cold running problem

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jemery.wa
Posts: 12
Joined: Sat May 16, 2009 12:52 am
What year is your cabby?: 1981
Do you own a Cabriolet?: Yes
Location: vancouver, wa

cold running problem

Post by jemery.wa »

Hello all, i am having a problem with my 1984 cabby, i will try to post pics of both of my cabbys, it starts right up and idles nice (around 900 rpm) but if you try to press on the gas it will die, unless you press the gas very lightly and baby the rpm's up and even then it will sputter. once the car has warmed up it runs great. i have set the timing (have one question about that, will ask later) used a duty cycle meter to set the mixture, tested the aux air, replaced the lambda relay, WUR, and oxygen sensor. at this point the car is doing 150% better than it was doing (oxygen sensor was shorting out) but i need to get this last detail completed.

as far as timing goes the bentley isn't to clear on certain detail in the procedure of setting timing for either of my cars. on the 84 1.8 it doesn't specify whether or not you disconnect the vacuum advance when setting the timing. on my 81 1.7l the only mark i can find is what i believe to be TDC.
Attachments
1984 Wolfsberg, just bought it a month ago for $200
1984 Wolfsberg, just bought it a month ago for $200
Picture 024-1.jpg (227.65 KiB) Viewed 6384 times
1981, with short shift kit, weighted shift rod, scirocco shifter and front sway bar, upper and lower front braces, euro bumpers, prothane bushings for suspension and steering rack, k&n, g-grind cam, adjustable cam gear, and full 2 1/4 exhaust from cat back.  still need a few things but it is fun to drive and was only $250 when i bought her 3 years ago.
1981, with short shift kit, weighted shift rod, scirocco shifter and front sway bar, upper and lower front braces, euro bumpers, prothane bushings for suspension and steering rack, k&n, g-grind cam, adjustable cam gear, and full 2 1/4 exhaust from cat back. still need a few things but it is fun to drive and was only $250 when i bought her 3 years ago.
Picture 004-1.jpg (227.44 KiB) Viewed 6384 times
sixsracing
Forum Niceguy
Posts: 1102
Joined: Mon Jan 19, 2004 3:14 pm
What year is your cabby?: 1991
Do you own a Cabriolet?: Yes
Location: Bangor, Maine

Re: cold running problem

Post by sixsracing »

There is a small solenoid/valve called a frequency valve on the backside
of the airbox/fuel distributor. It has a blue electrical connector and some
lines hooked up to it. Have somebody turn the key and see if it vibrates.
Chances are it doesn't. If it does vibrate then post back here and we will
have more suggestions. If it doesn't vibrate then I or someone else can
go over how to fix it so it does. I don't know how familiar you are with
these cars so if I'm being to simple I apologize, don't recognize your name.
91 Cabriolet, red w/white
86 Cabriolet white/white (oldest daughter)
97 Golf, black (youngest daughter)
98 Beetle, red
94 Cabrio, dark green (oldest son)
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jemery.wa
Posts: 12
Joined: Sat May 16, 2009 12:52 am
What year is your cabby?: 1981
Do you own a Cabriolet?: Yes
Location: vancouver, wa

Re: cold running problem

Post by jemery.wa »

the freq valve is working, i think my timing may be off a little bit, i need to find out if i should remove the vacuum advance or not when setting the timing, the bentley isn't very clear about it. i know that for most other cars you do but with a volkswagen you can never be to sure. When i got this cabby the oxs sensor was actually shorting out to the aux air valve and causing it to be confused about lean and normal, the freq valve would freak out and the only way to make it run correct was how the previous owner tied the full throttle switch closed with a wire. i have since then set the timing (possibly retarded a little), set the idle, and adjusted the mixture (duty cycle 50%).

i understand about starting simple so no need to apologize, i have had my 81 cabby for about 3 years and have had to do a lot of work on almost all parts of the car, i have parted out 2 rabbits, and now in typical rabbit fasion they multiply and i have 2 now. i do plan on trying to sell one of them soon, just not sure which one yet.

i have to locate a coolant leak tomorow and try to reset the timing to see if that helps the problem. today i focused on replacing an axle and wheel bearing, drives soo much better now.

thanks for taking the time to respond.
sixsracing
Forum Niceguy
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Joined: Mon Jan 19, 2004 3:14 pm
What year is your cabby?: 1991
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Location: Bangor, Maine

