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Author Topic: Hanging idle: stretching spring how much?  (Read 680 times)

August 14, 2017, 10:51:03 pm

vwzzuk

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Hanging idle: stretching spring how much?
« on: August 14, 2017, 10:51:03 pm »
I've searched the forum for members that have solved their hanging idle issues by stretching the idle spring in their injection pumps.

Specs: 1.6TD, non-high idle cold start rod, 1986 engine, fresh rebuilt pump by service provider. Problem existed with previous owner that I bought the pump from. I thought having it rebuilt would have it fixed. However, it came back from the rebuilder with the same high idle problem.

Problem: idle hangs up too long/high before coming back to idle. It hangs so much that there is no "compression braking" when coming down a hill. Its like it stays on throttle until you hit the flats on the road.

Question: "how much do you stretch the idle spring to correct the idle?" 1/8th inch? more?

Thanks,
dave


--Dave

82 Rabbit Pickup, 1.6NA
91 Jetta, 1.6NA
87 Samurai, 1.9TD AAZ
92 Sidekick, 1.6TD

Reply #1August 15, 2017, 09:27:24 pm

vwzzuk

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Re: Hanging idle: stretching spring how much?
« Reply #1 on: August 15, 2017, 09:27:24 pm »
I measured the idle spring (what i think is the idle spring. Little independent spring on the far right side of the governor setup) at 8.2mm long and stretched it out to about 11.2mm.

Stretching it that far is way too much stretch as it idles now at about 1700 rpms. Hummmm.

I guess I will have to put another stock 1.6 idle spring back in place from another parts pump I have and see if it idles again.
--Dave

82 Rabbit Pickup, 1.6NA
91 Jetta, 1.6NA
87 Samurai, 1.9TD AAZ
92 Sidekick, 1.6TD

Reply #2August 18, 2017, 08:45:10 pm

vwzzuk

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Re: Hanging idle: stretching spring how much?
« Reply #2 on: August 18, 2017, 08:45:10 pm »
Well, I couldn't seem to get it to run with another idle spring alternative.

So, I got another governor spring assembly along with the accompanying throttle lever indexed to it from another pump. I put the assembly in my rebuilt pump and it now runs again. BUT, it still has that hanging rpm issue. Not sure how to get rid of it now after messing with it.

Any suggestions?
--Dave

82 Rabbit Pickup, 1.6NA
91 Jetta, 1.6NA
87 Samurai, 1.9TD AAZ
92 Sidekick, 1.6TD

Reply #3August 19, 2017, 01:39:26 am

burn_your_money

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Re: Hanging idle: stretching spring how much?
« Reply #3 on: August 19, 2017, 01:39:26 am »
Are your injectors good?
Tyler

Reply #4August 19, 2017, 03:00:23 am

vwzzuk

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Re: Hanging idle: stretching spring how much?
« Reply #4 on: August 19, 2017, 03:00:23 am »
Yep. Rebuilt 1.6TD injectors.
Did them the same time as the pump.
--Dave

82 Rabbit Pickup, 1.6NA
91 Jetta, 1.6NA
87 Samurai, 1.9TD AAZ
92 Sidekick, 1.6TD

Reply #5August 23, 2017, 07:21:39 pm

libbydiesel

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Re: Hanging idle: stretching spring how much?
« Reply #5 on: August 23, 2017, 07:21:39 pm »
What is your idle rpm?
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #6September 01, 2017, 06:11:15 pm

vwzzuk

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Re: Hanging idle: stretching spring how much?
« Reply #6 on: September 01, 2017, 06:11:15 pm »
I measured it at 1,100 rpms.

I adjusted the fuel residue screw to bring it down to 900 rpms. No change with hanging idle.
I messed with the governor assembly set-up regarding the idle spring and throttle lever position. Went back and forth with no success.

After that, I adjusted the fuel screw down (less fuel) below the rebuilders setting by 1/8th a turn each adjustment. No change with hanging idle.

