Computer Diagnostics and Tuning Technical discussion on diagnostics and programming of the F-body computers

PCM/Tuning - 1st start of the Day

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Old May 18, 2019 | 12:13 PM
  #1  
Busterburch's Avatar
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From: Conroe, Tx
PCM/Tuning - 1st start of the Day

Hey guys, Is there a setting in the PCM for "priming" the motor when starting? My 96 starts absolutely awesome on the first start of the day with no pressure on the gas pedal.. after the motor warms up a bit i have to depress the gas pedal a little to get it to fire up.. I am using E-Hack and Tuner Pro/RT but i don't see anything that looks like a "primer" setting.. Any ideas or suggestions are greatly appreciated!! Thanks

PS: I recently installed LTCC but this behavior existed prior to and after the install.
Old May 18, 2019 | 04:31 PM
  #2  
Injuneer's Avatar
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Re: PCM/Tuning - 1st start of the Day

Good cold start, but problems on hot start - may be related to a faulty coolant temp sensor reading. The PCM richens the mixture for cold start based on coolant temp. If the engine is hot, and the coolant temp sensor is showing cold, it may take that extra air from the throttle being open to lean it out.

Can't help you on the "priming" question..... ditched the factory PCM almost 20 years ago.
Old May 18, 2019 | 05:19 PM
  #3  
Busterburch's Avatar
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From: Conroe, Tx
Re: PCM/Tuning - 1st start of the Day

Thank you Injuneer.. I appreciate the quick response. Have a great weekend.
Old May 27, 2019 | 06:53 PM
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From: Wisconsin
Re: PCM/Tuning - 1st start of the Day

I've been wondering about this too. Only mine is a bear both ways, hot and cold. Before I even think about sending the starter in motion I cycle the key 5 or 6 times to keep throwing more fuel at the rails. Doing so helps me from wear and tear on the starter. I've been looking into getting a fuel gauge to see what's going on. I just acquired this car and it is a bit of a basket case and no good history. I pulled codes for other issues which I think would muddy the waters here so I'll hold back on that. I've been considering everything from fuel regulator or filter to tuning. Just not going there until I invest in my own diagnostic and tuning equipment. When I figure out which software/s I will use then I might get to the bottom of this. Just guessing right now that erroneous sensor reporting to the PCM may not be all inclusive for all sensors especially when pulling a code. Merely put, the PCM is simply responding to data received from sensors, some fatal and some not.

Go easy on me still new to this platform.
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