Fu@#ing miss fire still
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Fu@#ing miss fire still
I'm lost at what to try next . Had a miss before install of new mini ram an injectors and still have a miss at idle after the install. Parts that are new . Mini ram: injectors: IAC: tps : and yes are installed and volts are right and did the IAC set up by unplugging it and plugging back in the 1/4 throttle and start for five seconds and shut offvstart again ten seconds later. New fuel pump . Mass air flow sensor. Ingnition coil. Ingnition module. And now I just put new cap and rotor and plugs and wires and still have a miss at idle but goes away when reved up. The was only one plug I didn't change was number 6 I couldn't get it with the new headers but what's the odds that's the one that's bad? I did a old school check to see if I have a burnt valve I held a a peace of plastic bag over the tail pipes and it didn't try to suck it into the exsaust . I'm scared now I'm afraid I either got a cam lob starting to go flat or I have a valve that's bad. The new engine only got 450 miles on it . PLEASE HELP
Le Mans Master
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From: New Jersey
I'm lost at what to try next . Had a miss before install of new mini ram an injectors and still have a miss at idle after the install. Parts that are new . Mini ram: injectors: IAC: tps : and yes are installed and volts are right and did the IAC set up by unplugging it and plugging back in the 1/4 throttle and start for five seconds and shut offvstart again ten seconds later. New fuel pump . Mass air flow sensor. Ingnition coil. Ingnition module. And now I just put new cap and rotor and plugs and wires and still have a miss at idle but goes away when reved up. The was only one plug I didn't change was number 6 I couldn't get it with the new headers but what's the odds that's the one that's bad? I did a old school check to see if I have a burnt valve I held a a peace of plastic bag over the tail pipes and it didn't try to suck it into the exsaust . I'm scared now I'm afraid I either got a cam lob starting to go flat or I have a valve that's bad. The new engine only got 450 miles on it . PLEASE HELP
Flat lobe is easy to spot... pull the valve cover and watch the rockers... they should all move evenly. That being said it would get worse as you drove it not go away... you also would hear it... and if you drained the oil right now you would also see it...
To see if the #6 is the culprit... take an IR probe to the exhaust ports and check temp across them. They should all be even.
So the order I would check? Answer the first couple things I asked in the first block. (Plug condition etc.) Then report back. Photos help.
next... Check temp with an IR probe or water... if one is weak it won't sizzle as fast if you squirt water on it.
Then pull the V/C and look at the rocker movement on the side that isn't up to snuff (if so)...thats all pretty much free.
Then if you are flattening a lobe pull the oil and get the cam out. You're only hurting things. However that is if the troubleshooting runs like that...
Last edited by 84 4+3; Mar 28, 2020 at 02:28 PM.
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Couple of suggestions below but first... what kind of plugs are you running? How did the old ones look. Even color on all of them?
Flat lobe is easy to spot... pull the valve cover and watch the rockers... they should all move evenly. That being said it would get worse as you drove it not go away... you also would hear it... and if you drained the oil right now you would also see it...
To see if the #6 is the culprit... take an IR probe to the exhaust ports and check temp across them. They should all be even.
So the order I would check? Answer the first couple things I asked in the first block. (Plug condition etc.) Then report back. Photos help.
next... Check temp with an IR probe or water... if one is weak it won't sizzle as fast if you squirt water on it.
Then pull the V/C and look at the rocker movement on the side that isn't up to snuff (if so)...thats all pretty much free.
Then if you are flattening a lobe pull the oil and get the cam out. You're only hurting things. However that is if the troubleshooting runs like that...
Flat lobe is easy to spot... pull the valve cover and watch the rockers... they should all move evenly. That being said it would get worse as you drove it not go away... you also would hear it... and if you drained the oil right now you would also see it...
To see if the #6 is the culprit... take an IR probe to the exhaust ports and check temp across them. They should all be even.
