Dead Miss on cyl #1 : Lots of things checked, HELP!
07-25-2006, 10:04 AM
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Dead Miss on cyl #1 : Lots of things checked, HELP!
Alright guys, here's the background information on the issue. I've got a 92 Accord DX with a swapped in F22A6 motor and it's Turbo'd to around 8-10 psi. I pulled her down yesterday, pulled the plugs and did a compression check and a leakdown test. Compression on all cylinders was between 148-152 and the leakdown showed less than 20% on all the cylinders.
I saw I needed plugs, so I put them back in and as soon as I started her up she had a dead miss at idle. Weird, I figured it would smooth out so I drove home. Drove this morning and still had the same dead miss at idle, but driving any other speed is fine and boost is fine, power is there and like you can see above, compression and leakdown tests show nothing.
I came to my shop today, changed out the plugs and swapped cyl #1 wire and it still has the dead miss. I pulled the dist. cap and found some oil in it from the distributor shaft so I swapped it out with a known distributor with less than 500 miles on it new. Cleaned the cap and tightened her down and the same miss is still there.
So I have compression, I have spark and clean, smooth spark at that, so on to fuel. With a stethoscope I checked all 4 injectors, all of which are clicking rather smoothly with no hesitations. So there are no blockages in there, they are moving smoothly. I went on and pulled the fuel rail up and pulled the #1 injector out. I cleaned her with some fuel system cleaner and also checked that fuel was getting there, and it is. I put it all back together and started her up, STILL THAT DAMN DEAD MISS!
I'm out of ideas. There appears to be current going to the injector electronically and it just happened completely out of the blue.
I am running a chipped p75 with Crome, so the "tuner" is coming by a little later to check the values, but geez! Only at idle it misses, everything else is fine, maybe a little lean but I can't complain too hard.
Cliffnotes:
Accord with a dead miss at idle, cyl #1 is to blame.
-Compression is dandy
-Leakdown showed less than 20%
-Injector is getting fuel and is clicking
-Plugs are new and wire is not fault
-Distributor is new and cap is clean
UPDATE: Injectors #1 and #2 were swapped and the dead miss is still on #1.
WHAT THE HELL! HELP!!!!
Colin
I saw I needed plugs, so I put them back in and as soon as I started her up she had a dead miss at idle. Weird, I figured it would smooth out so I drove home. Drove this morning and still had the same dead miss at idle, but driving any other speed is fine and boost is fine, power is there and like you can see above, compression and leakdown tests show nothing.
I came to my shop today, changed out the plugs and swapped cyl #1 wire and it still has the dead miss. I pulled the dist. cap and found some oil in it from the distributor shaft so I swapped it out with a known distributor with less than 500 miles on it new. Cleaned the cap and tightened her down and the same miss is still there.
So I have compression, I have spark and clean, smooth spark at that, so on to fuel. With a stethoscope I checked all 4 injectors, all of which are clicking rather smoothly with no hesitations. So there are no blockages in there, they are moving smoothly. I went on and pulled the fuel rail up and pulled the #1 injector out. I cleaned her with some fuel system cleaner and also checked that fuel was getting there, and it is. I put it all back together and started her up, STILL THAT DAMN DEAD MISS!
I'm out of ideas. There appears to be current going to the injector electronically and it just happened completely out of the blue.
I am running a chipped p75 with Crome, so the "tuner" is coming by a little later to check the values, but geez! Only at idle it misses, everything else is fine, maybe a little lean but I can't complain too hard.
Cliffnotes:
Accord with a dead miss at idle, cyl #1 is to blame.
-Compression is dandy
-Leakdown showed less than 20%
-Injector is getting fuel and is clicking
-Plugs are new and wire is not fault
-Distributor is new and cap is clean
UPDATE: Injectors #1 and #2 were swapped and the dead miss is still on #1.
WHAT THE HELL! HELP!!!!
Colin
07-25-2006, 10:15 AM
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Re: Dead Miss on cyl #1 : Lots of things checked, HELP! (teamlegacy)
Why not replace the item you swapped that caused the problem? 
