Miss after long periods of driving, then exhaust starts to pop
07-15-2006, 07:49 PM
#31
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Location: Evansville,IN,USA
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Re: Miss after long periods of driving, then exhaust starts to pop
I replaced the 02's today. didn't make any difference. IT did throw a code 41 which is a ESC or ignition control open circut code, and a left O2 lean code.
What can cause the code 41?
What can cause the code 41?
07-16-2006, 07:30 AM
#32
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Re: Miss after long periods of driving, then exhaust starts to pop
I have more questions than answers: Sorry about that.
Are we still talking about a 93 that belongs to Flyboy? I have to assume not since a 93 PCM doesn't appear to use a code 41. I could be wrong. I have no experience with 93's. They are a wierd animal.
A code 41 concerns the IC circuit which is the white wire going from the PCM to the ICM and it is used to actually fire the ignition. Check pin conditions at both ends. Ohm the connection from end to end. If the engine runs, check for intermittent pin contact or the wire just behind the connector. I've seen wires bent at extreme angles start to break just behind the pin where it is crimped.
Incidentally, regarding the lean O2 code. If the purple/white wire going to the O2 is shorted to ground somewhere, it would produce this code. That would explain if you had the same code after you replaced the O2(hard to tell from your last post). This is a common problem for people with headers who aren't careful in there routing. When this code is present, the ECM goes into open loop operation. If the wire being shorted were the problem, it would show up immediately when scanned in real time.
Have you ever scanned it real time to see what the sensors are reporting particularly after closed loop?
My problem turned out to be a bad O2 that was reporting a rich condition from start up and into closed loop. The first thing I checked was to see if all the cylinders were firing. During open loop, it ran fine. When it went into closed loop it would go to negative fuel trims and ran crappy all the while the O2 was saying it was rich. The point here was, once I truly looked at the sensor readings while the engine was running, it was easy to see the problem.
Are we still talking about a 93 that belongs to Flyboy? I have to assume not since a 93 PCM doesn't appear to use a code 41. I could be wrong. I have no experience with 93's. They are a wierd animal.
A code 41 concerns the IC circuit which is the white wire going from the PCM to the ICM and it is used to actually fire the ignition. Check pin conditions at both ends. Ohm the connection from end to end. If the engine runs, check for intermittent pin contact or the wire just behind the connector. I've seen wires bent at extreme angles start to break just behind the pin where it is crimped.
Incidentally, regarding the lean O2 code. If the purple/white wire going to the O2 is shorted to ground somewhere, it would produce this code. That would explain if you had the same code after you replaced the O2(hard to tell from your last post). This is a common problem for people with headers who aren't careful in there routing. When this code is present, the ECM goes into open loop operation. If the wire being shorted were the problem, it would show up immediately when scanned in real time.
Have you ever scanned it real time to see what the sensors are reporting particularly after closed loop?
My problem turned out to be a bad O2 that was reporting a rich condition from start up and into closed loop. The first thing I checked was to see if all the cylinders were firing. During open loop, it ran fine. When it went into closed loop it would go to negative fuel trims and ran crappy all the while the O2 was saying it was rich. The point here was, once I truly looked at the sensor readings while the engine was running, it was easy to see the problem.
Last edited by Guest47904; 07-18-2006 at 05:34 AM.
07-16-2006, 02:47 PM
#33
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Location: Evansville,IN,USA
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Re: Miss after long periods of driving, then exhaust starts to pop
Yes, we are talking about Flyboys 93Z. I think the code 41 was from my dumb *** leaving the ignition module unhooked. I hooked it back up and it wouldn't start, I reconnected the tach wire, white wire w/ black tracer and it fired up.
As I mentioned I replaced the o2's, and they switch really fast like they are supposed to, the ones that were in there were pretty old.
I just got done driving it with the scanner hooked up. Again it ran great till it warmed up.
I watched the 02's when the car was bucking really bad, they would drop down to 20-40 range, then I would get off the gas and they would go up.
ST fuel trim would go up to 250.
no knock present.
ECT reads 203 degrees
it won't even pull itself on flat ground with my foot just sitting on the pedel. actually it's getting to the point right now it won't even idle. it's at about 450 rpms, the IAC is out to 160. what that means I don't know.
As I mentioned I replaced the o2's, and they switch really fast like they are supposed to, the ones that were in there were pretty old.
I just got done driving it with the scanner hooked up. Again it ran great till it warmed up.
I watched the 02's when the car was bucking really bad, they would drop down to 20-40 range, then I would get off the gas and they would go up.
ST fuel trim would go up to 250.
no knock present.
