knowing the 914 has to drive next weekend, I went full DACO and soldered a pigtail of wires into the ICV and then crimped them into place.

About to find out if it works, and will continue to work for a couple weeks while I sleuth out the right sockets for the plug Wish me luck!

Zach

Sometimes you gotta do what you gotta do

My '67 bus I broke the shift rod coupler 1500 miles from home, I cobbled it together with wire from a paint can handle that I found on the side of the road to get home.

You do what you have to...and have AAA.

Once, whilst stranded in Mexico, I had to build an entire VW Beetle out of coat-hangers just to get back to town...

Worked like a champ.

Go for it.

Bought another IAC and found a proper plug and pigtail on ebay. It will come in May, so my cludge will just have to work till then.

Zach

I would just plug the line to the IAC, and open the air bypass on the throttle body for now and run without it. Once we get your idle mixture and warmup curve dialed in it wont be as much of an issue (for sure will be better than a cold start with carbs) maybe 20-30 seconds of feathering the throttle to avoid stalling, or possibly even just a low idle during warm up.

I suspect the amount of air this was letting through was masking other issues with your idle quality that should be sorted out before enabling the IAC at all. Your car should be able to idle strong without it.

The SDS in my bug doesn't even have an IAC as it's an option. When cold I let the fuel pump cycle, give it a couple of pumps as I start (as opposed to before I start) and that's it. I might have to keep the gas to it for a few seconds, depending how cold it is out.

My new system for the /6 has an IAC but it doesn't look to me to be much more than an on/off air valve. I don't know for sure, but I think the fuel enrichment is nothing more than the MAP sensor seeing the vacuum change.

https://www.youtube.com/watch?v=1BbU4JeyzMo


Found an air leak on the throttle body with my homemade smoke machine. The cellophane is what I used to block smoke from going from the TB into the air intake box. The first time I did the test smoke just started rolling out the air intake box. Not helpful.

The leak seems to be on the shaft that controls the butterfly. I’m guessing this is the source of my intermittent leak and high-at-times idle?

Is this fixable or do I need to replace the TB?

Also I’ve removed the IAC valve from the engine and gotten it to where it will idle fine once warm. Then it will suddenly want to idle a good bit higher I guess as the throttle shaft moves around.

Click to view attachment
Here is a pic of the smoke machine I made the other day.
@JamesM

Zach

Nice job.

I am leaning towards replacing the TB with the larger until off a bus. As well as the throttle shaft leaking, the butterfly is sticking open, and engine power is way down without the IAC valve feeding more air into the engine.

The butterfly sticking open slightly is the cause of my intermittent very high idle. Don't know if its a carbon ring or just wear, but as the engine gets hot it sticks open more and the idle sits around 2000rpm until it finally closes some time later.

Zach

You can ream out that shaft bushing in the TB and press in a new bronze one if you're getting a poor seal. There's a thread HERE by r3dplanet that is well documented. I still have a couple of leftover bearings and the bit, IIRC, that are needed. I'll send to you if you want.

Having said that, I'm curious about the bus TB as well. What cam do you have? I've had the Raby 9950 on a 2056 and now the 2270, and it just can't seem to get enough air the first couple of minutes after start up.

I have the Raby version of the Web494 carb cam. His version has more exhaust duration. I used to know the cam number but now I don’t.

I went on a drive for about an hour. With the IAC out and not getting the air though that, my motor felt pretty down on power. You could very much tell that it was being choked off.

I took the TB off tonight and there is a partial ridge where the butterfly meets the interior of the TB. That is I think where it’s hanging up as the engine gets hot.

Also the change to go from the 45mm Tb to the 50mm Tb looks simple from the attaching standpoint. Basically take the lip off the plenum and that’s it.

Well, and change the butterfly shaft so it’s clocked the right way and fab up a mount for my TPS that I need for Microsquirt. But that’s easy.

Zach

After reading this thread:
http://www.914world.com/bbs2/index.php?showtopic=244849

I bought a new 52mm Throttle Body from Bus Labs.
This unit:Click to view attachment

I looked at the GoWesty unit which is more stock looking, but they were not currently available. And the 2.1 Vanagon TBs I found all needed rebuilding if I bought them on Ebay.

