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Discussion Starter · #1 ·
Ok ever since my O2 sensor died and I had to replace it. My car has been running like crap.
At low speeds when the A/F ratio should be sweeping back and forth nice and smooth. It dosn't instead it kinda skecthes back and forth, like its fighting to stay rich but the ECU won't allow it, causing it to skip and pop. Then when I'm boosting it will skip and miss, like the spark is getting blowen out. And when I look at my A/F ratio gauge while boosting, I can see the A/F ration kinda skip into lean well actualy storich (but to me storich is lean) and thats when it will miss. This happens at any level of boost so its not because im leaning out from too much boost.
What really makes me mad is that I just replaced these things.
Plug wires, Disturbotor cap and rotor button, and a new O2 sensor...and now the car runs worse then it ever did. its so annoying, everytime I replace somthing, somthing else has to break. I only get a week here and there to enjoy my car when its running properly, all other times it dosn't run right and im forced to work on it.

So I know its not my plug wires, o2 sensor or my disturbotor cap and rotor button. so what other things should I be looking into. I was thinking along the lines of Fuel filter???
So to break this down into somthing more simple. Basicly my car will skip and pop at any speed and revs, as long as Im trying to hold a stedy throttle it skips and pops. But if I floor it it won't skip until I hit full "set" boost and its holding a stedy throttle. but as Im getting to full boost it will not skip only when the throttle goes to a position and holds there.

Methman
 

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hmm odd. Are you pulling any codes?

I know my car will skip at anything above 13 psi. I wound up having to smash the plug gap all the way down to .030 for it to go away. Only difference is that mine was only doing it at high boost. Yours does it throughout the RPM range.

What kind of parts are you using? I tried some Accel copper core spark plug wires and the car hated it. It skipped at low rpms and the tach was all messed up. I also have gone through 2 bosch 02 sensors, one of which was bad out of the box.
 

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This may sound dumb, and you may have thought of this, and it may not help. But, did you reset the computer after the changes. When I changed my o2 my car still ran like crap. I did the deal where I unhooked the negative terminal of my battery and held my foot on the brake for a minute or so, and it ran noticeably better.
 

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skippin & a poppin

While replacing the ignition parts, did you pull the plugs and check their condition ? Sometimes, the plug's gap or having loose torque into the head can cause problems.
Also ensure that you have the right rotor part.
 

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Discussion Starter · #8 ·
Thanks for all of the ideas guys.

I did reset the ECU after I changed the O2 sensor. I checked all of the plugs also. They were all fine and they're pretty much brand new anyway. I'm going to go buy some NGK plug wires, and get rid of the acell's. Just to see if the acells were the problem ( I certinly hope not, though, because I spent $80 on those plug wires). They were the universal ones, and to my surprise, they left it up to me to install the ends on the wires. I don't think its the wires though because they worked fine the day I installed them.
Thanks for the tip on the fuel filter Sicksix6 I was planing on getting a Blaster 2 coil.
Another symptom Im having is leaning out on idle, and stalling once in a while due to the idle droping too low so fast. When it dosn't stall it idles low and rough with the A/f gauge reading so lean that its blank.:shrug:
I really hope I can get this problem figured out.

methman
 

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Methman said:
Ok ever since my O2 sensor died and I had to replace it. My car has been running like crap.

At low speeds when the A/F ratio should be sweeping back and forth nice and smooth. It dosn't instead it kinda skecthes back and forth, like its fighting to stay rich but the ECU won't allow it, causing it to skip and pop. I can see the A/F ration kinda skip into lean well actualy storich (but to me storich is lean) and thats when it will miss.

What really makes me mad is that I just replaced these things.
Plug wires, Disturbotor cap and rotor button, and a new O2 sensor...and now the car runs worse then it ever did. its so annoying, everytime I replace somthing..........

So I know its not my plug wires, o2 sensor or my disturbotor cap and rotor button.
So to break this down into somthing more simple. Basicly my car will skip and pop at any speed and revs.
Hey Meth;
You stated that all of this started after the "O2 replacement", right ? Well you apparently decided to also replace the distributor cap, rotor & wires at the same time. So it could be any one of these things that caused a "change" in the running. Taking a step back, try putting the old ignition parts back on, thus leaving only the O2 sensor as being questionable.
Are you getting any trouble codes now ?
 

