Open Loop operation on a 98
Thread Starter
Staging Lane
Joined: Feb 2002
Posts: 83
Likes: 0
From: Knoxville TN
Open Loop operation on a 98 does the 98 ls1 pcm not go into Open Loop operation when WOT?
mine says it stays in closed loop...and the fuel cell changes to 15 sometimes during WOT but does not stay there and goes back to the normal Fuel cell for WOT....
Is this normal? i have no codes, TP shows 100%
does it affect performance not going into open loop if it is suppose to?
it also stays in closed loop when the motor is on decel... <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Every car i have checked goes into open loop under these two circumstances....however i don't believe that i have ever looked at another 98..
Thanks for any help!
mine says it stays in closed loop...and the fuel cell changes to 15 sometimes during WOT but does not stay there and goes back to the normal Fuel cell for WOT....
Is this normal? i have no codes, TP shows 100%
does it affect performance not going into open loop if it is suppose to?
it also stays in closed loop when the motor is on decel... <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Every car i have checked goes into open loop under these two circumstances....however i don't believe that i have ever looked at another 98..
Thanks for any help!
Re: Open Loop operation on a 98 Fuel cell 15 is WOT on a cold engine. Is the cooling system stock?
Anyhoo, no LS1 with the exception of a handful go into absolute Open Loop control on WOT. It is kind of a sudo-open loop in which the MAF is still referenced amongst a few other perameters to determing proper fueling.
Pure open loop control would be volumetric referencing and could only be done if you disconnected your MAF (amongst other things), set aside a good week on the dyno, and went to town on your cankcase volumetric efficiency eqations.
Anyhoo, no LS1 with the exception of a handful go into absolute Open Loop control on WOT. It is kind of a sudo-open loop in which the MAF is still referenced amongst a few other perameters to determing proper fueling.
Pure open loop control would be volumetric referencing and could only be done if you disconnected your MAF (amongst other things), set aside a good week on the dyno, and went to town on your cankcase volumetric efficiency eqations.
Thread Starter
Staging Lane
Joined: Feb 2002
Posts: 83
Likes: 0
From: Knoxville TN
Re: Open Loop operation on a 98 the car has a 160 stat...shows coolant temps at around 180 during the logging.
by open loop...i just mean the status that the efilive software says the car is in at WOT
the car switched between cell 15 and 22 2 or 3 times during a one gear pull
everytime the car goes into cell 15, it puts the ltrims at +5....in 22 they are 0
by open loop...i just mean the status that the efilive software says the car is in at WOT
the car switched between cell 15 and 22 2 or 3 times during a one gear pull
everytime the car goes into cell 15, it puts the ltrims at +5....in 22 they are 0
Re: Open Loop operation on a 98 Not an expert in the Fuel Cell stuff (never really pay attention to them honestly), but I am almost sure that 15 is WOT on a cold engine, and 22 is WOT on a normal operating engine. I don't know why it is switching between the two.
If your LTerms are flat-lining, your O2's are not switching, and your timing has dropped to sub 30's, dollars-to-donuts, you are in WOT control. I have never used EFI-Live, although I have drooled over the screen shots (I am a stoneage a-tap man myself) but are you sure openloop means WOT openloop. Or is the EFI-Live open/close loop indicator for startup and monitoring whether or not the car comes out of open loop soon enough?(if not it will set an SES)
<small>[ October 21, 2002, 08:13 PM: Message edited by: NoGo ]</small>
If your LTerms are flat-lining, your O2's are not switching, and your timing has dropped to sub 30's, dollars-to-donuts, you are in WOT control. I have never used EFI-Live, although I have drooled over the screen shots (I am a stoneage a-tap man myself) but are you sure openloop means WOT openloop. Or is the EFI-Live open/close loop indicator for startup and monitoring whether or not the car comes out of open loop soon enough?(if not it will set an SES)
<small>[ October 21, 2002, 08:13 PM: Message edited by: NoGo ]</small>
Thread Starter
Staging Lane
Joined: Feb 2002
Posts: 83
Likes: 0
From: Knoxville TN
Re: Open Loop operation on a 98 here is a link to a sreen shot from EFILIVE....showing all the info
notice that once the car is reving above 5k, the Fuel cell keeps switching between 15 and 22
there is one 2nd gear pull in that jumbled mess that you can see everything important...
thanks for the replies so far!
<img src="http://www.highperformancetoys.com/efisample.jpg" alt=" - " />
notice that once the car is reving above 5k, the Fuel cell keeps switching between 15 and 22
there is one 2nd gear pull in that jumbled mess that you can see everything important...
thanks for the replies so far!
<img src="http://www.highperformancetoys.com/efisample.jpg" alt=" - " />
Re: Open Loop operation on a 98 You are right. It makes 2 very noticeable dips down to FT 15. Your LTerms/fueling increase at these points as well.
Honestly, I cannot give you a definite answer as to why your car is switching between Fuel Trims 15 and 22. My only hunch is that your COT (Catalytic overtemperature) protection is coming into play, and this somehow is kicking your Fuel Cells to 15 to induce fueling and protect the CATs. It fits the bill: COT usually comes into play above 5000 rpm, and will typically tank your a/f down to low 11's.
11.7 * .95 (+5% LTerm adjustment.....) = 11.1 a/f
This is only my speculation though.
<small>[ October 21, 2002, 10:15 PM: Message edited by: NoGo ]</small>
Honestly, I cannot give you a definite answer as to why your car is switching between Fuel Trims 15 and 22. My only hunch is that your COT (Catalytic overtemperature) protection is coming into play, and this somehow is kicking your Fuel Cells to 15 to induce fueling and protect the CATs. It fits the bill: COT usually comes into play above 5000 rpm, and will typically tank your a/f down to low 11's.
11.7 * .95 (+5% LTerm adjustment.....) = 11.1 a/f
This is only my speculation though.
<small>[ October 21, 2002, 10:15 PM: Message edited by: NoGo ]</small>
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Thread Starter
Staging Lane
Joined: Feb 2002
Posts: 83
Likes: 0
From: Knoxville TN
Re: Open Loop operation on a 98 Thanks for the help NoGo!
Anyone else care to add to this....any suggestions as to why my car is doing this?
What sets the COT? and how can you prevent it from occuring?
Anyone else care to add to this....any suggestions as to why my car is doing this?
What sets the COT? and how can you prevent it from occuring?
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TECH Regular
Joined: Feb 2002
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From: the moon
Re: Open Loop operation on a 98 if your running a ported maf this is VERY common.
Seen it MANY MANY times.
Ported mafs read less load and are very erratic.
This tricks the pcm into going in and out of cell 15 when it should stay in 22.
Steve
Seen it MANY MANY times.
Ported mafs read less load and are very erratic.
This tricks the pcm into going in and out of cell 15 when it should stay in 22.
Steve
Thread Starter
Staging Lane
Joined: Feb 2002
Posts: 83
Likes: 0
From: Knoxville TN
Re: Open Loop operation on a 98 Thanks steve!
It's a stock maf, that has been descreened, i plan on trying a different maf however to see if it makes a difference?
if i can't find the cause of the problem, is it actually hurting anything?
It's a stock maf, that has been descreened, i plan on trying a different maf however to see if it makes a difference?
if i can't find the cause of the problem, is it actually hurting anything?