DataMaster -- LTerm Counts read low (108) running rich...
04-11-2012, 04:29 PM
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DataMaster -- LTerm Counts read low (108) running rich... Hi guys,
I've been doing some diagnostic work on my car, (1984 Jaguar XJ6 w/T56 & 1994 Camaro LT1) and I've noticed that my LTerm Counts in DataMaster are coming in at 108. They go up from time to time, but normally they are hovering around 108 -- very rarely do they make it to the desired 128.
My STerm Counts are usually OK -- sometimes slightly low (125/126). What can I do about addressing this problem? I know the car is running rich because I can smell it -- It's been a nagging problem for a while.
New Opti, plugs, wires, coil, fuel pressure regulator & recently had the fuel system cleaned.
I have TunerCats, so I can change the tables -- but I don't know why the LTerm Counts would be so low.
Any help would be great!
Thanks,
Tyler W.
I've been doing some diagnostic work on my car, (1984 Jaguar XJ6 w/T56 & 1994 Camaro LT1) and I've noticed that my LTerm Counts in DataMaster are coming in at 108. They go up from time to time, but normally they are hovering around 108 -- very rarely do they make it to the desired 128.
My STerm Counts are usually OK -- sometimes slightly low (125/126). What can I do about addressing this problem? I know the car is running rich because I can smell it -- It's been a nagging problem for a while.
New Opti, plugs, wires, coil, fuel pressure regulator & recently had the fuel system cleaned.
I have TunerCats, so I can change the tables -- but I don't know why the LTerm Counts would be so low.
Any help would be great!
Thanks,
Tyler W.
04-12-2012, 02:02 PM
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motor is totally stock, the O2 sensors have about 500 miles on them -- I checked out the Datamaster file a bit more thoroughly and noticed that as soon as the car enters CLOSED LOOP, the LTerm BLM's go way down. The injector duty cycle also goes way down, to 1.8 or so. The O2 sensors appear responsive at least judging from the .uni file. I don't know if one or more of the injectors is leaky, but because the cycle looks good in OPEN LOOP, i would suspect they are OK.
I have tried 2 sets of O2 sensors, same result. It seems like like exhaust leak is the only possibility?
I have tried 2 sets of O2 sensors, same result. It seems like like exhaust leak is the only possibility?
04-12-2012, 02:59 PM
#4
motor is totally stock, the O2 sensors have about 500 miles on them -- I checked out the Datamaster file a bit more thoroughly and noticed that as soon as the car enters CLOSED LOOP, the LTerm BLM's go way down. The injector duty cycle also goes way down, to 1.8 or so. The O2 sensors appear responsive at least judging from the .uni file. I don't know if one or more of the injectors is leaky, but because the cycle looks good in OPEN LOOP, i would suspect they are OK.
I have tried 2 sets of O2 sensors, same result. It seems like like exhaust leak is the only possibility?
I have tried 2 sets of O2 sensors, same result. It seems like like exhaust leak is the only possibility?
04-12-2012, 04:57 PM
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that's the thing, i don't hear anything out of the ordinary, but the performance speaks for itself. I suppose i could swap in another set of O2 sensors, but it's getting a bit ridiculous -- I've already tried 2 pairs.
04-12-2012, 07:36 PM
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What are the O2s saying?, are they cycling like normal or do they read something rediculous?
Lok over what youre Coolant temp for the puter is saying and see if it is in line with what the temp is. Also check what the MAF is reading according to what the car is doing etc, if its the throttle is just cracked the MAF should be reading lower than witht he RPMs up.
Lok over what youre Coolant temp for the puter is saying and see if it is in line with what the temp is. Also check what the MAF is reading according to what the car is doing etc, if its the throttle is just cracked the MAF should be reading lower than witht he RPMs up.
04-12-2012, 09:11 PM
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o2s cycle very rapidly from 70 to 900 (on datamaster). The engine temp doesn't get above 83.6 degrees. I'm running a 160 degree thermostat and I've adjusted the fan on temps based on recommendations from shbox. where are the MAF readings?
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04-12-2012, 10:23 PM
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at idle the AFGS reads 8.x at closed loop. I noticed that when my LTerm counts are at 108, the AFGS reads around 14~ at 2k RPM. The AFGS reads in the high 40s when my LTerm counts are reading what they are supposed to (128~). Both readouts seem to vary wildly.
What do you think this means? I purchased the MAF used off the forum -- it came de-screened.
What do you think this means? I purchased the MAF used off the forum -- it came de-screened.
04-12-2012, 10:47 PM
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One thing you could do since the motor and tune are mostly stock is unplug the MAF with tunercats set it to Speed Density mode, and see if the car behaves better, if so the MAF is glaringly suspect. The maf should be pretty consistant climbing under load as the RPMs increase and somewhat steady at idle, at tip in it should increase and then drop slightly as load comes on and then climb back up as you slowly accelerate.
04-13-2012, 08:41 AM
#11
at idle the AFGS reads 8.x at closed loop. I noticed that when my LTerm counts are at 108, the AFGS reads around 14~ at 2k RPM. The AFGS reads in the high 40s when my LTerm counts are reading what they are supposed to (128~). Both readouts seem to vary wildly.
What do you think this means? I purchased the MAF used off the forum -- it came de-screened.
What do you think this means? I purchased the MAF used off the forum -- it came de-screened.
) The screen is there for a reason...don't mess with it. You can get a new one at autozone for a little over $100 and they work great; plus you get a warranty.
04-13-2012, 01:53 PM
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Do you have a chart that shows how an MAF is supposed to function? I can always pick up another MAF from autozone/kragen and test it to see if it fixes the problem.
I called a mechanic today and he said that it could be the temperture sensor, but it's basically new, and I'm getting proper readings.
The fact that when the car is running in speed density mode it is working OK (even 128 for S and L term counts) tells me there's something wrong with what the o2 sensors are seeing, or the 02 sensors themselves.
I called a mechanic today and he said that it could be the temperture sensor, but it's basically new, and I'm getting proper readings.
The fact that when the car is running in speed density mode it is working OK (even 128 for S and L term counts) tells me there's something wrong with what the o2 sensors are seeing, or the 02 sensors themselves.
04-13-2012, 02:39 PM
#13
Do you have a chart that shows how an MAF is supposed to function? I can always pick up another MAF from autozone/kragen and test it to see if it fixes the problem.
I called a mechanic today and he said that it could be the temperture sensor, but it's basically new, and I'm getting proper readings.
The fact that when the car is running in speed density mode it is working OK (even 128 for S and L term counts) tells me there's something wrong with what the o2 sensors are seeing, or the 02 sensors themselves.
I called a mechanic today and he said that it could be the temperture sensor, but it's basically new, and I'm getting proper readings.
The fact that when the car is running in speed density mode it is working OK (even 128 for S and L term counts) tells me there's something wrong with what the o2 sensors are seeing, or the 02 sensors themselves.
