Finally got a break in our Ohio weather so I got take my GN for a ride. My O2 numbers on my scanmaster are all over the place though. Any where from 112 to 688 at idle and not consistent at all. Normal driving was all over the place too. Didn't run it at WOT, so I don't know that value. Question is, will gas stabilizer for storage do that. If it doesn't is my O2 bad? I replaced it about 9 months ago. Have about 12 passes with high octane fuel on it. Second problem was that my idle at start up after letting sit for a few minutes would go up to about 1800 rpms then come back down to normal real slowly. What would cause that. Any help would be appreciated usa
O2 Number
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If you had leaded gas in it, it may not be working correctly. On the other hand, it is supposed to range back and forth several times a second from one side of .441 to the other. It is a closed loop sysem and the o2s should be constantly adjusted.
You might clean the tb, check the iacs, and set the tps to less than .48 idling. Might be some of the airways are gummy after setting.
You might clean the tb, check the iacs, and set the tps to less than .48 idling. Might be some of the airways are gummy after setting.
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Assuming everything is working correctly, the tps and the iac control the idle. That assumes there are no vacuum leaks, etc.
Your tps setting is fine.
What are the iac counts when the engine is warm, the tranny in Park, and the AC is OFF?
Your tps setting is fine.
What are the iac counts when the engine is warm, the tranny in Park, and the AC is OFF?
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Was that in Park?
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Those are not too high...normally, a lot of us seem to aim for 15-25 these days.
You might remove the iac motor and spray carb cleaner thru the passages in the tb...both thru the iac motor hole and from the inlet side of the tb to make sure none of the air passages are clogged.
The put the iac back in...be gentle when tightening it...it needs to be snug enuf to compress the gasket but not tight enuf to crack the plastic housing inside.
Reset the iac to the 15-25 range using iac screw. Turning the screw clockwise should drop the counts. Check the iac when the engine is hot, turn the screw as required, about a half turn at a time, kill the engine and restart, verify the counts. It is important to restart to reference the ecm to the iac after each adjustment. Watch the tps, it will rise when turning the iac in. Don't let it exceed .46 at idle when the engine is running. Adjust it, if required.
If this does not sort out the idle, then it would be time to check for vacuum leaks, malfunctioning egr, maf, etc.
You might remove the iac motor and spray carb cleaner thru the passages in the tb...both thru the iac motor hole and from the inlet side of the tb to make sure none of the air passages are clogged.
The put the iac back in...be gentle when tightening it...it needs to be snug enuf to compress the gasket but not tight enuf to crack the plastic housing inside.
Reset the iac to the 15-25 range using iac screw. Turning the screw clockwise should drop the counts. Check the iac when the engine is hot, turn the screw as required, about a half turn at a time, kill the engine and restart, verify the counts. It is important to restart to reference the ecm to the iac after each adjustment. Watch the tps, it will rise when turning the iac in. Don't let it exceed .46 at idle when the engine is running. Adjust it, if required.
If this does not sort out the idle, then it would be time to check for vacuum leaks, malfunctioning egr, maf, etc.
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With 12 passes with race gas. Your O2 sensor is dead. Put in a new one then check your readings before you make any adjustments. Also try and get the BLM's in the 127-129 range at idle. As Steve said IAC's should be around 15-25 range. But make sure car is hot when you check this. This can also vary on what performance upgrades you did to your motor. My car likes 27
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oops, I ignored the high octane sentence..put an o2 sensor in there whether, or not, you have a code 13.
Like Ed said, 12 passes on leaded will kill the average sensor.
Like Ed said, 12 passes on leaded will kill the average sensor.
Steve
I pulled the IAC out last night. There was some residue in the opening but no major blocking. I cleaned it all out and the IAC itself. The passages in the TB were unobstucted and the cleaner flowed well both ways. I put it all back together and took her for a ride. After warming her up, I put her in the garage. Shut it off and restarted it. My IAC count was 24-27. Mostly above the 25 range. Where is the IAC adjustment screw? I looked around the housing and TB but didn't see an adjusting screw. TPS stayed at .42 also. On a side note, did you take your El Camino to Buick Raceday at Norwalk Race Park in Ohio last year. I remember seeing one there. Thanks for your help and let me know.
I pulled the IAC out last night. There was some residue in the opening but no major blocking. I cleaned it all out and the IAC itself. The passages in the TB were unobstucted and the cleaner flowed well both ways. I put it all back together and took her for a ride. After warming her up, I put her in the garage. Shut it off and restarted it. My IAC count was 24-27. Mostly above the 25 range. Where is the IAC adjustment screw? I looked around the housing and TB but didn't see an adjusting screw. TPS stayed at .42 also. On a side note, did you take your El Camino to Buick Raceday at Norwalk Race Park in Ohio last year. I remember seeing one there. Thanks for your help and let me know.
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I think that is close enuf. But, the iac is on the tb...looks like a tb adjust screw altho that is not the purpose. the head is covered by a plastic cap from the factor. On the driver's side side of the tb with the screw tip aimed toward the radiator and contacting the throttleblade lever at the top.
I always forget about the o2 sensor as I run MaxEffort chips which does not use the o2 input. Good idea to pop a new one in.
I always forget about the o2 sensor as I run MaxEffort chips which does not use the o2 input.
Good idea to pop a new one in.1 - 16 of 16 Posts
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