Replace the #1 spark plug and see what happens.
Replace the #1 spark plug and see what happens.
07-25-2006, 10:25 AM
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Re: Dead Miss on cyl #1 : Lots of things checked, HELP! (locash)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by locash »</TD></TR><TR><TD CLASS="quote">Why not replace the item you swapped that caused the problem?
Replace the #1 spark plug and see what happens.</TD></TR></TABLE>
I swapped injectors between 1 and 2 and the miss is STILL on 1. The injector 2 was working fine before swapped to 1, so it's something in that cylinder.
As for swapping spark plugs, I just put a BRAND new set in there this morning.
Replace the #1 spark plug and see what happens.</TD></TR></TABLE>
I swapped injectors between 1 and 2 and the miss is STILL on 1. The injector 2 was working fine before swapped to 1, so it's something in that cylinder.
As for swapping spark plugs, I just put a BRAND new set in there this morning.
07-25-2006, 11:17 AM
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Re: Dead Miss on cyl #1 : Lots of things checked, HELP! (teamlegacy)
UPDATE again: We swapped computers and chips, and the dead miss is still there. We checked valves/springs/cam lobes and all of those appear to be fine and undamaged. There seem to be "noise" coming from the 1 and 2 injector harnesses...
07-25-2006, 11:48 AM
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Re: Dead Miss on cyl #1 : Lots of things checked, HELP! (teamlegacy)
now whats really weird is that the engine runs fine when not at idle. If we give it some revs and try pulling one plug wire out at a time you can noticably tell a difference when pulling the #1 out....but at idle you cant. At idle its missing 
07-25-2006, 12:34 PM
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please post leakdown #'s on all 4 cyclinders
20% is quite a high # for leakdown is it not?
i thought anything more then 10% was a problem?
whats your fuel pressure like?
how do the plugs look? do they all look the same? color wise?
20% is quite a high # for leakdown is it not?
i thought anything more then 10% was a problem?
whats your fuel pressure like?
how do the plugs look? do they all look the same? color wise?
07-25-2006, 12:37 PM
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Re: (BlackCRX)
Ghetto rig a wire from the fuel injector all the way back to the ECU, bypass the entire harness. Also ghetto rig a wire from the resistor box to the injector, bypass the entire harness. Use an ecu pin to completely remove the stock wire. That will eliminate wiring as a problem.
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07-25-2006, 12:44 PM
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Re: (BlackCRX)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BlackCRX »</TD></TR><TR><TD CLASS="quote">please post leakdown #'s on all 4 cyclinders
20% is quite a high # for leakdown is it not?
i thought anything more then 10% was a problem?
whats your fuel pressure like?
how do the plugs look? do they all look the same? color wise?</TD></TR></TABLE>
It's a varying 20% and I'm not all that confident that this gauge is correct. Either way, it's not a GROSS leak so it's eliminating the fact that the cylinder is toast.
Fuel pressure is perfect, 45-46psi at idle.
The plugs are brown-ish. All look the same, they are brand new. They seem a bit rich, but it does need a few adjustments do to the new exhaust. This problem happenend OUT OF NOWHERE, so it makes it all the harder to figure out.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by raene »</TD></TR><TR><TD CLASS="quote">please post leakdown #'s on all 4 cyclinders
Ghetto rig a wire from the fuel injector all the way back to the ECU, bypass the entire harness. Also ghetto rig a wire from the resistor box to the injector, bypass the entire harness. Use an ecu pin to completely remove the stock wire. That will eliminate wiring as a problem. </TD></TR></TABLE>
I'm not confident it's a wiring issue either because a. no wire has been touched b. there is "noise" at the connector and c. the plug is burning and there is a bit of fuel residue on the plug because of the semi-rich idle condition.
20% is quite a high # for leakdown is it not?
i thought anything more then 10% was a problem?
whats your fuel pressure like?
how do the plugs look? do they all look the same? color wise?</TD></TR></TABLE>
It's a varying 20% and I'm not all that confident that this gauge is correct. Either way, it's not a GROSS leak so it's eliminating the fact that the cylinder is toast.
