Please take a look at the following Scan Data and Tell me what you think?

[LeeS97Z28]

Hi Guys!

I used a actron scanner that we sell at Autozone where I work to read live data on my car!
Shortterm fuel left was 131-145
Shortterm fuel right was 133-145

Longterm fuel (right) 160
Longterm fuel (left) 160

O2 sensors were changing but they were like stoping at a certain number then moving on.

Map sensor Volts 1.06 at idle
Throttle Position sensor volts .65 at idle
Engine coolant tem. was 182
Knock was 0
Mass Airflow was 5grams
IAT was 125
Spark advance was 25

No codes stored

I wonder if it could be those O2 sensors?

What if I had a whole drilled and new O2 bings welded in the exhaust pipe pipes to replace the O2 sensors that are in the exhaust manifolds.

I am scared to death that these will either strip out or break. Do you think this would work or should I just trying and get the O2 sensors out of their stock wholes?

Let me know! Thanks Lee!

[Craig 94 TA GT]

What concerns me is that your BLMs are at 160/160. This means your PCM is trying to compensate for a lean condition. Do you know what cell your long terms were read?
In my opinion, you either have some kind of leak after the MAF, you have bad O2s, or you have an exhaust leak that's causing your O2s to think it's running lean and trying to compensate by richening the mixture.
I'm not sure about replacing/removing your O2s because you have them in different locations than my '94. I'm sure someone here will answer those questions.

[LeeS97Z28]

Craig 94 TA GT, the Cell the Longterm fuel was read from was 16

Thanks Lee!

[Joe 1320]

Here's the deal..... Ideally the car should be tuned so that the BLMs are at 128, this gives the computer the widest range of adjustment from both rich to lean . Ultimately the computer adjusts and the BLM figure gives you an idea of what the computer is doing to the fuel curve. When you were doing work, was any part of the exhaust system opened up? If there is an exhaust leak prior to the 02 sensor, the computer see the additional oxygen and interprets it as being lean. Therefore, it adds fuel to compensate. At this point you are technically very rich but the computer doesn't see that. It can only compensate for what it sees. Both your long term and short term fuel corrections are above 128. The other possible scenerio is ignition breakup. When a cylinder misfires or doesn't completely burn, the extra oxygen in the exhaust event is picked up by the 02 sensor and the computer interprets that as lean. It doesn't detect fuel, it detects oxygen. Guess what happens....... yep. More fuel is added to compensate. All this can happen without throwing a code. If it gets bad enough it eventually will, but often times won't trigger the code until it is way past what a motorhead would have already noticed.

I can't tell you for sure, but the first place I would look over is the ignition. I've seen goofy things like the metal boot shields on the spark plug end of the wires installed backwards and creating an ignition miss, I've seen misaligned IC module pins cause an intermittant miss (no codes on that one either) Faulty coil, bad wires, plugs, heat soaked coil and module, the list goes on and on. Oxygen sensors that start going bad begin to behave slowly. Fresh ones should be changing values at idle so quickly that following it would be next to impossible. If you see them operating lazy, that may be an issue.

Not that I suspect a thing, but did you check fuel pressure?

[Injuneer]

All the data indicates it was logged at closed throttle idle, so it would have been in Cell 16.

MAP is a shade low..... I would expect comething over 1.1V (~8.9"HG). Engine appears to have excellent vacuum, so that sort of shoots the vacuum leak theory down.

TPS volts are normal. MAF looks a little low.... maybe a leak between the MAF and the throttle body. That would elevate the BLM's, since the MAF would not be reporting the full air flow, the PCM would not be adding enough fuel because is doesn't "see" all the air actually entering the engine, and the resulting lean mixture would require the BLM's to increase. But the increase in BLM's looks worse that the small under reporting of the MAF (data I've seen is typically in the 6-9gps range.

What is your idle speed.... the timing appears to be a shade high.