So my plan: I have a 400 mile drive coming up Memorial day weekend.
If everything goes to crap, I plug my old TB back in and do it, and deal with an occasional high idle and knowing that I'm leaving almost 10% of power on the table at WOT.

BUT if the new unit arrives on time, I have plenty of time to make a mount for my TPS (since I can't use the 2 position switch the Vanagon uses), expand the horn on the plenum, mount the unit and get at least one test drive in to collect data for James to adjust the tune if needed.

Somehow its always a rush.... lol. I'm sure the day I leave I'll have the car on the lift to change SOMETHING last minute.

Zach

Zach, please send build details of the smoke machine.

Thanks

https://www.youtube.com/watch?v=tixozqgSwN0


He has a complete parts listing in the video description, but I used a lot of stuff I had at home. The important part I did not have was the pipe fittings (way cheaper at home depo) and the resistor wire - though even he used whatever welding wire he had. The resistance (Nicrom) wire needs considerably less for the winding around the wick.

Zach

Let me know how this works out. It has been many years since I did mine using the stock 2.1 50mm throttle body, but I vaguely remember having to swap the arm on the throttle shaft for the one off the 1.8 in order to get the proper orientation. Hoping the aftermarket shaft is of the same design to allow this.

I figured it may just be easier to move the throttle cable to the centerline using something similar to the set up I used when I had carbs. I’ll be able to play with it more when I get it.

Zach

The GoWesty unit is pretty awesome, and converting it was a piece of cake. This unit is 52mm at the butterfly. This makes it larger then the 1.8 914 TB (45mm) and larger then the 2.1 Wasserboxer TB that people usually swap over (50mm). Also, this unit is MUCH EASIER to swap then the 2.1TB, had double bearings for the throttle shaft and is BRAND NEW not 40 years old and worn out.

Here is how I went about doing it:

First thing to notice for these units: Stock 1.8 L-jet in on the left, GoWesty on the right. THE FLATS ARE THE SAME! The throttle arm on the GoWesty is angeld all wrong for a 914, so off it must come. We are going to cut up this nice shiny new piece of metal. We will need bits from the 1.8 throttle - in particular the arm for the barrel nut.


Mocking up the old arm, you can see it takes the PERFECT angle on the new TB, versus the bus arm that is far too low. But the bus arm has the throttle stops, so we don't want to eliminate it completely.


Here are the cut lines. We preserve both throttle stops on the GoWesty piece, and just take off the nub on the 914 L-jet piece.


Boom! perfect! Lower arm controls the throttle stops, upper will attach to the throttle. I also preserved the lug to mount an aux return spring since the GWesty unit has a weaker spring and may need help.


another view of the top put back together.


And mocked on to the plenum. Perfection.


lower half of the GoWesty unit. This is where things get really awesome. I have already remove the Vanagon 2 position switch from the shaft. Look at those nice threaded holes. I wonder....


the shaft is 4.5mm too long for the Microsquirt TPS to fit without a spacer. So I marked it and cut it to size. I DID NOT remove the throttle shaft from the throttle body, just cut it in place. Still really easy.


BOOM! The TPS was able to use the two drilled and tapped holes on the GoWesty plate. Its almost like they planned for this kind of modification.


and here we have the ONLY sticking point. My friends at the shop up the street got a little too aggressive with the expander die, and took the intake horn on the Plenum from 45 to 55mm - but they left me no taper to go into the TB. So I am slowly tap-tap-tapping the opening with a small engraving chase hammer and putting a taper back into the opening. I MAY need to trim it a little too. But I'm going to slowly keep tapping until I reshape the opening to 52mm and see how the TB fits. Even the work that I have done in this picture has helped a TON.

I am not planning on using the rubber gasket, but using a RTV gasket sealant instead.

Zach

After my test drive tonight the idle was still a little high. I decided to run the smoke machine again since I found and fixed the larger leak on the throttle body.

