Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Thanks for the heads up on the leak. I haven't changed that gasket yet because I saw no smoke. and I forgot to check the dip stick for vacuum. Just a thought... would I have to block off the Pcv valve? That would create vacuum at the dip stick too wouldn't it?
you clamp off the PCV hose and the fresh air inlet PCV tube(passanger side front of the engine). when you run the engine this would produce pressure at the dipstick, but if you have an internal intake gasket leak you will have vacuum at the dipstick instead. smoke will not work because your checking for vacuum not pressure. the leak would be pulling extra air in from the crankcase into the intake runner causing a lean condition.
"an open mind let's knowledge flow in and wisdom flow out for a man who has neither never listens to those who have both".
Being wrong doesn't bother me, it's being right and not understanding why that does
Hey ScannerJohn… I owe you a Thanks and a coffee. Went out today and hooked the smoke machine up and waited for a few minutes and looked the engine over good and saw nothing. Pulled the oil fill cap off and we got smoke. Pulled the dipstick and got nothing at first. Then it start coming out of the dip stick tube too.
Appreciate everyone's help on this!!!
I'll write back when I get those gaskets in and check my fuel trims again. My guess is that the worse part of the leak must be at cylinder #6 because of the misfires.
When you change those gaskets, make sure that your manifolds flat and not warped.
If they are warped you have a few options.
1. You can build a lapping rig and lap them until they are flat
2. You can send them to a machine shop and they will flatten them
3. You can replace them
4. You can attempt to keep adding more sealant where it matters to get it to seal.
I've had really good luck with #1. I've done it many times.
I have some heads off an Intrepid with a 2.7 that I lapped by hand. They were cast so it wasn't so easy but not too bad... just time consuming. Kept checking it with a straight edge with .002-.003" slop. I ordered some graphite head gaskets just to make sure it seals good. I couldn't finish it because I got involved with this dag-gone truck. First thing this spring... but not until I finish this truck. So, so glad to have found that leak finally. It was making me nuts!!! Just hope that it's done after I fix the intake..
Last edit: 4 years 1 month ago by Potanist. Reason: To correct a bad sentence
Well... put new intake manifold gaskets in and it seemed slightly better using one scanner then in hooking up the GM scanner it basically showed the same readings as before even after a trim reset. Both long terms are at 25 and the short terms are fluttering around in the single digits sometimes hitting 10. What an unexpected disappointment
with new gaskets, unless you pinched them or pushed them out of position when putting the intake back on, I would say they sealed Ok... your just getting too much air. unplug the MAF when engine at hot idle and read the trims. if they get better then your MAF is not reporting properly. I know you said you replaced it, but its worth checking.
One last thought. Put you foot on the brake when you start the engine. Does the peddle drop/bump when you start? Hold the brake pedal down and check trims. Do they get worse?
"an open mind let's knowledge flow in and wisdom flow out for a man who has neither never listens to those who have both".
Being wrong doesn't bother me, it's being right and not understanding why that does
Hey SJ... held my foot on the brake peddle and it dropped when it started. At warm idle pressing the brake didn't change anything and neither did unplugging the MAF sensor. I wish my fuel pressure gauge tester had a longer line so that I could watch the fuel pressure as I drove it under load. SMH this is going to be something so simple when we find it I bet.
Brake pedal should not drop, should bump and be firm. A leaking brake booster can cause lean problem. Test buster further don't just replace it. Clamp off booster vacuum line then check trims.
"an open mind let's knowledge flow in and wisdom flow out for a man who has neither never listens to those who have both".
Being wrong doesn't bother me, it's being right and not understanding why that does
Here is a simple and cheap trick that I have used to make a fuel gauge longer:
Cut the hose about in half
Go to the auto parts store and buy a piece of metal brake line that is the right size to tightly slip inside the hose on the fuel gauge.
Get two fuel injection clamps of the right size and put them on the fuel gauge hose
Tape a wad of towels just under the face of the gauge, that way you can put the line under one of your wiper blades and have the gauge face down on the windshield while driving without chipping or breaking the windshield
Set up a video camera and record it while you drive
You can bend the brake line to make it go where ever you need and it won't leak. Just don't kink the brake line.
Super cheap, easy to do and gets the job done.
Use a camera though. Trying to focus on a fuel gauge while you are horsing it ( probably doing 55mph on a back road ) is amazingly dangerous!
I went back and re-read all the posts on this... you mentioned a couple of time that you replaced the MAF, a couple of times, BUT you have never posted the MAF readings. What is your MAF g/s on hot idle and voltage.
"an open mind let's knowledge flow in and wisdom flow out for a man who has neither never listens to those who have both".
Being wrong doesn't bother me, it's being right and not understanding why that does
Could be a stretch, but isn't there an alcohol sensor of some sort under the vehicle on these? Could there be a problem there that could be throwing off the mixture? To be honest, I'm not really sure how they work or what they impacts. Just thinking/typing out loud.
Never really heard of that through doing everything else to this stupid truck. I know earlier in this post ScannerJohn mentioned T 5.3 motors are gas only and Z 5.3 motors are multi-fuel. I have the T motor. Is that what you're talking about?
Hey SJ... I didn't find the volts reading on my scanner. I'll recheck it today to see if it's on a different screen on my scanner. But this is what I found at Hot Idle, Loop is closed... MAF = 5.87 G/S and 2643 Hz
