ecm junk?
#1
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
ecm junk?
82 z28 cfi. car was running great just rebuilt the motor put a bigger cam and 1.6 rockers. all of a sudden its struggling to start and the idle is up and down. so i connect the computer to it and its in and out of connection. when the connection disappears from the computer to ecm is when the idle starts going up and down. not sure if the prom is bad or maybe the ecm or both. i went under the hood and checked the main wire harness on driver side fire wall and it was tight pulled it out just to check prongs. cleaned some of the tar off of it wiped the prongs clean and replugged it in. still same problem. checked vacuum and it seems to be right. the only diagram i have to look at is the little one on the fan shroud. but every vacuum line i pulled out i marked a number on each end with a number and tape so i made sure it went to the right place. I've been screwing around with this thing for that past 7 hours and can't figure it out. at first it was throwing a code 33 map sensor or circuits something can't remember exactly. i checked the troubleshooting on that and it said vacuum leak. i looked at the throttle bodies and noticed the vacuum line that went to the air pump was open so i plugged it because it is no longer existent. but now its not throwing any codes at all. this is my first non carb rebuild and its not easy so if any of you know anything i may have overlooked, please help.
#2
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
Re: ecm junk?
also the computer stays connected until i start the car then 30 seconds into it it disconnects and it also says e cell expired
#3
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
Re: ecm junk?
I'm sure someone has to know something. any help would be amazing
#4
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Re: ecm junk?
from what i understand,the E-cell (a simple plug in
circuit board inside the little tan plastic box with 3
wires)is just a 1-shot timer module to indicate when
the o2 sensor needs changed or something like that-
does not effect engine operation at all.
The idle going up and down can be caused by wrong
"minimum air"setting or too-low fuel pressure.
circuit board inside the little tan plastic box with 3
wires)is just a 1-shot timer module to indicate when
the o2 sensor needs changed or something like that-
does not effect engine operation at all.
The idle going up and down can be caused by wrong
"minimum air"setting or too-low fuel pressure.
#5
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
Re: ecm junk?
from what i understand,the E-cell (a simple plug in
circuit board inside the little tan plastic box with 3
wires)is just a 1-shot timer module to indicate when
the o2 sensor needs changed or something like that-
does not effect engine operation at all.
The idle going up and down can be caused by wrong
"minimum air"setting or too-low fuel pressure.
circuit board inside the little tan plastic box with 3
wires)is just a 1-shot timer module to indicate when
the o2 sensor needs changed or something like that-
does not effect engine operation at all.
The idle going up and down can be caused by wrong
"minimum air"setting or too-low fuel pressure.
#7
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
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#8
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
#9
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Re: ecm junk?
the timing being off could have an effect...(did you
find the EST bypass plug yet?) I don't know what may
be causing the ALDL/computer link problem-never used
on of those...
find the EST bypass plug yet?) I don't know what may
be causing the ALDL/computer link problem-never used
on of those...
#10
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
Re: ecm junk?
is the est bypass a single orange plug. on my crossfire its in the wire harness that runs by the egg valve down behind the distributor. if its that wire. the only thing that weirds me out is the connection problem. the motor just starts messing up without giving me enough time to even try to time the engine. unless unplugging the est will stop that problem
#11
Supreme Member
Re: ecm junk?
checked my factory manual,doesn't give plug color but
the EST bypass plug is in the position you describe-next
to the EGR valve.
the EST bypass plug is in the position you describe-next
to the EGR valve.
#12
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
#13
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Re: ecm junk?
Unpluggine the EST connector will take the ECU out of the equation and provide a steadier idle. Effect is the timing is locked at whatever you set it to.
I believe your vehicle does not use a resister in ALDL cable.
I believe your vehicle does not use a resister in ALDL cable.
Last edited by Ronny; 04-30-2012 at 03:06 PM.
#14
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
Re: ecm junk?
i cant even keep the car running long enough to even atempt to set the timing. this time i started it and it held to the ecm but then back fired out of a throttle body and died. the rest of the times it loses connection to the ecm and the rpms just start rising.
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Car: 82 Ponitac Firebird
Engine: 350 TPI
Transmission: 4L60e/TCI TCU
Axle/Gears: 2.73
Re: ecm junk?
Did you reconnect all of the grounds at the back of the engine? Also if there was any welding etc around the engine, then most likely the ECM is blown.
Back in 2003 when my 82 bird was be rebuild, I told the body shop manager to make shure that the ECM was disconnected during welding. Well, he didn't and the ECM end up being bad. They also missed up the MAF etc on my TunePort 350.
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
Re: ecm junk?
I going to take a shot at this.
Did you reconnect all of the grounds at the back of the engine? Also if there was any welding etc around the engine, then most likely the ECM is blown.
Back in 2003 when my 82 bird was be rebuild, I told the body shop manager to make shure that the ECM was disconnected during welding. Well, he didn't and the ECM end up being bad. They also missed up the MAF etc on my TunePort 350.
Did you reconnect all of the grounds at the back of the engine? Also if there was any welding etc around the engine, then most likely the ECM is blown.
Back in 2003 when my 82 bird was be rebuild, I told the body shop manager to make shure that the ECM was disconnected during welding. Well, he didn't and the ECM end up being bad. They also missed up the MAF etc on my TunePort 350.
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Car: 82 Z28
Engine: 350
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#19
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Car: 82 Z28
Engine: 350
Transmission: Turbo 200C
Axle/Gears: 3.43
Re: ecm junk?
i pulled the est connection apart and set up the timing light. started up the car and by the time i got to the light it died. then next i started it up and sat in it giving it about 2000 rpms a little bit to warm it up let off and it back fired and died. not sure what to do
#20
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Car: 82 Ponitac Firebird
Engine: 350 TPI
Transmission: 4L60e/TCI TCU
Axle/Gears: 2.73
Re: ecm junk?
i pulled the est connection apart and set up the timing light. started up the car and by the time i got to the light it died. then next i started it up and sat in it giving it about 2000 rpms a little bit to warm it up let off and it back fired and died. not sure what to do
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Car: 1989 IROC-Z Hardtop
Engine: L98 w/SLP Performance Package
Transmission: 700R4
Axle/Gears: Borg-warner 9 bolt
Re: ecm junk?
I have a replacement ECM in transit. In the meantime I verified all ground connections, and I am making my way slowly through the wiring harness looking for any faults before I try another ECM.
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Engine: 355 cu in CFI
Transmission: 700 R4
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Re: ecm junk?
BF through the TBs usually means a lean condition ....... how's you fuel pump and filter .... could have a pump going south .....
from you posts one assumes it was running good ... and this condition just started ...without anything else being done ...????
just a thought ........
from you posts one assumes it was running good ... and this condition just started ...without anything else being done ...????
just a thought ........
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