ECT reads 203 degrees
it won't even pull itself on flat ground with my foot just sitting on the pedel. actually it's getting to the point right now it won't even idle. it's at about 450 rpms, the IAC is out to 160. what that means I don't know.
Last edited by LilJayV10; 07-16-2006 at 02:49 PM.
07-17-2006, 12:11 PM
#34
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Location: High Ridge, MO
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Re: Miss after long periods of driving, then exhaust starts to pop
If the IAC is maxed out (160) then it is openned all of the way trying to let air in and make the car idle. I don't understand how the STFT's are up to 250. They're supposed to stop at 160 I thought, unless the tuner adjusted that in the tune, which I don't think is necessary. Have you tried just unplugging both O2's and driving the car? This will keep the car in open loop and you can determine if it is something getting hot and breaking down or not. If you can drive the car and it doesn't get stupid, then you know it has something to do with the car switching to closed loop. Give that a try.
Also, is the ECT reading 203 degrees C? or F?
Also, is the ECT reading 203 degrees C? or F?
Last edited by Sweetred95ta; 07-17-2006 at 12:14 PM.
07-17-2006, 02:44 PM
#35
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Location: Evansville,IN,USA
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Re: Miss after long periods of driving, then exhaust starts to pop
the 203 degrees is in F
When it was on the scanner yesterday I watched to see if it made a difference when it went to clsd loop and it didn't. I will unplug the 02's and see if that makes a difference.
Do you know what an injector fault is? When I had it on the snap on scanner when it was running bad it said there was one. After the car sat and cooled down and I restarted it, it went away.
When the IAC was maxed out, the car was running at about 500rpms, it was all it could do keep running. I think I am going to drive it tonight and see if it will completely stop running, then check injector pulse, pull the coil wire see which of the two isn't their.
It's obviously something heating up and breaking down.
What does the 02's dropping down to 40 mean? Lean.
It feels like the car is running out of gas. pressure is 43lbs. Racetronix said with that kind of pressure the volume is ok.
Thank you
Jason
When it was on the scanner yesterday I watched to see if it made a difference when it went to clsd loop and it didn't. I will unplug the 02's and see if that makes a difference.
Do you know what an injector fault is? When I had it on the snap on scanner when it was running bad it said there was one. After the car sat and cooled down and I restarted it, it went away.
When the IAC was maxed out, the car was running at about 500rpms, it was all it could do keep running. I think I am going to drive it tonight and see if it will completely stop running, then check injector pulse, pull the coil wire see which of the two isn't their.
It's obviously something heating up and breaking down.
What does the 02's dropping down to 40 mean? Lean.
It feels like the car is running out of gas. pressure is 43lbs. Racetronix said with that kind of pressure the volume is ok.
Thank you
Jason
07-18-2006, 05:31 AM
#36
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Re: Miss after long periods of driving, then exhaust starts to pop
Originally Posted by LilJayV10
When it was on the scanner yesterday I watched to see if it made a difference when it went to clsd loop and it didn't.
It's obviously something heating up and breaking down.
It's obviously something heating up and breaking down.
When O2's read below 450, that indicates it sees (or it thinks it sees) a lean condition.
Your O2s are indicating that you have a lean condition and the fuel trims are trying to compensate for it by maxing out. Then because it can't run like that, the IAC is maxing out to try to keep it running. A quick ex gas analysis would confirm whether it is actually lean or not. Let's assume that it is actually lean.
It would appear that one or more of the injectors is NOT squirting fuel. Funny how you also got an injector fault.
If an injector is not firing correctly, it may be that the cylinder it's in is not firing either. Check for a dead cylinder.
The problem injectors should be investigated. An injector fault will come up due to a electrical condition, not because it's clogged. You may have both problems on more than one injector. If the vehicle were an OBDII, the problem child would be easy to find since we can turn on or off individual injectors WHILE the vehicle is running. (small bit of useless trivia)
I suggest you remove them and have them cleaned and flow tested.
I think these guys can do that. fuelinjection@fuelinjection.com.
I know these folks have them as replacements.
http://store.getgmparts.com/fuel-injectors.html
good luck.
07-18-2006, 07:24 AM
#37
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Re: Miss after long periods of driving, then exhaust starts to pop
I would think that if an injector wasn't squirting or it wasn't working correctly, then it would be the same in cold (open loop) and warm (closed loop) operation.
Are the O2's reading the same in each bank? Are you fuel trims the same for each bank?
It still makes no sense to me why the STFT's are hitting 250. Why would the tuner set the boundary that high? I'd have to look at the software, but I don't even remember if they can be set that high or not.