Fuel pressure is perfect, 45-46psi at idle.
The plugs are brown-ish. All look the same, they are brand new. They seem a bit rich, but it does need a few adjustments do to the new exhaust. This problem happenend OUT OF NOWHERE, so it makes it all the harder to figure out.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by raene »</TD></TR><TR><TD CLASS="quote">please post leakdown #'s on all 4 cyclinders
Ghetto rig a wire from the fuel injector all the way back to the ECU, bypass the entire harness. Also ghetto rig a wire from the resistor box to the injector, bypass the entire harness. Use an ecu pin to completely remove the stock wire. That will eliminate wiring as a problem. </TD></TR></TABLE>
I'm not confident it's a wiring issue either because a. no wire has been touched b. there is "noise" at the connector and c. the plug is burning and there is a bit of fuel residue on the plug because of the semi-rich idle condition.
07-25-2006, 12:59 PM
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Re: (teamlegacy)
You could've broken a bad old joint or wire just by moving it, it's not guaranteed perfect 'cause it's OEM. I suffered from a VERY similar misfire problem - revved fine, drove fine but random misfiring, finally tracked it down to a bad injector-ecu connection. I haven't located the exact point in the harness where it's failed because my bypass is working fine and I'm ghetto, but the "oem" part of the wire failed - I quadruple-checked and reflowed all my solder joints.
It's worth eliminating
As for hearing noise, if it's sometimes firing and sometimes not, the engine will still splutter, and you'll still hear noise. I'm assuming here by "noise" you're referring to the injector tick. Just a thought!
Have you checked for a failed or broken lifter or anything of that sort? How's the valve clearance?
It's worth eliminating
As for hearing noise, if it's sometimes firing and sometimes not, the engine will still splutter, and you'll still hear noise. I'm assuming here by "noise" you're referring to the injector tick. Just a thought!
Have you checked for a failed or broken lifter or anything of that sort? How's the valve clearance?
07-25-2006, 01:05 PM
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Re: (raene)
The car is running on crome. We have been trouble shooting this damn thing all day. It ran perfectly fine until he did a compression test on the motor. Ever since then it has had the miss at idle. By pulling the plugs they look pretty damn rich considering they are brand new and the car has only been idling. Dont look like new plugs at all. Hopefully tomorrow i can hook the laptop back up and wideband to verify everything is correct with the tune now that he has gotten a whole new exhaust setup. I wouldn't think it would have changed that much to be running so rich at idle as it was idling perfect at high 13's to low 14's before, but could be something with different iat's than before too. It really has to be some kind of mechanical or electrical problem though because the miss is only on one cylinder.
Colin I think you should do what raene is suggesting and bypass the wiring harness altogether so we can eleminate a wiring problem.
Colin I think you should do what raene is suggesting and bypass the wiring harness altogether so we can eleminate a wiring problem.
07-25-2006, 01:11 PM
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Re: (raene)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by raene »</TD></TR><TR><TD CLASS="quote">You could've broken a bad old joint or wire just by moving it, it's not guaranteed perfect 'cause it's OEM. I suffered from a VERY similar misfire problem - revved fine, drove fine but random misfiring, finally tracked it down to a bad injector-ecu connection. I haven't located the exact point in the harness where it's failed because my bypass is working fine and I'm ghetto, but the "oem" part of the wire failed - I quadruple-checked and reflowed all my solder joints.
It's worth eliminating
As for hearing noise, if it's sometimes firing and sometimes not, the engine will still splutter, and you'll still hear noise. I'm assuming here by "noise" you're referring to the injector tick. Just a thought!
Have you checked for a failed or broken lifter or anything of that sort? How's the valve clearance?</TD></TR></TABLE>
Well, I guess that's what I'll have to do per your suggestion and Matt's [SOHC_Mshue], I'll bypass that bad boy tomorrow. It's just so damn random!
