adjusting idle speed on FI ... almost bottomed out.

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TrollFromDownBelow
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adjusting idle speed on FI ... almost bottomed out.

Post by TrollFromDownBelow » Mon Jun 27, 2011 5:00 am

I am only about 1/2 a turn from completely closing (tightening) the big idle adjustment screw to get my bus in the 900 rpm range. Loosing does a very good job of speeding the idle up (meaning the passage isn't blocked/the adjustment works).

What does this mean? What else may be out of adjustment to cause this to be so radically off?

Cheers,
Mike
1976 VW Bus aka tripod
FI ...not leaky, and not so noisy...and she runs awesome!
hambone wrote: There are those out there with no other aim but to bunch panties. It's like arguing with a pretzel.
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BellePlaine
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by BellePlaine » Mon Jun 27, 2011 5:28 am

TrollFromDownBelow wrote:What else may be out of adjustment to cause this to be so radically off?

Cheers,
Mike
Too much fuel pressure?
1975 Riviera we call "Spider-Man"

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Westy78
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by Westy78 » Mon Jun 27, 2011 6:36 am

Faulty/lazy decel valve. Squeeze the hose from the S boot to the valve and see if the idle drops.
Sticky throttle body not returning to fully closed position. This was a problem on mine the other day.
Throttle cable adjusted to tight.
Just to name a few spots to check.
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Amskeptic
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by Amskeptic » Mon Jun 27, 2011 10:25 pm

Westy78 wrote:Faulty/lazy decel valve. Squeeze the hose from the S boot to the valve and see if the idle drops.
Sticky throttle body not returning to fully closed position. This was a problem on mine the other day.
Throttle cable adjusted to tight.
Just to name a few spots to check.
Add to the list, the very typical auxiliary air regulator not closing fully, and add VACUUM LEAK that has been compensated by a fuel mixture adjustment that now allows the engine run fine, but too much air to let the idle drop down.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Re: adjusting idle speed on FI ... almost bottomed out.

Post by jackstar » Sun Jul 08, 2012 7:33 pm

Not to high Jack but I just fixed a tear in my EEC diaphram per Colin. Because my fuel ratio was running lean (1979 CA stock) I needed to get my head temps down. I got the glob of silicone out of the set screw on the wiper adjustment and moved it one tooth CCW. It is now running rich (13 MPG) with black sooty plugs. The idle pre set was 1 1/2 turns before bottoming out. I unscrewed it to 4 1/2 out.
If I set the tooth back to original setting does it stand to reason the head temps will go up some but the af ratio will also go up and go to a more factory default rich?

Thank
Jack

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airkooledchris
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by airkooledchris » Mon Jul 09, 2012 11:00 am

jackstar wrote:Not to high Jack but I just fixed a tear in my EEC diaphram per Colin. Because my fuel ratio was running lean (1979 CA stock) I needed to get my head temps down. I got the glob of silicone out of the set screw on the wiper adjustment and moved it one tooth CCW. It is now running rich (13 MPG) with black sooty plugs. The idle pre set was 1 1/2 turns before bottoming out. I unscrewed it to 4 1/2 out.
If I set the tooth back to original setting does it stand to reason the head temps will go up some but the af ratio will also go up and go to a more factory default rich?

Thank
Jack

your talking about the idle mixture adjustment on the AFM though, and not the idle speed adjustment on the throttle body correct?

it should be noted here that you do have the O2 sensor disconnected at this point, otherwise none of those adjustment changes would have done anything.

I wouldn't assume that your temps will go back up. You can go too far to the rich side of things where leaning it out some could actually maintain your temps and get you better fuel economy.

question - when your at a stop light - if you pump the brakes, does the idle speed increase?
1979 California Transporter

jackstar
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by jackstar » Mon Jul 09, 2012 6:35 pm

Funny you should mention idle speed. Not long after making my adjustments I noticed my engine would have a high idle anytime I came up to a light, stop sign or to park. It would stay high even after tapping the gas pedal and would only return to a normal idle if I put in gear and let clutch out a bit to put under load. After that no problem until the next stop.

I don't know the significance of it but I am sure someone does. I think I am going check the mix with Randy in Maine's LM-1. And then put back to the original tooth location and see where that puts me. Yes Chris the 02 is very disconnected. When you get around to that toggle idea let me know I am interested.

Jack

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dtrumbo
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by dtrumbo » Tue Jul 10, 2012 5:39 am

Another possibility is your distributor is sticky and therefore not un-advancing (that's a word?) as the engine slows down. I had the exact same thing in my Beetle. I'd have to slip the clutch at a stop light to get it to idle properly. Getting the distributor overhauled fixed the problem immediately.
- Dick

1970 Transporter. 2015cc, dual Weber IDF 40's
1978 Riviera Camper. Bone stock GE 2.0L F.I.
1979 Super Beetle convertible.

