GA 97 3.1 is this EGR or CAT problem? GENISYS SPX OTC SCANNER WAS USED

[Operator10]

Originally Posted by xeroinfinity

Cheap o2 sensors dont last ling, you get what you pay for.
btw Bosch O2's are crap!



I've never seen that in any of my GM tech manuals.
The car should die when the MAF is disconected.

I think your guys problem, is the scan tool
Or you both have a Bad PCM/ECU, this shouldnt be that much of a mystery to solve....

Maybe you two should test the circuits with a volt/ohm meter, not that GENISYS scann tool.

Yes, almost all of my checks have been done with my mutimeter. However. I just started using my Genisys scanner to learn all of the features it has. I do need the Genisys scanner to do the Case Learn procedure, but before I do that, the problems have to be resolved and the DTC's have to been cleared. It is very interesting that aki334 and I have the same symptoms with the P0300 DTC setting and no other code setting for the EGR valve. The unmetered air coming in may be something we should check on. Thanks for your support, Tommy.

[xeroinfinity]

Well thats the first I heard you were having the p0300 Tommy

Then I would say you have injector issues.
Could be damaged wiring to the injectors Or they are jjust not pulsing properly.
Which if it's causing it to run rich, you will get those high values/readings .

Good Luck

[Operator10]

Originally Posted by Aki334

I have the same problem Tommy with the pending code p0300. I see misfires on #3 and #4 cylinder. I am sure we have the exact same problem. But one quick question if there is problem with the EGR circuit why don't we have DTC set?, if there is problem with the same circuit how come I can do a test on EGR through PCM and order opening and closing the EGR pintle you can try this on your scanner under special tests. So far the closest I got to stop my misfires was disconnecting MAF sensor that is according to original GM service manual. Manual said if you disconnect MAF and misfires stop replace MAF I did disconnect it and misfires were gonne but when I put in the new MAF the same thing happened. This tells me we have some unmetered air comming in somewhere. Did you do vacuum gauge reading on your intakemanifold? This problem I had for a long time and I was never able to fix it. Hopefully once you get that new pcm I will know if I need to do the same thing. I was thinking to replace all my injectors because of the p0300 but I will wait for this now (I assume you have clean injectors). Back to EGR did you try takaing off the EGR and plugging those EGR openings on manifold with aluminum foil just to see if misfires stop. I am also thinking that this could be problem with one of the valves onot opening or closing properly or bad MAP reading.

My misfires are across all 6 cylinders. Yes, I don't understand why a DTC for the EGR in not setting. I think we should look into the unmetered air coming in, that sounds like a good idea. I believe I did do a vacuum test. This was done months back and I don't recall what the reading was. I will take another reading to make sure. My fuel injectors are new. I tested them on the fuel rail with the fuel rail removed from the intake, away from the engine compartment. They all had a nice strong spray pattern. I disconnected the two EGR tubes and plugged the intake openning, and the openning on the exhaust with metal blanks and exhaust gaskets that I fabricated. No difference, the engine still ran the same. By the way, does your engine operate this way: Whenever I start it up when it is cold, it won't idle on it's own. I have to work the throttle manually to keep the engine idling. I need to do this for a good 4 to 5 minutes then the engine starts to run better. At that point I can then start reving the engine slowly, which I can't do when the engine first starts up. I get no response if I try to rev the engine as soon as it starts up when cold. It's as if the PCM does not remember what the last learn adjustment was. I know that if you unplug your PCM, your PCM then has to go through a short learn procedure to reset itself. I believe that the learn memory in my PCM has been affected by the shorts I have been talking about. Everytime I shut off the engine and let it get cool, then start it up, I need to do the same thing with the throttle all over again. I have to work the throttle manually for that 4 to 5 minutes then the engine will start to run better and idle on it's own. Thank you, Tommy.

[Operator10]

Originally Posted by xeroinfinity

Well thats the first I heard you were having the p0300 Tommy

Then I would say you have injector issues.
Could be damaged wiring to the injectors Or they are jjust not pulsing properly.
Which if it's causing it to run rich, you will get those high values/readings .

Good Luck

Sorry, I thought I mentioned it previously. I have checked the wiring from each fuel injector back to the PCM. It checked out OK. I also checked the voltage at each of the injector wires with the ignition switch on. I had 12 volts at each wire. Now, like you said, if it's pulsing correctly, that's another story. That's why I keep thinking various systems within the PCM have shorted out due to all of the cross wiring that I found and corrected. Thank you, Tommy.

[xeroinfinity]

You cant tell much by way of a "spray pattern" if they are working properly. And just because it has 12volt doesnt mean they are working right either.