I'm refering to noise in terms of electrical, hence the quotes. We put a noid light on it and it's blinking on cyl 1 and 2, so it's throwing current that way...apparently. It was kind of a ghetto noid light, but hmm.
The valve cover has been pulled and the motor was rotated by hand. The cam lobes do not look wiped out, there is clearance between the valve springs, and nothing appears to be broken. Would it be possible for carbon buildup to have semi-blocked a valve seat or something, but wouldn't that make the idle a little more lopey?
AH FOR THE MOTHERLAND! I won't be sleeping well tonight, haha!
It's worth eliminating
As for hearing noise, if it's sometimes firing and sometimes not, the engine will still splutter, and you'll still hear noise. I'm assuming here by "noise" you're referring to the injector tick. Just a thought!
Have you checked for a failed or broken lifter or anything of that sort? How's the valve clearance?</TD></TR></TABLE>
Well, I guess that's what I'll have to do per your suggestion and Matt's [SOHC_Mshue], I'll bypass that bad boy tomorrow. It's just so damn random!
I'm refering to noise in terms of electrical, hence the quotes. We put a noid light on it and it's blinking on cyl 1 and 2, so it's throwing current that way...apparently. It was kind of a ghetto noid light, but hmm.
The valve cover has been pulled and the motor was rotated by hand. The cam lobes do not look wiped out, there is clearance between the valve springs, and nothing appears to be broken. Would it be possible for carbon buildup to have semi-blocked a valve seat or something, but wouldn't that make the idle a little more lopey?
AH FOR THE MOTHERLAND! I won't be sleeping well tonight, haha!
07-25-2006, 01:41 PM
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Re: (BlackCRX)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BlackCRX »</TD></TR><TR><TD CLASS="quote">when you guys did the compression test, did you guys disable fuel?
if so how did you guys do it?</TD></TR></TABLE>
well when he did it he sais he didnt disable fuel. When i did it a second time today I disabled fuel on it by pulling the injector clips.
if so how did you guys do it?</TD></TR></TABLE>
well when he did it he sais he didnt disable fuel. When i did it a second time today I disabled fuel on it by pulling the injector clips.
07-25-2006, 01:42 PM
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Re: (BlackCRX)
Compression was checked last night and today. Checked last night I didn't disable fuel just ignition.
Today, we unplugged every injector and pulled every spark plug. Compression was checked one cylinder at a time with the engine "hot" with the throttle completely open. It rang us up a total of about 165-168 psi on all cylinders.
Today, we unplugged every injector and pulled every spark plug. Compression was checked one cylinder at a time with the engine "hot" with the throttle completely open. It rang us up a total of about 165-168 psi on all cylinders.
07-25-2006, 04:12 PM
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Re: (teamlegacy)
Anyone else have any suggestions?
On tap for tomorrow is to "ghetto-rig" cyl 1 injector wiring, re-burn my chip through Crome and adjust idle values as neccessary.
On tap for tomorrow is to "ghetto-rig" cyl 1 injector wiring, re-burn my chip through Crome and adjust idle values as neccessary.
07-25-2006, 05:17 PM
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Re: (Tchleung)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tchleung »</TD></TR><TR><TD CLASS="quote">Could be bad valve lash</TD></TR></TABLE>
yea did you check to see if it was out of spec yet Colin?
Modified by SOHC_MShue at 1:25 AM 7/26/2006
yea did you check to see if it was out of spec yet Colin?
Modified by SOHC_MShue at 1:25 AM 7/26/2006
07-25-2006, 06:02 PM
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Re: (SOHC_MShue)
I haven't touched it since you saw it last, Matt. We'll go over a few more things tomorrow. I'm just trying to gather **** to look for.
So far:
Check valve lash and/or clearance
Re-Burn ROM chip
Rewire injector independently straight to computer
Anything else?
So far:
Check valve lash and/or clearance
Re-Burn ROM chip
Rewire injector independently straight to computer
Anything else?
