Pulsing at idle/lower RPMs

[JimiD]

Sorry for the long time between updates.

I tried a different air flow meter, and it had the same exact issue. So I’m doubtful that my air flow meter is the culprit.

I checked most of vacuum lines, and didn’t see any signs of leaks, but don’t have a vacuum gage/tester. So I moved on from that.

I replaced the original injectors/pigtails, since I figured it couldn’t hurt, especially with the engine at ~150k miles.
That doesn’t seem to have solved the issue either, but I’m still happy I did it nevertheless.

I was worried my distributor didn’t have the proper advance/retard due to a vacuum leak, so I ended up replacing the distributor with a rebuilt option, and there was a noticeable improvement in driving. But unfortunately the strange idle issue was still there.

At this point I’m confident the only other issue it could be is a vacuum leak somewhere. So after looking online, I realized I can buy some cigarettes and blow smoke into the intake to try to find a leak.
I think there’s a sight leak at the throttle body, and I’m wondering if anyone has had any luck with the gowesty throttle body? And if theres anything I need to consider if I’m going to switch to that from the 2 switch digijet throttle body?

Thank you all for your help so far!

-Jimi

[djkeev]

Remove your injectors and send them to Mr Injector in
Idaho.
They will come back looking and performing like new.
You'll be out about $100 with shipping.

Put them back in, your erratic idle may just be gone.

Dave
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[JimiD]

[kaalualu]

How's your throttle body?
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'84 Transporter 16" CLK's/LED's/ AT's/Mansi injectors
'86 Wolfey Weekender Westfalia AT's/otherwise stock
Sold-'82 TinTop Diesel

[Steve M.]

A D.I.Y. vacuum leak check device.

https://www.thesamba.com/vw/forum/viewtopic.php?t=674702
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[JimiD]

The throttle body might be an issue, but I can’t tell 100% yet. It seems like I have an “early version” vacuum throttle body with the 2 spots for vacuum on the throttle body housing.
BUT my vacuum lines are ran as a bit of a Frankenstein mashup between the “early” and “late” versions of vacuum lines.
I’m not entirely sure if that is the main issue with my idle though, since if ran without leaks, I would think it should still be work appropriately...

Does anyone know how a van would behave if one of the throttle body enrichment switches didn’t test as it is supposed to?

On page 24.34 in the Bentley, it shows how to test “switch 3”.
When I test it, it tests appropriately (no continuity) in the closed position, but in the open position, it also tests with no continuity, even though it should have no resistance.
I’m wondering if this might be the main culprit with my idle surging issue?

Also, does anyone have any experience switching from the 2 switch digijet system to the new “upgraded” gowesty branded 1 switch throttle body? I’m considering switching to that system to see if it will solve my issue.
The other reason for my interest in switching to the new throttle body is that I assume it’ll be easier to find replacement parts down the road? Especially considering I’m not confident I’ll even be able to find the full throttle switch that currently tests as bad.

I only have a limited amount of time on some nights after work to work on things, so I apologize for the slow responses to the thread, but I appreciate all of the feedback I’ve gotten so far!

-Jimi

[Xevin]

Have you looked at this yet?


Link

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[Xevin]

Here’s my thread on hunting idle. As far as the throttle body compatibility with yours. I don’t think it’s a problem using the later style. The 1.9 wbx 85 model year used the early style then went to the later style used on 2.1 engines. My 85 had a rebuilt late style throttle body. Not sure what was originally on my 85 when new. I did replace it with a another used late style throttle body and my problem has not shown up in 1500 miles.


https://www.thesamba.com/vw/forum/viewtopic.php?t=...7a9ab9a8ab
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[JimiD]

[JimiD]

[Xevin]

Yes, my issue was solved with a different but same style throttle body and switch.

If you have access to a nice loaner throttle body with a switch that is in spec. Try it. Very easy to swap out. I will say both switches checked out to spec on mine but for whatever reason the new to me used one, fixed the idle issue.
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[JimiD]

Hey everyone.

So I’ve had a hard time figuring out exactly where my vacuum leak was coming from, but now I’m pretty confident it’s coming from the AUX air valve.
I made this video showing the issue as well as what happens when I pinch off the hose that comes off of the manifold, as well as the hose that goes to the S-boot.
https://youtu.be/MBN72gWJ0GU

Is this what would happen if the valve was stuck open? For reference, when pinching the hose during warm up, it does the “normal” thing it should, and the RPMs just go down slightly, but right when it gets up to temperature, the issue starts.

Thank you all for your help so far!

-Jimi

[brickster]

I have an early 1984 with automatic and AC (no PS), and your vacuum line arrangement is nothing like anything else I’ve seen.

Take a look at Bentley pp. 24.24 to see the original layout. I can post a photo of mine if that would be helpful.

You can use a cigar with a hand transfer pump to locate leaks.

[Nickel_Nackel]

[Nickel_Nackel]

[JimiD]

[kaalualu]

Had same issues, hunting, stuttering
idle, rich running, replaced TB with gowesty's, plenum seal and TPS conversion kit, so much smoother idle, huge improvement. Easy install.
Alika pointed me in that direction, Mahalo Alik's!!!
_________________
'84 Transporter 16" CLK's/LED's/ AT's/Mansi injectors
'86 Wolfey Weekender Westfalia AT's/otherwise stock
Sold-'82 TinTop Diesel

[JimiD]

[mjosoba]

Informative thread. I’ve definitely got some similar issues to run down. I have a surging idle, and also lots of power loss/missing once warm. I think I have water in fuel. But this is definitely a good post for me!!

[JimiD]