I found one of the tube connectors leaking from the plenum to the intake runners, and found a pinhole on a gasket at the plenum. I doubt the pinhole was doing much, but it’s easy enough to fix so I will.

There were no leaks at all with the new GoWesty TB. I figured there may be one at the join of the TB to the Plenum. But that area was sealed very well.

Since I have to wait and install a new throttle cable (!!!!) I’ll have plenty of time to put some hose clamps on the connectors and put a little RTV into the pinhole where the cold start injector used to be.

Zack, really cool writeup! Thank you for sharing.

There is some information on Shoptalkforums about the use of the 1.7 or bus plenum with the 2.0 runners and the 2.0 heads. I believe some have used this kind of setup on 2256 (2270) size engines too.

In your case, what is your plenum, runner, and head setup? Thanks!

A mishmash.
The engine is using a Bus case, 1.7 heads which have been bored out. A friend was getting rid of an entire 1.8 Ljet system so I took it for the parts (this engine used to be carbed). So my airbox, plenum and runners are 1.8. I removed the flapper box from the 1.8 and replaced it with some exhaust pipe that was the right size and put a bung in that for the ambient air temp sensor.

The 52mm throttle body is the same outside dimensions as the stock LJet unit so everything fit back together perfectly.

Zach

Thank you for the info.

This topic came up again recently so I thought I'd update this thread.

After I did the swap in May, @JamesM and I did more tuning and we were able to open up new bins in the fuel map with the larger TB.

I did eventually replace the IAC with the new Hyundai unit and got that tuned in. Idle is much more even and cold starts are MUCH easier!

Ive put about 1000 miles on the car this summer, and I can say its never done as well as it had this year.


So, obviously, its time to pull that 2056 out and put in a 2.3.
Yes. Yes. I know.

But the 2056 will go into my bus, and we will see how well is does moving that around.

Zach

@VaccaRabite

Zach, i am not familiar with the 1.8 plenum and its orientation, so i am wondering how this would go on a 2.0 914 plenum? i am sure my new 2.1 need more air, and i think this would be a good option , but before i buy a $250 part i better make sure i will be able to use it.

Phil

Dunno. I did not have 2.0 induction gear to work with, and don't know its geometry well enough to say for sure.

I suspect it would work just fine, but that's really just a guess.

Googling up the different 914 plenums, looks like my mods would work on the 1.7 and 1.8. The 2.0 is different. But in the end it still need to react to a throttle cable pulling on an arm, and the cable runs from a similar place. So while the mods may be a little different, the result would be the same.

Zach

i am bumping this thread again for the purpose of asking if anyone has done this mod to adapt a larger throttle body onto a 2056 2.0 build using d-jet and 2.0 runners and plenum etc? or is there another way? it would be nice to get the 52mm TB ans mount it on the existing plenum, but i assume i’d have to do the same mods zach did for the TPS and the cable attachment?
any thoughts ? I think my 2.1 would benefit from the increased intake size.


Phil

I run a modified 2.0l TB with on my 2056 which is 48mm instead of the 45mm original diameter. If you stay with the D-Jet I would not go lager in diameter, as you would potentially run into trouble with your acceleration enrichment.

Cheers, Frank

If you are sticking with d-jet I would say its probably not worth the cost/effort as D-jet itself (and a d-jet compatible cam) will always be your most limiting factor.

If you wanted to I think your best bet with the 2.0 TB is just to get your existing one enlarged. The vanagon TB makes sense when using it with a 1.8 plenum as they share the same basic mounting configuration and the 1.8 plenum itself is easy to open up to match. The 2.0 throttle body is of a different style (flat bottom) and the plenum itself would be significantly more difficult to modify to a 52mm opening. Also when sticking with d-jet you would also need a TB that can handle the d-jet TPS, so your options are pretty limited.

d-jet compatible cam on a 2056 you are probably looking at best case power output in the range of ~115hp which is still within the limits of the stock TB. More of a concern when your 2056 is build to spin to 7k ~140hp

2.6, just get it over with
Worth it btw .

Rich