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stalling........

Methman said:
Another symptom Im having is leaning out on idle, and stalling once in a while due to the idle droping too low so fast. When it dosn't stall it idles low and rough with the A/f gauge reading so lean that its blank.:shrug:
Sorry Meth;
Just read your latest post.........
Have you looked at the TBI boot and coolant level ?
Sometimes the "simple stuff" is over-looked, ya know all about vacuum leaks and the ISC valve affecting the motor's idle and overall runability.
Ya never really know !
 

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Discussion Starter · #11 ·
well its acting like a vacume leak, in a way. The low idle ect.
I pulled a code yesterday "Ego sensor rich", can someone explain what the EGO sensor does and if this could cause the problems that I am having??
What are some diagnostic test I can do on the ISC valve???

Thanks

PS: Does anyone on this board know anything about VW's? I just bought a 1990 VW golf for $100! It needed a clutch which costed me $200. So I spent $300 for a decent 1990 VW glof (I installed the cluch myself)....not too bad of a deal eh?
Anyway, Its all set to go except for one problem, It seems to be running rich. When its cold (Its the middle of winter here right now), the Car will run OK, although its still rich. Once the car warms up it starts to bogg and run really rough, puffing out black smoke when trying to rev.
What should I be looking into in order to start diagnosting this problem. Do VW's use "Map sensors"? Because if they do, I would say that a map sensor would be the problem.
Also does anyone know of any VW fourms like we have here for MX-6's?

Methman
 

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EGO sensor

Methman said:
well its acting like a vacume leak, in a way. The low idle ect.
I pulled a code yesterday "Ego sensor rich", can someone explain what the EGO sensor does and if this could cause the problems that I am having??
What are some diagnostic test I can do on the ISC valve???

Meth;
The "Exhaust Gas Oxygen Sensor" is your O2 sensor which you replaced. Understanding that it's brand spankin new and you cleared the codes after installing it, possibly you have another condition causing the "richness". The sensor is doing it's job by detecting this.
Possibly something in the motor's air/fuel management needs attention ? Have you done any recent mods ? Check all the air intake and VAF fittings. The Turbo motor uses the exhaust gas to pressurize the incoming air, thus requiring more air with the fuel to ignite.
Some other things to consider may be the EGR valve or even the coolant sensors. It could be that your ECU thinks that the motor is cold, thus remaining in a rich state ?
The ISC valve has coolant running through it, if your coolant level is low.....this valve won't operate properly. If it's stuck, try tapping the housing to see if it makes a difference. Testing it requires removal and checking for internal flow restrictions. They're a pain to get off.
 

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Discussion Starter · #13 ·
Thanks Johnie. Well I fixed the skiping and poping....it turned out to be a bad plug wire (the electroid in the middle of the wire was burnt..I had to cut the wire down apx 3" to get to some electroid (sorry, sp, but I hope you know what I mean) that wasn't burnt. lol $80 plug wires).
Anyway, My car drives fine now withoout the skipping and poping and backfiring. And I can reach full boost and sustain it without the problem of it missing. But I still get the EGO rich code, and my A/F is obvousily rich.
Could this be the problem....I recentaly replaced my Coolant temp sensor with one from a 1991 NA MX-6 (I thought the car was a GT at the time) Are the coolant temp sensors different in the 90+ NA's and the 90+ GT's. What I mean is would it list as a different part #? Or are they the same sensor weather its NA or GT? My temp reading on the gauge in the car reads Normal:shrug: .

But thats the only thing I can think of, because just before my O2 sensor "bit the dust" I installed that temp sensor from the NA (1991 NA). Then I replaced the O2 sensor (because my A/F gauge was going blank, and I had No power at all when it did go blank, so I assumed it was my O2 sensor). After I replaced it the car ran again without the gauge going blank and losing power. But it was skiping and popping and I couldn't boost without missing. That turned out to be the plug wire...but I still have the EGO rich problem. Everything worked fine before I changed the O2 sensor (perhaps the symptoms from the bad O2 sensor, were masking any problems that the NA temp sensor was causing???)

Anyway thanks so far.

Methman
 

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Discussion Starter · #14 ·
No one knows if the NA temp sensor is different from the GT's temp sensor???
 
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