Code 55 Lean Condition at WOT - ZR-1 Net Registry Forums

XfireZ51 · 06-24-2008

Took the car out after installing the new NGKs. Part throttle is very nice and idle is much smoother. Trying a blast at WOT, I got an SES which was a Code 55. This was a hard code which didn't drop with driving as it had done previously. I went out once again, this time with the scantool. Here's the part of the scan where the Code 55 was set. It happened at the top of the rpm band. I've checked FP and that seems to check out. Also, secondary port throttle is not the cause here.
Any observations are welcome.

-=Jeff=- · 06-24-2008

Swap back to your old plugs that you just removed and see fi the Lean condition goes away..

XfireZ51 · 06-24-2008

Jeff,

I'm going to take the NGKs and re-gap them to .035-.040, but looking at the scan, something causes the injectors to drop PW. At the same time, the timing goes to 14.1d. My theory is that something happened to cause the injectors to drop PW which then caused the Lean condition with the code 55. This all happened at a point on the rpm range where the Fuel Kill was set, 7175rpm. Just a thought.

-=Jeff=- · 06-24-2008

so set the Fuel kill to 7225.. see if that helps too.. but worst case, go back to the old plugs cause at WOT you had no issues

XfireZ51 · 06-24-2008

Quote:

Originally Posted by -=Jeff=-

so set the Fuel kill to 7225.. see if that helps too.. but worst case, go back to the old plugs cause at WOT you had no issues

I have a new cal that I'll load into Ostrich when I get back. I've raised Fuel Kill to 7400rpm. And I'll re-gap plugs to .040".

Aurora40 · 06-24-2008

Why does your speed drop from 90mph to 77mph within one frame? It seems weird the line you highlighted as the code setting, because that's when the throttle is closed. Or does that hightlighted line not really signify that?

I can't tell if that one column is R O2 volts, but maybe it is, looks like it goes from .9ish to < .1ish That would certainly seem to indicate a lean condition.

FWIW, I've tapped the limiter several times in my car and it's never set a lean code.

XfireZ51 · 06-24-2008

A40,

The Vehicle Speed is in kph. But its still a drop of 8mph or so during an upshift. I was fighting the ASR also. Didn't turn that off which I should have. I wouldn't think Fuel Kill would cause a lean condition but right now looking at all options.

tpepmeie · 06-24-2008

Dom,
pulse widths are in cols. Q & V. Your secondary injectors shut off, it looks like to me.

What does your PT Closed spark advance look like? About 20d at high RPM & Load (14.1+6)? Notice also the pulsewidths have obviously changed after the shift to the PT Closed map, as they never recover to the 23ms range as before the shift.

Todd

XfireZ51 · 06-24-2008

Todd,

Exactly. Actually, Closed Throttle SA is set to 16. My suspicion is that the injectors shutdown because of the DRPs. With the injectors shutdown, I got a code 55 which closed the Port Throttle. Question is what happened to the timing there? Car runs fine otherwise. Thanks for your help. Maybe there's something in the logic you could find.

tpepmeie · 06-24-2008

Quote:

Originally Posted by XfireZ51

Todd,

Exactly. Actually, Closed Throttle SA is set to 16.

No, what I mean is what is the spark advance in your Port Throttle Closed SA table, above 5000 rpm, 100KPA? I suspect it is around 20d. When the secondaries shut off, the ECM switched to that SA table.

What have you done with the secondary vacuum sensor? If I remember, you have removed the port throttles. Any other mechanical modifications to the port throttle system?

Quote:

Originally Posted by XfireZ51

My suspicion is that the injectors shutdown because of the DRPs.

Not following you on this one. What do you mean?

Todd

06-24-2008	#1
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Code 55 Lean Condition at WOT Took the car out after installing the new NGKs. Part throttle is very nice and idle is much smoother. Trying a blast at WOT, I got an SES which was a Code 55. This was a hard code which didn't drop with driving as it had done previously. I went out once again, this time with the scantool. Here's the part of the scan where the Code 55 was set. It happened at the top of the rpm band. I've checked FP and that seems to check out. Also, secondary port throttle is not the cause here. Any observations are welcome.

06-24-2008	#2
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,169	Re: Code 55 Lean Condition at WOT Swap back to your old plugs that you just removed and see fi the Lean condition goes away.. __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

06-24-2008	#3
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: Code 55 Lean Condition at WOT Jeff, I'm going to take the NGKs and re-gap them to .035-.040, but looking at the scan, something causes the injectors to drop PW. At the same time, the timing goes to 14.1d. My theory is that something happened to cause the injectors to drop PW which then caused the Lean condition with the code 55. This all happened at a point on the rpm range where the Fuel Kill was set, 7175rpm. Just a thought.

06-24-2008	#4
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,169	Re: Code 55 Lean Condition at WOT so set the Fuel kill to 7225.. see if that helps too.. but worst case, go back to the old plugs cause at WOT you had no issues __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

06-24-2008	#6
Aurora40 Join Date: May 2005 Location: Leesburg, VA Posts: 2,713	Re: Code 55 Lean Condition at WOT Why does your speed drop from 90mph to 77mph within one frame? It seems weird the line you highlighted as the code setting, because that's when the throttle is closed. Or does that hightlighted line not really signify that? I can't tell if that one column is R O2 volts, but maybe it is, looks like it goes from .9ish to < .1ish That would certainly seem to indicate a lean condition. FWIW, I've tapped the limiter several times in my car and it's never set a lean code. __________________ Bob Saveland Former owner of #2517 [IMG]http://a.random-image.net/aurora40/vette.jpg[/img]

06-24-2008	#7
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: Code 55 Lean Condition at WOT A40, The Vehicle Speed is in kph. But its still a drop of 8mph or so during an upshift. I was fighting the ASR also. Didn't turn that off which I should have. I wouldn't think Fuel Kill would cause a lean condition but right now looking at all options.

06-24-2008	#8
tpepmeie Join Date: Aug 2005 Location: Fishers, IN Posts: 815	Re: Code 55 Lean Condition at WOT Dom, pulse widths are in cols. Q & V. Your secondary injectors shut off, it looks like to me. What does your PT Closed spark advance look like? About 20d at high RPM & Load (14.1+6)? Notice also the pulsewidths have obviously changed after the shift to the PT Closed map, as they never recover to the 23ms range as before the shift. Todd

06-24-2008	#9
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: Code 55 Lean Condition at WOT Todd, Exactly. Actually, Closed Throttle SA is set to 16. My suspicion is that the injectors shutdown because of the DRPs. With the injectors shutdown, I got a code 55 which closed the Port Throttle. Question is what happened to the timing there? Car runs fine otherwise. Thanks for your help. Maybe there's something in the logic you could find.