Newbie, not able to connect
Moderators: robertisaar, dex
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Newbie, not able to connect
Hi there, this is all new to me. I have two problems:
1. I can't connect. I have a USB ALDL cable, but the manual talks about COM ports only
2. I can't find a proper ADX file for my 1990 3.1 Beretta GT, only Buicks or 1991 and above
Any help will be appreciated
1. I can't connect. I have a USB ALDL cable, but the manual talks about COM ports only
2. I can't find a proper ADX file for my 1990 3.1 Beretta GT, only Buicks or 1991 and above
Any help will be appreciated
- Six_Shooter
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- Six_Shooter
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Finally I'm connected and can see a bit about how it behaves. Thanks for the help
Now the real problems start. I'm not sure what to look for, but I did notice that the O2 value was up and down in steady cycles, from 80 up to 1000, and further down it constantly switched between LEAN and RICH.
I've just changed the O2 sensor, so if that's the culprit, then the previous was also bad, because changing it had no influence on the rough idle.
Any ideas? Or what else to look for.
Now the real problems start. I'm not sure what to look for, but I did notice that the O2 value was up and down in steady cycles, from 80 up to 1000, and further down it constantly switched between LEAN and RICH.
I've just changed the O2 sensor, so if that's the culprit, then the previous was also bad, because changing it had no influence on the rough idle.
Any ideas? Or what else to look for.
- Six_Shooter
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- Author of Defs
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Yes, I've read that now, new to all this. But the article I read said it should cycle 5-7 times per second on a MFI engine. But mine cycles less than 1 time per second, and you can hear the engine going up and down with the change from RICH to LEAN to RICH.Six_Shooter wrote:In closed loop, that's how the O2 sensor should act.
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- Author of Defs
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- Joined: Sat Feb 21, 2009 3:18 pm
- Location: Camden, MI
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- Posts: 9
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- Author of Defs
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- Location: Camden, MI
what kind of O2 sensor did you install? certain brands do not play well with GM ECMs/PCMs at all, Bosch seems to be a common one.
idle instability can be caused by a few different factors with these since idling is done via a hybrid alpha-n method. any kind of problem with the MAP sensor/vacuum line, IAC, TPS, IAT or a vacuum leak/throttlestop moved from it's factory set position will wreak havoc on the fueling calculation.
when the idle is upset and in closed loop, what do BLM and INT values look like?
idle instability can be caused by a few different factors with these since idling is done via a hybrid alpha-n method. any kind of problem with the MAP sensor/vacuum line, IAC, TPS, IAT or a vacuum leak/throttlestop moved from it's factory set position will wreak havoc on the fueling calculation.
when the idle is upset and in closed loop, what do BLM and INT values look like?
- Six_Shooter
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Have you checked fuel pressure?
Have you performed a tune up?
Have you cleaned the IAC passage/throttle body?
Have you filled up at a different station than usual or different grade of fuel?
The O2 sensor is a reactive device, not a controlling device, so stop being so focused on it.
Yes, the feed back can have an effect on the fuel amount delivered to the engine, but it's not nearly that instant, it takes several seconds for sampling to occur, and then a change in the fueling delivered.
Have you performed a tune up?
Have you cleaned the IAC passage/throttle body?
Have you filled up at a different station than usual or different grade of fuel?
The O2 sensor is a reactive device, not a controlling device, so stop being so focused on it.
Yes, the feed back can have an effect on the fuel amount delivered to the engine, but it's not nearly that instant, it takes several seconds for sampling to occur, and then a change in the fueling delivered.
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BLM and INT showed around 128 both early on, later in drive BLM was a bit lower, and Red.robertisaar wrote:when the idle is upset and in closed loop, what do BLM and INT values look like?
When I started it I had a 2200 rpm idle, and the IAC at a level of around 90, later the idle was less annoyingly high, but still 1400 rpm, and IAC was 55.
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Well, tried som basic stuff, put a vacuum gauge on it, nice and high, took out all the plugs, all looked fine. Wiggled wires and sprayed to find leaks, nothing. Put it all back together, and now I have a perfect idle! Has been so for an hour, but how long?Six_Shooter wrote:Have you checked fuel pressure?
Have you performed a tune up?
Have you cleaned the IAC passage/throttle body?
Have you filled up at a different station than usual or different grade of fuel?
The O2 sensor is a reactive device, not a controlling device, so stop being so focused on it.
Yes, the feed back can have an effect on the fuel amount delivered to the engine, but it's not nearly that instant, it takes several seconds for sampling to occur, and then a change in the fueling delivered.
(TPS and IAC are new, no change when I replaced them)