Sudden loss of boost

[TurboBuRick]

A couple things come to mind. The waste gate dumping the boost is not one.

Intake air or fuel is being choked. Turbo abruptly stops spinning.

Post a log file when you get it.

 

[MCH86GN]

A couple things come to mind. The waste gate dumping the boost is not one.

Intake air or fuel is being choked. Turbo abruptly stops spinning.

Post a log file when you get it.

Of all days to get sick, the weekend. Unfortunately I didn't get out of bed. Hopefully I will be able to post acquire data during the evenings this week.

 

[MCH86GN]

Well, I got a couple of logs and it appears that the boost level might not be dropping instantaneously.
If you have PL take a look and see what you think. Attached are 2 files. The only thing I notice is that my AFR seems to be stuck at 12.8, when it is supposed to be 10.8 above 13PSI.

I'm also going to get Eric's input.

 

[MCH86GN]

A couple things come to mind. The waste gate dumping the boost is not one.

Intake air or fuel is being choked. Turbo abruptly stops spinning.

Post a log file when you get it.

Posted log file.

 

[MCH86GN]

I don't believe this is applicable, but when the ambient temp's would get into the 40's, my alchy would blow out the wick and the car would fall on it's face. Could you be putting too much alchy through it?

Posted log file, if you're interested.

 

[MCH86GN]

Well, I got a couple of logs and it appears that the boost level might not be dropping instantaneously.
If you have PL take a look and see what you think. Attached are 2 files. The only thing I notice is that my AFR seems to be stuck at 12.8, when it is supposed to be 10.8 above 13PSI.

I'm also going to get Eric's input.

I just started running a volt booster last year, I wonder if I'm pumping to much alky?

 

[MCH86GN]

This is another PL file when I wasn't having this issue. One of the things I notice is IPW vs IDC for street_driving vs boost_drop. In boost drop IPW is 20ms vs 12ms for street driving.

 

[SHADOWII]

At 20 or 25psi it will drop to zero and you hear a loud pssshhh. .

Do you suspect the loud psh to be the boosted air or exhaust escaping? Like the early stages of a cracked header? I was running a TE-60 @ 28# and the max boost started falling off, 25, 23 etc. The ambient tps were above a 100* so attributed the loss to the humid air. But a big boom and buzzing sound revealed the true nature of the problem.

 

[Eric Stage I]

I would replace the wideband O2 sensor and go from there. Looks to me like it might be dying. That will cause the correction to add a bunch of fuel, and could cause it to fall on its face.

 

[MCH86GN]

I would replace the wideband O2 sensor and go from there. Looks to me like it might be dying. That will cause the correction to add a bunch of fuel, and could cause it to fall on its face.

Ok. The WB02 is 4 years old, what is the life span?

 

[MCH86GN]

Do you suspect the loud psh to be the boosted air or exhaust escaping? Like the early stages of a cracked header? I was running a TE-60 @ 28# and the max boost started falling off, 25, 23 etc. The ambient tps were above a 100* so attributed the loss to the humid air. But a big boom and buzzing sound revealed the true nature of the problem.

It is boosted air. I have had an issue where exhaust was escaping before and I would build to 25PSI and then slowly lose boost. In a 1/4 mile run I would build 25PSI and trap somewhere around 17 to 18 PSI. My crossover pipe had loosened up.

 

[MCH86GN]

I would replace the wideband O2 sensor and go from there. Looks to me like it might be dying. That will cause the correction to add a bunch of fuel, and could cause it to fall on its face.

Eric, one other thing is there anyway to diagnose if the WBO2 going bad? Because I don't want to start swapping components in hopes of finding a solution. One other thing to note, I'm running a volt booster which I wasn't previously and I upgrading from a stock IC to a Precision SLIC. However, the car has ran fine with the new Precision IC. Here are some comparisons. The shows AFR, which should be leaner at 12.5 than 10.62 and clearly it isn't.

Boost drop issue IPW = 18.04ms and IDC = 60.2 and boost at 19.9PSI AFR = 12.5

Normal driving, with no issue IPW = 13ms, IDC =47.9 and boost @ 19.9PSI AFR = 10.62

Also I did set an error code 51, but I'm not sure if this was the cause because it was intermittent and but it happened during a run that I wasn't recording. I had to pull my ECM out of its normal location in order to plug in my USB cable, when I try and do it with the ECM mounted it causes all kinds of codes to get set, the PL appears to not be connected. Would that cause and fault 51 to set? I do plan on notching the plastic case for the ECM so I can plug USB such that it doesn't exert any force on the PL board. Before I mount my ECM back in its normal location, I'm going to check and make sure the 6.0 TT chip is plugged into the socket correctly.