Are the O2's reading the same in each bank? Are you fuel trims the same for each bank?
It still makes no sense to me why the STFT's are hitting 250. Why would the tuner set the boundary that high? I'd have to look at the software, but I don't even remember if they can be set that high or not.
07-19-2006, 01:10 PM
#38
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Re: Miss after long periods of driving, then exhaust starts to pop
I don't think those two statements contradicted(sp?) each other and this is why. The problem doesn't start as soon as it goes into closed loop. It takes about 10-15 minutes of running/driving.
I said it seemed like something was heating up and breaking down because it doesn't do it till after the car gets hot.
Yes the injector fault does make sense since the car seems to be running lean. Once the car cooled down, there was no injector fault and the car ran fine.
I don't know why the stft went up to 250. pcmsforless did the tune. I am just telling you what I saw on the scanner.
What drives the injectors? Is it the opti?
I would think that if it's an injector it would do it all the time, and not the same way everytime. and it's not just one cylinder, it's not just a dead miss, it's I have it to the floor and the engine will not rev up at all and it back fires really bad.
As I mentioned the fuel psi is 43, but if the injectors are not opening it could have 75psi and it wouldn't matter.
I am glad there are places like this board where people can ask questions and help people like me figure things out.
I said it seemed like something was heating up and breaking down because it doesn't do it till after the car gets hot.
Yes the injector fault does make sense since the car seems to be running lean. Once the car cooled down, there was no injector fault and the car ran fine.
I don't know why the stft went up to 250. pcmsforless did the tune. I am just telling you what I saw on the scanner.
What drives the injectors? Is it the opti?
I would think that if it's an injector it would do it all the time, and not the same way everytime. and it's not just one cylinder, it's not just a dead miss, it's I have it to the floor and the engine will not rev up at all and it back fires really bad.
As I mentioned the fuel psi is 43, but if the injectors are not opening it could have 75psi and it wouldn't matter.
I am glad there are places like this board where people can ask questions and help people like me figure things out.
07-20-2006, 05:21 AM
#39
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Re: Miss after long periods of driving, then exhaust starts to pop
The injectors are activated directly by the PCM. It has a transistorized output that pulls the injector to ground to activate it on one wire. The other wire to the injector is hot all the time the engine is on.
The injector pulses can be viewed with a noid light.
The health of the injector can be seen by checking the coil resistance with an ohm meter.
You never mentioned whether you have a dead cylinder or not.
The injector pulses can be viewed with a noid light.
The health of the injector can be seen by checking the coil resistance with an ohm meter.
You never mentioned whether you have a dead cylinder or not.
07-20-2006, 02:40 PM
#40
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Re: Miss after long periods of driving, then exhaust starts to pop
Originally Posted by speedygonzales
The injectors are activated directly by the PCM. It has a transistorized output that pulls the injector to ground to activate it on one wire. The other wire to the injector is hot all the time the engine is on.
The injector pulses can be viewed with a noid light.
The health of the injector can be seen by checking the coil resistance with an ohm meter.
You never mentioned whether you have a dead cylinder or not.
The injector pulses can be viewed with a noid light.
The health of the injector can be seen by checking the coil resistance with an ohm meter.
You never mentioned whether you have a dead cylinder or not.
I am going to get a noid light in the morning and look at it tomorrow since i am off work.
As far as dead cylinders, when it's cold it runs smooth as can be. IT runs so bad when it gets hot it feels like two cylinders are firing.
Oh, and what should the resistance be on the injector, i tested two and they were 0.00, given i set the meter up right.
Last edited by LilJayV10; 07-20-2006 at 03:13 PM.
07-20-2006, 04:28 PM
#41
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Location: High Ridge, MO
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Re: Miss after long periods of driving, then exhaust starts to pop
You didn't do something right because it shouldn't read 0. I don't think anything is 0, unless you touch the two posts of the meter together.
07-22-2006, 06:35 PM
#42
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Location: Evansville,IN,USA
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Re: Miss after long periods of driving, then exhaust starts to pop
Well, I recheck the injectors and all of them had 15 ohms of resistance. I checked them when they were hot and were about 16ohms, I couldn't check the ones in very rear because it was so damn hot.
I unhooked the 02's, still ran bad. SES light never came on. surprised me.
hooked the 02's back up and drove it, verified the 250 ST fuel trim, 02's would drop to 20-40 when it was missing.
Backfires out of the exhaust really bad and randomly out the intake.
Checked the alternator voltage, it was 13.1. replaced it, 14.2 but didn't make a difference.
Put the stock tune back in it, didn't make any difference.
