Split BLMs with closed throttle
#1
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Hi guys,
First post here. I have been fighting an issue with the BLMs being split in
low load, 0% throttle conditions. I probably had this when I got the car, didn't notice it until I logged it.
* At idle(Cell 16) in neutral the MAP is 47-50 KPa. Driver side LT BLM: 115-118, Passenger side BLM: 145-155.
* At idle(Cell 16) in gear with foot on the brake MAP is at about 60 KPa. Driver side LT BLM: 128, Passenger side BLM: 140-142.
* Low speed / <3% throttle(Cell 18) MAP is around 55 KPa, Driver side LT BLM: 120, Passenger side LT BLM: 140.
* Decel at 65 MPH(Cell 1) MAP is at 30-35, Driver side LT BLM: 108, Passenger side BLM: 135.
In normal driving both sides are between 122-132 and the split is 0-4 BLM's.
This is my current setup:
- Stock bottom LT1
- Ported alu heads
- LT4 hotcam kit w/ 1.6RR
- #30 Bosch III Injectors from FIC
- Edelbrock AirGap intake
- Tri-Y headers, 2,5" exhaust, hiflow cats
- CAI
- Stock 48mm throttle body
- Opti was replaced about 2 years ago by previous owner.
This is what I have done since I first found out about the BLM's being split:
- Replaced the stock injectors with FIC Bosch #30's
- Installed headers + exhaust.
- Replaced MAF with a new one.
- Replaced FPR(old one didn't hold pressure).
- 2x new Delco AFS75 o2's, later swapped them side to side with no difference.
- Closed throttle blades with stop screw as much as possible and adjusted TPS to 0,67v.
- Installed new MSD plug wires + new spark plugs.
- Checked / replaced intake gaskets.
- Adjusted valve lash to zero lash + 1/2 turn preload.
- Triple checked for vacuum leaks.
- Checked for exhaust leaks, can't find any.
It runs great IMO. I'm not sure how smooth idle should be with the hotcam though, it sure is a bit rough.
This is getting frustrating to say the least. Thanks a lot for spending your time reading this,
First post here. I have been fighting an issue with the BLMs being split in
low load, 0% throttle conditions. I probably had this when I got the car, didn't notice it until I logged it.
* At idle(Cell 16) in neutral the MAP is 47-50 KPa. Driver side LT BLM: 115-118, Passenger side BLM: 145-155.
* At idle(Cell 16) in gear with foot on the brake MAP is at about 60 KPa. Driver side LT BLM: 128, Passenger side BLM: 140-142.
* Low speed / <3% throttle(Cell 18) MAP is around 55 KPa, Driver side LT BLM: 120, Passenger side LT BLM: 140.
* Decel at 65 MPH(Cell 1) MAP is at 30-35, Driver side LT BLM: 108, Passenger side BLM: 135.
In normal driving both sides are between 122-132 and the split is 0-4 BLM's.
This is my current setup:
- Stock bottom LT1
- Ported alu heads
- LT4 hotcam kit w/ 1.6RR
- #30 Bosch III Injectors from FIC
- Edelbrock AirGap intake
- Tri-Y headers, 2,5" exhaust, hiflow cats
- CAI
- Stock 48mm throttle body
- Opti was replaced about 2 years ago by previous owner.
This is what I have done since I first found out about the BLM's being split:
- Replaced the stock injectors with FIC Bosch #30's
- Installed headers + exhaust.
- Replaced MAF with a new one.
- Replaced FPR(old one didn't hold pressure).
- 2x new Delco AFS75 o2's, later swapped them side to side with no difference.
- Closed throttle blades with stop screw as much as possible and adjusted TPS to 0,67v.
- Installed new MSD plug wires + new spark plugs.
- Checked / replaced intake gaskets.
- Adjusted valve lash to zero lash + 1/2 turn preload.
- Triple checked for vacuum leaks.
- Checked for exhaust leaks, can't find any.
It runs great IMO. I'm not sure how smooth idle should be with the hotcam though, it sure is a bit rough.
This is getting frustrating to say the least. Thanks a lot for spending your time reading this,
#3
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Thank you for your help. I have removed all the plugs(which are new NGK TR55ix) and they at least looked okey. Plug wires are new, I will however go and check the resistance as you suggested next time I'm out in the garage.