Bank 1 Lean Fuel: Potential vacumn leak locations?
 

Hello Everyone,
well after my misfire problems on cylinder #7 I sent all injectors out to be balanced, tested, and ultrasonically cleaned, so all 8 fuel injectors are now within .5cc of each other (racing engine specs).

P0171 appeared with restricted performance after I reassembled the MAF assembly, and reassembled both fuel rails. This occurred when I first start the car and notice a little rough idling for a short time. After I reset the code and start to drive it takes about 10 minutes and the code and restricted performance occur again. I notice the fuel long-term trims on Bank 1 to be lower than Bank 2 and then after 10 minutes driving they seem to match. I will record the live data tomorrow and report the results for comments.

Just another challenge.......

New fuel filter, strainer, and pump installed 2-weeks before for a stalling issue. New coils and spark plugs installed 3-weeks before the above issue started with my car.


BIG QUESTION; can someone guide me to all of the locations I should smoke test that would contribute to a Bank 1 Lean Fuel code?

1999 VDP XJ8 non-aspirated engine



NOTE: I will share photos and step-by-step process I used for changing and replacing all of the fuel injectors on my 1999 VDP for newbies later this week.

Tank you for your time

<<<Mathew>>>

The part load and full load breathers, cracks in the plenum, leaking joints at the MAF and throttle module, injector o rings, manifold gskets. Hows that for a start. Any place air can get in between the MAF and the engine. Since you had it all apart, I eould try litening with a stethescope (or piece of small tube) , then try smoke.

Great suggestion!
 

Thank you, Sir

It could easily be one of the fuel injectors that are not sitting flush to the engine and that the gasket is not compressed. If I find that the fuel rail and injector cannot be pushed down any lower I may put a little silicone around the bottom "accordion" gasket rather than disassembling the entire fuel rail.

I suppose you could try that. My experience when I try such things is that I end up tearing it back down to fix what I screwed up anyway, so now I just cuss and stomp a while and tear back into it! de AJ4P