Process For Different Computer
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From: Flourtown, PA | Bethany, DE
Process For Different Computer Hey all,
So with all the weird issues my '98 has been having, I think it may be a computer problem.
Hooked it up to a SnapOn scanner to monitor the car while running. Hooked up fine while the car was off. Then when the car was running it had several issues trying to connect. Finally it worked and we got this...
-Cyl #5 misfire
-Cyl #7 misfire
-Random Cyl #8 misfire
-Random Cyl #6 half fire
CEL is on. Codes are only showing P0420 (Catalyst efficiency below threshold on bank 1). However, o2 sensors are reading as normal. Cat temps are running within normal ranges as well. Other code is "Cylinder misfire detected". The CEL blinks when I exceed 35 MPH (obviously not a good thing).
Other issues:
-Third brake light sometimes illuminates like a rear tail light. On while lights are on, then brighter when the brakes are applied. I have an LED 3rd brake light installed btw.
-Turn signals are also acting weird. They blink quickly, slowly, normal, and anything between.
Have checked the injectors & coils. They are fine. So I am thinking harness or computer. I am borrowing a computer from my buddy who removed it from a '98 Camaro SS. Should be the same computer. Do I need to go through some idle, driving and warmup cycles? Or anything else special need to be done?
I REALLY want to be able to enjoy my car again, but I haven't been able to drive it in months 'cause of this crap. Thanks!
So with all the weird issues my '98 has been having, I think it may be a computer problem.
Hooked it up to a SnapOn scanner to monitor the car while running. Hooked up fine while the car was off. Then when the car was running it had several issues trying to connect. Finally it worked and we got this...
-Cyl #5 misfire
-Cyl #7 misfire
-Random Cyl #8 misfire
-Random Cyl #6 half fire
CEL is on. Codes are only showing P0420 (Catalyst efficiency below threshold on bank 1). However, o2 sensors are reading as normal. Cat temps are running within normal ranges as well. Other code is "Cylinder misfire detected". The CEL blinks when I exceed 35 MPH (obviously not a good thing).
Other issues:
-Third brake light sometimes illuminates like a rear tail light. On while lights are on, then brighter when the brakes are applied. I have an LED 3rd brake light installed btw.
-Turn signals are also acting weird. They blink quickly, slowly, normal, and anything between.
Have checked the injectors & coils. They are fine. So I am thinking harness or computer. I am borrowing a computer from my buddy who removed it from a '98 Camaro SS. Should be the same computer. Do I need to go through some idle, driving and warmup cycles? Or anything else special need to be done?
I REALLY want to be able to enjoy my car again, but I haven't been able to drive it in months 'cause of this crap. Thanks!
Ive really never like 98 or older computers for some reason, they are more complicated for a few things. 99 and newer are what I have always used for tuning reasons (I dont tune, but for my tuners) but man your car has gone crazy. Have you tried swapping computer to see how it works?
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From: Flourtown, PA | Bethany, DE
Ive really never like 98 or older computers for some reason, they are more complicated for a few things. 99 and newer are what I have always used for tuning reasons (I dont tune, but for my tuners) but man your car has gone crazy. Have you tried swapping computer to see how it works?
could it be a bad ground? when i first got my car fired up everytime i would launch hard or hit a bump the car would want to stall out. i found out it was that my ecu wasnt grounding out good. i took one of the bolts out and ran a ground strap to it and now it works great
Yes it needs to idle to relearn your fuel trims. If both cars are stock then shouldn't be a problem but it sounds like the common grounds are corroded in the harness and running to other systems besides ground. Find the harness grounds on the radiator support and follow them back in the harness till they meet(you will have to cutback the wireloom and some tape) then clean those grounds and try it again with your PCM.
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From: Flourtown, PA | Bethany, DE
First I'm going to see if I can get the new computer to learn everything and work. If not, on to the grounds.