07-25-2006, 08:30 PM
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Re: (SOHC_MShue)
does he need a valve adjustment shue 
jk
Do all 4 cylinders seem to be burning the same when you pull the plugs?
Have you tried to throw in another set of fresh plugs and regap them?
Have you tried swapping injectors around or check to make sure you dont have trash in an injector?
I had that bad miss at idle but ran great when I had Oring trash in my 1000's that time.
goodluck
jk
Do all 4 cylinders seem to be burning the same when you pull the plugs?
Have you tried to throw in another set of fresh plugs and regap them?
Have you tried swapping injectors around or check to make sure you dont have trash in an injector?
I had that bad miss at idle but ran great when I had Oring trash in my 1000's that time.
goodluck
07-25-2006, 09:08 PM
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Re: (JDMs1eeper)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMs1eeper »</TD></TR><TR><TD CLASS="quote">does he need a valve adjustment shue
jk
Do all 4 cylinders seem to be burning the same when you pull the plugs?
Have you tried to throw in another set of fresh plugs and regap them?
Have you tried swapping injectors around or check to make sure you dont have trash in an injector?
I had that bad miss at idle but ran great when I had Oring trash in my 1000's that time.
goodluck</TD></TR></TABLE>
haha we are checking the valves tomorrow. Yes all 4 seem to be burning the same which is weird. Yes we have tried new plugs. After only letting the car idle on them they all look pretty damn rich which like i said is weird. The only thing thats changed on the setup since we tuned is the new exhaust and downpipe. Were gonna throw the wideband and laptop back on tomorrow. We have tried swapping injectors with no luck as well. Basically almost everything you can think of except for the direct wiring of the injector output from the ecu and valve lash.
jk
Do all 4 cylinders seem to be burning the same when you pull the plugs?
Have you tried to throw in another set of fresh plugs and regap them?
Have you tried swapping injectors around or check to make sure you dont have trash in an injector?
I had that bad miss at idle but ran great when I had Oring trash in my 1000's that time.
goodluck</TD></TR></TABLE>
haha we are checking the valves tomorrow. Yes all 4 seem to be burning the same which is weird. Yes we have tried new plugs. After only letting the car idle on them they all look pretty damn rich which like i said is weird. The only thing thats changed on the setup since we tuned is the new exhaust and downpipe. Were gonna throw the wideband and laptop back on tomorrow. We have tried swapping injectors with no luck as well. Basically almost everything you can think of except for the direct wiring of the injector output from the ecu and valve lash.
07-25-2006, 09:32 PM
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Re: (SOHC_MShue)
well soot is unburnt fuel. i'm sure its possible something isnt atomizing correctly? I know you dont like doing it but up the fuel pressure to 60 or 70 and retune the idle just to see what happens. Should help make a cleaner cumbustion, what you think?
07-25-2006, 09:36 PM
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Re: (JDMs1eeper)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMs1eeper »</TD></TR><TR><TD CLASS="quote">well soot is unburnt fuel. i'm sure its possible something isnt atomizing correctly? I know you dont like doing it but up the fuel pressure to 60 or 70 and retune the idle just to see what happens. Should help make a cleaner cumbustion, what you think?</TD></TR></TABLE>
I wouldn't mind turning the fuel pressure up, but he doesn't have an adjustable fpr anyways. It really seems like something weird is going on. I'll know when the wideband is on there tomorrow if its running rich. Still doesn't explain the one cylinder not firing only at idle. This is a new problem. Just randomly happened after the engine was compression tested yesterday. Before that no problems.
Oh and its not that i dont like turning fuel pressure up to 60psi or so...just 90psi is a bit much
I wouldn't mind turning the fuel pressure up, but he doesn't have an adjustable fpr anyways. It really seems like something weird is going on. I'll know when the wideband is on there tomorrow if its running rich. Still doesn't explain the one cylinder not firing only at idle. This is a new problem. Just randomly happened after the engine was compression tested yesterday. Before that no problems.
Oh and its not that i dont like turning fuel pressure up to 60psi or so...just 90psi is a bit much