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Discussion Starter · #1 ·
Well I've been running for a couple of weeks with my old O2 sensor unplugged and have had no problems other than questionable mileage. I installed a new one today and am having some surging/almost stalling out occurances when the water temp goes up and the fan is about to engage. The idle starts to drop in 'burps' downwards until about 3-400 rpm and then catches and jumps right back up to 1000 rpm, and continues to do so until I drive it around a bit and get her cooled off. It also started to occur randomly on the way home, but with a smaller decrease in rpm (1000-800, then back up like it's missing) Anyone have any ideas?
 

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Discussion Starter · #2 ·
Re: Installed new O2 sensor and still having problems.. any ideas? (Shaggy)

A little update, related to this problem..
When I start the car up cold now, after a minute or so the idle bogs down and jumps back up quite a few times and then goes back to what is somewhat of a normal rpm.

Would this likely be a fuel system, or electrical related problem?
I'd appreciate any sort of suggestions as this is really getting to me and I can't seem to figure it out, thanks
Shane
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (Shaggy)

K-lambda? K-Jetronic? KE-Jetronic? KE-Motronic?
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (rocco2nr)

CO, idle adjustment, bad computer, bad tempsensor(s)what down pipe, never use a header down pipe that locates O2 too far down stream remember the Cis lambda cars do not have pre heated O2s they like to be hot right near the motor so it send constant voltage signals
 

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Discussion Starter · #5 ·
Re: Installed new O2 sensor and still having problems.. any ideas? (rocco2nr)

quote:[HR][/HR]K-lambda? K-Jetronic? KE-Jetronic? KE-Motronic?
[HR][/HR]​
Well duh on my behalf, should've specified.. It's an 84' GTI, k-lambda http://****************.com/smile/emthup.gif
Could it possibly be my CPR?
 

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Discussion Starter · #6 ·
Re: Installed new O2 sensor and still having problems.. any ideas? (eurotrashrabbit)

CO, idle adjustment, bad computer, bad tempsensor(s)what down pipe, never use a header down pipe that locates O2 too far down stream[/QUOTE
I am running a 4 into 1 header with the 02 at the collector, I guess that might be what's causing the 'burps' on cold starts until the car is up to temp.

I've adjusted the CO and idle. http://****************.com/smile/emthup.gif

How could I determine if it's the computer, or which sensor is causing these fluctuations after the water temp goes up high enough to play with the mixture like that?
thanks for the suggestions...
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (Shaggy)

the 81 dual out let manifold is the best to use locates the 02 in the manifold as opposed to the down pipe I have the same problem with my rabbit after I put the header on my car makes the car run super rich
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (eurotrashrabbit)

since i'm about to switch to the euro fuel injection, what pointers can you give me regarding running without the O2 sensor? this is supposed to be a 8-10 hp gain over the O2 sensor stock injection.
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (Steve H)

Steve, tell me more about this euro injection system, I can't see how changing the injection gaining you more than a 1-2 hp unless it accompanied other changes.
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (ABA Scirocco)

ABA, all i can tell you about this euro injection is that its brand new, and has a warm up regulator and european fuel distributor. it doesn't use the O2 sensor. unfortunately, the seller via ebay hasn't provided much help. i only paid $175,(sold elsewhere for over $600) and i was willing to try it as i already knew my regulator wasn't working properly. (poor cold idling, and stumbling) i posted here asking feedback before i bought it. those who responded said it was great, and worthwhile. the claims of 8-10 hp seemed a little optimistic. however, i have no intention of adding a turbo/supercharger to this car, and just wanted to give it as much grunt as possible while still maintaining the naturally aspirated characteristics. i've done the 16v airbox, g-grind cam, bigger tb and ported intake, along with a tt cat back with full euro exhaust manifold and tt dual downpipe. after installing the regulator, my cold start/idling problem disappeared.
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (Steve H)

Actually the Euro injection fuel distributor gives better fueling for bigger motors than the US system remember they hot rod without cats in Europe. You can make your own quasi Euro system with 79/80 and ealier injection system and use a Jetta Gli sensor plate and early fuel distributor with out the lambda valve
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (eurotrashrabbit)

But don't expect to be able to pass emissions....
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (Shaggy)

Shaggy, Since its temp related start with everything that measures temp as an input to the fuel control system. The two things that come to my mind are the coolant temp sensor (not the sender for the gauge, the big one) and fuel pressure regulator. Sounds more like the temp sensor because the car ran fine in open loop without the O2 sensor. Do any of your friends have similar cars? Maybe you can swap one of their temp sensors in before you go shell out the cash for a new one. Good luck.
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (eurotrashrabbit)

About this euro injection. I actually bid on this and then got to thinking. Couldn't you just unplug the O2 sensor (and run the wire into the dash plus a ground so you can monitor your mixture while driving with a multimeter) and make a bypass tube to put in place of the frequency valve? Then the only diff would be the flow plate size. If you're just trying to get some extra grunt from an old car it might work quite well. I agree that you'd want to use the bigger plate if you're going to do more. Opinions please.
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (QB)

Without the signal for the O2 sensor, the ecu throws the car into a sort of limp mode. The car will run real rich like this, but don't expect 10 hp out of this... I'd say more like 10 mpg.
Perhaps if you switched over to the setup that eurotrash was talking about, but I don't have any experience with this. Good luck.
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (sirhcorrado)

Removing the frequency valve gets around the "limp home" issue. Anyone else?
 

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Re: Installed new O2 sensor and still having problems.. any ideas? (QB)

Ah, your saying remove the freq. valve. Hmmm.... it's way too early to be up.

I wonder what significance the the flow plate plays in this euro setup. I would imagine that is where the majority of the power increase comes from. Anyone?
 
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