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Bad intermiting miss by Lilchief
Started on: 05-29-2013 06:19 PM
Replies: 13 (176 views)
Last post by: Lilchief on 08-19-2013 11:16 PM
Lilchief
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Report this Post05-29-2013 06:19 PM Click Here to See the Profile for LilchiefSend a Private Message to LilchiefEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well it all started on the way to my gf's house for a M day cook out. Had a short straight stretch before I got there and decided to open it up. It acted like the ICM was going back, run go then try to die or just die. Well managed to get to her house and tried to start it the next day. Started but really ran rough, sounded like a funny car, very distinct miss or misses, running very rich. After warmed up it smoothed out on excelleration but missed bad at cruise or less. I changed the ICM no change, wondering if it's the MSD box. Really acts like a loose wire somewhere. Any suggestions ?
Thanks Rick

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85 GT 3.4
14.9 @ 90 1.9 60' Old TH125/3.06
Unknown New 4T60/3.42

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FFIEROFRED
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Report this Post05-29-2013 08:20 PM Click Here to See the Profile for FFIEROFREDClick Here to Email FFIEROFREDSend a Private Message to FFIEROFREDEdit/Delete MessageReply w/QuoteDirect Link to This Post
This last week end my son's 3800sc new install was running on 5, most of the time. He changed a lot of things over the 3 days trying to fix it. in the end it was a cracked plug. not a broke plug, just cracked. He was safer when it was on 5.
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Lilchief
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Report this Post05-29-2013 08:53 PM Click Here to See the Profile for LilchiefSend a Private Message to LilchiefEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm trying to get caught up from the week end. I did change the ICM but no luck there. Plugs, cap and rotor next to check.
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TK
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Report this Post05-29-2013 09:21 PM Click Here to See the Profile for TKSend a Private Message to TKEdit/Delete MessageReply w/QuoteDirect Link to This Post
Arcing wires? Fuel pump going bad? The smell of being rich can also be the smell of unburnt fuel from dead cylinders.

[This message has been edited by TK (edited 05-29-2013).]

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Lilchief
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Report this Post05-30-2013 05:14 PM Click Here to See the Profile for LilchiefSend a Private Message to LilchiefEdit/Delete MessageReply w/QuoteDirect Link to This Post
Did some more checking today. Not the MDS box. I did notice the rotor seems to fit losely. How would you check the distributor ? Fuel pressure holds at 42 psi when running but does leak down rather quickly when turn off 2-3 minutes to 0. Should not have any dead cylinders only 20K miles on the engine plus it runs smooth under light /medium acceleration. I did check for arcing at night time and moved the wires around but no change.
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Gall757
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Report this Post05-30-2013 05:45 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Lilchief:

I did notice the rotor seems to fit losely.


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Lilchief
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Report this Post05-30-2013 06:22 PM Click Here to See the Profile for LilchiefSend a Private Message to LilchiefEdit/Delete MessageReply w/QuoteDirect Link to This Post
The rotor seems to rock. Got a new one coming.
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Gall757
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Report this Post05-30-2013 06:25 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Clean the distributor shaft with steel wool or emery cloth. The rotors will split if you force them.
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Lilchief
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Report this Post05-31-2013 01:23 AM Click Here to See the Profile for LilchiefSend a Private Message to LilchiefEdit/Delete MessageReply w/QuoteDirect Link to This Post
Can a leaky cold start injecter cause a miss and rich running condition ? I don't know much about the cold start injector system. I changed the rotor today, fits alittle tighter, still no change. I'll try pulling the plugs tomorrow to look for a rich condition, maybe narrow it down some.
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Ry86GT
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Report this Post05-31-2013 02:03 PM Click Here to See the Profile for Ry86GTSend a Private Message to Ry86GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
I had a very similar situation to you. Try unplugging the 02 sensor and see if it smoothes out.

I had a very similar driveability issue, did a complete tune up on my own to no avail: plugs/wires/coil/cap/rotor/fuel filter/etc.... Turns out it was a combination of too-far advanced timing from the previous owner and a bad O2 sensor. My O2 was giving the ecm a false lean condition causing it to run pig rich.
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Lilchief
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Report this Post05-31-2013 06:03 PM Click Here to See the Profile for LilchiefSend a Private Message to LilchiefEdit/Delete MessageReply w/QuoteDirect Link to This Post
Didn't get any testing done today because of the rain. But did let it run to normal temperature at which time it kind of went into a hunt idle mode. Would idle to 2500 rpms load up with gas and when about die. Doing this constently. Any ideas ? Haven't tried the O2 sensor yet.
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Lilchief
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Report this Post08-19-2013 10:18 PM Click Here to See the Profile for LilchiefSend a Private Message to LilchiefEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hope to get it to one of my mechanics to put on his scanner. It has developed a new problem, Idles to 3k+ and won"t come down. I disconnected the map/fuel pressure vacuum from the intake (blocked it off) and went back to the original problem. Any ideas?
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EvilSqueezles
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Report this Post08-19-2013 10:48 PM Click Here to See the Profile for EvilSqueezlesClick Here to Email EvilSqueezlesSend a Private Message to EvilSqueezlesEdit/Delete MessageReply w/QuoteDirect Link to This Post
Constant 3k? Ouch. Have you checked the egr tube for cracks or leaks?
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Lilchief
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Report this Post08-19-2013 11:16 PM Click Here to See the Profile for LilchiefSend a Private Message to LilchiefEdit/Delete MessageReply w/QuoteDirect Link to This Post
No EGR
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