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5.3 Conversion all of a sudden having misfires, rough rich smelling idle and stumbling off from a stop, anyway today I was on the road going from AZ to San Diego and at cruise it felt fine but got about halfway into 29 Palms and at every stop light it was getting worse, pulled over and by luck carried some spare plugs, so I disconnected the coil packs 1 at a time at idle was able to narrow it down to number 3 and replaced the plug and idle improved but not perfect again it ran pretty good at cruise, the plugs only have about 1000 miles on them, there NGK TR55s
,when I got back it was idling rough again and smelling rich at idle,,not sure where to start I have no CEL light, enclosed
photos of the plug I swapped out.
G Atsma,,, The plugs and wires are all new ,I swapped the whole rack of coils off another 5.3 and its running the same ,,so I think I eliminated it being ignition related and it finally threw a code po171 and 174 lean condition on right and left banks so I did a water test squirting water on the base of the intake and it got a bit rougher and noticed water came out of the exhaust ,I'm going to change the intake gaskets hoping that will work, seems odd though it smelling so rich at idle guessing maybe the ecm is trying to compensate for the extra air?, Iv got the gaskets on order in the mean time Im going to borrow the 02sensors off my other project and give that a shot.. Thanks Much will report back
OK, great! You hadn't mentioned the new wires, so that's off the table.
It does sound like you found "A" problem with the water test. Good thinking! Let's hope it's the ONLY problem!
Are you near Escondido? I went there once to pick up a Meyers Manx buggy body from Bruce and Winnie Meyers. Neat area!
G Atsma,,, The plugs and wires are all new ,I swapped the whole rack of coils off another 5.3 and its running the same ,,so I think I eliminated it being ignition related and it finally threw a code po171 and 174 lean condition on right and left banks so I did a water test squirting water on the base of the intake and it got a bit rougher and noticed water came out of the exhaust ,I'm going to change the intake gaskets hoping that will work, seems odd though it smelling so rich at idle guessing maybe the ecm is trying to compensate for the extra air?, Iv got the gaskets on order in the mean time Im going to borrow the 02sensors off my other project and give that a shot.. Thanks Much will report back
the water you are spraying along the intake is not coming out of your exhaust. What you are seeing out of your exhaust is normal condensation from your catalytic converters converting the harmful gases gases from an engine into liquid. Like you said when you have a lean condition your ecm tries to compensate for the extra air. It’s better to use propane or even brake clean around the intake to check for intake leaks. Also try to do it when the engine isn’t fully warm.
OK, great! You hadn't mentioned the new wires, so that's off the table.
It does sound like you found "A" problem with the water test. Good thinking! Let's hope it's the ONLY problem!
Are you near Escondido? I went there once to pick up a Meyers Manx buggy body from Bruce and Winnie Meyers. Neat area!
G Atsma ,,actually Im in Valley Center the next town east of Escondido, Bruce Meyers lived just about a mile away from me, I didn't realize that until a couple of years ago I would of liked to meet him ,thru the 70s and 80s my buddy's and I lived to build VWs and off road buggy's ,was sorry to hear he passed away last year here is a link to his story https://media.vw.com/en-us/releases/1478
the water you are spraying along the intake is not coming out of your exhaust. What you are seeing out of your exhaust is normal condensation from your catalytic converters converting the harmful gases gases from an engine into liquid. Like you said when you have a lean condition your ecm tries to compensate for the extra air. It’s better to use propane or even brake clean around the intake to check for intake leaks. Also try to do it when the engine isn’t fully warm.
Thanks Steve ,,,I used water being that's all I had on hand , I don't have cats on it and a true dual exhaust ,not sure what to make of it was thinking about it I'm not sure why it wasn't steam just some water dripping out more on the right side then the left, and the engine was warmed up not hot it was at about 140 degrees. I was running it off and while swapping coils and spark plugs prior to the water test. Guess Il know more when i get the gaskets swapped out there due to be here Monday Im hoping thats the case with the rich stink of fuel at idle being un metered air getting by, it does make sense
Well my intake gaskets got here today ,replaced them and it appears to be running exactly the same, guess in the AM I will give the 02s a shot. Seems I may have another problem, a month or so ago had low oil pressure and a valve tap at idle so I dropped the pan and replaced the o ring, my oil pressure responded well and the lifter noise at idle went away but I notice now I have some tapping noise at around 2k , not sure if my lifters are bunk would it be causing my rough idle? and how would I tell if it in my valvetrain or something else ..thanks much
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