2002 Isuzu Axiom 6 cyl Four Wheel Drive Automatic 107000 miles
I'm trying to help my father-in-law. When you start the vehicle there is a raw gas smell. It goes away when you begin driving. It returns if you are stopped at a light for a few minutes and goes away when you begin driving again. This is my father-in-law's vehicle. I am a mechanic visiting from out of state. I specialize in brake/suspension/drivetrain and own a restoration shop. I do NOT specialize in computer controlled systems. I have thoroughly checked out the gas tank and fuel lines, vapor/vacuum connections, manifold, throttle body, etc. The vehicle has been taken to local mechanics and as well as the dealer with no success in finding the problem. I'm wondering if it is some kind of issue with the computer and communication with the TPS that may provide an over rich mixture at idle or something like that. I have had no luck in finding a TSB covering this issue and I have no access to any diagnostic equipment while I'm here. I'm certain there are no external leaks unless there is a high pressure leak that completely vaporizes into the air and leaves no evidence other than smell. Any suggestions?
Hi chevellehoot, Welcome to 2carpros and TY for the donation
Check the fuel pressure with a fuel gauge if its within specs and also the charcoal canister if its fill with gas and also the operation of the charcoal canister-let me know
November, 6, 2010 AT 10:53 PM
Fuel pressure is ok and cannister is ok according to my father-in-law (previously checked by Isuzu Service Department). I would recheck myself if I had my tools (from Oregon) with me (in North Carolina). The smell is immediate and strong at the intake manifold at an idle. No visible external leaks. Exhaust smells like it's running rich and tail pipe is coated with black soot. No codes. He has an appointment at the dealer on Tuesday to check out his vehicle again. I was wondering about the cannister purge solenoid but if it was staying open wouldn't it be constantly purging making a noticable purge at idle unlikely? Again, my specialty is classic analog and carburetors, not computer controlled systems. It acts like a bad needle and seat on a carb.
November, 7, 2010 AT 8:48 AM
Check engine light is it coming on?
Probable causes of an engine running rich are as follows: 1. Excessive fuel pressure can be cause by restricted fuel return line
2. Defective Oxygen Sensors.
3. Leaking injectors and fuel pressure regulator.
4. Coolant temperature sensor out of calibration.
5. Restricted air intake system
November, 7, 2010 AT 11:39 AM
According to the dealer the pressure regulator is ok. No codes or check engine light so defective O2 sensor WITHIN parameters? (Internal) leaking injectors? - Without popping a code? Coolant sensor without popping a code? No restrictions in air intake.
My theory is a leaky valve on an injector like a bad needle and seat as I mentioned before. Any more thoughts?
November, 7, 2010 AT 2:20 PM
That's all I got for an engine running rich- if there's no external leak-fuel pressure regulator checks out and a clogged fuel return line-
November, 7, 2010 AT 11:06 PM
I'll be here for another week. I'm going with my father-in-law to the dealer to verify first hand what they have checked and to be positive that no codes are stored. If nothing is solved I'm planning on pulling the injectors to physically check them along with anything else I can come up with tools here to do. I'll keep you posted on what I find as well as a solution if the problem is solved.
November, 9, 2010 AT 4:21 PM
Took vehicle to dealer. NO CODES.
Fuel system is okay.
Guess what.I wanted to check the spark plugs to see how they were burning and 5 out of 6 were LOOSE. Carbon on the outside of all 5 and on the outside of the boots. 1 was clean.
The plugs looked okay but I put in a new set and tightened them down and the smell is gone!
I can't believe that's all it was but that's it.
Loose spark plugs. Not finger tight but loose enough to blow fumes past the threads.
No more smell !
November, 9, 2010 AT 8:46 PM
That will exit unburned fuel HC to include partly burned CO out those cylinders-TY for coming back with the fix so that others in need will benefit from it- Good Luck