 

[Eric Stage I]

Ok. The WB02 is 4 years old, what is the life span?

It varies a lot with conditions. But if you are using it to control fueling on your engine, you should consider changing it often. I usually change mine once a year. It should be considered a disposable item, like spark plugs.
I diagnose it by noticing if the injector dc is higher than normal, but the AFR is not reflecting that (like you've noticed), and the fuel pressure is good. When an O2 sensor starts to become contaminated, it is harder for them to read further away from stoich.

In your case, you could turn off wideband correction and tune using the stock O2. See if the problem goes away.

 

[MCH86GN]

It varies a lot with conditions. But if you are using it to control fueling on your engine, you should consider changing it often. I usually change mine once a year. It should be considered a disposable item, like spark plugs.
I diagnose it by noticing if the injector dc is higher than normal, but the AFR is not reflecting that (like you've noticed), and the fuel pressure is good. When an O2 sensor starts to become contaminated, it is harder for them to read further away from stoich.

In your case, you could turn off wideband correction and tune using the stock O2. See if the problem goes away.

One thing I forgot to mention is the FRP goes to 60PSI at 19PSI of boost, best I can tell. Fuel pump was replaced last year when it was exhibiting the same symptoms. I would have to tune again if I turn off the WBO2? How do you turn off the WBO2 correction? Do you just set the WBO2 in cell one and two to 9.9?

 

[MCH86GN]

It varies a lot with conditions. But if you are using it to control fueling on your engine, you should consider changing it often. I usually change mine once a year. It should be considered a disposable item, like spark plugs.
I diagnose it by noticing if the injector dc is higher than normal, but the AFR is not reflecting that (like you've noticed), and the fuel pressure is good. When an O2 sensor starts to become contaminated, it is harder for them to read further away from stoich.

In your case, you could turn off wideband correction and tune using the stock O2. See if the problem goes away.

Eric, one more question. What WBO2 combo do you sell? AEM Inline or AEM gauge 0/5? On the PL screen I have always had AEM Inline selected.

I assume it is the AEM Inline. What is the part number for the replacement UEGO sensor?

 

[Eric Stage I]

Correct, set param 1 and 2 to 99 to turn off wideband correction (param 3 should already be a 99) with the 6.0 and 6.1 chip.

I used to sell both the Inline and gauge type. The replacement sensor for either one is AEM 30-2001. You can get them from summit racing or other places.

 

[MCH86GN]

Correct, set param 1 and 2 to 99 to turn off wideband correction (param 3 should already be a 99) with the 6.0 and 6.1 chip.

I used to sell both the Inline and gauge type. The replacement sensor for either one is AEM 30-2001. You can get them from summit racing or other places.

Thanks.

 

[MCH86GN]

Correct, set param 1 and 2 to 99 to turn off wideband correction (param 3 should already be a 99) with the 6.0 and 6.1 chip.

I used to sell both the Inline and gauge type. The replacement sensor for either one is AEM 30-2001. You can get them from summit racing or other places.

Eric, that appeared to fix the issue. Turned off WB CL correction and I went with the base values and I hit 20PSI for as long as I elected to keep my foot on the peddle. I got two runs in, the second was awesome. Car took off like a bat out of hell. Unfortunately I didn't record the second run and I couldn't do a third because this was a public road that doesn't have night traffic, but a person seen me launching and hauling ass, so I got out of there. Anyway, I'll upload the first run and everything looks good. I'm still going to replace the WBO2.
Furthermore it is nice to isolate an issue and not start replacing a bunch of parts. PL helped save the day.

 

[MCH86GN]

Correct, set param 1 and 2 to 99 to turn off wideband correction (param 3 should already be a 99) with the 6.0 and 6.1 chip.

I used to sell both the Inline and gauge type. The replacement sensor for either one is AEM 30-2001. You can get them from summit racing or other places.

Ordered the replacement sensor off Amazon. Free shipping. If it doesn't work, I can return it and continue to manually tune.