Tuning information.

[Jsup]

Here's what I'm doing....just for the hell of it.

Like I said, I want to see if my O2 sensor is operating correctly. Therefore, I am going to add an O2 bung on the driver's side, for a total of 3 in the car. One in each collector and a third one on the driver's side right behind the one in the collector.

This new bung will hold a wideband O2. So I will have 2 wide bands, one on each side of the motor AND the heated stock unit.

I'm going to run the car to see if the stock unit is sending the ECU the correct information and get a feel as to where I stand.

My goal is to see if there is a discrepancy between the stock O2 and the wideband. If there isn't, then I have to see if there is a discrepancy between the two widebands.

I want to have an idea of where I sit and see if I have a good starting point.

 

[Jsup]

I'm back...I went to TTP performance, worked with Matt and his guys, they were fantastic. Matt told me "I've never seen him so excited doing a dyno pull"...talking about my car. He strapped it down with four straps in back, he usually uses two. The car walked sideways on the dyno, he really enjoyed that. He said to me when I left "that's one sick C4"...they do a ton of C5/6 work there. It was a good afternoon.

here's some of the results. The RED LED AFR meter is on the passenger side, the one on the dyno screen is on the drivers side. To recap, the wideband I was using was on the passenger side, and it was reading lean. Yet the ECU was trying to pull fuel out.

You can see the passenger side is lean, and after we hit 4500 RMPs, it goes very rich. down to 10.0, which is as low as the meters will read.

Following is some pictures of the two side by side.

 

[Bullshark]

Would have been interesting to swap sides with the wideband O2's A/F systems to see if the A/F readings tracked with the sensors or stayed with the sides. Is the red LED O2 A/F system an Innovation LC or LM-1? If it is truly reading biased lean, you might have to do a little troubleshooting. Make sure the power and signal grounds are clean and hooked up optimally. Solid 12v power?? Also trade O2 sensors between A/F meters to see if reading track with the sensor itself. I Assume you did a free air calibration. You will have to do it again if you swap sensors.

Is the output slope setup compatible with the meter? Just thinking out loud here.

Bullshark

 

[Jsup]

Would have been interesting to swap sides with the wideband O2's A/F systems to see if the A/F readings tracked with the sensors or stayed with the sides. Is the red LED O2 A/F system an Innovation LC or LM-1? If it is truly reading biased lean, you might have to do a little troubleshooting. Make sure the power and signal grounds are clean and hooked up optimally. Solid 12v power?? Also trade O2 sensors between A/F meters to see if reading track with the sensor itself. I Assume you did a free air calibration. You will have to do it again if you swap sensors.

Is the output slope setup compatible with the meter? Just thinking out loud here.

Bullshark

The red gauge is a second WB I had on that side. The first one was a completely different WB. They read the same. That's two separate and independent WBs reading the same on the passenger side.

The one on the dyno screen was on the drivers side. It is consistent with what the stock narrow band is doing with the ECU.

What I find confusing about this is that it is batch fire if there were a delta, shouldn't it be seen at every RPM range all the way up to some extent.

 

[Jsup]

I pulled the plugs, here's what I found, they all look about the same:

 

[BBShark]

SpellCheck Jesus:

I'm confused. The red LED meter is the A/F of the WB on the passenger side, the screen A/F is the WB on the driver side. Is that right?

 

[Jsup]

SpellCheck Jesus:

I'm confused. The red LED meter is the A/F of the WB on the passenger side, the screen A/F is the WB on the driver side. Is that right?

That is correct.

Today I pulled the valve cover on the passenger side just to see how the valve adjustment was, looked good.

I also switched the 4 injectors from the passenger side to the driver's side to see if the problem moves.

I pulled out the Iridium plugs as you see above, I'm going to replace them two heat ranges down, they are "5" heat range on the current plugs, I'm going to 7 at least.

I couldn't buy plugs today, everything is closed here on Sunday.

If it still pops, I'm going to pull 2 degrees of timing out in that range.

What do you think?

 

[Bullshark]

SpellCheck Jesus:

I'm confused. The red LED meter is the A/F of the WB on the passenger side, the screen A/F is the WB on the driver side. Is that right?

That is correct.

If it still pops, I'm going to pull 2 degrees of timing out in that range.

What do you think?

Glad to see I'm not the only one confused hereh:
Jsup, If I understand things correctly now, you have two WB A/F meters on the passenger side. One is the red led meter in the pics and another one, which is not shown, but tracks the red meter very close? Is that correct? the WB on the driver side is displayed on the monitor screen and reads biased rich. With two completely separate meters reading almost identical on the passenger side, I would say odds are good that you have an accurate reading on that side. The driver side may be in question? That is why I was suggesting moving one of the passenger side WBs over to do a sanity check.
Assuming accurate readings on both sides, there are numerous reasons why there is an imbalance side to side. Possible injector problem, like you are presently chasing, Air flow to the sides may be different for some reason. Partially blocked exhaust, stuck heat riser, Poor intake flow due to turbulence? Valve openings, etc. etc. Now the witch hunt starts

Off the cuff I would think timing would effect both sides equally

Bullshark

 

[Jsup]

SpellCheck Jesus:

I'm confused. The red LED meter is the A/F of the WB on the passenger side, the screen A/F is the WB on the driver side. Is that right?

That is correct.

If it still pops, I'm going to pull 2 degrees of timing out in that range.

What do you think?