Check the O2's.... its something that is affecting both sides of the engine... bad MAF reading, wrong MAP data, too low a fuel pressure, large air leak, possibly before the TB, bad wiring on the O2's, an air leak at both O2's, etc.

[Kevin - Blown 95 TA]

You might be able to probe around with some propane and see if you got any leaks around the intake tract or manifold (are the bolts tight?). Like Fred says - it's affecting both sides of the engine. like a torn elbow would do. Also check the PVC hoses & all the little hoses coming off the throttle body for cracks & rot to make sure air isn't getting in there. I forget if you did anything with the EGR, but check that that isn't rotted out, convoluted tube cracked, or diaphragm punctured and sucking in air somehow to the intake or exhaust.

[LeeS97Z28]

Update! Update! Update!

Hey Guys!

I checked the Air Check Valves both with the airpump on and off.

I found that the pipe that goes to the airpump still sucks air into the exhaust manifold even after the airpump stops is the normal or not?
Would this cause my problem?

Thanks Lee! Sorry to bother you guys!

[Injuneer]

Are you saying that there is air flow into both of the check valves at the exhaust manifolds? That would certainly screw things up and contribute to the 160 BLM's. The air goes into the exhaust, the O2 sensors "see" it and think its running lean, the PCM adds fuel the engine doesn't need. Runs pig rich.

A leak in the exhaust before the O2 sensors always caused problems.

[LeeS97Z28]

Another Update! Another Update!

Well Guys!

I took both rubber lines off the Air Check Valves and it sounded like two kids sucking on lolie pops.

I blocked them both off and it didn't make my car idle any better. It did make the BLM left (145) and BLM right (143).

Do you think it is the O2 sensors now?

I looked at the IAC counts and It was 0 while idling until I turned on the AC then it went to only 4.

What do you think?

Thanks Lee!

[Injuneer]

Could be the engine is getting the air it needs to idle from some other source, if it isn't going through the IAC passages. If its air that's not being measured by the MAF, that would also contribute to the high long term fuel values.

[Joe 1320]

Seeing how the IAC is directly responsible for metering additional air into the engine when teh throttle blades are closed, you might try the IAC reset proceedure. Not only that you might want to try spraying either starting fuild or propane around the external lines and around the TB to see if it affects the engine. Any vacuum leak will draw the combustable substance into the engine and a difference in engine rpm will be noted. Obviously the stuff is flammable so common sense should be used, ie no smoking. Even the thottle shaft could be worn, causing a leak.

[LeeS97Z28]

Another Update! Another Update!

Well Guys!

I feel much better and have much better news.

I have changed both O2 sensors and Thank God! THe studder and irratic idle is gone. It is 100% smoother. The BLM's are still BLM (left) 145 BLM right (141).

The popping and surging is gone.

Do you think the Air check Valves sucking in air could be responsible for the still High BLM's ?

They are sucking in a lot of air. I don't see how they do it but they do.

Thanks Lee!

[Injuneer]

As the exhaust gasses pass the port for the AIR connections, it lowers the pressure in the connection... its called "eduction", or the Bernoulli principle. The air goes into the exhaust, the O2 sensors see the excess air and scream "LEAN" and the PCM raises the BLM's to add extra fuel the engine doesn't need. The check valves should seal well enough to prevent that.

Misfires have the same affect.

[Kevin - Blown 95 TA]

Well Guys!

I feel much better and have much better news.

I have changed both O2 sensors and Thank God! THe studder and irratic idle is gone. It is 100% smoother. The BLM's are still BLM (left) 145 BLM right (141).

The popping and surging is gone.

Do you think the Air check Valves sucking in air could be responsible for the still High BLM's ?

They are sucking in a lot of air. I don't see how they do it but they do.

Thanks Lee!

Hook all that AIR back up and block the intake to the air pump and see if it changes the BLMs. Those check valves are known to go bad, just from plain heat over time. I had one go bad and burn right thru the rubber hose and exhaust was coming out the hole.