Very Bad Idle Issues
03-10-2012, 06:28 PM
#1
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Very Bad Idle Issues
95 T/A 383 stroker/professional products 58mm TB/New MSD OPti, Map sensor,MSd coil and ignition module, tune. No trouble codes.
Car will not idle. No matter how much I play with the Blade set screw and reset TPS to .067. Keeps repeatedly stalling upon let off of throttle regardless of speed. Car also surges a little while on throttle and holding it steady. Any suggestions?
Car will not idle. No matter how much I play with the Blade set screw and reset TPS to .067. Keeps repeatedly stalling upon let off of throttle regardless of speed. Car also surges a little while on throttle and holding it steady. Any suggestions?
Last edited by Macs95LT1; 03-10-2012 at 06:31 PM. Reason: Forgot year
03-10-2012, 07:18 PM
#4
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Re: Very Bad Idle Issues
Tune is from PCM4less. Problem has gotten much worse since new parts were installed. I'm gonna run Data Master on it tomorrow. What should the range of my IAC counts be, so I know what to look for?
03-11-2012, 04:36 AM
#7
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Re: Very Bad Idle Issues
If your car has a T56 and they accidentally tuned it for an auto, I think that could screw with your idle and coasting. Not positive though 
Last edited by AdsoYo; 03-11-2012 at 04:39 AM.
03-11-2012, 10:22 AM
#8
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Re: Very Bad Idle Issues
Did you reset the TPS sensor to .067V (incorrect) or 0.67V (correct)?
Most 58mm TB's seem to have issues with idle air. Not sure about the Professional Products TB.
When you adjust the throttle stop screw, are you watching the IAC counts? Are they in the range of 20 - 40 counts? Do the IAC counts respond to changes in the stop screw position? You only address the TPS voltage after you have the idle RPM to where the program wants it, and the IAC counts are under control.
Most 58mm TB's seem to have issues with idle air. Not sure about the Professional Products TB.
When you adjust the throttle stop screw, are you watching the IAC counts? Are they in the range of 20 - 40 counts? Do the IAC counts respond to changes in the stop screw position? You only address the TPS voltage after you have the idle RPM to where the program wants it, and the IAC counts are under control.
Last edited by Injuneer; 03-11-2012 at 10:33 AM.
03-11-2012, 04:30 PM
#9
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Re: Very Bad Idle Issues
Did you reset the TPS sensor to .067V (incorrect) or 0.67V (correct)?
Most 58mm TB's seem to have issues with idle air. Not sure about the Professional Products TB.
When you adjust the throttle stop screw, are you watching the IAC counts? Are they in the range of 20 - 40 counts? Do the IAC counts respond to changes in the stop screw position? You only address the TPS voltage after you have the idle RPM to where the program wants it, and the IAC counts are under control.
Most 58mm TB's seem to have issues with idle air. Not sure about the Professional Products TB.
When you adjust the throttle stop screw, are you watching the IAC counts? Are they in the range of 20 - 40 counts? Do the IAC counts respond to changes in the stop screw position? You only address the TPS voltage after you have the idle RPM to where the program wants it, and the IAC counts are under control.
03-11-2012, 07:22 PM
#12
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Re: Very Bad Idle Issues
Tried to post my data files so you guys could to see what the car is doing, but site won't allow me to. Adjusted TB set screw while running Data Master, but turning screw had no affect on counts. However opening blades a bit and then resetting IAC, I was able to get the IAC counts to drop from 160 to 110 at 950 rpm idle. 950 rpm is good, but this count is still too high. Don't know what else to do, except maybe trying adjusting blades open a little more and then resetting IAC again, then checking to see if the count comes down again?
Last edited by Macs95LT1; 03-11-2012 at 07:36 PM.
03-11-2012, 09:57 PM
#13
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Re: Very Bad Idle Issues
Both those codes turn on the SES light. At least according to the 94 factory shop manual. 95 should be similar.
You have to upload your data file to an FTP site and post the link.
How do you know 950RPM is "good"? What does Datamaster show as the target idle speed? The IAC counts should respond to moving the throttle blades, wothout requiring a reset procedure. Note that if you open the blades up to the point where the TPS voltage exceeds about 0.90V, the PCM no longer considers the engine to be idling, and will use different settings.
As mentioned above, some large TB's don't appear to flow enough idle air, and require a modification to get them to flow enough. A TB that can't flow enough idle air would result in high IAC counts, and usually will produce "split" BLM's. What are the long term fuel trims for the left and right banks when the PCM is operating in Cell 16 (idle cell)?
You have to upload your data file to an FTP site and post the link.
How do you know 950RPM is "good"? What does Datamaster show as the target idle speed? The IAC counts should respond to moving the throttle blades, wothout requiring a reset procedure. Note that if you open the blades up to the point where the TPS voltage exceeds about 0.90V, the PCM no longer considers the engine to be idling, and will use different settings.
As mentioned above, some large TB's don't appear to flow enough idle air, and require a modification to get them to flow enough. A TB that can't flow enough idle air would result in high IAC counts, and usually will produce "split" BLM's. What are the long term fuel trims for the left and right banks when the PCM is operating in Cell 16 (idle cell)?
03-12-2012, 05:02 PM
#14
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Posts: 41
Re: Very Bad Idle Issues
Both those codes turn on the SES light. At least according to the 94 factory shop manual. 95 should be similar.
You have to upload your data file to an FTP site and post the link.
How do you know 950RPM is "good"? What does Datamaster show as the target idle speed? The IAC counts should respond to moving the throttle blades, wothout requiring a reset procedure. Note that if you open the blades up to the point where the TPS voltage exceeds about 0.90V, the PCM no longer considers the engine to be idling, and will use different settings.
As mentioned above, some large TB's don't appear to flow enough idle air, and require a modification to get them to flow enough. A TB that can't flow enough idle air would result in high IAC counts, and usually will produce "split" BLM's. What are the long term fuel trims for the left and right banks when the PCM is operating in Cell 16 (idle cell)?
You have to upload your data file to an FTP site and post the link.
How do you know 950RPM is "good"? What does Datamaster show as the target idle speed? The IAC counts should respond to moving the throttle blades, wothout requiring a reset procedure. Note that if you open the blades up to the point where the TPS voltage exceeds about 0.90V, the PCM no longer considers the engine to be idling, and will use different settings.
As mentioned above, some large TB's don't appear to flow enough idle air, and require a modification to get them to flow enough. A TB that can't flow enough idle air would result in high IAC counts, and usually will produce "split" BLM's. What are the long term fuel trims for the left and right banks when the PCM is operating in Cell 16 (idle cell)?
Two columns r shown for L Term counts. left one is high lighted in pink and says 124, right is green and says 136.
I find this interesting:
spark advance 17
spark retard 9
knock count 51314
No DTC