is that hesitating a miss fire?? or something else?
03-07-2005, 10:51 PM
#1
is that hesitating a miss fire?? or something else? i have a problem with my 2000 M6 Z28 camaro it has the 5.7L LS1 engine. the problem is that that when i'm at normal driving and specialy 1/2 WOT or WOT the car surges for a 2 seconds or 3 and like it lost power then the engine back to its power then it repeats that as long as i'm driving the car.
when i put the car in nutral and press the gas pedal to WOT i don't know i don't feel this thing but i might be wrong it might be still present.
the trouble codes i found were DTC430, DTC420, DTC204, this is using the LS1edit scan tool and i cleared the PCM from these codes but they are back after a week or so.
i deleted the cats for DTC430 and DTC420 but they still come back some times although they can be cleared. for DTC204 i couldn't find it in my Helms manual.
i did do a tune up for my car yesterday where i replaced the spark plugs, spark plug wires, fuel filter, cleaned injectors but that didn't solve the hesitating (surging) problem although the car felt stronger.
what do you think the problem is? is that hesitating a miss fire? is it an acitng up injector or 2? or and acting coil? cloged fuel pressure regulator? i can't understand what this problem is?
sorry if the message is too long , thanks for your help.
when i put the car in nutral and press the gas pedal to WOT i don't know i don't feel this thing but i might be wrong it might be still present.
the trouble codes i found were DTC430, DTC420, DTC204, this is using the LS1edit scan tool and i cleared the PCM from these codes but they are back after a week or so.
i deleted the cats for DTC430 and DTC420 but they still come back some times although they can be cleared. for DTC204 i couldn't find it in my Helms manual.
i did do a tune up for my car yesterday where i replaced the spark plugs, spark plug wires, fuel filter, cleaned injectors but that didn't solve the hesitating (surging) problem although the car felt stronger.
what do you think the problem is? is that hesitating a miss fire? is it an acitng up injector or 2? or and acting coil? cloged fuel pressure regulator? i can't understand what this problem is?
sorry if the message is too long , thanks for your help.
03-08-2005, 03:13 AM
#5
i already deleted the cats ( converters ) as i stated in my first post, no change still hesitating. today i went to a shop and they diagnosed the car using Tech 2 after diagnosing and a test run they told me you have bad rear O2 sensors and you also need to reprogram (upgrade program) the PCM i will try them and see what will happen. offfff those rear O2 sensors are expensive i bought 2 for $130.
03-08-2005, 03:56 AM
#6
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I have a very similar problem with mine. Got similar codes. But for me I am now notcing from time to time Fuel pump noise. But my Fuel pump is flowing properly- But I get my problem at idle very mildly as well, To me I think I have some problem with the fuel delivery- maybe a really bad fuel filter and a bad injector or 2, I have about 100K miles. - Whats ur AF like mines like 15.0 so - Its late =)
03-08-2005, 08:38 AM
#7
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At 70k miles, I am having similar problems. At lower RPMs (1800-2200), the car stumbles (as if it were running out of fuel) and then comes back to life. I have no such diagnostic device so I guess I'll have to take it somewhere and pay someone.
Last edited by BigBadWolf; 03-08-2005 at 08:45 AM.
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03-08-2005, 08:43 AM
#8
i think my problem is the same as BigBadWolf's problem.
BuffJoeyD, actualy i don't know what the A/F ratio is.
the 2 rear O2 sensors are back ordered they are not in stock i will have to wait 15 days to get them and see if they will fix my hesitating problem.
BuffJoeyD, actualy i don't know what the A/F ratio is.
the 2 rear O2 sensors are back ordered they are not in stock i will have to wait 15 days to get them and see if they will fix my hesitating problem.
03-08-2005, 01:32 PM
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It may be that this problem relates to the speed-density tune
being way off from the MAF reported airflow. If this is an export
vehicle it may have no O2s (though, then, why the codes?)
and it may be full time open loop.
I don't know the programming history here. If a domestic .bin
were, say, put down on this vehicle then it might wake up a
bit confused by things it finds missing. But this is all just some
speculation.
At any rate, every time you have an unsteady-MAP situation
(like moving throttle) the car ditches the MAF and falls back
to straight speed density airflow mode. If the SD tune is bad,
power loss, perhaps transient KR, is a likely result. When the
MAF is reapplied and a more accurate (if you didn't mess with
it) airflow reading makes a better fueling. This would have a
power-lag signature as described.
Also check that the PE mode delay is zeroed and the PE
enrichment rate is 1.0 ("give it to me now!). PE enable TPS
should also be lower-than-hangs-you-up, barely, and the
same for MAP. If your airflow metering is trustworthy but
you get ping / KR with a decent O2 reading then maybe PE
needs to be brought in sooner. But if you see a "lean hole"
in the O2 readings (here the export guys are kind of out of
luck, without a wideband) suspect that your VE table is in
fact leaner / lighter than it really needs to be.
being way off from the MAF reported airflow. If this is an export
vehicle it may have no O2s (though, then, why the codes?)
and it may be full time open loop.
I don't know the programming history here. If a domestic .bin
were, say, put down on this vehicle then it might wake up a
bit confused by things it finds missing. But this is all just some
speculation.
At any rate, every time you have an unsteady-MAP situation
(like moving throttle) the car ditches the MAF and falls back
to straight speed density airflow mode. If the SD tune is bad,
power loss, perhaps transient KR, is a likely result. When the
MAF is reapplied and a more accurate (if you didn't mess with
it) airflow reading makes a better fueling. This would have a
power-lag signature as described.
Also check that the PE mode delay is zeroed and the PE
enrichment rate is 1.0 ("give it to me now!). PE enable TPS
should also be lower-than-hangs-you-up, barely, and the
same for MAP. If your airflow metering is trustworthy but
you get ping / KR with a decent O2 reading then maybe PE
needs to be brought in sooner. But if you see a "lean hole"
in the O2 readings (here the export guys are kind of out of
luck, without a wideband) suspect that your VE table is in
fact leaner / lighter than it really needs to be.
03-08-2005, 02:26 PM
#14
jimmyblue, my car is not exported by the dealer, it is directly from the US i guess from Texas and the speedo is in MPH not KPH, so it has open/closed loop not as the ones exported by the dealer where they have open loop only as was my 1994 Z28 which was exported by the dealer. i didn't play with the fueling tables in the LS1edit since i don't know much about them just lowered the Fans temp and disabled CAGS. so basicaly my current program is stock.
BigBadWolf, even when i had cats i had exactly the same hesitating problem, i thought deleting the cats would solve my problem.
BigBadWolf, even when i had cats i had exactly the same hesitating problem, i thought deleting the cats would solve my problem.
03-09-2005, 09:10 AM
#15
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From everything I've been able to read searching old threads, here are the possibilities;
Bad spark plug and/or wire
Running too rich/lean
Bad O2 sensor
Curse was put on car
The moon is in the 7th power
Bad spark plug and/or wire
Running too rich/lean
Bad O2 sensor
Curse was put on car
The moon is in the 7th power