Re: cold running problem

Post by sixsracing »

Ignition timing shouldn't cause what you are experiencing. The ignition timing on both cars can be set roughly by aligning the notches on the crank pulley with the marks an removing the distributor cap and aligning the rotor with the line on the distributor. This should allow the car to run normally. The vacuum advance does get disconnected for timing light fine tuning. In my experience it doesn't make any difference whatsoever. As these cars get older I adjust timing by ear 90% of the time. There are timimg marks on the flywheel, remove the green plug in the top of the bellhousing and rotate the crankshaft by hand until you find them. There are a few marks, by aligning both ends of the crankshaft and using the distributor you can figure out which ones are correct.

Have you done a fuel pressure test? Does the in-tank pump operate?
91 Cabriolet, red w/white
86 Cabriolet white/white (oldest daughter)
97 Golf, black (youngest daughter)
98 Beetle, red
94 Cabrio, dark green (oldest son)
Cogito Ergo Zoom
Bugly
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Re: cold running problem

Post by Bugly »

sixs would be correct in testing fuel pressure. I had similar problem and changed the in tank pump and the fuel filter and she runs just fine now.
'89 cabby
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Briano1234
Whats that smell?
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Re: cold running problem

Post by Briano1234 »

84's depending on if you have a full sized spare tire, or the space saver means that you have the in-tank pump or not.

space saver yes.

full size no.
Briano

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jemery.wa
Posts: 12
Joined: Sat May 16, 2009 12:52 am
What year is your cabby?: 1981
Do you own a Cabriolet?: Yes
Location: vancouver, wa

Re: cold running problem

Post by jemery.wa »

it has a full size spare, so i guess that means it has no in tank fuel pump. one thing i noticed yesterday is that it looks like there is a drip coming from the bottom of the intake manifold on one of the runners, i don't think it is all oil. i am going to check to make sure there isn't a gasket problem and also replace a could of vacuum lines. also i need to make sure that the cold start injector is turning off when it should.

this car runs great once it is warmed up for like 3-5 min it runs good, it's only right when it is started up. i don't have a fuel pressure gauge for the cis system so i can't test for sure what the pressure in the system is, i do have another WUR i could test with.
sixsracing
Forum Niceguy
Posts: 1102
Joined: Mon Jan 19, 2004 3:14 pm
What year is your cabby?: 1991
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Location: Bangor, Maine

Re: cold running problem

Post by sixsracing »

Intake leaks would cause idling problems, shouldn't affect acceleration to the point your experiencing. Good to check though. For some reason I thought that you had checked the cold start valve already. You can disconnect the valve electrically but if you have a stuck open valve then disconnecting it won't help.

Have you pulled the spark plugs and looked for coloring?

Also, that's a good rule for in-tank pumps (spare tire size) but I have run into discrepencies with it. Check anyway.

Have you pulled the warm up regulator and cleaned the screens?
91 Cabriolet, red w/white
86 Cabriolet white/white (oldest daughter)
97 Golf, black (youngest daughter)
98 Beetle, red
94 Cabrio, dark green (oldest son)
Cogito Ergo Zoom
jemery.wa
Posts: 12
Joined: Sat May 16, 2009 12:52 am
What year is your cabby?: 1981
Do you own a Cabriolet?: Yes
Location: vancouver, wa

Re: cold running problem

Post by jemery.wa »

sometimes we don't look at the smallest things, i haven't pulled the spark plugs yet, but it hasn't given me a big reason to do so.

it's 84 and sunny today so i decided to drive it for my weekly grocery shopping, it ran great, nice acceleration, good idle, and no misses. i did realize that i need to replace the shifter linkage bushings and maybe a short shift kit.
sixsracing
Forum Niceguy
Posts: 1102
Joined: Mon Jan 19, 2004 3:14 pm
What year is your cabby?: 1991
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Location: Bangor, Maine

Re: cold running problem

Post by sixsracing »

Not necessarily for replacement. Reading the colors of the plugs can
sometimes identify problems. One plug more black or white than another
for instance.