So the order I would check? Answer the first couple things I asked in the first block. (Plug condition etc.) Then report back. Photos help.
next... Check temp with an IR probe or water... if one is weak it won't sizzle as fast if you squirt water on it.
Then pull the V/C and look at the rocker movement on the side that isn't up to snuff (if so)...thats all pretty much free.
Then if you are flattening a lobe pull the oil and get the cam out. You're only hurting things. However that is if the troubleshooting runs like that...
Ngk heat range 4
Le Mans Master
Joined: Aug 2017
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From: New Jersey
Definitely not what I'd call even... hmm... do the temperature test. Let it run for a bit warm up then either probe or squirt the water on each tube... then report back.
Was the miss occurring right away or did it take time to happen? Also, are you able to monitor afr?
Edit: that new plug looks alright.
Was the miss occurring right away or did it take time to happen? Also, are you able to monitor afr?
Edit: that new plug looks alright.
Last edited by 84 4+3; Mar 28, 2020 at 02:58 PM.
Thread Starter
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Definitely not what I'd call even... hmm... do the temperature test. Let it run for a bit warm up then either probe or squirt the water on each tube... then report back.
Was the miss occurring right away or did it take time to happen? Also, are you able to monitor afr?
Edit: that new plug looks alright.
Was the miss occurring right away or did it take time to happen? Also, are you able to monitor afr?
Edit: that new plug looks alright.
Le Mans Master
Joined: Aug 2017
Posts: 6,943
Likes: 1,490
From: New Jersey
You have a compression tester or do you want to pull the valve cover? If you have a tester just check compression on that cylinder then say #4 and see if there is a difference. Or pop the valve cover and see if the rockers move equally or if just by touching them they are loose.
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You have a compression tester or do you want to pull the valve cover? If you have a tester just check compression on that cylinder then say #4 and see if there is a difference. Or pop the valve cover and see if the rockers move equally or if just by touching them they are loose.
Last edited by Brandonvette; Mar 28, 2020 at 03:42 PM.
Le Mans Master
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From: New Jersey
Ill see if I can get a compression tester from someone tomorrow plus I might even pull the cover tomorrow an see what's up thanks ALOT I really appreciate the help and advice I'll keep ya posted on my findings hopefully tomorrow but what's your thoughts of now? Either a burnt valve or cam lobe ? Either way its bad
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I'm hoping valves not adjusted right for you... but it is a flat tappet? Solid or hydraulic? Do you hear any valve noise? The other thing it could be is a valve sticking in the guide... I have had that happen and it'll behave similar. Cold not as bad because the richer idle masks it. It drove fine around too off idle.
I do hear some noice on cold start bit goes away after 2 min of warming up
Last edited by Brandonvette; Mar 28, 2020 at 05:07 PM.
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Took the valve cover off and pulled the fuel pump fuse and had the wife crank while I watched. The number two cylinder exsaust valve moved equal to the rest. Just did a compression check on number 2 cylinder and got 130. Did another on the number 3 cause is the easiest to get to and got 160. Burnt valve ???
Le Mans Master
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From: New Jersey
Took the valve cover off and pulled the fuel pump fuse and had the wife crank while I watched. The number two cylinder exsaust valve moved equal to the rest. Just did a compression check on number 2 cylinder and got 130. Did another on the number 3 cause is the easiest to get to and got 160. Burnt valve ???
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Un able to hook air up and I think the rockers are adjusted right there's no noice from the passenger side I hear it from the drivers drive and after two min it goes away . When I pulled the plug out number two it doesn't look like it's trying to turn brown like the one on the pic I showed you after a five min run
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O of it means anything else too. I took the oil cap off while it's running and now it's blowing a little air out I don't remember it doin that before
Plus now you can hear puff sounds out the mufflerdont ever remember it idle like that
Plus now you can hear puff sounds out the mufflerdont ever remember it idle like that
Last edited by Brandonvette; Mar 29, 2020 at 01:49 PM.