LS2 New heads, new lifters, now barely starts and runs like hell. Please help
10-24-2019, 05:41 PM
#21
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Did you change injectors?
10-24-2019, 05:41 PM
#22
I'm definitely concerned about the pushrod length as I was having some issues getting good measurements at first, but then I felt I got it good. I measured pushrods using the measuring tool to zero lash then added the .030 preload per the lifter mfr instructions. Will a compression check verify if my valves aren't fully seating?
Correct, the head builder I went to used 2.200 on a 4.0 bore LS2. Are there concerns with this?
Correct, the head builder I went to used 2.200 on a 4.0 bore LS2. Are there concerns with this?
Regarding the heads, which heads did you put on?
10-24-2019, 06:03 PM
#25
This sounds like something else changed besides the heads. Fueling would be off at higher RPMs as the heads will let in more air (we assume).
I'm not quite sure why you went with a 2.200" intake in a 4" bore motor. That is a different issue, however.
What you're describing sounds like a stock tune was added back to the PCM for some reason or new injectors swapped in.
I'm not quite sure why you went with a 2.200" intake in a 4" bore motor. That is a different issue, however.
What you're describing sounds like a stock tune was added back to the PCM for some reason or new injectors swapped in.
10-24-2019, 06:04 PM
#26
A leak down test will expose any valve sealing issues. Compression test may/may not. Easier way to check, loosen the rockers a bit and see if it will start up and idle. Don't run it long, but it can show you if you are going in the right directional.
Regarding the heads, which heads did you put on?
Regarding the heads, which heads did you put on?
Heads were custom built locally by a guy name Santos at Engine One Performance in Phoenix. He gets his heads from his supplier and does all the machine work in house.
10-24-2019, 06:06 PM
#28
This sounds like something else changed besides the heads. Fueling would be off at higher RPMs as the heads will let in more air (we assume).
I'm not quite sure why you went with a 2.200" intake in a 4" bore motor. That is a different issue, however.
What you're describing sounds like a stock tune was added back to the PCM for some reason or new injectors swapped in.
I'm not quite sure why you went with a 2.200" intake in a 4" bore motor. That is a different issue, however.
What you're describing sounds like a stock tune was added back to the PCM for some reason or new injectors swapped in.
I went with the suggestion of my performance guy here. I can't speak to the why or why not with a 4" bore motor. Please enlighten me.
The computer wasn't touched and I have no way to interface with it and the injectors are the same.
10-24-2019, 06:24 PM
#31
I've never had a supercharged engine, don't know anything about them. But what are the odds of MAP being exactly 29.8 psi every time the engine is run? 
The supercharger can't even build boost free revving, right? Engine will run pig rich if the MAP is false high reading.
On a side note, your coolant channel isn't going up in temp as you run the engine. Acting like the sensor is in air (coolant level really low).
The supercharger can't even build boost free revving, right? Engine will run pig rich if the MAP is false high reading.On a side note, your coolant channel isn't going up in temp as you run the engine. Acting like the sensor is in air (coolant level really low).
Last edited by QwkTrip; 10-24-2019 at 06:34 PM.
10-24-2019, 07:37 PM
#32
I've never had a supercharged engine, don't know anything about them. But what are the odds of MAP being exactly 29.8 psi every time the engine is run? The supercharger can't even build boost free revving, right? Engine will run pig rich if the MAP is false high reading.
On a side note, your coolant channel isn't going up in temp as you run the engine. Acting like the sensor is in air (coolant level really low).
The supercharger can't even build boost free revving, right? Engine will run pig rich if the MAP is false high reading.On a side note, your coolant channel isn't going up in temp as you run the engine. Acting like the sensor is in air (coolant level really low).
10-24-2019, 11:53 PM
#37
I went back to the first post and must have missed it, The heads may make a difference but nothing severe. Will the scanner let you check the MAP reading without the car running? Being that it reads PSI it's obviously wrong 28.9 PSI at 600rpm and 2,000rpms If the computer is seeing that number it's going to add a ton of fuel.
10-25-2019, 09:54 AM
#38
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Forgive me if I missed the information OP, your heads are 243/799s? More than likely 2.02" intake valves. Do you know if the heads were milled and what head gaskets were used. Did compression change?
10-25-2019, 10:07 AM
#39
I went back to the first post and must have missed it, The heads may make a difference but nothing severe. Will the scanner let you check the MAP reading without the car running? Being that it reads PSI it's obviously wrong 28.9 PSI at 600rpm and 2,000rpms If the computer is seeing that number it's going to add a ton of fuel.
10-25-2019, 10:20 AM
#40
I'm not the machinist...but he told me he calculated the head gasket thickness I needed to maintain stock compression. I installed Cometic gaskets, 4.060 bore and .045 thickness.