Whenever I start it up when it is cold, it won't idle on it's own. I have to work the throttle manually to keep the engine idling. I need to do this for a good 4 to 5 minutes then the engine starts to run better. At that point I can then start reving the engine slowly, which I can't do when the engine first starts up.

This would be the IAC not working properly.

Well, If you expect a proper diagnosis here, then you have to give all the details, DTC's and all the problems you are having.

Your PCM is not the problem here, your fuel system or ignition sysytem(plugs coils wires) are your problem.

You should also read up on that POS GENISYS scanner you have. Because you are reading things wrong IMO.

If its not broke, dont fix it.


XI

[Operator10]

[quote=xeroinfinity]You cant tell much by way of a "spray pattern" if they are working properly. And just because it has 12volt doesnt mean they are working right either.



This would be the IAC not working properly.

Well, If you expect a proper diagnosis here, then you have to give all the details, DTC's and all the problems you are having.

Your PCM is not the problem here, your fuel system or ignition sysytem(plugs coils wires) are your problem.

You should also read up on that POS GENISYS scanner you have. Because you are reading things wrong IMO.

If its not broke, dont fix it.


OK, here are some of the latest readings I took with my scanner:
Trouble code - P0300 Multiple Random Misfire with Mil light blinking
Misfire counts:
Cylinder # 1 - 10 counts
Cylinder # 2 - 7 counts
Cylinder # 3 - 6 counts
Cylinder # 4 - 5 counts
Cylinder # 5 - 12 counts
Cylinder # 6 - 15 counts
Engine Temp - 199 degF
IAT - 122 degF
IAC - 70 counts
Air Fuel Ratio - 14.1 :1
Barometric Pressure - 30 inHg
Barometric Pressure - 2.0 volts
Fuel Trim Cell (BLM) - 2 counts
Fuel Trim Learn - Disabled
H02S Bank 1 sensor 1v - 0 mv
H02S Bank 2 sensor 1v - 447 mv
H02S Bank 1 sensor 3v - 9 mv
Inj Pulse Width - 11.0 msec
Loop Status - Open (both banks were constantly openning and closing changing every second) Not sure if this is normal or not?
Mass Air Flow - 13 g/s
Power enrichment - Inactive
Ing volts - 12.8 volts

Since then I have installed the following new parts:
Spark plugs, all 6 NGK Iridium
02 sensors, all 3 of them.
Catalytic converter
EGR valve

As mentioned in my previous posting, the symptom has always been, poor engine performance. Alot of hesitation and bad response when the engine starts up cold. The engine won't even idle. I have to work the throttle to keep the engine running. I can't even rev the engine to get the rpm up. When I attempt to do so, there is no response. However, after approximately 4 to 5 minutes I'm slowly able to get the engine to rev up. I would have to consistantly try to rotate the throttle slowly and keep at it, then all of a sudden it's like something changed or a setting kicked in, then I'm able to rev up the engine with a quicker response. The longer I do that, the better the response. Now, I don't what is causing that to happen, if it's because the engine is getting warmer or some electrical system kicks in or what. I keep thinking it has something to do with the learn memory in the PCM. I say that because if I let the engine cool off, the same thing happens all over again. I don't know how to explain it better than that. The IAC is also new. I have checked and adjusted the pintle height at least 3 times. The spec's call for it to be no more than
1-1/8" from the flange to the tip of the pintle. Any other info you would be interested in? Thank you, Tommy.

[Aki334]

I just wish I drove 5.7 l impala all this years or something similar because my GA is 3.1l and is probably giving me the same MPG as 5.7 L so it must be something around EGR because if there is something bad with them you will use a lot of gas. Tommy if we really have the same problem and you do not fix it you will probably wish you had 6.1L Trans Am . What is your IAC count I compared my reading with the same GA that did not have any problems. His IAC count was 30 and my was 17-20 cnt (this indicates air leak somewhere). I did use all possible methods to find my vacuum leasks except the smoke machine and still was not able to find any leaks. Did you try disconecting your MAF whille you are monitoring your misfires? Are you able to drive your car at all? if you can, you can also monitor you EGR position error in % that is difference between your actual EGR position and PCM desired position. It also could be that something (some sensor) is retarding our ignition timing. Do the test with your vacuum gauge at idle. I can bet it will be close to 17 or 18 " of mercury and it will flactuate rapidly up and down by 1" of mercury. If yes we could have retarded ignition timing. When are you expecting to receive your new PCM? I can not wait to see the results.
And one more quick question before I go: the PCM that you are using now, does it belong to the same engine?

