95 LT1 surging, misfire
10-31-2012, 02:51 PM
#1
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95 LT1 surging, misfire
i just had a fresh rebuild put in my car and since i have gotten it back in i have been fighting a misfire surge problem, it has new plugs wires and optispark.i removed all my plugs to inspect them and found my driver side bank looks good but the passenger side looks like its runnin a bit richer.i have eliminated the secondary air injection pump and plugged the header bungs.the car dont set a check engine lite.it seems to load of at in town speeds but cleans out some on the hiway but never completly goes away .. any ideas other then maybe the plugs i have or my coil.car does not have a chip yet .could that be a prob to?
10-31-2012, 03:22 PM
#2
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Re: 95 LT1 surging, misfire
I seen u mentioned that one side of ur plugs looked like they are rich my wifes did the same thing as urs surge n the misfire,its was her fuel injectors they were leaking after the change the truck ran smooth
10-31-2012, 05:10 PM
#3
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Re: 95 LT1 surging, misfire
but would they all go bad at the same time . every cylinder on bank 2 looked fuel fouled the porcelain on the electrode side of the plug is all black i only have 6000 on the motor now.
BANK 2 (all are blackened like this)
BANK 1 (all look like this)
BANK 2 (all are blackened like this) BANK 1 (all look like this)
10-31-2012, 05:45 PM
#4
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Re: 95 LT1 surging, misfire
I wouldn't think that you would have 4 leaking injectors, all on the same side. Seems pretty unlikely, doesn't it?
Anyway, look to things that affect fueling on one side of the engine. First place to look is for an exhaust leak on the side that running rich. An exhaust leak makes the O2 sensor think the engine is running lean and has the system add fuel.
You can see all this with a logging scan like that possible with TTS Datamaster.
If there is no exhaust leak look to a bad, or sluggish O2 sensor...
Good luck!
Anyway, look to things that affect fueling on one side of the engine. First place to look is for an exhaust leak on the side that running rich. An exhaust leak makes the O2 sensor think the engine is running lean and has the system add fuel.
You can see all this with a logging scan like that possible with TTS Datamaster.
If there is no exhaust leak look to a bad, or sluggish O2 sensor...
Good luck!
10-31-2012, 07:02 PM
#6
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Re: 95 LT1 surging, misfire
the car dont set any codes at all..just starts running rough.... was also curious what the chances of it being a prob with my cam senor? it runs ok til it warms up then thats when i start to notice it more
10-31-2012, 07:36 PM
#8
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Re: 95 LT1 surging, misfire
Look at bw hunters post and do check for any exhaust leaks as they will effect o2 sensors readings. If no leaks I would consider swapping sides with o2 sensors and see if the richness switches sides or remains. Just because your light dont trip dont mean scanning wont help or narrow down your search. Has the computer been flashed for the cam and are the injectors stock or did you go bigger. Are you running the same setup as last motor basicly or what if anything was changed.What do you mean by chip?
10-31-2012, 08:51 PM
#9
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Re: 95 LT1 surging, misfire
have not had the computer flashed for the new cam i was told the pcm would automatically relearn. runnin stock sized injectors was told as well that they had plenty of flow. stock heads has gm hot cam kit. it has a k&n intake stock motor parts other then the cam kit. motor was bored 20 over .. car ran fine till i had the motor rebuilt .
11-01-2012, 05:29 AM
#10
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Location: Kissimmee, Fl, USA
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Re: 95 LT1 surging, misfire
The computer in the 94+ cars don't need a new chip for updates, the computer can be reprogrammed through the port under the dash.
Just because there is non SES light, doesn't mean the computer doesn't have information you can use.
If you have headers than changing the O2 sensors from side to side is pretty easy. If you have stock manifolds is a pain in the ....
Start by looking for an exhaust leak....it could even be a loose O2 sensor..
Just because there is non SES light, doesn't mean the computer doesn't have information you can use.
If you have headers than changing the O2 sensors from side to side is pretty easy. If you have stock manifolds is a pain in the ....
Start by looking for an exhaust leak....it could even be a loose O2 sensor..
11-01-2012, 01:21 PM
#11
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Re: 95 LT1 surging, misfire
Just for clarity your old motor ran fine but this one is rebuilt and from startup has had this issue? The only change was the cam and a few replacement parts. One of the replacement parts is the opti? What opti did you use(brand)
11-01-2012, 05:36 PM
#13
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Re: 95 LT1 surging, misfire
i put in a delphi opti in it.i rebuilt the motor that was origonally in the car and since i have had the problem. .i checked the fuel press reg and it is ok no problems there.i also checked for vac leaks i replaced all my lines when i put the motor back in the car
Last edited by vicki711; 11-01-2012 at 05:39 PM.