... as it turns out, it was the coil!

jackstar
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by jackstar » Tue Jul 10, 2012 7:22 am

I will look at both situations. I need to do a search on testing the decel valve and if faulty I will start there. If that is not a solver, then onto the dizzy. Thanks guys for the insight.

Jack

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Gypsie
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by Gypsie » Tue Jul 10, 2012 10:37 am

Westy78 wrote:Faulty/lazy decel valve. Squeeze the hose from the S boot to the valve and see if the idle drops.
This is the easiest way to see if the Decel diaphram is blown. Nuthin but a squeeze to block the flow. If the idle drops when you squeeze it it's a great indicator.

If it does drop, disconnect and block the hose and try a test drive.

All the other items can follow if this aint it.
So it all started when I wanted to get better gas mileage....

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Amskeptic
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by Amskeptic » Fri Jul 13, 2012 11:18 am

dtrumbo wrote:Another possibility is your distributor is sticky and therefore not un-advancing (that's a word?) as the engine slows down. I had the exact same thing in my Beetle. I'd have to slip the clutch at a stop light to get it to idle properly. Getting the distributor overhauled fixed the problem immediately.
Return, Dick, the word is "return" and you are spot-on.
Colin
(set warm idle for 950-999 rpm to not trigger the centrifugal advance > note: if you lubricate the advance weights and all, you will make the problem worse of course, so bend the spring post of the weight that has no slop to make sure it is exerting a slight pull)
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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airkooledchris
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by airkooledchris » Wed Aug 08, 2012 3:44 pm

jackstar wrote:I will look at both situations. I need to do a search on testing the decel valve and if faulty I will start there. If that is not a solver, then onto the dizzy. Thanks guys for the insight.

Jack
did you get it fixed?

if so, which was it?
1979 California Transporter

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airkooledchris
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by airkooledchris » Thu Aug 09, 2012 8:34 am

Amskeptic wrote:(set warm idle for 950-999 rpm to not trigger the centrifugal advance > note: if you lubricate the advance weights and all, you will make the problem worse of course, so bend the spring post of the weight that has no slop to make sure it is exerting a slight pull)

Image



does the above look/sound right? I still have the picture you drew for me, but looking through that little window is trickier than id expected.
one of the springs looks slightly longer than the other one, if that means anything.

I checked out my own decel but pinching didn't cause the idle to slow down and disconnecting it from the S boot and revving hard will create suction on that hose, so I think it's OK.
1979 California Transporter

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SlowLane
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by SlowLane » Thu Aug 09, 2012 11:04 am

Chris wrote:one of the springs looks slightly longer than the other one, if that means anything.
It very much means something.

The two springs in the distributor are constructed quite differently. One has a circular loop in both ends, the other has a circular loop on one end and an elongated loop on the other. The one with both circular loops should be under tension under all conditions. That's the one for which you want to adjust the post until there is no slop.

The elongated loop on the other spring is there to prevent it from coming into play until a certain amount of advance is attained, then once it is in play, it will slow the rate of advance by providing more resistance to the weights.

That's why you see advance specifications like this example:
Old Volks wrote:Advance/Retard Range: Vacuum: 8.5-11deg Adv @ 7.9 In. Hg; Centrifugal: 8-13deg @ 1600 rpm, 20.5-24.5 @ 3400 rpm
The 8-13 degrees @ 1600 RPM is entirely due to the action of the two-circular-loop spring. At that RPM, the elongated-loop-spring comes into play because the weights have moved far enough that the end of the elongated loop has been reached. From 1600 RPM to 3400 RPM, both springs are resisting the weights movement, so you get less advance per RPM increase. At 3400 RPM the weights should hit their hard stops and no more advance should be seen as engine speed increases over 3400 RPM.
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airkooledchris
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Re: adjusting idle speed on FI ... almost bottomed out.

Post by airkooledchris » Tue Aug 14, 2012 6:48 pm

I am going to try this sometime this week.

My issue is def the distributor and I was able to replicate it last night in my driveway.

Went for a cruise around town to get everything warmed up, then backed it into the driveway to check the timing. Timing was holding steady at 5* ATDC but when I went to rev it up to see where the max advance was it wouldn't come back down - then holding steady at 1* ATDC and blipping the throttle wasn't bringing it back down to 5* again - it was just stuck here. Shutting the engine off and letting it cool for a bit will set it back of course.

This has been sending me on a wild good chase of trying to get it to idle properly because it'll be running at 1200/1300 RPM and if I bring that down to 950 - it'll end up idling at 700 RPM the next time I start it up.


I can't say that im too excited to be trying to bend that metal post inside my distributor but ill give it a shot - but will keep the Philbin group in mind in case I want to have it professionally overhauled instead.

There is a federal coil and distributor in my tool box that I know works - but I read a thread over at TS earlier this year where someone had a lot of issues trying to just swap in the federal setup (for starters it's just a SVDA where my current is a DVDA unit)




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Image
1979 California Transporter

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