2 interesting things. First, I just noticided this on the ECU I pulled from my car:
Second here's the crap that's all over both the ECU and the harness side:
2 interesting things. First, I just noticided this on the ECU I pulled from my car:
Second here's the crap that's all over both the ECU and the harness side:
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The flashing CEL is caused by a dead miss it alerts you by flashing because driving it in that condition will damage the cats. But all is not lost they may come back to life and do there job after the misfires are fixed they won't be drowning in gas. Cyl.5 is where I would start because of the misfire echo on the sister cyl 8. 02 readings are not normal with misfires without going to a custom data screen the refresh rate on the scanner is most likely too slow to even see it. Normal tune-up checks are in order have you pulled\changed the plugs ?
The lights just sound like a bad bulb with a crossed element buy a box of bulbs and replace them all
The lights just sound like a bad bulb with a crossed element buy a box of bulbs and replace them all
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From: Flourtown, PA | Bethany, DE
The flashing CEL is caused by a dead miss it alerts you by flashing because driving it in that condition will damage the cats. But all is not lost they may come back to life and do there job after the misfires are fixed they won't be drowning in gas. Cyl.5 is where I would start because of the misfire echo on the sister cyl 8. 02 readings are not normal with misfires without going to a custom data screen the refresh rate on the scanner is most likely too slow to even see it. Normal tune-up checks are in order have you pulled\changed the plugs ?
The lights just sound like a bad bulb with a crossed element buy a box of bulbs and replace them all
The lights just sound like a bad bulb with a crossed element buy a box of bulbs and replace them all
Can bad o2's and/or cats cause misfires on 2+ cylinders?
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From: Flourtown, PA | Bethany, DE
The seals all good great. That's what worries me...
I just spent 2.5 hours working on it. I removed the ECU connectors from the ECU and cleaned them with electrical cleaner spray. Then, I removed the 4 easily accessible grounds: Driver side strut tower, driver side front next to the intake, passenger side strut tower, passenger side front next to the intake. I filed down the grounds metal contacts and wire brushed them as well.
Started up the car and it ran basically 99%! I took it for a 0.5 mile drive and it slowly got worse. At stops it would almost stall. I brought it back and parked it. It seemed to get worse the longer it was running. However, overall it seems much quieter and seems to run much smoother as well.
This is all on the "new" ECU from my buddies '98 Camaro SS. Should I be cleaning out my other ECU (Which is remanned it seams) and try to run it again?
I just spent 2.5 hours working on it. I removed the ECU connectors from the ECU and cleaned them with electrical cleaner spray. Then, I removed the 4 easily accessible grounds: Driver side strut tower, driver side front next to the intake, passenger side strut tower, passenger side front next to the intake. I filed down the grounds metal contacts and wire brushed them as well.
Started up the car and it ran basically 99%! I took it for a 0.5 mile drive and it slowly got worse. At stops it would almost stall. I brought it back and parked it. It seemed to get worse the longer it was running. However, overall it seems much quieter and seems to run much smoother as well.
This is all on the "new" ECU from my buddies '98 Camaro SS. Should I be cleaning out my other ECU (Which is remanned it seams) and try to run it again?
One thing by now id look for would be some plugged cats if you have checked the grounds. Hit rhe bolts with pb blaster and drop the cats, then see how it runs in the bay. See if u can feel the ground at the back of the cylinder head too.
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Did not check the lights after I swapped ECU's. I've cleaned up my remanned one and will reinstall that to see what happens.
I'm either doing a new Y-Pipe from Walker or new cam / crank sensor. One guy is stating he had the exact same issues as mine, no crank or cam sensor codes. He replaced both sensors and it fixed the problem. Is there a test for these sensors or really just remove them and install new ones?
I'm either doing a new Y-Pipe from Walker or new cam / crank sensor. One guy is stating he had the exact same issues as mine, no crank or cam sensor codes. He replaced both sensors and it fixed the problem. Is there a test for these sensors or really just remove them and install new ones?
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From: Flourtown, PA | Bethany, DE
