Misfire (no codes) advise?
December 14th, 2016, 11:11 AM
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Misfire (no codes) advise?
I have a 1998 K1500 w/ Z71 package. 238K on the OD.
Got this truck rode hard put up wet kinda thing; they did not take care of it. Has a miss/putter thought it would just be a tune up; service engine light on and strobing lights. This is what I've done so far.
Strobing Lights:
Replaced Altenator ; belt drive pullies and so on; power charging line from bat to alt; (Was broke) and ground wires. - that took care of the strobing only thing left is a tick in the gauge when flashers are on (Different thread)
Miss-putter
well basically its always started well and runs; doesnt try and die or nothing like that just has this miss;; sometimes is not even there while other times it is... its kinda a burp randomly or sometimes its like its really missing, mainly under acceleration and a purp while at constant speed; has plenty of power when getting on it... heavy acceleration; there is still what feels like a miss but i'd say its worse at lower throttle position.
So before i strart throwing TPS and stuff like that.. this is what i've done so far.
Tune up; plugs; wires; cap; roter; coil.
Service engine light was P0138 (02 sensor bank 2 ) found wires broken so i spliced them back togeather and cleared the code; its not yet turned back on cel but ive not really driven it much.
next i mystery oiled the engine like you would sea foam, going to do that a few more times to burn off any built up carbon and put B12 in the gas tank.
I do know that i have on the 2nd cly back on passenger side valve guide seal leak based on the old plug; and new plug had oil on it after it set... small puff of smoke at startup but nothing while its running.. put a non fouler on this one to help it out until i can get it fixed.
Do not think this is causing what feels to be random miss though.. there are no miss codes of any kind.
Only other thing i can think of there is no muffler on this yet* old one was cut about 2 ft past the cats there was a small leak at the factory exust. manf. and pipe i replaced the donut and its sealed and secured.. I dont think there was a 'leak' but it was enough i could wiggle the pipe before i fixed it.
So at this point before i start throwing parts at the truck what are the most likely causes? I was thinking timing chain slop; TPS, MAP sensor? MAF could need cleaning... really surprised it does not produce a misfire cel though sometimes when it has this putter/miss feeling to it... so I'm kinda stumped at what it could be.
Got this truck rode hard put up wet kinda thing; they did not take care of it. Has a miss/putter thought it would just be a tune up; service engine light on and strobing lights. This is what I've done so far.
Strobing Lights:
Replaced Altenator ; belt drive pullies and so on; power charging line from bat to alt; (Was broke) and ground wires. - that took care of the strobing only thing left is a tick in the gauge when flashers are on (Different thread)
Miss-putter
well basically its always started well and runs; doesnt try and die or nothing like that just has this miss;; sometimes is not even there while other times it is... its kinda a burp randomly or sometimes its like its really missing, mainly under acceleration and a purp while at constant speed; has plenty of power when getting on it... heavy acceleration; there is still what feels like a miss but i'd say its worse at lower throttle position.
So before i strart throwing TPS and stuff like that.. this is what i've done so far.
Tune up; plugs; wires; cap; roter; coil.
Service engine light was P0138 (02 sensor bank 2 ) found wires broken so i spliced them back togeather and cleared the code; its not yet turned back on cel but ive not really driven it much.
next i mystery oiled the engine like you would sea foam, going to do that a few more times to burn off any built up carbon and put B12 in the gas tank.
I do know that i have on the 2nd cly back on passenger side valve guide seal leak based on the old plug; and new plug had oil on it after it set... small puff of smoke at startup but nothing while its running.. put a non fouler on this one to help it out until i can get it fixed.
Do not think this is causing what feels to be random miss though.. there are no miss codes of any kind.
Only other thing i can think of there is no muffler on this yet* old one was cut about 2 ft past the cats there was a small leak at the factory exust. manf. and pipe i replaced the donut and its sealed and secured.. I dont think there was a 'leak' but it was enough i could wiggle the pipe before i fixed it.
So at this point before i start throwing parts at the truck what are the most likely causes? I was thinking timing chain slop; TPS, MAP sensor? MAF could need cleaning... really surprised it does not produce a misfire cel though sometimes when it has this putter/miss feeling to it... so I'm kinda stumped at what it could be.
December 15th, 2016, 3:44 PM
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So question.. I'm wondering if the off balance could be causing issue too... the factory setup is dual pipe up to a dual in/single out muffler it looks like on these trucks; so that is the balance at the muffler; i have a dual in/out magnaflow so should i put the cross pipe there before the muffler in between the cats and muffler? How far aware/close does it need to be or does it even matter or can i just run it strait through the dual in/out and not even worry about it?
December 16th, 2016, 11:31 AM
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Jokingly I say this... I'm stupid and sorry for dumb questions.. Just realized the dual in/out are internally balanced.. I put it on today and will see what happens from here.. i just dont have any pipe behind the muffler.. Yet*... for a while.
December 17th, 2016, 8:42 AM
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So muffler is on.. no difference but does sound great. So I'm thinking spider injector.. or distributer? Funny thing is like this morning it ran smooth cold up to my dad's less than 1/4 mile. Turned off then went back to house puttering bad. When driving it seems really light throttle it putters.. when press accelerator ever so slightly seems to run good. Want to put a timing light on to check for timing if there is any slop.. thoughts?