When you drive the right bank 02 seems to drop lower than the other.
checked the injector pulse. it's getting one. faster you rev the engine the brighter it gets. Checked spark, getting it too.
If anyone knows of a good f body mechanic let me know. Cause I am out of idea's.
I unhooked the 02's, still ran bad. SES light never came on. surprised me.
hooked the 02's back up and drove it, verified the 250 ST fuel trim, 02's would drop to 20-40 when it was missing.
Backfires out of the exhaust really bad and randomly out the intake.
Checked the alternator voltage, it was 13.1. replaced it, 14.2 but didn't make a difference.
Put the stock tune back in it, didn't make any difference.
When you drive the right bank 02 seems to drop lower than the other.
checked the injector pulse. it's getting one. faster you rev the engine the brighter it gets. Checked spark, getting it too.
If anyone knows of a good f body mechanic let me know. Cause I am out of idea's.
07-23-2006, 05:56 AM
#43
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Re: Miss after long periods of driving, then exhaust starts to pop
I know you did everything you could so far and getting frustrated but can you try one more thing. Remember it takes several minutes before a code will come up when the O2s are unplugged.
See what the O2s are showing with KOEO.
As I mentioned earlier, if the wire from the O2 harness is shorted to ground, it will do what you mention whether the O2 is plugged in or not.
IF you unplugged the O2s and the reading stayed at the low end, then either the wiring is bad or the PCM is bad.
In my case, as soon as I went KOEO the left O2 would go full rich reading. Even the new one that had never seen the engine running. Checked all the wiring and it turned out to be a bad channel in the PCM. I still have a closed loop problem but at least the O2 isn't pegged to rich any more.
See what the O2s are showing with KOEO.
As I mentioned earlier, if the wire from the O2 harness is shorted to ground, it will do what you mention whether the O2 is plugged in or not.
IF you unplugged the O2s and the reading stayed at the low end, then either the wiring is bad or the PCM is bad.
In my case, as soon as I went KOEO the left O2 would go full rich reading. Even the new one that had never seen the engine running. Checked all the wiring and it turned out to be a bad channel in the PCM. I still have a closed loop problem but at least the O2 isn't pegged to rich any more.
07-24-2006, 11:05 AM
#44
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Re: Miss after long periods of driving, then exhaust starts to pop
Funny I found this thread. My 95/ported/boltons/stock cam runs perfect 126-130 everywhere and no knock....very good performance and 24mpg on the highway 19-20 around town.
However, my brothers stock 97/autotap/ltedit is leaning out on the right bank, O2's just keep dropping and the left bank is hanging at 900mv.
It comes on after a heavy acceleration like getting on the highway...then the right bank leans out and it starts poppin'.....I'm just starting to look at this, and found this thread.
Curiously, it sounds common....
However, my brothers stock 97/autotap/ltedit is leaning out on the right bank, O2's just keep dropping and the left bank is hanging at 900mv.
It comes on after a heavy acceleration like getting on the highway...then the right bank leans out and it starts poppin'.....I'm just starting to look at this, and found this thread.
Curiously, it sounds common....
07-24-2006, 11:10 AM
#45
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Location: Evansville,IN,USA
Posts: 471
Re: Miss after long periods of driving, then exhaust starts to pop
Originally Posted by speedygonzales
I know you did everything you could so far and getting frustrated but can you try one more thing. Remember it takes several minutes before a code will come up when the O2s are unplugged.
See what the O2s are showing with KOEO.
As I mentioned earlier, if the wire from the O2 harness is shorted to ground, it will do what you mention whether the O2 is plugged in or not.
IF you unplugged the O2s and the reading stayed at the low end, then either the wiring is bad or the PCM is bad.
In my case, as soon as I went KOEO the left O2 would go full rich reading. Even the new one that had never seen the engine running. Checked all the wiring and it turned out to be a bad channel in the PCM. I still have a closed loop problem but at least the O2 isn't pegged to rich any more.
See what the O2s are showing with KOEO.
As I mentioned earlier, if the wire from the O2 harness is shorted to ground, it will do what you mention whether the O2 is plugged in or not.
IF you unplugged the O2s and the reading stayed at the low end, then either the wiring is bad or the PCM is bad.
In my case, as soon as I went KOEO the left O2 would go full rich reading. Even the new one that had never seen the engine running. Checked all the wiring and it turned out to be a bad channel in the PCM. I still have a closed loop problem but at least the O2 isn't pegged to rich any more.
Yeah it's frustrating. I will figure it out eventually. I hope
We drove the car for about 10 minutes with the 02's unhooked.
On the computer, I don't remember what the values were with KOEO, but when driving down the road they both were 450.