Glad to see I'm not the only one confused hereh:
Jsup, If I understand things correctly now, you have two WB A/F meters on the passenger side. One is the red led meter in the pics and another one, which is not shown, but tracks the red meter very close? Is that correct? the WB on the driver side is displayed on the monitor screen and reads biased rich. With two completely separate meters reading almost identical on the passenger side, I would say odds are good that you have an accurate reading on that side. The driver side may be in question? That is why I was suggesting moving one of the passenger side WBs over to do a sanity check.
Assuming accurate readings on both sides, there are numerous reasons why there is an imbalance side to side. Possible injector problem, like you are presently chasing, Air flow to the sides may be different for some reason. Partially blocked exhaust, stuck heat riser, Poor intake flow due to turbulence? Valve openings, etc. etc. Now the witch hunt starts

Off the cuff I would think timing would effect both sides equally

Bullshark

For sake of clarity:

Passenger side: one wideband at a time. One during tuing. One on the dyno. Both tracked closely based on my notes. Never two in there at the same time. The passenger side is the one with the red LED display shown above.

Driver's side: One narrowband, heated. One Wideband. The wideband is the on the screen. The wideband and the stock O2 sensor were in at the same time, and the narrowband was doing exactly what the wideband was showing.

Does that help?

I am going to cooler plugs and I'm going to lower the fuel pressure, as I discussed with TPIS.

 

[Bullshark]

Ahh Haa!! said the blind man. Now I see. :lol:

FWIW, I would focus on trying to understand the difference between right and left bank A/F readings. Which sounds like what you are doing! A reading of 2-3 difference is not insignificant. You probably have enough data to convince yourself of what truth is. Have you installed one of the passenger side WB meters on the drivers side yet? Just to validate those readings?

I am not understanding how changing timing, cooler plugs, and or fuel pressure might help diagnose the imbalance.

If your readings are accurate, lowering the fuel pressure will change the fuel map across the board and make the passenger side even leaner in those other map areas....correct?.....which is already too lean for comfort. Why change plug range at this time? I would think that would only be a very minor adjustment to the whole equation.

Bullshark

 

[big_G]

Ahh Haa!! said the blind man. Now I see. :lol:

FWIW, I would focus on trying to understand the difference between right and left bank A/F readings. Which sounds like what you are doing! A reading of 2-3 difference is not insignificant. You probably have enough data to convince yourself of what truth is. Have you installed one of the passenger side WB meters on the drivers side yet? Just to validate those readings?

I am not understanding how changing timing, cooler plugs, and or fuel pressure might help diagnose the imbalance.

If your readings are accurate, lowering the fuel pressure will change the fuel map across the board and make the passenger side even leaner in those other map areas....correct?.....which is already too lean for comfort. Why change plug range at this time? I would think that would only be a very minor adjustment to the whole equation.

Bullshark

I agree. F/I is complicated enough...why make more changes until you find the reason 1 bank is leaner than the other. Don't overlook vacuum or exhaust leaks. Even small ones can throw off the O2 data.

 

[Bullshark]

Ahh Haa!! said the blind man. Now I see. :lol:

FWIW, I would focus on trying to understand the difference between right and left bank A/F readings. Which sounds like what you are doing! A reading of 2-3 difference is not insignificant. You probably have enough data to convince yourself of what truth is. Have you installed one of the passenger side WB meters on the drivers side yet? Just to validate those readings?

I am not understanding how changing timing, cooler plugs, and or fuel pressure might help diagnose the imbalance.

If your readings are accurate, lowering the fuel pressure will change the fuel map across the board and make the passenger side even leaner in those other map areas....correct?.....which is already too lean for comfort. Why change plug range at this time? I would think that would only be a very minor adjustment to the whole equation.

Bullshark

I agree. F/I is complicated enough...why make more changes until you find the reason 1 bank is leaner than the other. Don't overlook vacuum or exhaust leaks. Even small ones can throw off the O2 data.

Yep, probably the most probable!

 

[Jsup]

Ahh Haa!! said the blind man. Now I see. :lol:

FWIW, I would focus on trying to understand the difference between right and left bank A/F readings. Which sounds like what you are doing! A reading of 2-3 difference is not insignificant. You probably have enough data to convince yourself of what truth is. Have you installed one of the passenger side WB meters on the drivers side yet? Just to validate those readings?

I am not understanding how changing timing, cooler plugs, and or fuel pressure might help diagnose the imbalance.

If your readings are accurate, lowering the fuel pressure will change the fuel map across the board and make the passenger side even leaner in those other map areas....correct?.....which is already too lean for comfort. Why change plug range at this time? I would think that would only be a very minor adjustment to the whole equation.

Bullshark

The only reason I'm changing the plugs now is because the ones that were in there look a little hot, very slightly, and since I have them out, no point in doing the work twice. Won't hurt anything.

It's only on light throttle I get this problem. The FP is at 55, TPIS recommended lowering it.

 

[big2bird]

I may get flamed for this, but ditch the irridium plugs. They are designed for high milage/hard to change modern powerplants, and actually do not perform as well as plain old plugs in these old engines. My source on this I trust. Lars.

 

[Jsup]

I may get flamed for this, but ditch the irridium plugs. They are designed for high milage/hard to change modern powerplants, and actually do not perform as well as plain old plugs in these old engines. My source on this I trust. Lars.

I already did. The Iridium plugs are gone....I went to standard NGK V Power copper core.

I heard the same thing about Iridium, I went one heat range cooler.

I'm hoping to get some time tonight to put them in and fire it up.

I got the Iridium plugs because they were on sale when I walked in the store, no other reason.