Author Topic: Very low idle at cold start/fine after glow plug switch of  (Read 3676 times)

August 11, 2019, 02:35:26 pm

carrizog60

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Very low idle at cold start/fine after glow plug switch of
« on: August 11, 2019, 02:35:26 pm »
Hi

How can i solve this?
Rpm drops too much as soon as something causes drag on the engine(fan,steering...) but the worse is glow plugs at starting.
Is there any adjustment for this?
Pump isnt on stock settings:rotated aceleretor lever and backed the resting screw,fuel delivery screw almost at max,changed the pivot point on the fuel shut off device(the one in the back of the pump).

Thanks!


vw golf gti G60--vw passat 1.9td gt2052v
yamaha vmax 1200- yamaha tdm 850
Portugal

Reply #1August 11, 2019, 03:47:01 pm

ORCoaster

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Re: Very low idle at cold start/fine after glow plug switch of
« Reply #1 on: August 11, 2019, 03:47:01 pm »
Well you could drop in a new engine that runs right but I don't think you are looking for that solution.

If I understand the symptoms you have a low idle until the glow plug relay turns off, about 10 seconds after starting the engine, correct?

During that time I watch my alternator gauge, something VW forgot to install stock.  I see it shoot up to close to 30 amps at initial start, then it drops to around 15 for a bit then near Zero when that relay goes click.  At the same time the volt gauge, yeah I love real data not some stupid led glowing at me, goes from 12 or so to 13.8 once the click is heard. 

What that tells me is that the glow plugs, the starting of the car and running the heater at start up demands a bit of juice from the alternator.  That shouldn't drag the engine down if you have the RPM set at the recommended spot.  Do you know if you are at 850 or 750?  Makes a big difference.  Thing shakes like crazy at 750.  Does the Alternator get hot to the touch at startup?  It should be warm but not hot to the touch.  If so you may have one that is bad and just has to work too hard to keep up with the demand.  55 amp or better in VW remember.

As to how you have adjusted the throttle and fuel screws I can only say that without a good look and hear of the engine I am not sure all is well with it.  Adjusting the throttle is odd in that you turn it counter clockwise to reset it to get better fueling at times, not the other way around.  Marking the position of the throttle BEFORE you adjust it is also a good idea, No, it is the only way to be sure you are going the right way and the right amount.  One of those splines at a time.

There is another adjustment to the internal pressure of the first stage of the IP that might be affecting all of your woes.  The internal pump pressure is regulated by tapping the inside part of the that button on the front of the pump in with a punch.  More often than not it goes too far and you have to remove it, and reset it from the beginning.  I use the outflow of the fuel at the back of the pump to gauge if the internal pressure is close. If I really want to get it spot on I have a fitting and gauge I use.  But at 1000 rpm you should be pumping a liter of fluid out the back.  Just use a 2 liter bottle and mark it half way.  That gives you plenty of time to shut it all down, drain the container, and tap the button down a bit more. 

Hope that helps.

Reply #2August 17, 2019, 05:58:47 am

carrizog60

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Re: Very low idle at cold start/fine after glow plug switch of
« Reply #2 on: August 17, 2019, 05:58:47 am »
Hello.
Regarding charging components: its a 90a alternator,new. Did that already with the previous one.
Battery is a new 90a too.

My guess is that the problem might be on some adjustment as it started to do that after some more fiddling with the pump in order to get the most out of it.
Idle is fine,but only after all power consumers are off or not in need.
If i turn the power steering with the car stoped the darg of the steering pump will cause the idle to drop,but as soon as its not in use idle climb back to normal,around 800rpm.
Higher or lower idle wont matter,it behaves the same way.
Glow plugs work longer than 10s,and work every time i switch the ignition off.
Dont know if its normal in that model,its a passat b3 1993 1.9ecodiesel from factory,latest idi engine model before the arrival of the tdi engine.
Other than that it works fine,its just annoying to pull the cold start to bump the idle a bit every time i start it...
vw golf gti G60--vw passat 1.9td gt2052v
yamaha vmax 1200- yamaha tdm 850
Portugal

Reply #3August 17, 2019, 12:16:26 pm

ORCoaster

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Re: Very low idle at cold start/fine after glow plug switch of
« Reply #3 on: August 17, 2019, 12:16:26 pm »
Almost sounds like you don't have the fuel screw on the drivers side screwed in quite enough.  Like lacking 1/8 to 1/4 turn.  Also I think you may need to look for a loose wire or bad connection on the temp sender for the glow plugs.  Mine is around the coolant flange on the Rabbit, 1.6 engine.  With that wire on and a warm engine the glows don't turn on.  They draw lots of amps and may be setting up the alternator to come on in an instant if anything else is going.
GP's on all the time is going to burn them up too.  Not so good.  Maybe a 12 volt measurement check on the most accessible one after about 10 seconds to see if indeed they turned off. 

