Knowledge Is Power
05-20-2021, 09:15 AM
#1
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Join Date: Mar 2020
Location: Cincinnati
Posts: 92
Knowledge Is Power
Some of you guys are quite knowledgeable on these LT1s. So one an under-knowledged side, can someone fill me in?1996 Formula 5.7L Lt1. Bbk tb, ac delete, 8.5 wires, accel coil, ram air box Im guessing suncoast creations hood and box because oe ram filter wont fit, but kn 33-2118 will (98 and up).
1. Map readings- So what readings should appear in inHg at idle? At WOT? If greater or lesser values, what could be the cause? Im at 650' ASL....in my before life I was Sebastián from little mermaid (under the sea song plays in head)
2. Timing Advance for Cylinder #1- What should I be getting, what if its greater or lesser?
3. Calculated Engine Load Value- what is good/ bad?
4 . MAF Rate- with my setup, what's good/ bad?
5. ST and LT Fuel Bank - I can look at 2ST readings, 2LT....but it doesn't say which side is which in detail. Is there a way to tell? Also the good/bad readings I should get.
6. Without pulling it out, how to tell if theres a different cam installed by previous owner if possible.
7. How hard is it 1-10 and estimated time to change out timing set?
8. Does air intake temp sensor have to be after maf sensor(from what I read its supposed to)? This guy has it installed on air box before maf. Does it throw readings off?
8.Why do I come here? Because you guys are awesome.
1. Map readings- So what readings should appear in inHg at idle? At WOT? If greater or lesser values, what could be the cause? Im at 650' ASL....in my before life I was Sebastián from little mermaid (under the sea song plays in head)
2. Timing Advance for Cylinder #1- What should I be getting, what if its greater or lesser?
3. Calculated Engine Load Value- what is good/ bad?
4 . MAF Rate- with my setup, what's good/ bad?
5. ST and LT Fuel Bank - I can look at 2ST readings, 2LT....but it doesn't say which side is which in detail. Is there a way to tell? Also the good/bad readings I should get.
6. Without pulling it out, how to tell if theres a different cam installed by previous owner if possible.
7. How hard is it 1-10 and estimated time to change out timing set?
8. Does air intake temp sensor have to be after maf sensor(from what I read its supposed to)? This guy has it installed on air box before maf. Does it throw readings off?
8.Why do I come here? Because you guys are awesome.
Last edited by scope513; 05-20-2021 at 09:24 AM.
05-20-2021, 12:18 PM
#2
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,825
Re: Knowledge Is Power
Auto or manual trans? Affects idle speed and idle timing..
1, 2 - see attached link
https://www.camaroz28.com/forums/com...-guide-886891/
3 - engine load is not an indication of engine health. It's a calculated value based on MAP, RPM, TP%, etc. It's telling the PCM which long term fuel correction cell it is operating in.
4, 5 - see attached link (from above)
6 - Stock cam should pull about 20"Hg vacuum. From scan data, Vacuum = Barometric pressure - MAP. Stock cam, healthy engine will pull about 30-35 kPa at idle. Should be fairly steady. But elevation above sea level affects the numbers.
7 - Probably a difficulty of 8. Have to pull entire front of engine, and drop front of oil pan. Shoebox has a cam removal procedure and a cam install procedure that detail the process.
http://shbox.com/1/engine_front_diagram.jpg
4th Gen LT1 F-body Cam Removal
4th Gen LT1 F-body Cam Install
Focus on "Front of Engine" sections of writeup.
8 - IAT can be anywhere in intake track. Relocating it to the air box eliminates the heat soak from the stock location. On the other hand, if the MAF sensor fails and the PCM has to default to speed-density mode, it's a toss up whether it is more accurate on the air box free of heat soak, or closer to the throttle body measuring heat picked up by the air as it travels through the intake duct. When my engine was still stock, I relocated the IAT to the cap of the filter in the cold air intake. Eliminated a bit of rough idle and sluggishness that seemed to appear when the IAT in the stock location heat soaked (sitting in traffic, with A/C on, on a hot day) and started to indicate temperature above 140-degF. I think, but never could confirm the PCM pulls a little timing out when the IAT gets excessive.
1, 2 - see attached link
https://www.camaroz28.com/forums/com...-guide-886891/
3 - engine load is not an indication of engine health. It's a calculated value based on MAP, RPM, TP%, etc. It's telling the PCM which long term fuel correction cell it is operating in.
4, 5 - see attached link (from above)
6 - Stock cam should pull about 20"Hg vacuum. From scan data, Vacuum = Barometric pressure - MAP. Stock cam, healthy engine will pull about 30-35 kPa at idle. Should be fairly steady. But elevation above sea level affects the numbers.
7 - Probably a difficulty of 8. Have to pull entire front of engine, and drop front of oil pan. Shoebox has a cam removal procedure and a cam install procedure that detail the process.
http://shbox.com/1/engine_front_diagram.jpg
4th Gen LT1 F-body Cam Removal
4th Gen LT1 F-body Cam Install
Focus on "Front of Engine" sections of writeup.
8 - IAT can be anywhere in intake track. Relocating it to the air box eliminates the heat soak from the stock location. On the other hand, if the MAF sensor fails and the PCM has to default to speed-density mode, it's a toss up whether it is more accurate on the air box free of heat soak, or closer to the throttle body measuring heat picked up by the air as it travels through the intake duct. When my engine was still stock, I relocated the IAT to the cap of the filter in the cold air intake. Eliminated a bit of rough idle and sluggishness that seemed to appear when the IAT in the stock location heat soaked (sitting in traffic, with A/C on, on a hot day) and started to indicate temperature above 140-degF. I think, but never could confirm the PCM pulls a little timing out when the IAT gets excessive.
05-24-2021, 09:28 PM
#3
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Join Date: Mar 2020
Location: Cincinnati
Posts: 92
Re: Knowledge Is Power
Its an a4 with a 4l60e (dont know if tranny makes a difference). Im just really interesed in learning more about this car I guess because Ive invested so much time in it. But I got it running, and you guys reaaalllllyyyyyy dont understand my respect for your sharing of knowledge.
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