Running lean only in boost - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

jasonkg · 12-18-2006, 02:09 PM

My car is running lean as soon as I get into positive pressure. It starts sputtering and hesitating and the engine makes a knocking sound. I am able to attain 7 psi.
This started happening directly after I changed out the dump pipe gasket and I got a new intake filter (not the piping). I don't understand how this would give me a problem.

Here is the list of checks I have completed so far:

• Swapped out the mafs twice
• Inspected the intake tube for cracks
• Inspected all couplers for the intercooler
• Inpected fuel pump connector
• Did a FPR test
• Checked timing
• Changed spark plugs
• Inspected fuel lines
• Checked for vacuum leaks
• Swapped out ECU
• Checked turbo for shaft play (none)
• Checked BOV for leaks none (none)

I thought it was a boost leak at first, but it does not appear to be since I checked all parts that would be associated with this problem.

Is there something I missed other than engine internals. It seems like I am having a fuel pressure problem, or a sensor issue. Help please!

yokotas13 · 12-18-2006, 02:56 PM

how do you know you are lean?
Are you running a wideband or any datalogging setup?

jasonkg · 12-18-2006, 04:03 PM

No I am not running a wideband, but if the engine is knocking that seems to be a sign that I am running lean. Is there anything else it could be?
As I stated this started happening right after I changed the intake. Before I got a new intake I had an old K&N intake. I used the filter charger on it. Is there any other problem excess K&N filter charger can cause other than a fouled mafs and would it contribute to my problem?

12-18-2006, 02:09 PM	#1
jasonkg Join Date: Sep 2006 Location: Melbourne, Fl Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	Running lean only in boost My car is running lean as soon as I get into positive pressure. It starts sputtering and hesitating and the engine makes a knocking sound. I am able to attain 7 psi. This started happening directly after I changed out the dump pipe gasket and I got a new intake filter (not the piping). I don't understand how this would give me a problem. Here is the list of checks I have completed so far: • Swapped out the mafs twice • Inspected the intake tube for cracks • Inspected all couplers for the intercooler • Inpected fuel pump connector • Did a FPR test • Checked timing • Changed spark plugs • Inspected fuel lines • Checked for vacuum leaks • Swapped out ECU • Checked turbo for shaft play (none) • Checked BOV for leaks none (none) I thought it was a boost leak at first, but it does not appear to be since I checked all parts that would be associated with this problem. Is there something I missed other than engine internals. It seems like I am having a fuel pressure problem, or a sensor issue. Help please!

12-18-2006, 02:56 PM	#2
yokotas13 Post Whore! Join Date: Apr 2006 Location: Milford, CT Age: 40 Posts: 10,519 Trader Rating: (8) Rides Gallery: yokotas13 Feedback Score: 8 reviews	how do you know you are lean? Are you running a wideband or any datalogging setup? __________________ 2015 Subaru Outback Overlander - Wagonofdoom

12-18-2006, 04:03 PM	#3
jasonkg Join Date: Sep 2006 Location: Melbourne, Fl Posts: 20 Trader Rating: (0) Feedback Score: 0 reviews	... No I am not running a wideband, but if the engine is knocking that seems to be a sign that I am running lean. Is there anything else it could be? As I stated this started happening right after I changed the intake. Before I got a new intake I had an old K&N intake. I used the filter charger on it. Is there any other problem excess K&N filter charger can cause other than a fouled mafs and would it contribute to my problem?