Very odd behavior, But hey it's a VW, what do you expect?

Reply #4August 18, 2019, 01:22:55 pm

carrizog60

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Re: Very low idle at cold start/fine after glow plug switch of
« Reply #4 on: August 18, 2019, 01:22:55 pm »
Yeah,something as to make me work on it everyday...
If i screw the fuel screw more it will make it smoke more,and i dont want to. Also,idle will be up again and lower it will make me mess with screws even more...
Strange,it looks like the pump cant compensate for load at idle,even wipers make idle go up and down a bit...
When going to stop at a intercection idle will go to 700rpm and then climb slowly to normal...

Tomorrow will be buying a new temp.sender(its the 4 wire one i think) as it might be out and causing glow plugs issue.
vw golf gti G60--vw passat 1.9td gt2052v
yamaha vmax 1200- yamaha tdm 850
Portugal

Reply #5August 18, 2019, 01:58:31 pm

carrizog60

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Re: Very low idle at cold start/fine after glow plug switch of
« Reply #5 on: August 18, 2019, 01:58:31 pm »
I assume my problem is on the adjustment of the residual fuel screw and on the seesaw thing that also controls idle.
My throtle lever almost rests at the pump body,because i needed to turn down the idle by all means i could find.
Also i change the indexing point on the seesaw thing because the vertical rod was out of the adjustment.
If i adjust the residual screw it may solve the idle drop but also will raise idle...
I want to get as much fuel as i can without plunger change(vnt2052 can clean the burn) but retain a good idle..
Any idea on how to do it?
vw golf gti G60--vw passat 1.9td gt2052v
yamaha vmax 1200- yamaha tdm 850
Portugal

Reply #6August 18, 2019, 11:14:54 pm

ORCoaster

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Re: Very low idle at cold start/fine after glow plug switch of
« Reply #6 on: August 18, 2019, 11:14:54 pm »
I have to admit I too am chasing some smoke troubles.  I don't like the black in the back, seems like a waste of fuel to me.  I am trying for smileage, (Hagar).  I put a turbo on a bit ago and I think the IP I have was tuned for a different sized engine, 1.9 versus my 1.6. 

I am not willing to just change one thing at a time, Not a Good strategy, I do write down the changes like timing, number of turns on this or that.  I finally really looked at the cone shape of the boost pin I have in the LDA.  We read that we need to take note of the position of the dot or mark on the rubber diaphragm.  But I think someone had pulled mine out and gave it a twist so I was not on the max slope for the cone.  I will try it at max, then min, then on one of the sides in-between. 

I was having trouble backing up a med steep slope. The engine would rev up but then die as I started to engage the clutch and really get a load on it.  Only if I really stomped on it and had black smoke rolling coal out the back would it back up.  I gave it a little more pump pressure by tapping in the regulator.  Then changed the timing a bit more retarded and that seems to have taken care of the power at clutch play and reduced the lag on the timing.

I reset the big spring tension under the LDA by putting more tension against the diaphragm.  Not willing to change it more than a half turn at a time for now.  I will run it like it is and watch the tailpipe as I drive.  If I get over to the middle of the lane I can see the color of the smoke where there is a diving line between the two lanes.  I just need to look in the sideview mirror adjusted downwards. 

I think I may fill it up and see what kind of mileage I have so far and then do it again in another week or so.  If I can get it to go in the upwards direction from the current mark that is what I am hoping for.   

Reply #7August 19, 2019, 11:17:52 am

carrizog60

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Re: Very low idle at cold start/fine after glow plug switch of
« Reply #7 on: August 19, 2019, 11:17:52 am »
My experience is,for mileage get a longer gearbox  and a decent turbo.
vw golf gti G60--vw passat 1.9td gt2052v
yamaha vmax 1200- yamaha tdm 850
Portugal

Reply #8August 20, 2019, 01:05:21 am

ORCoaster

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Re: Very low idle at cold start/fine after glow plug switch of
« Reply #8 on: August 20, 2019, 01:05:21 am »
Turbo on, and trans is FF with the 0.71 fifth gear.  Can't get no bedder. 

 

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