When I answered initially I had assumed that the problem didn't go away
after a few minutes. I think pulling the warm up regulator and or checking
the thermo-time switch is a next step.
91 Cabriolet, red w/white
86 Cabriolet white/white (oldest daughter)
97 Golf, black (youngest daughter)
98 Beetle, red
94 Cabrio, dark green (oldest son)
Cogito Ergo Zoom
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gull
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Re: cold running problem

Post by gull »

jemery.wa wrote:as far as timing goes the bentley isn't to clear on certain detail in the procedure of setting timing for either of my cars. on the 84 1.8 it doesn't specify whether or not you disconnect the vacuum advance when setting the timing. on my 81 1.7l the only mark i can find is what i believe to be TDC.
Check the underside of the hood for a yellow sticker. This is the final word on anything emissions related (timing procedure, idle speed, spark plugs, etc.) because it takes into account any production changes. Usually vacuum advance isn't active at idle anyway, so it probably won't matter too much. The cars you have to watch out for are ones with a vacuum retard circuit.

This PDF has a very good photo of the timing marks: http://www.cabby-info.com/Files/AdjustingTheTiming.pdf
As usual for VW, the mark you're not supposed to time to is the obvious one, and the one you're supposed to time to is hard to see. ;)
VW fan who fell to the Honda side of the force
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jemery.wa
Posts: 12
Joined: Sat May 16, 2009 12:52 am
What year is your cabby?: 1981
Do you own a Cabriolet?: Yes
Location: vancouver, wa

Re: cold running problem

Post by jemery.wa »

so here is the latest update, i have checked for vacuum leaks, re-adjusted the idle and mixture (w/duty cycle meter), so far i am on my 3rd WUR, replaced the cold start injector. today i replaced the lambda coolant temp switch. here is what it does still;

starts right up
idles good
hit the gas and it will accelerate
after a minute if you hit the gas it wants to instantly die, unless you barely press the gas and baby it, when it exhibits this symptom if you press the WOT switch the problem goes away, as well if you short the coolant temp switch leads the problem goes away but the idle is very low.
if you let it idle and warm up for a few minutes the problem isn't quite as bad but still present, if you instantly start driving it the problem goes away quicker.

the problem is only present in the warm up phase, once warmed up it runs like a rapped ape and even when cold the idle is very good, no miss. i am close to taking the fuel distributor out to see if it has good even movement.

it does smell like it is running rich when cold, but that could just be the fact that the cat isn't warmed up and it is supposed to run richer during warm up. :banghead:
jemery.wa
Posts: 12
Joined: Sat May 16, 2009 12:52 am
What year is your cabby?: 1981
Do you own a Cabriolet?: Yes
Location: vancouver, wa

Re: cold running problem

Post by jemery.wa »

just pulled the spark plugs, they are bosch platinum (with the 4 prongs) and they are blackish, not completely fouled but i am wondering if they where that way because of the problems it was having (bad oxs sensor). guess i will try cleaning them first.

what plug does everybody recommend for the 1.8?
sixsracing
Forum Niceguy
Posts: 1102
Joined: Mon Jan 19, 2004 3:14 pm
What year is your cabby?: 1991
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Location: Bangor, Maine

Re: cold running problem

Post by sixsracing »

Bosch single tip platinum work just fine. The numerous tips are slightly ridiculous.
Electricity takes the path of least resistance, it's going to one and that's it. When
Splitfire first came out I was racing motorcycles and we did back to back dyno runs
with different plugs. Splitfires lost power on almost every bike. Progress right?

I think you are at the point of pulling the injectors and checking spray pattern.
The fuel distributor is almost never the problem and is pricey.
91 Cabriolet, red w/white
86 Cabriolet white/white (oldest daughter)
97 Golf, black (youngest daughter)
98 Beetle, red
94 Cabrio, dark green (oldest son)
Cogito Ergo Zoom
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kamzcab86
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Re: cold running problem

Post by kamzcab86 »

From my research, 4-electrode plugs do more harm than good in these cars. The plugs recommended are Bosch W7DC (single) and Bosch W7DTC (triple). However, NGK's are just as good. Here is a cross-reference plug chart: http://www.cabby-info.com/ignition.htm#plugs .

While the fuel distributor can fail (first step is to clean it up: http://www.vintagewatercooleds.com/tech ... cismaf.htm , and verify the sensor plate position), it doesn't sound to be the problem in this case.

Checking the injectors is a good idea (one or more may be leaking, etc.) as well as the fuel pressure, but also test the auxiliary air regulator/valve (it may not be opening at start-up as it should).
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