[Aki334]

Cylinder # 1 - 10 counts
Cylinder # 2 - 7 counts
Cylinder # 3 - 6 counts
Cylinder # 4 - 5 counts
Cylinder # 5 - 12 counts
Cylinder # 6 - 15 counts
Engine Temp - 199 degF
IAT - 122 degF
IAC - 70 counts
Air Fuel Ratio - 14.1 :1
Barometric Pressure - 30 inHg
Barometric Pressure - 2.0 volts
Fuel Trim Cell (BLM) - 2 counts
Fuel Trim Learn - Disabled
H02S Bank 1 sensor 1v - 0 mv
H02S Bank 2 sensor 1v - 447 mv
H02S Bank 1 sensor 3v - 9 mv
Inj Pulse Width - 11.0 msec
Loop Status - Open (both banks were constantly openning and closing changing every second) Not sure if this is normal or not?
Mass Air Flow - 13 g/s
Power enrichment - Inactive
Ing volts - 12.8 volts

what was the RPM for these readings?
red ones I believe are not normal at idle speed. Did you ever check your MASTER SENSOR (COOLANT TEMPERATURE SENSOR MAYBE IT HAS INTERMITENT CONNECTION) LOOP STATUS should't change once the engine reaches the operating temperature loop should be closed, and your pcm should start adjusting your air/fuel ration based on your O2 sensor readings. Check that Master Sensor everything depends on it you know that Tommy. Now if that O2 sensor shows 3V that is very bad, I would try something for fun (see if you can find 2 or 3 ohm resistor and instal it in your signal wire of your O2 sensor that shows 3v) see what happens. Also try this site compare your vacuum gauge readings and let me know which one describes your condition http://www.users.bigpond.com/ergoff/vac1.htm

[xeroinfinity]

Ok Operator10, this thread has drug onlong enough.

If you do a search for misfires you will find that it is very common.
Right off I can say your spark plugs could be the "partail" cause, NGK are not GM recomended thier for wont last long.
AC Delco Iridiums are recomended and will last 75-100k miles.
As I stated before misfires are from either of two soarces;

You ignition system, plugs & wires & coils and circuits.

OR from the injectors being bad due to a clog, bad coil inside, contaminated fuel, bad injector wiring harness, Even the ground for the Injection system(on the lower intake) wiring harness has been known to cause misfires.

Misfire counts:
Cylinder # 1 - 10 counts
Cylinder # 2 - 7 counts
Cylinder # 3 - 6 counts
Cylinder # 4 - 5 counts
Cylinder # 5 - 12 counts
Cylinder # 6 - 15 counts
Engine Temp - 199 degF
IAT - 122 degF
IAC - 70 counts
Air Fuel Ratio - 14.1 :1
Barometric Pressure - 30 inHg
Barometric Pressure - 2.0 volts
Fuel Trim Cell (BLM) - 2 counts
Fuel Trim Learn - Disabled
H02S Bank 1 sensor 1v - 0 mv
H02S Bank 2 sensor 1v - 447 mv
H02S Bank 1 sensor 3v - 9 mv
Inj Pulse Width - 11.0 msec
Loop Status - Open (both banks were constantly openning and closing changing every second) Not sure if this is normal or not?
Mass Air Flow - 13 g/s
Power enrichment - Inactive
Ing volts - 12.8 volts

So lets break this down a little ....
You have excessive misfires throughout all 6 cyl.
Your readings for the IAC is off too(probly bad IAC or cloged port).
With the exception of the open loop everything else seems in range. A/F ratio is dead on too.

The open loop is probly why the readings previously posted by you are high on the EGR and CAT , this tells me the O2 sensor(s) is not working correctly.
These readings from a cold motor or Hot ??

If you havent already, clean the port for the IAC with TB cleaner. Since you say the IAC is new, then its not set right or damaged/faulty.
This is what controls idle wheather your engine is hot or cold.

My 99 SE had these misfires for over 2 years
Replaced every ignition component, including the coils and I still had the misfires.
So, After replacing ALL the injectors and repairing the wiring harness I havent had a misfire in about 2 1/2-3 yrs.

And you can try all of Aki334's mad scientist ideas,
but you are just wasting your time.
If you suspect your PCM is the trouble, then you'll have to have a dealer properly diagnos wheather it is or not, but I suspect its not bad.

Aki , I wont tell you again

Hope this clears things up!

[Aki334]

I was always a nice gay XI never looked for problems but man I have to tell you something and clear FU and your smart a.. ideas. You did not say anything different from what I said, you are not smart enough to understand my ideas and toughts. Maybe you should invent your own spark plugs and scanners, and why are you suggesting people to go and have thier car tested at dealerships if they have people like you that is a wast of money and time. And for your information "199 degrees F is hot engine" so there is no need to ask a guy what engine hor or cold when you took these readings. Again FU and thank you for reading. OUT Aki

[BNaylor]

Time out guys. This discussion has gone into the gutter so I have closed the thread. Criticize ideas or the message and not the person. Personal attacks, name calling, and flaming will not be tolerated.