So, currently back running where I started from but rpms are at 900...and the idle still hanging.
--Dave

82 Rabbit Pickup, 1.6NA
91 Jetta, 1.6NA
87 Samurai, 1.9TD AAZ
92 Sidekick, 1.6TD

Reply #7September 05, 2017, 07:02:59 pm

libbydiesel

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Re: Hanging idle: stretching spring how much?
« Reply #7 on: September 05, 2017, 07:02:59 pm »
Keep turning the residual pressure screw out until the idle no longer drops.  Then adjust idle with the idle screw.
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #8September 07, 2017, 07:17:22 pm

vwzzuk

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Re: Hanging idle: stretching spring how much?
« Reply #8 on: September 07, 2017, 07:17:22 pm »
OK, just to make sure I'm using the same vocabulary you already know:

You are saying that I need to:

1) turn the residual pressure screw (the fuel screw at the top of the pump with the stainless steel collar spot welded to it) out until the idle no longer drops off.

2) Then adjust the idle speed (with the lower approximate two inch long set screw that the throttle lever rests against).

Just want to make sure I get the two adjusters right in my mind before I start messing with it again.

Thank you!
--Dave

82 Rabbit Pickup, 1.6NA
91 Jetta, 1.6NA
87 Samurai, 1.9TD AAZ
92 Sidekick, 1.6TD

Reply #9September 07, 2017, 11:42:56 pm

ORCoaster

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Re: Hanging idle: stretching spring how much?
« Reply #9 on: September 07, 2017, 11:42:56 pm »
That is the way I understand them to work.  Any additional screwing in of the fuel screw will increase your idle once you do get it all the way down. 

That is why it is a two step process to increase or decrease the base fueling and then set the idle accordingly.

Hope you get it corrected. 
Now Own 1981 Caddy as the NEW DISTRACTION to all that is around me.  Project Away!

Reply #10September 08, 2017, 09:24:54 pm

vanbcguy

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Re: Hanging idle: stretching spring how much?
« Reply #10 on: September 08, 2017, 09:24:54 pm »
The screw with the welded collar is the max fuel screw, not the residual fuel screw.

You have the pump with the idle speed set by adjusting a rod on the side of the pump, correct? If so the residual fuel screw is what the accelerator lever rests on at idle.

Sent from my LG-H873 using Tapatalk

Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
2004 Jetta Wagon - 1.8T - Blitzen

Reply #11September 08, 2017, 09:26:03 pm

libbydiesel

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Re: Hanging idle: stretching spring how much?
« Reply #11 on: September 08, 2017, 09:26:03 pm »
OK, just to make sure I'm using the same vocabulary you already know:

You are saying that I need to:

1) turn the residual pressure screw (the fuel screw at the top of the pump with the stainless steel collar spot welded to it) out until the idle no longer drops off.

2) Then adjust the idle speed (with the lower approximate two inch long set screw that the throttle lever rests against).

Just want to make sure I get the two adjusters right in my mind before I start messing with it again.

Thank you!

No, terminology is not correct.  The collared screw is the Max Fuel screw.  Depending on the year of your pump, the long threaded rod at the back of the pump that the accelerator lever rests on is either the Residual Pressure screw (if yours is a later pump with the fast idle cold start lever setup) or it is the Idle screw (if yours is an earlier pump with just the timing advance and no fast idle).  You mentioned in an earlier post that you had turned the Residual Pressure screw and so I assumed you knew what was what and that you had one of the later pumps as the earlier pumps do not even have any Residual Pressure screw.

Post a picture of the back of your pump showing the cold start lever assembly.  I need to know which style of pump you have before I can give appropriate advice. 
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #12September 11, 2017, 06:01:16 pm

vwzzuk

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Re: Hanging idle: stretching spring how much?
« Reply #12 on: September 11, 2017, 06:01:16 pm »
The pump doesn't have the fast idle long rod that moves when you pull out the cold start cable.

--Dave

82 Rabbit Pickup, 1.6NA
91 Jetta, 1.6NA
87 Samurai, 1.9TD AAZ
92 Sidekick, 1.6TD

Reply #13September 11, 2017, 07:03:09 pm

libbydiesel

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Re: Hanging idle: stretching spring how much?
« Reply #13 on: September 11, 2017, 07:03:09 pm »
As a test, lower the idle speed until it is very low, like <800 rpms.  See if it still hangs.

...did the pump EVER have that fast idle setup?  Post a pic of the pump.
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

 

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